taxonID	type	description	language	source
03F9BE50FF9BF53DFCD9953D5B6C6C41.taxon	description	Hypoptoma Miranda Ribeiro, 1911: 97 – 99 (misspelling; list of fishes of Brazil). Otocinclus not of Cope, 1871. — Eigennman, 1914: 229 (description of O. spectabilis).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FF9BF53DFCD9953D5B6C6C41.taxon	diagnosis	DIAGNOSIS: Distinguished from all other loricariids by having the nuchal plate laterally expanded to such an extent that the distance between distal tips is at least twice the width of the base of the dorsal spine at its widest point (fig. 3 B – C). In members of the Loricariinae and Hypoptopomatinae except Niobichthys and Acestridium, the nuchal plate is round to polyhedral, its width equal or slightly surpassing that of the base of the pectoral spine (fig. 3 A). In Niobichthys, and members of the Ancistrinae and Hypostomatinae, there is a pair of nuchal plates in contact in the midline. Species of Acestridium possess 2 – 4 median unpaired predorsal plates (Reis and Lehman, 2009). Hypoptopoma can also be distinguished from all other loricariids, except the hypoptopomatin genus Oxyropsis, by the shape of the head, which is depressed, and by the ventrolateral placement of the eyes. This typical ‘‘ Hypoptopoma ’’ head shape is further reflected anatomically by a series of uniquely derived osteological characters (shared with Oxyropsis): the lateral ethmoid laterally elongated; the T-shaped third infraorbital, with its lateral platelike side positioned ventrally on the head (fig. 4); the canalbearing plate presenting more than threefourths of its surface area positioned ventrally on the head, and the fourth infraorbital reduced, smaller than the fifth infraorbital (fig. 5) (except in H. spectabile). In other taxa, the position of the eyes is lateral to dorsolateral and not visible from below. Accordingly, the lateral ethmoid is not laterally elongated, the third infraorbital is platelike and laterally positioned on the head, the canal-bearing plate presents less than three-fourths of its surface area positioned ventrally on the head, and the fourth infraorbital is larger than the fifth infraorbital.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FF9BF53DFCD9953D5B6C6C41.taxon	description	DESCRIPTION: Adult body size moderately small relative to most other loricariids; maximum size of Hypoptopoma species ranging from 18 to 105 mm SL, attaining greatest body length among genera of Hypoptopomatinae. Head and body almost entirely covered by bony dermal plates, except for area surrounding lips and base of pectoral, pelvic, dorsal, and anal fins. Dermal bones exposed on head and pectoral girdle, and fin rays covered by dermal teeth or odontodes (Bhatti, 1938). Odontodes rather evenly distributed on head, slightly enlarged and variably aligned in dorsal and ventral series on rostral margin of snout, and typically arranged in well-defined longitudinal series on trunk plates. Distinct column of slightly enlarged and flattened marginal odontodes arranged along posterior margin of trunk plates. Anterior surface of pectoral-fin spine and ventral surface of pelvic-fin spine with enlarged odontodes. Series of smaller, irregularly shaped pararostral plates present anterior to each nasal plate between mesethmoid and lateral rostral plates (first to third canal-bearing infraorbitals) and adjacent to naris between nasal plate and lateral rostral plates (fig. 7 A). In some species, one or more paranasal plates can be present (one in H. gulare and H. machadoi; two or more in H. steindachneri) (fig. 7 B – C). Dorsal-fin rays I, 7; anal-fin rays i, 5; pectoral-fin rays I, 6; pelvic-fin rays i, 5; caudal-fin rays i, 7 - 7, i. Adipose fin variably present. Premaxillary teeth 10 – 36; dentary teeth 10 – 37. Oral disk rounded, surface papillose and with scattered unculi. Dermal plates on trunk arranged in five longitudinal, serially homologous rows (fig. 1). Lateral line complete and continuous; total lateral plates (medial series) 20 – 26; dorsal series 17 – 22; middorsal series 3 – 5; midventral series 11 – 15; ventral series 17 – 22. Number of midventral series plates between posterior process of cleithrum and first plate of ventral series (roughly triangular plate at base of pelvic-fin spine) three (H. bianale, H. elongatum, H. gulare, H. incognitum, H. inexspectatum, H. machadoi, H. spectabile, H. sternoptychum) (figs. 1 B, 8 B) or four (H. baileyi, H. brevirostratum H. guianense, H. muzuspi, H. psilogaster, and H. thoracatum) (figs. 1 A, 8 A), rarely five. Second plate of midventral series contacting a single plate (H. bianale, H. elongatum, H. gulare, H. incognitum, H. inexspectatum, H. machadoi, H. spectabile, H. sternoptychum) (figs. 1 B, 8 B) or two plates of medial series (H. baileyi, H. brevirostratum H. guianense, H. muzuspi, H. psilogaster, and H. thoracatum) (figs. 1 A, 8 A). Abdominal plates arranged according to three main patterns: (1) plates arranged in paired series of lateral sickle-shaped plates and medial series of roughly squared plates, each series composed of more than three plates (H. baileyi, H. brevirostratum, H. guianense, H. muzuspi, H. psilogaster, and H. thoracatum) (fig. 9 A); (2) plates arranged in paired series of lateral sickle-shaped plates and only one roughly triangular medial plate between anteriormost pair of lateral plates (all other species, except H. spectabilis and H. sternoptychum) (fig. 9 B – C), and (3) presence of a pair of slender plates posterior to the coracoids, followed by a series of 1 – 3 unpaired abdominal plates anterior to the anal plate (H. spectabilis and H. sternoptychum) (Schaefer, 1996 a: fig. 1). Thoracic plates present or absent (H. baileyi, H. brevirostratum, H. guianense, H. muzuspi, H. psilogaster, H. spectabilis, and H. thoracatum); when present, forming shield between left and right ventral canal-bearing plates (fig. 9 B – C). Anal plate composed of single plate (fig. 9 A – B), except in H. bianale, whose shield is two plates (fig. 9 C). Fully developed anal plate shaped as blunt, posteriorly oriented arrowhead. Complete development of lateral series of trunk plates achieved ontogenetically before full development of abdominal shield and plates anterior to naris (fig. 10). Development of trunk-plate series progresses in rostral direction, with individual plates near- est caudal fin developing first. Plates of medial series and bony canals of lateral line develop asynchronously, with lateralis canal ossifying prior to ossification of surrounding plate lamina. Platelike connecting bone (sensu Schaefer, 1987), counted as second middorsal plate, develops prior to plates lying immediately anterior and posterior to middorsal series. Development of abdominal plates initiates with lateral series in an approximately lateral to medial direction. Fully developed individuals can be recognized by having ventral region between pectoral fins entirely covered by abdominal plates. SEXUAL DIMORPHISM: Male urogenital papilla pointed, short, variably slender, more or less covered by anterior flaplike anus. Males of some species with patch of tightly arranged small odontodes positioned lateral to urogenital papilla and anus, variably developed on plates 1 – 4 of ventral trunk series. In some species, males with variably developed fringe of soft tissue along posterior margin of pelvic-fin spine, proximal to first branched ray when developed, typically restricted to basal one-third to one-half of spine length. Anus of females tubular, without separate urogenital papilla. In fe- males of all species, size and arrangement of odontodes on plates lateral to anus similar to adjacent plates, without distinct patch of differentially arranged odontodes.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FF9BF53DFCD9953D5B6C6C41.taxon	distribution	DISTRIBUTION: Widely distributed in lowland cis-Andean South America, with representatives in the major tributaries of the Amazon, Orinoco, Essequibo, Nickerie, Tocantins, and Paraguay / Paraná rivers (fig. 11). COMPARISONS: The pattern of odontode distribution on the trunk plates changes during ontogeny. In the smallest specimens of each species, odontodes on the plate lamina have a relatively dense and regular distribution in multiple longitudinal rows, a condition observed widely among species of Loricariidae. In larger specimens (actual size of specimen depends on the species), the distribution of odontodes is more uneven and irregular over the plate surface, resulting in one or more relatively open areas lacking odontodes and giving the plate surface a smoother appearance. A pattern of increased irregularity in odontode distribution and greater proportion of the plate surface without odontodes is correlated with increase in the size of specimens. It has not been determined whether trunk-plate smoothing is due to actual loss of odontodes or plate growth in surface area without corresponding increase in number of odontodes, thus expanding the space among odontodes. Observation of open ‘‘ sockets, ’’ or alveoli, would suggest both odontode loss and surface ossification as responsible for plate smoothing during ontogeny. Although odontode loss would not be uncommon among loricariids, progressive plate smoothing has not been reported. Among Hypoptopoma species, the greatest degree of plate smoothing is observed mostly among species of the clade at node 7 (see fig. 45) and the largest specimens of H. thoracatum and H. psilogaster. Among non-loricariid loricarioids, some callichthyids have odontodes arranged along the posterior margin of the trunk plates. However notable differences in morphology of individual odontodes and in arrangement of odontodes suggest nonhomology with the condition observed among Hypoptopoma species. Within the Hypoptopomatinae, Hypoptopoma is most similar to Oxyropsis in external appearance. Representatives of these two genera share the depressed head and the ventrolateral position of eyes (Schaefer, 1997). In addition to the unique presence of the laterally expanded nuchal plate and marginal trunk-plate odontodes, Hypoptopoma can be further distinguished from Oxyropsis by having a trunk ovoid in cross section, the ratio of the caudal-peduncle depth in the caudal-peduncle width. 1 (vs. cross section of trunk depressed, rectangular to oblate spheroid shaped in cross section, ratio of caudal-peduncle depth in caudalpeduncle width, 1), and by the absence of the single row of enlarged odontodes along the trunk midline lying adjacent and immediately dorsal to the lateral-line canal, a derived character state unique for Oxyropsis (Aquino and Schaefer, 2002). TAXONOMIC REMARKS: Günther (1868 a) distinguished Hypoptopoma by characteristics related to the head: head depressed and spatulate, with the eyes located on the lateral margins of the head. Following this diagnosis, Steindachner (1879) assigned his new species carinatum to the genus Hypoptopoma. Aquino and Schaefer (2002) provided evidence in support of Oxyropsis monophyly and demonstrated that the characteristics used by Günther to distinguish Hypoptopoma are shared with Oxyropsis. A phylogenetic diagnosis of Hypoptopoma (Schaefer, 1991) distinguished the genus on the basis of two osteological characters: (1) canal in the preopercle forming a semicircle, and (2) preopercular canal passing through the fifth infraorbital before entering the preopercle. The present study shows that those two characters are not shared by all species of Hypoptopoma. In a revised analysis, Schaefer (1998) recognized four derived unreversed characters supporting the Hypoptopoma clade (Schaefer, 1998: fig. 3): (1) sphenotic with expanded anterior lamina, (2) preopercle canal semicircular, (3) presence of notch on canal-bearing ventral plate, and (4) trunk plates with enlarged odontodes concentrated along posterior margin (in this paper, marginal odontodes). Likewise, the present study shows that character (1) is shared with other genera of the tribe, and characters (2), (3), and (4) are not shared by all species of Hypoptopoma.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FF8BF52BFD34946259CC6D45.taxon	materials_examined	HOLOTYPE: AMNH 39828 (♀, 38.9 mm SL) Bolivia: Beni, backwater, Río Itenez, 10 km SE Costa Marques, Brazil; collected by R. M. Bailey and R. Ramos, 10 September 1964. PARATYPES (collected with holotype): AMNH 243579 (61 ♀ + 18 ³, 27.5 – 44.0 mm SL). UMMZ 205171 (75 ♀ + 32 ³, 6 cs, 27.7 – 40.6 mm SL).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FF8BF52BFD34946259CC6D45.taxon	description	OTHER MATERIAL EXAMINED: BOLIVIA, Beni: AMNH 39764 (1 ♀, 25.5 mm SL) Río. H, F; steindachneri. H, E; gulare. H, D; guianense. H, C; psilogaster. H. B; thoracatum. H, A: fin caudal the of pattern. Pigmentation. machadoi, H G; 17 Fig.. elongatum Itenez, 3 km SE Costa Marques, Brazil; AMNH 39788 (8 ♀ + 1 ³, 3 cs, 26.6 – 33.9 mm SL) Río Itenez, 9 km SE Costa Marques, Brazil; AMNH 39841 (4 ♀, 27.7 – 32.9 mm SL) Oxbow Río Itenez, 9 km SE Costa Marques, Brazil; AMNH 39861 (27 ♀ + 7 ³, 24.9 – 41.5 mm SL) Río Itenez, 9 km SE Costa Marques, Brazil; SIUC 30815 (12 ♀, 29.7 – 35.4 mm SL) Río Matos in Estación Biológica del Beni (bridge nearest entrance, 6 km E of EBB on road to San Ignacio). Santa Cruz: AMNH 229206 (2 ♀, 29.7 – 31.8 mm SL) Noel Kempff Mercado Nacional Park, Río Paucerna, about 500 m upstream from mouth at Río Itenez; AMNH 229310 (2 ♀, 28.5 – 33.3 mm SL) Noel Kempff Mercado Nacio- nal Park, Río Itenez, Bahía Piuba at mouth; AMNH 229353 (17 ♀ + 2 ³, 25.1 – 37.6 mm SL) Noel Kempff Mercado Nacional Park, Río Itenez, beach about 200 m upstream from Bahía Agua Blanca; CBF 2859 (1 ♀ + 1 ³, 33.7 – 43.7 mm SL) Guarayos, Perseverancia, Río Negro.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FF8BF52BFD34946259CC6D45.taxon	diagnosis	DIAGNOSIS: Hypoptopoma baileyi is distinguished from all congeners except H. muzuspi by having trunk pigmentation in the form of a lateral band that is progressively darker along medial, midventral, and ventral series of plates, and a caudal-fin pigmentation pattern formed by 6 – 8 narrow dark brown bars and a dark spot at the base of the lower lobe. Hypoptopoma baileyi is distinguished TABLE 1 Morphometric and Meristic Data for Hypoptopoma baileyi Holotype: AMNH 39828. Paratype: AMNH 243579.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FF8BF52BFD34946259CC6D45.taxon	description	from H. muzuspi by having preopercle reduced, not reaching hyomandibular-opercle condyle (vs. preopercle not reduced, reaching to hyomandibular-opercle condyle) and absence of canal in preopercle (vs. presence of canal in the preopercle) (fig. 14 A). DESCRIPTION: Morphometric and meristic data presented in table 1. Body size relatively small, moderately elongate, and depressed; greatest body depth at dorsal-fin origin. Dorsal profile of head and body from tip of snout to dorsal-fin origin straight, slightly angled dorsally at anterior supraoccipital tip; straight from dorsal-fin origin to anteriormost procurrent caudal-fin ray. Head moderately depressed, almost as wide as cleithral width; lateral process of lateral ethmoid dorsally not visible. Snout slightly rounded in dorsal view, concave at region anterior to naris. Posterior surface of bony pit of nasal organ gradually inclined. Body cross section between pectoral- and pelvic-fin origins ovoid to transversely depressed, progressively compressed posterior to anal-fin base. Eyes moderately large, positioned slightly closer to posterior tip of compound pterotic than to tip of snout. Ventral margin of orbit located close to ventral surface of head. Dorsal interorbital distance shorter than ventral interorbital distance. Total plates in lateral medial series 22 – 23 (23). Dorsal series 19 – 21 (20); middorsal series 3 – 4 (4); midventral series 12 – 14 (13), with four plates anterior of first plate of ventral series; ventral series 19 – 21 (20). Second plate of midventral series contacting single plate of medial series. Abdomen covered by paired series of lateral sickle-shaped plates, with unequal number of plates between left and right side series, 3 – 9 each; medial series of 3 – 8 (6) roughly squared plates; anterior azygous plate absent; medial series occasionally absent, in which case paired series make contact along midline in fully developed individuals. Single anal plate present. Thoracic plates absent. Preopercular canal absent. Posterolateral margin of canal-bearing plate and lateral margin of fourth infraorbital smooth; pore between canal-bearing ventral plate and fourth infraorbital absent. Small odontodes evenly distributed on head, roughly arranged in closely spaced longitudinal lines. Odontodes ventral to tip of snout slightly enlarged. Lamina of trunk plates with longitudinal rows of odontodes, becoming progressively smoother ontogenetically; largest specimens maintain longitudinal rows dorsal to lateral-line canal, rows otherwise absent; distinct column of marginal odontodes on posterior plate border in mature adults. Total vertebrae 27 – 28; ribs present. Premaxillary teeth 14 – 22; dentary teeth 11 – 18. Maxillary barbels short, not reaching to anterior margin of ventral canal-bearing plate. Dorsal-fin origin located slightly posterior of vertical through pelvic-fin origin. Depressed dorsal fin reaching to vertical through midpoint of anal-fin length. Pectoral fin reaching to vertical through midpoint along pelvic-fin spine. Depressed pelvic fin close or reaching to plate anterior to anal-fin spine. Extension of serrae along length of pectoral-spine margin, except for short basal segment; serrae of oblique type. Pelvic fin short, unbranched slightly shorter than first branched rays. Depressed fin reaching to anus, not reaching to insertion of anal-fin spine. Caudal fin forked. Adipose fin absent. COLOR IN ALCOHOL: Ground color tan to pale ochre. Melanophores light to dark brown on trunk and particularly clustered at base of plates resulting in mottled appearance. Melanophores slightly more concentrated on compound pterotic dorsal to swimbladder capsule, anterior half of supraoccipital, frontals, plate anterior to naris, lateral rostral plates on snout, on posterior half of lip surface, band on maxillary barbel, anterior half of branchiostegal membrane, and posterior tip of naris flap. Melanophores scattered or absent on dorsal surface of mesethmoid, anterior rostral plate, and narrow band anterior to epiphysial branch of supraorbital canal in frontal. Deep-lying melanophores arranged in narrow transverse bands posterior to dorsal-fin base, noncoincident with posterior margin of plates. Midlateral stripe situtated along medial, midventral, and ventral series of plates, progressively less pigmented toward ventral surface of body, which is mostly unpigment- ed except for scattered melanophores on posterior portion of trunk, soft tissue along base of pectoral and anal fins, anterolateral margin of cleithra and posterior tip of cleithral process, ventral canal-bearing plate, and lateral portions of lateral abdominal series. Paired and unpaired fins with relatively numerous narrow dark brown bands. Series of lanceolate plates at base of caudal fin and small posteriormost plate of trunk medial series more densely pigmented with black melanophores. Last 1 – 2 posteriormost plates of dorsal and ventral trunk series less pigmented, whitish. Upper and lower marginal and branched rays of caudal-fin with 7 – 10 bands of brown melanophores, with slightly darker area at base of lower lobe. SEXUAL DIMORPHISM: Male urogenital papilla elongate, slender papilla covered by flaplike anus. Males with patch of tightly arranged small odontodes on second, third, and fourth plates of ventral series, lateral to urogenital papilla. Female anus tubular, without separate urogenital papilla. In females, size and arrangement of odontodes on plates lateral to anus similar to adjacent plates, without distinct patch of differentially arranged odontodes.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FF8BF52BFD34946259CC6D45.taxon	distribution	DISTRIBUTION: Río Iténez, in the upper Rio Madeira basin, along the border between Bolivia and Brazil (fig. 19).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FF8BF52BFD34946259CC6D45.taxon	etymology	ETYMOLOGY: The specific epithet baileyi is a patronym honoring Reeve M. Bailey (1911 – 2000), who collected the specimens of the new species in 1964 during an expedition of the AMNH to the Río Itenez.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FF86F52FFFBE95B159316C9A.taxon	materials_examined	HOLOTYPE: RMNH 26919 (61.5 mm SL) Suriname, left tributary of the Nickerie River, a few kilometers upstream from the Stondansi Falls; collected by H. Boeseman, 30 January 1971 (not seen). PARATYPES: RMNH 26922 (1 ♀ + 3 ³, 47.0 – 56.0 mm SL) Suriname, Nickerie River, below Blanche Marie Falls; collected by H. Boeseman, 11 February 1971. USNM 213484 (2 ♀, 48.9 – 51.6 mm SL) Surinam, left tributary creek upper Nickerie River; collect- ed by H. Boeseman, 30 January 1971.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FF86F52FFFBE95B159316C9A.taxon	description	OTHER MATERIAL EXAMINED: Guyana, Cuyuni-Mazaruni: INHS 49274 (1 ♀, 27.6 mm SL) 1.5 mi. SW Rockstone [Essequibo river]; INHS 49366 (1 juvenile, 29.3 mm SL) 31.9 mi. SSW Rockstone. Potaro-Siparuni: INHS 49402 (1 juvenile, 23.3 mm SL) Essequibo River drainage, Tumatumari Cataract, S bank, below old hydroelectric plant. Upper Demerara-Berbice: AMNH 13341 (2 ♀, 35.5 – 40.7 mm SL) Malali; AMNH 13666 (1 ♀ + 1 ³, 38.5 – 39.2 mm SL) Rockstone, Essequibo River drainage; AMNH 220509 (2 ♀, 46.3 – 47.5 mm SL) Essequibo River drainage; INHS 49660 (10 ♀ + 2 juveniles, 25.2 – 63.4 mm SL) Rockstone. Upper Takutu – Upper Essequibo: BMNH 1983.7.26: 12 – 28 (16 ♀ + 1 ³, 2 cs, 28.5 – 47.8 mm SL) Rupununi River; BMNH 1983.26: 49 – 54 (6 ♀, 37.2 – 46.1 mm SL) Rupununi River, Kamarang; FMNH 69962 (3 ♀, 37.3 – 42.1 mm SL) Moco Moco River.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FF86F52FFFBE95B159316C9A.taxon	diagnosis	DIAGNOSIS: Hypoptopoma guianense is distinguished from all congeners by the presence of an elongated dark spot along the median caudal-fin branched rays, involving the lanceolate plates at the base of the fin. The spot is typically extended over an equal number of branched rays of both the upper and lower lobes and along more than twothirds of the ray length (fig. 17 C).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FF86F52FFFBE95B159316C9A.taxon	description	DESCRIPTION: Morphometric and meristic data presented in table 2. Body moderately elongate and low. Dorsal profile of head and body slightly convex from tip of snout to dorsal-fin origin; straight from dorsal-fin origin to anteriormost caudal-fin procurrent ray. Head moderately depressed and narrow. Lateral process of lateral ethmoid dorsally not visible. Snout rounded to slightly spatulate in dorsal view; smoothly rounded in dorsal view; dorsally variably concave anteri- or to naris. Posterior surface of bony pit of nasal organ sharply inclined. Body cross section between pectoral- and pelvic-fin origins horizontally ovoid, posterior to dorsal fin changing from ovoid to rounded, posterior to adipose-fin base progressively compressed. Eyes moderately large, positioned closer to posterior tip of compound pterotic than to tip of snout. Ventral margin of orbit located close to ventral surface of head. Dorsal interorbital distance shorter than ventral interorbital distance. Total plates in lateral medial series 23 – 24 (23). Dorsal series 20 – 21 (20); middorsal series 3 – 4 (4); midventral series 13 – 15 (13), with four plates (rarely five) anterior of first plate of ventral series; ventral series 19 – 21 (20). Second plate of midventral series contacting single plate of medial lateral series. Abdomen covered by paired series of lateral sickle-shaped plates, with unequal number of plates between left and right series, 4 – 10 each; medial series of 3 – 8 (5) roughly squared plates; anterior azygous plate absent. Single anal plate present. Thoracic plates absent. Preopercular canal absent. Posterolateral margin of canal-bearing plate and lateral margin of fourth infraorbital smooth; pore between canalbearing ventral plate and fourth infraorbital absent. Small odontodes evenly distributed on trunk and head. Odontodes ventral and dorsal to tip of snout not arranged in aligned series. No odontode-free discontinuity between ventral and dorsal odontodes; odontodes dorsal to tip of snout slightly larger than those on head. Lamina of trunk plates with longitudinal lines of odontodes, becoming progressively smoother ontogenetically; distinct column of marginal odontodes on posterior plate border in mature adults. Total vertebrae 27. Premaxillary teeth 21 – 26 (23), dentary teeth 17 – 24 (20). Maxillary barbels short; reaching to anterior margin of ventral canal-bearing plate in adults. Dorsal-fin origin located slightly posterior of vertical through pelvic-fin origin. Depressed dorsal fin reaching to vertical through midpoint of anal-fin base length. Pectoral fin reaching to vertical through midpoint of pelvic-fin length. Extension of serrae along pectoral spine margin except for short basal segment; serrae of oblique type. Pelvic fin short, 2 – 3 longest branched rays slightly longer than spine. Depressed fin reaching to plate anterior to anal-fin spine. Caudal-fin margin forked; upper and lower lobes equal and elongate. Adipose fin variably present; when present, minute. COLOR IN ALCOHOL: Ground color tan and pale ochre. Melanophores dark brown, on trunk and head clustered resulting in mottled appearance; distinct light spot dorsally on each lateral rostral plate. Melanophores slightly more concentrated on anterior surface of lip, along narrow area among compound pterotic, cleithral process and dorsal tip of opercle, at base of dorsal and pectoral fins. Deep-lying melanophores arranged in narrow transverse bands posterior to dorsal-fin base, noncoincident with posterior margin of plates. Midlateral stripe situated along trunk variably defined. Ventral surface of body mostly unpigmented except for scattered melanophores on posterior portion of trunk, soft tissue along base of pectoral and anal fins, anterolateral margin of cleithra, and lateral portions of lateral abdominal series. Paired and dorsal fins with dark brown bars. Caudal-fin bars variable defined (fig. 17 C). Presence of elongated dark spot along middle caudal-fin branched rays; spot typically extending over equal number of upper- and lower-lobe rays and along more than two-thirds of ray length; spot connected to lanceolate plates at base of fin. Tip of upper and lower lobes slightly pigmented with reddish-brown melanophores. SEXUAL DIMORPHISM: Male urogenital papilla well developed, pointed, joined at base to anterior flaplike anus. Males with patch of tightly arranged small odontodes oriented as a swirl, variably covering first to fourth plates of ventral series, lateral to urogenital papilla. Female anus tubular, TABLE 2 Morphometric and Meristic Data for Hypoptopoma guianense Paratypes: RMNH 26922. Nontypes: AMNH 13666, 220509; BMNH 1983.7.26: 12 – 28; FMNH 69962; INHS 49960. without separate urogenital papilla. In females, size and arrangement of odontodes on plates lateral to anus similar to adjacent plates, without distinct patch of differentially arranged odontodes.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FF86F52FFFBE95B159316C9A.taxon	distribution	DISTRIBUTION: Known from of the basins of the Essequibo (Guyana) and Nickerie (Surinam) rivers (fig. 19). TAXONOMIC REMARKS: Prior to the present revision, Hypoptopoma guianense was the only nominal species of Hypoptopoma to be established on the basis of a relatively large number of individuals (approximately 31). The species is most similar to H. psilogaster Fowler, 1915, which has been reported from the Ríos Ampiyacu, Itaya, Nanay, Napo, and Yaguas in Amazonian Peru. Valid taxonomic status of both species is supported on the basis of differences in the caudal-fin pigmentation: both species possess an elongate spot along the middle caudal-fin branched rays, but in H. guianense the spot is continuous with the dark spot on the lanceolate plates, versus discontinous in H. psilogaster. Further differences are shown in an analysis of the overall morphometric variation among H. guianense, H. psilogaster, and H. thoracatum. In a sheared principal component analysis on 18 distance variables (fig. 21; table 3), the scatter plot of the component scores on sheared PC 2 and PC 3 shows near complete separation among the three species. The second and third components represent 3.1 % and 0.9 % of the total morphometric variance, respectively. The morphometric variance explained by PC 2 reflects differences in the elongation of the body (caudal-peduncle length, trunk length, caudal-peduncle depth); likewise, PC 3 appears to reflect differences in head width at the level of the eyes (least distance between orbit and naris).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FF82F515FF4B94D658FD683C.taxon	materials_examined	HOLOTYPE: ANSP 21922 (juvenile, 51.0 mm SL) Peruvian Amazon; collected by J. Orton, 1873. OTHER MATERIAL EXAMINED: PERU, Loreto: ANSP 21921 (1 ♀, 45.6 mm SL) Peruvian Amazon; ANSP 138868 (5 ♀, 33.4 – 66.5 mm SL) Río Nanay, vicinity of Iquitos, well above Morona Coché (coché 9 m. above Río Amazonas); ANSP 138869 (2; 35.5 – 39.0 mm SL) Río Nanay, vicinity of Iquitos just above Coché Morona (above 9 m. Río Amazonas); ANSP 138871 (1 ³ + 3 juveniles, 1 cs, 33.4 – 66.5 mm SL) Río Nanay, vicinity of Iquitos, Morona Coché outlet (about 9 m. above Río Amazonas); ANSP 178335 (2 ♀, 32.6 – 41.0 mm SL) Río Itaya at bridge on Iquitos-Nauta highway, approx. 25 miles SSW of Iquitos; CAS 134254 (1 ♀, 32.8 mm SL) Río Ampiyacu; CAS 134255 (1 ♀, 38.1 mm SL) Río Ampiyacu; INHS 39826 (6 ♀, 44.0 – 70.1 mm SL) Río Nanay, Miz Playa, about 1 hr by canoe upstream from Santa Clara; INHS 44076 (9 ♀ + 2 ³, 38.9 – 53.9 mm SL) Río Nanay, Pampa Chica, 4.5 km W center of Iquitos; INHS 44125 (2 ♀, 42.8 – 48.5 mm SL) Río Napo and Quebrada, Mazán, 33.3 km NE Iquitos; MUSM 7655 (1 ♀ + 1 ³, 49.7 – 50.8 mm SL) Río Nanay, Maynas, Iquitos; NRM 18000 (1 ♀, 35.6 mm SL) Río Nanay dr., Caño Puñuisiqui; NRM 47511 (5 ♀, 28.9 – 35.8 mm SL) Río Nanay dr., small tahuampa cocha on left bank, second left bend above Mishana; SIUC 23560 (83 ♀ + 14 ³, 5 cs, 28.8 – 55.9 mm SL) Maynas, Río Nanay at Santa Clara, NW of Iquitos; SIUC 28015 (3 ♀ + 1 ³, 32.8 – 48.7 mm SL) Río Nanay at Santa Clara; SIUC 28180 (2 ♀, 35.0 – 40.2 mm SL) Río Nanay, Pamachica Beach in Iquitos; SIUC 28997 (3 ♀, 29.9 – 44.0 mm SL) Río Nanay, Miz Playa; SIUC 29489 (1 ♀, 46.5 mm SL) Miz Playa just upstream from Santa Clara, 13.9 km from Iquitos; SIUC 29645 (4 ♀ + 2 ³, 38.4 – 56.3 mm SL) Maynas, Río Nanay, Pampachica Beach 4.5 km from Iquitos center; SIUC 67367 (2 ♀, 44.6 – 51.9 mm SL) Maynas, Río Itaya and Quebrada Mazana, 11 km from Iquitos center; SU 60557 (1 ♀, 41.3 mm SL) Rio Yaguas Yacu; USNM 284882 (2 ♀, 47.3 – 47.3 mm SL) Río Nanay at Nanay beach, W of Iquitos; USNM 284876 (1 juvenile, 47.2 mm SL) Río Nanay approx- imately 20 km upstream of mouth; USNM 284883 (2 ♀, 30.7 – 30.7 mm SL) Río Nanay approximately 20 km upstream of mouth.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FF82F515FF4B94D658FD683C.taxon	diagnosis	DIAGNOSIS: Hypoptopoma psilogaster is distinguished from all congeners by the presence of an elongated dark spot along the middle caudal-fin branched rays, not involving the lanceolate plates at the base of the fin; the spot is typically extended over TABLE 3 Sheared Principal Component Loadings from the Morphometric Analysis of Head and Trunk of Hypoptopoma guianense, H. psilogaster and H. thoracatum equal number of upper- and lower-lobe branched rays and along more than twothirds of the ray length (figs. 17 B, 23).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FF82F515FF4B94D658FD683C.taxon	description	DESCRIPTION: Morphometric and meristic data presented in table 4. Body elongate, moderately depressed, greatest body depth at dorsal-fin origin, trunk most shallow at caudal peduncle anterior to caudal fin. Dorsal profile of head and body straight from tip of snout to dorsal-fin origin; straight from dorsal-fin origin to anteriormost procurrent caudal-fin ray. Head moderately depressed and narrow; lateral process of lateral ethmoid not visible dorsally. Snout rounded in dorsal view; dorsally smoothly round, slightly concave to flat anterior to naris. Body cross section between pectoral- and pelvic-fin origin horizontally ovoid, vertically ovoid posterior to dorsal fin, progressively compressed posterior to adipose fin. Eyes moderately large, positioned slightly closer to posterior tip of compound pterotic than to tip of snout. Ventral margin of orbit located close to ventral surface of head. Dorsal interorbital distance shorter than ventral interorbital distance. Total plates in lateral medial series 24 – 26 (24); when total plates 25 or 26, posterior- most plate very small, with canal not reaching to posterior border of plate. Dorsal series 20 – 22 (21); middorsal series 3 – 4 (4); midventral series 13 – 14 (13), with 4 – 5 (4) plates anterior of first plate of ventral series; ventral series 20 – 22 (21). Second plate of midventral series contacting a single plate of medial lateral series. Abdomen covered by paired series of lateral sickle-shaped plates, with unequal number of plates between left and right series, 6 – 10 each; medial series of 6 – 10 (8) roughly squared plates; anterior azygous plate absent; medial series occasionally absent, in which case paired series make contact along midline in fully developed individuals. Single anal plate present. Thoracic plates absent. Preopercular canal absent. Posterolateral margin of canal-bearing plate and lateral margin of fourth infraorbital smooth; pore between canal-bearing ventral plate and fourth infraorbital absent. Small odontodes evenly distributed on head. Odontodes ventral and dorsal to tip of snout not arranged in aligned series. No odontode-free discontinuity between ventral and dorsal odontodes; odontodes dorsal to tip of snout slightly larger than those on head. Lamina of trunk plates bearing longitudinal rows of odontodes, plates becoming progressively smoother ontogenetically; distinct column of marginal odontodes on posterior plate border in mature adults. Total vertebrae 28. Premaxillary teeth 19 – 26 (22), dentary teeth 16 – 24 (19). Maxillary barbels short; almost reaching to or slightly surpassing anterior margin of ventral canalbearing plate in adults. Dorsal-fin origin located at vertical through pelvic-fin origin. Depressed dorsal fin reaching to vertical through midpoint of anal-fin base. Pectoral fin reaching to vertical through posterior half of pelvic-fin length. Extension of serrae along pectoral spine margin, except for short basal segment; serrae of oblique type; teeth of serrae progressively smaller toward distal end of spine. Pelvic fin short, two longest branched rays slightly longer than spine. Depressed fin reaching to plate anterior to anal-fin spine. Caudal-fin margin forked; upper and lower lobes equal and elongate. Adipose fin present. COLOR IN ALCOHOL: Ground color tan and pale ochre. Melanophores dark brown, clustered on trunk and head resulting in mottled appearance. Melanophores slightly more concentrated dorsally on head, narrow area among compound pterotic, cleithral process and opercle, and at base of dorsal fin. Deeplying melanophores slightly more concentrat- ed along midline posterior to dorsal-fin base. Midlateral stripe situated mostly along medial series of trunk plates. Ventral surface of body mostly unpigmented, except for scattered melanophores on soft tissue along base of pectoral-fin branched rays and anterior surface of lip. Paired and dorsal fins with dark brown bands. Black melanophores slightly more concentrated over lanceolate plates. Caudal-fin bars variable defined. Presence of elongated dark spot along middle caudal-fin branched rays; spot typically extending over equal number of upper- and lower-lobe branched rays and along more than two-thirds of ray length; spot not distinctly connected to lanceolate plates at base of fin (fig. 17 B). Tip of upper and lower lobes pigmented with dark melanophores. SEXUAL DIMORPHISM: Male urogenital papilla short and conical, covered by anterior flaplike anus. Males with patch of tightly arranged small odontodes, variably covering first to fourth plates of ventral series, lateral to urogenital papilla. Males with poorly developed soft-tissue flap along posterior margin of pelvic spine. Female anus tubular, TABLE 4 Morphometric and Meristic Data for Hypoptopoma psilogaster Holotype: ANSP 21922. Nontypes: ANSP 138868; INHS 39826, 44076, 44125; SIUC 23560, 29645. without separate urogenital papilla. In females, size and arrangement of odontodes on plates lateral to anus similar to adjacent plates, without distinct patch of differentially arranged odontodes. Female pelvic spine without flap of soft tissue on posterior surface.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FF82F515FF4B94D658FD683C.taxon	distribution	DISTRIBUTION: Ríos Ampiyacu, Itaya, Nanay, Napo, and Yaguas in Western Amazon (fig. 19). TAXONOMIC REMARKS: Fowler (1915) established the new species Hypoptopoma psilogaster on the basis of a single specimen. He compared his new species only with H. thoracatum, from which he distinguished the new species by the presence of two rows of abdominal plates separated by an unplated surface (vs. complete cover of the abdominal region with three rows of plates). Our examination of specimens of various size from across an extensive range of the Peruvian Amazon allowed us to confirm that the specimen examined by Fowler possesses the typical arrangement of abdominal plates observed in immature developmental stages in all speces of Hypoptopoma. Adults of H. psilogaster have the abdominal region completely covered by three rows of plates, similar to the condition observed in H. thoracatum. Nevertheless, we provide new evidence supporting the valid taxonomic status of H. psilogaster on the basis of the caudal-fin pigmentation, in addition to a combination of morphometric and meristic characteristics. A multivariate analysis of the overall morphometric variation among H. guianense, H. psilogaster, and H. thoracatum is included in the Taxonomic Remarks section of the systematic account of H. guianense.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFB8F51AFFA4903A58CC6F73.taxon	materials_examined	HOLOTYPE: BMNH 1867 - 6: 13 – 38, 76.2 mm SL, Peru, Xeberos. NON- TYPES: Bolivia, Beni: INHS 37227 (11 ♀ + 2 ³ + 1 juvenile, 19.9 – 42.4 mm SL) Río Apere / Amazonas dr., Río Chevejecure, 41 km E Estación Biológica del Beni on road to San Ignacio; ZSM 28426 (1 ♀, 44.7 mm SL) Espiritu, Río Yacuma. Pando: FMNH 107059 (3 ³, 42.1 – 47.8 mm SL) Río Madeira dr., Río Nareuda, 7 km río arriba de la desembocadura en el Tahuamanu; FMNH 107060 (19 ♀ + 2 ³, 30.2 – 42.0 mm SL) Río Madeira dr., Río Manuripi, + / 2 12 km río arriba de Puerto Rico; FMNH 107061 (7 juveniles, 25.0 – 29.4 mm SL) Río Madeira dr., lago del campamento, + / 2 10 km río arriba de Puerto Rico; FMNH 107063 (2 ♀ + 1 ³ + 9 juveniles, 30.8 – 47.2 mm SL) Río Madeira dr., Río Manuripi, + / 2 13 km río arriba de Puerto Rico; FMNH 107064 (3 ♀, 28.0 – 33.1 mm SL) Río Madeira dr., Río Manuripi, + / 2 13 km río arriba de Puerto Rico; FMNH 107065 (1 ♀ + 14 juveniles, 25.6 – 47.1 mm SL) Río Madeira dr., lago s / n, + / 2 15 km río arriba de Puerto Rico; FMNH 107066 (9 juveniles, 29.1 – 33.4 mm SL) Río Madeira dr., lago s / n; + / 2 13 km río arriba de Puerto Rico; FMNH 107067 (31 ♀ + 2 ³, 29.5 – 40.2 mm SL) Río Madeira dr., lago s / n; + / 2 12 km río arriba de Puerto Rico; FMNH 107068 (4 ♀, 32.8 – 36.6 mm SL) Río Madeira dr., Río Orthon, + / 2 2 km río abajo de Puerto Rico; FMNH 107069 (1 ♀ + 1 ³ + 10 juveniles, 24.1 – 49.3 mm SL) Río Madeira dr., Río Manuripi; + / 2 8 km río arriba de Puerto Rico; FMNH 107070 (3 ♀, 32.4 – 34.1 mm SL) Río Madeira dr., Río Manuripi at playa, 5.78 km from camp, 9.23 from Puerto Rico; FMNH 107071 (54 juveniles, 26.9 – 31.9 mm SL) Río Madeira dr., lagoon and backwater off Río Manuripi, 1.70 km above Puerto Rico; FMNH 107072 (4 ♀, 30.8 – 32.3 mm SL) Río Madeira dr., lagoon on SW side of island 3.47 km up river from Puerto Rico on the Río Manuripi. Brazil, Amazonas: INPA 14036 (8 ♀ + 5 ³, 41.1 – 47.4 mm SL) Rio Solimões, Paraná do Rei, Ilha do Careiro; USNM 308312 (1 ♀, 49.9 mm SL) near Manaus, Lago January, Lago Terra Preta; USNM 308336 (1 ³, 40.3 mm SL) near Manaus, Lago January, Lago Terra Preta; USNM 316539 (7 ³, 33.3 – 38.8 mm SL) Rio Purus. Pará: FMNH 59620 (1 ♀, 40.20 mm SL) Santarém. Colombia, Amazonas: CAS 76651 (1 ♀, 46.0 mm SL) Caqueta Dept., Tres Esquinas; CAS 153141 (6 ♀ + 1 ³, 41.8 – 73.1 mm SL) Caqueta Dept., Río Orteguaza, tributary of Río Caqueta, within 2 mi. of Tres Esquinas; SU 50479 (4 ♀ + 2 ³, 36.9 – TABLE 5 Morphometric and Meristic Data for Hypoptopoma thoracatum Syntype of H. bilobatum: ANSP 8280. Nontypes: AMNH 78033, 78099; CAS 153141; FMNH 101544, 107058, 107059, 107060, 107063, 107069; INHS 101389; LACM 38608; MUSM 1845, 4413; SIUC 29199; SU 36218. 43.9 mm SL) Caqueta Dept., vecinity of Tres Esquinas, Río Orteguaza near juncture with Río Caqueta; USNM 360864 (1 ♀ + 1 ³, 68.8 – 75.8 mm SL) Leticia. Ecuador, Napo: FMNH 101544 (3 ³, 53.2 – 62.2 mm SL) Tributary to Rio Tarapuy. Peru, Loreto: AMNH 78033 (1 ♀, 55.7 mm SL) Río Tahuayo at Huasi Villeage; AMNH 78099 (9 ♀ + 1 ³, 1 cs, 45.8 – 76.9 mm SL) Río Yarapa, tributary of Río Ucayali, several sites along a 10 km stretch of river; AMNH 218005 (1 ♀, 66.4 mm SL) Iquitos, Río Itaya; ANSP 8280 / 81 (syntypes of Hypoptopoma bilobatum) (2, unsexed, 59.5 – 74.9 mm SL) Pebas; CAS 59599 (3 ♀, 43.03 – 48.78 mm SL) mouth of Río Pacaya; CAS 134256 (1 ♀, 46.3 mm SL) Río Ampiyacu; CAS 136219 (1 ♀, 56.5 mm SL) Caño del Chancho, near Pebas; INHS 53870 (8 ♀, 33.0 – 53.7 mm SL) Río Itaya, Ullpa caño, SE of Belem (Iquitos), near confluence with Moena caño; INHS 101388 (1 ♀ + 1 ³, 52.3 – 64.8 mm SL) Río Yanashi, Yanashi, 69.8 mi E Iquitos; INHS 101389 (8 ♀ + 2 ³, 2 cs, 32.1 – 73.1 mm SL) Río Orosa, mouth of Tonche Caño, Madre Selva II field station 69.4 mi. E Iquitos; INHS 101391 (1 ♀, 68.6 mm SL) Quebrada Mazama, Río Itaya dr., ca. 1 km upstream from confluence with Río Itaya, S of Belem (Iquitos); MUSM 4413 (3 ♀, 49.7 – 54.5 mm SL) Alto Amazonas, Yurimaguas, Río Shanusi; MUSM 6515 (1 ♀, 64.3) Maynas, Puesto de Vigilancia Arcadia, Río Napo, Cocha de Conchas; NRM 17992 (3 ♀, 45.8 – 48.7 mm SL) Río Samiria drainage, Atún caño; NRM 57232 (1 ♀ + 1 ³, 54.2 – 60.9 mm SL) Rio Tahuayo dr., caño Huayti; SIUC 29199 (1 ♀ + 1 ³, 68.3 – 78.3 mm SL) Maynas, Río Itaya, upriver of Belén, approx. 4.5 km; SIUC 29316 (1 ♀, 66.6 mm SL) Río Napo, Mazan, 33.3 km from center of Iquitos; SIUC 29782 (1, 54.6 mm SL) Maynas, Río Itaya, 11 km from Iquitos center; SIUC 67366 (5 ♀, 44.6 – 53.1 mm SL) Maynas, Río Itaya and Quebrada Mazana, 11 km from Iquitos center; SU 36218 (2 ♀, 57.4 – 67.6 mm SL) Río Amazonas, Caño del Chancho, near Pebas. Ucayali: LACM 38608 (3 unsexed, 47.0 – 66.6 mm SL) Central Ucayali, brook between Lake Cocha and Lake Yarina; MHNG 2407.98 (1 ♀, 35.3 mm SL) Pucallpa, Tapistica Alejandria; MHNG 2409.26 (1 ♀, 50.6 mm SL) Pucallpa, Masisea, Río Ucayali; MHNG 2409.27 (1 ♀, 41.4 mm SL) Pucallpa, Masisea, Río Ucayali; MHNG 2618.84 (1 ³, 55.07 mm SL) Río Puntichao and Río Chicosa, two tributaries entering Ucayali River near Chicosa; MHNG 2708.059 (2 ♀, 37.4 – 38.6 mm SL) Yarina Cocha, an oxbow lake near Pucallpa; MUSM 32157 (3 ♀ + 2 ³, 1 cs, 43.3 – 59.6 mm SL) Coronel Portillo, Pucallpa, Tapistica Alejandria; MUSM 32158 (2 ♀, 47.2 – 50.1 mm SL) Coronel Portillo, Pucallpa, Río Ucayali, Cocha Tacshitea; NRM 17987 (2 ♀, 64.4 – 64.6 mm SL) Río Ucayali dr., Yarinacocha, caño to Paca Cocha.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFB8F51AFFA4903A58CC6F73.taxon	diagnosis	DIAGNOSIS: Hypoptopoma thoracatum is distinguished from all congeners by the presence of an elongated spot of black melanophores along the caudal-fin branched rays, not distinctly connected to the lanceolate plates at the base of the fin; spot extended over a larger number of lower-lobe rays than upper-lobe rays and along one-half to more than two-thirds of the ray length (figs. 17 A, 24).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFB8F51AFFA4903A58CC6F73.taxon	description	DESCRIPTION: Morphometric and meristic data presented in table 5. Body moderately robust. Dorsal profile of head and body straight from tip of snout to dorsal-fin origin, slightly elevated at predorsal plates; straight from dorsal-fin origin to anteriormost caudal-fin procurrent ray. Head moderately depressed and wide. Lateral process of lateral ethmoid bone visible dorsally. Snout slightly rounded in dorsal view; dorsally smoothly rounded, slightly concave anterior to naris. Posterior surface of bony pit of nasal organ gradually inclined. Body cross section between pectoral- and pelvic-fin origins horizontally ovoid, vertically ovoid to progressively rounded posterior to dorsal fin, progressively compressed posterior to adipose-fin base. Eyes moderately large, positioned slightly closer to posterior tip of compound pterotic than to tip of snout. Ventral margin of orbit located close to ventral surface of head. Dorsal interorbital distance slightly shorter than ventral interorbital distance. Total plates in lateral medial series 22 – 24 (23). Dorsal series 19 – 21 (20); middorsal series 3 – 4 (4); midventral series 13 – 14 (13), with 4 – 5 (4) plates anterior of first plate of ventral series; ventral series 19 – 21 (20). Second plate of midventral series contacting a single plate of medial lateral series. Abdomen covered by paired series of lateral sickle-shaped plates, with unequal number of plates between left and right series, 5 – 11 each; medial series of 5 – 13 (8) roughly squared plates; anterior azygous plate absent; occasionally, transversal series of more than three small plates posterior of coracoids, not aligned with main three longitudinal series. Single anal plate present. Thoracic plates absent. Preopercular canal absent. Posterolateral margin of canal-bearing plate and lateral margin of fourth infraorbital smooth; pore between canalbearing ventral plate and fourth infraorbital absent. Small odontodes evenly distributed on head. Odontodes ventral and dorsal to tip of snout not arranged in aligned series. No odontode-free discontinuity between ventral and dorsal odontodes; odontodes dorsal to tip of snout slightly larger than those on head. Lamina of trunk plates bearing longitudinal rows of odontodes, and becoming progressively smoother ontogenetically; distinct column of marginal odontodes on posterior plate border in mature adults. Total vertebrae 27. Premaxillary teeth 19 – 34 (24); dentary teeth 14 – 28 (20). Maxillary barbels short, almost reaching to or slightly surpassing anterior margin of ventral canalbearing plate in adults. Dorsal-fin origin located slightly posterior of vertical through pelvic-fin origin. Depressed dorsal fin reaching to vertical through posterior half of anal-fin base. Pectoral fin reaching to vertical through midpoint of pelvic-fin base. Extension of serrae along pectoral spine margin, except for short basal segment; serrae of oblique type. Pelvic fin short, two longest branched rays slightly longer than spine. Depressed fin reaching to plate anterior to anal-fin spine. Caudal-fin margin forked; upper and lower lobes equal and not extremely elongate. Adipose fin present. COLOR IN ALCOHOL: Ground color tan and pale ochre. Melanophores light to dark brown, clustered resulting in mottled appearance. Melanophores slightly more concentrated dorsally on head, narrow area among compound pterotic, cleithral process, and opercle, at base of dorsal fin, anterior surface of lip, and anterior half of branchiostegal membrane. Head uniformly tan dorsally, except for darker area over brain. Deep-lying melanophores arranged in narrow transverse bands posterior to dorsal-fin base, noncoincident with posterior margin of plates. Midlateral stripe situated mostly along medial series of trunk plates (fig. 24). Ventral surface of body mostly unpigmented, except for scattered melanophores on posterior portion of trunk, soft tissue along base of pectoral and anal fins, anterolateral margin of cleithrum and posterior tip of cleithral process, ventral canal-bearing plates, and lateral portions of lateral series of abdominal plates. Dorsal and anal fins with dark brown bands. Caudal-fin bars variable defined. Presence of an elongated spot of black melanophores along caudal-fin branched rays, not distinctly connected to lanceolate plates at base of fin; spot typically extending over larger number of lower-lobe rays than upper-lobe rays and along one-half to more than two-thirds of ray length (figs. 17 A, 24). Tip of upper and lower lobes variably dark. SEXUAL DIMORPHISM: Male urogenital papilla short and slender, covered by anterior flaplike anus. Males with patch of tightly arranged small odontodes oriented as a swirl, variably covering first to fourth plates of ventral series, lateral to urogenital papilla. Males with flaplike anus along posterior margin of pelvic spine variably developed; when present, short, weakly developed, restricted to basal one-third to half of spine. Female anus tubular, without separate urogenital papilla. In females, size and arrangement of odontodes on plates lateral to anus similar to adjacent plates, without distinct patch of differentially arranged odontodes. Female pelvic spine without flap of soft tissue on posterior surface. TAXONOMIC REMARKS: The genus Hypoptopoma was established by Günther (1868 a) for his new species Hypoptopoma thoracatum (fig. 2) on the basis of one specimen collected by Barlett at Xeberos (Peru, upper Amazon). He distinguished the new taxon from the loricariid Plecostomus [5 Hypostomus] by the ‘‘ peculiar formation of the head, depressed, spatulate, the eyes being on the lateral edges of the head. ’’ During 1868, Günther published two papers in which he provided a taxonomic account of the new genus and species. In the first publication, Günther (1868 a) provided a brief diagnosis for the genus and the new species H. thoracatum that only specified counts for fin rays and lateral-line plates. A subsequent expanded description of H. thoracatum was published later during the same year (Günther, 1868 b). Therefore, H. thoracatum is considered the type species of the genus. Regarding Hypoptopoma bilobatum, Cope (1870) estab- lished the new species on the basis of one specimen collected in 1869 by Hauxwell in Pebas, Ecuador (a region which is now part of Peru), but failed to provide a justification for the proposition of a new species distinguishable from H. thoracatum Günther 1868 a, the only species described for the genus at the time. Ultimately, Eigenmann and Eigenmann (1889) placed Cope’s species as junior synonym of H. thoracatum, a designation that has been maintained in the literature almost invariably since then, and confirmed herein.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFB8F51AFFA4903A58CC6F73.taxon	distribution	DISTRIBUTION: Ríos Caqueta, Mamore´, Purus, and Ucayali of Western Amazon (fig. 25).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFB7F51FFF5897735B626F35.taxon	materials_examined	HOLOTYPE: FMNH 105076 (♀, 34.0 mm SL) Colombia: Rio Amazonas, 1 mi. up- stream from Leticia; collected by Navarro, Thomerson et al., 11 November 1973. PARATYPES (collected with holotype): FMNH 117744 (14 ♀ + 4 ³, 29.1 – 39.3 mm SL). AMNH 243577 (1 ♀ + 1 ³, 33.2 – 34.0 mm SL). NON- TYPES: BRAZIL, Amazonas: INPA 14317 (11 ♀ + 2 ³, 2 cs, 24.1 – 32.1 mm SL) Rio Solimões, 1 km acima do Furo Paracuuba; INPA 14322 (1 ♀, 38.3 mm SL) Ihla Marchantaria. MZUSP 7015 (1 ♀, 28.2 mm SL) Rio Madeira, 25 km abaixo de Nova Olinda; MZUSP 36214 (1 ♀ + 1 ³, 29.0 – 44.0 mm SL) Rio Japura, Manacabi, approximatly 50 km from Foz; MZUSP 36221 (4 ♀, 25.5 – 38.00 mm SL) Braço do Rio Solimões, Ihla Sorubim, acima do Coari; MZUSP 56820 (1 ♀; 30.6 mm SL) Rio Juruá, 10,2 km abaixo do Lago Pauapix- una. ECUADOR, Napo: FMNH 101541 (1 ♀ + 3 ³, 41.0 – 50.6 mm SL) Río Jivino, lower 4 km (mostly) to ca. 6 km upstream from mouth. PERU, Loreto: INHS 44126 (1 ♀, 48.8 mm SL) Río Napo and Quebrada Mazán, 33.3 km NE Iquitos; ANSP 187332 (1 ♀ + 1 ³ + 2 juveniles, 29.6 – 49.0 mm SL) Río Itaya at bridge on Iquitos- Nauta highway, approx. 25 miles SSW of Iquitos; SIUC 27969 (1 ³, 41.8 mm SL) Río Mazán. TABLE 6 Morphometric and Meristic Data for Hypoptopoma brevirostratum Holotype: FMNH 105076. Paratypes: FMNH 117744; AMNH 243577. Nontypes: FMNH 101541; INHS 44126; INPA 14317; SIUC 27969.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFB7F51FFF5897735B626F35.taxon	diagnosis	DIAGNOSIS: Hypoptopoma brevirostratum is distinguished from all congeners, with the exception of H. muzuspi, by having the preopercle constricted medially (vs. preopercle with no constriction); canal in preopercle present, semicircular, located posterior to the preopercle constriction (vs. canal absent from preopercle). Hypoptopoma brevirostratum is distinguished from H. muzuspi by its wider body (cleithral width 23.7 – 27.0 (25.7) vs. 19.1 – 23.5 (22.2 )), a deeper caudal peduncle (caudal-peduncle depth 6.4 – 9.1 (7.7) vs. 5.2 – 6.7 (5.8 )), and a larger eye (horizontal eye diameter 19.8 – 23.3 (21.7) vs. 13.6 – 20.7 (18.4 )).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFB7F51FFF5897735B626F35.taxon	description	DESCRIPTION: Morphometric and meristic data presented in table 6. Body moderately wide and depressed; greatest depth at dorsalfin origin. Dorsal profile of head and body, from tip of snout to dorsal-fin origin, smoothly convex to straight; straight posterior to dorsal-fin base. Head moderately depressed, almost as wide as cleithral width; lateral process of lateral ethmoid not visible dorsally. Snout rounded and short in dorsal view; dorsally slightly concave anterior to naris. Posterior surface of bony pit of nasal organ sharply inclined. Body cross section between pectoral- and pelvic-fin origins approximately ovoid horizontally, slightly rectangular posterior to dorsal fin, slightly compressed at level of two posteriormost lateral trunk plates. Eyes large, positioned equally distant from posterior tip of compound pterotic and to tip of snout. Ventral margin of orbit located on ventral surface of head. Dorsal interorbital distance typically slightly greater than ventral interorbital distance. Total plates in lateral medial series 23. Dorsal series 19 – 20 (20); middorsal series 3 – 4 (3); midventral series, 12 – 15 (13), with four plates anterior of first plate of ventral series; ventral series 19 – 20 (20). Second plate of midventral series contacting one plate of medial lateral series. Abdomen covered by paired series of lateral sickle-shaped plates, with unequal number of plates between left and right series, 3 – 8; medial series of 1 – 3 (2) roughly squared plates; medial series occasionally absent, in which case paired series make contact along midline in fully developed individuals; ab- dominal shield fully developed in specimens greater than 25 mm SL. Single anal plate present. Thoracic plates absent. Canal in the preopercle present, semicircular; anteriormost pore opening between ventral canal-bearing plate and fourth infraorbital; posterolateral margin of canal-bearing plate and lateral margin of fourth infraorbital with notch for pore of semicircular canal poorly defined. Small odontodes evenly distributed on head. Odontodes ventral and dorsal to tip of snout on anterior rostral plate not arranged in well-defined series. No odontode-free discontinuity between ventral and dorsal odontodes; odontodes dorsal to tip of snout small, slightly larger than those on dorsal surface of head. Odontodes on lamina of trunk plates roughly arranged in longitudinal rows; feeble column of marginal odontodes on posterior border of plates. No visible progressive smoothening of plates ontogenetically. Total vertebrae 27. Premaxillary teeth 10 – 28 (19), dentary teeth 12 – 22 (18). Maxillary barbels short, not reaching to ventral canalbearing plate in adults. Dorsal-fin origin located at vertical through pelvic-fin origin. Depressed dorsal fin reaching to vertical through posterior half of anal-fin base. Pectoral fin almost reaching to vertical through tip of longest pelvic-fin ray. Extension of serrae along pectoral spine margin, except for short basal segment; serrae of oblique type. Pelvic fin short, unbranched rays slightly shorter than first branched. Depressed fin reaching to plate anterior to anal-fin spine. Caudal-fin margin slightly forked; upper and lower lobes equal. Adipose fin absent. COLOR IN ALCOHOL: Ground color tan and pale ochre. Melanophores dark brown, irregularly distributed on trunk resulting in an overall marbled pattern. Melanophores on head not uniformly distributed. Melanophores slightly more concentrated between left and right nares and anterior to each naris, on anterior margin of opercle, cleithral posterior process, lateral rostral plates and anterior surface of lip. Narrow line of dark melanophores along margin of tip of snout. In dorsal view, melanophores arranged in illdefined darker clusters (one on predorsal plate, two lighter clusters lateral to dorsal-fin base, two or three posterior to dorsal fin). Midlateral stripe fading toward dorsal surface of trunk and toward caudal fin. Ventral surface of body mostly unpigmented. Three to six dark blotches along dorsal-fin spine, weakly extended over branched rays. Basal triangular dark brown to black spot at base of caudal-fin lower lobe; 3 – 6 dark blotches along caudal-fin unbranched rays, weakly extended over branched rays. SEXUAL DIMORPHISM: Male urogenital papilla completely covered by flaplike anus; joined at base. Males with patch of tightly arranged small odontodes oriented as a swirl covering second, third, and fourth plates of ventral series, lateral to urogenital papilla. Males with soft-tissue flap along posterior margin of pelvic spine variably developed; when present, short, restricted to basal onethird to one-half of spine. Female anus tubular, without separate urogenital papilla. In females, size and arrangement of odontodes on plates lateral to anus similar to adjacent plates, without distinct patch of differentially arranged odontodes. Female pelvic spine without flap of soft tissue on posterior surface.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFB7F51FFF5897735B626F35.taxon	distribution	DISTRIBUTION: Tributaries of Río Amazonas between confluence of Ucayali-Marañon rivers and Manaus (fig. 27).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFB7F51FFF5897735B626F35.taxon	etymology	ETYMOLOGY: The specific epithet brevirostratum (Lt. brevis, meaning ‘‘ short’ ’; Lt. rostrum, meaning ‘‘ snout’ ’) is a reference to the short head.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFB2F502FD1997355CEA69D0.taxon	materials_examined	HOLOTYPE: MZUSP 52135 (³, 36.3 mm SL) Brazil: Tocantins State, Araguaçu, rio Agua Fria, fazenda Praia Alta 2, estrada Araguaçu / Barreira do Piqui, 27 km ao norte TABLE 7 Morphometric and Meristic Data for Hypoptopoma muzuspi Holotype: MZUSP 52135. Paratypes: MZUSP 95186; AMNH 243578. de Araguaçu; collected by Lima et al., 6 July 1997. PARATYPES (collected with holotype): MZUSP 95186 (24 ♀, 2 cs, 19.0 – 31.0 mm SL). AMNH 243578 (5 ♀, 1 cs, 28.0 – 32.0 mm SL).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFB2F502FD1997355CEA69D0.taxon	diagnosis	DIAGNOSIS: Hypoptopoma muzuspi is distinguished from all congeners by having the bifid neural spines of vertebra 10 – 12 expand- ed distally (vs. bifid neural spines progressively pointed distally). It can be further distinguished from all congeners, except H. brevirostratum, by the preopercle constricted medially (vs. preopercle without constriction) and canal in preopercle present, semicircular, and located posterior to the preopercle constriction. Hypoptopoma muzuspi can be readily distinguished from H. brevirostratum by its more elongated body and head (body depth 13.8 – 16.7 (14.7) vs. 15.5 – 19.2 (17.6); cleithral width 19.1 – 23.5 (22.2), vs. 23.7 – 27.0 (25.7); caudal-peduncle depth 5.2 – 6.7 (5.8) vs. 6.4 – 9.1 (7.7 )), and caudal-fin pigmentation comprised of 7 – 10 bars of brown melanophores on unbranched and branched rays (vs. 3 – 6 dark blotches along unbranched rays, weakly extended over branched rays).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFB2F502FD1997355CEA69D0.taxon	description	DESCRIPTION: Morphometric and meristic data presented in table 7. Body moderately elongate; greatest depth at dorsal-fin origin, trunk most shallow at origin of caudal-fin procurrent rays. Dorsal profile of head and body, from tip of snout to dorsal-fin origin, smoothly convex; straight posterior to dorsal-fin origin, smoothly tapering to caudal fin base. Head moderately depressed; lateral process of lateral ethmoid bone not visible dorsally. Snout rounded in dorsal view; smoothly concave anterior to naris. Posterior surface of bony pit of nasal organ sharply inclined. Trunk cross section between pectoral- and pelvic-fin origins horizontally ovoid, posterior to dorsal fin slightly rectangular, at level of two posteriormost trunk lateral plates slightly compressed. Eyes moderately large, positioned slightly closer to posterior tip of compound pterotic than to tip of snout. Ventral margin of orbit located close to ventral surface of head. Dorsal interorbital distance shorter than ventral interorbital distance. Total plates in lateral medial series 22 – 23 (23). Dorsal series plates 19 – 20 (19); middorsal series plates 3; midventral series plates 13 – 14 (13), with four plates anterior to first plate of ventral series; ventral series 19. Second plate of midventral series contacting a single plate of medial lateral series. Abdomen covered by paired series of lateral sickle-shaped plates, with unequal number of plates between left and right sides, 4 – 8; medial series of 4 – 5 (5) roughly squared plates; anterior azygous plate absent; medial series occasionally absent, in which case paired series make contact along midline in fully developed individuals; abdominal shield fully developed in specimens greater ca. 30 mm SL. Single anal plate present. Thoracic plates absent. Canal in the preopercle present, semicircular; anteriormost pore located between ventral canal-bearing plate and fourth infraorbital; lateral margin of fourth infraorbital with notch for semicircular canal better defined than on posterolateral margin of canal-bearing plate. Small odontodes evenly distributed on head. Odontodes on anterior rostral plate not arranged in well-defined series; no odontode-free discontinuity between ventral and dorsal odontode series; odontodes dorsal to tip of snout slightly larger than those on head. Odontodes on lamina of trunk plates arranged in longitudinal rows; progressive smoothing of plates with increased specimen size not observed; marginal odontodes on posterior border of trunk plates in specimens greater than 34 mm SL. Total vertebrae 27. Premaxillary teeth 15 – 21 (18), dentary teeth 13 – 18 (15). Maxillary barbels short, not reaching ventral canalbearing plate in adults. Dorsal-fin origin located slightly posterior of vertical through pelvic-fin origin. Depressed dorsal fin reaching to vertical through posterior third of anal-fin length. Pectoral fin reaching to vertical through midpoint of pelvic-fin length. Pectoral fin reaching second half of pelvic-fin spine. Pectoral spine serrae extended along posteri- or margin of spine shaft, except for short basal segment; serrae oriented oblique to spine shaft. Pelvic fin short, longest branched rays slightly longer than spine; when depressed reaching to plate anterior to anal-fin spine. Caudal-fin posterior margin forked, upper and lower lobes not elongate. Adipose fin absent. COLOR IN ALCOHOL: Ground color tan and pale ochre. Light to dark brown melanophores, clustered on trunk resulting in mottled appearance. Melanophores more densely concentrated on compound pterotic, supraoccipital, frontals, lateral rostral plates, at base of pectoral and anal fins, on anterior surface of lip, lateral half of branchiostegal membrane, and mesial portion of naris softtissue flap. Melanophores along dorsal midline between dorsal-fin base and caudal fin concentrated in irregular clusters, often defining darker outline on posterior margin of plates of dorsal series. Midlateral stripe situated along medial, midventral, and ventral series of plates, becomming progressively more pigmented between medial and ventral series. Ventral surface of body mostly unpigmented except for scattered melanophores on posterior portion of trunk, anterolateral to cleithral processes, on ventral canal-bearing plates and lateral portions of lateral abdominal plate series. Paired and unpaired fins with relatively numerous narrow, dark brown bars. Caudal-fin with 7 – 10 bands of brown melanophores on unbranched and branched rays. Series of lanceolate plates at caudal-fin base slightly darkened with black melanophores. Variably shaped dark brown to black spot over lower lobe of caudal-fin. Posteriormost plates of both dorsal and ventral series of lateral plates less pigmented, whitish. SEXUAL DIMORPHISM: Male urogenital papilla covered by flaplike anus. Males with patch of more tightly arranged small odontodes from fourth to sixth plates of ventral series, lateral to urogenital papilla. Female anus tubular, without separate urogenital papilla. In females, size and arrangement of odontodes on plates lateral to anus similar to those on adjacent plates, without distinct patch of differentially arranged odontodes.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFB2F502FD1997355CEA69D0.taxon	etymology	ETYMOLOGY: The specific epithet muzuspi is given in recognition of the Museu de Zoologia, Universidade de São Paulo, Brazil (MZUSP), as one of the leading institutional collections for ichthyology in South America. The name is treated as a noun in apposition to the generic name.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFB2F502FD1997355CEA69D0.taxon	distribution	DISTRIBUTION: Rio Tocantins basin; known only from Rio Agua Fria, in the drainage of Rio Araguaia (main tributary of Rio Tocantins) (fig. 27).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFA5F50BFD31904A5C6B6A0C.taxon	materials_examined	HOLOTYPE: FMNH 105077 (♀, 53.7 mm SL) Colombia: Amazonas, Amazon River at 2 to 3 miles upstream from Leticia; collected by Navarro et al., 13 November 1973. PARATYPES (all material collected with holotype): FMNH 117745 (7 ♀ + 3 ³, 2 cs, 37.2 – 47.9 mm SL); AMNH 243576 (1 ♀ + 1 ³, 46.1 – 47.3 mm SL). NON- TYPES: PERU, Loreto: MZUSP 36208 (1 ♀, 43.0 mm SL) Río Ucayali, Sgto. Lores; SIUC 28113 (1 ♀, 39.0 mm SL) Río Napo, confluence with Río Mazán, ca. 2 – 3 km N (town of) Mazán; SU 33272 (1 ³, 42.6 mm SL) Río Ampiyacu. Ucayali: MHNG 2390.25 (1 ♀, 44.5 mm SL) Pucallpa, Río Ucayali, San Antonio; MZUSP 36206 (1 ³, 43.2 mm SL) Pucallpa, Río Ucayali; MZUSP 36207 (1 ♀, 42.03 mm SL) Pucallpa, Río Ucayali, Laguna Yarinacocha. BRAZIL, Amazonas: MZUSP 27624 (1 ♀, 41.2 mm SL) Costa Japao, Baixao Rio Japurá, Mun. de Tefe´; MZUSP 36211 (4 ♀, 41.0 – 51.8 mm SL) Rio Solimões, prox. I. Bururuá acima do boca do Jutaí.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFA5F50BFD31904A5C6B6A0C.taxon	diagnosis	DIAGNOSIS: Hypoptopoma bianale is distinguished from all congeners by presence of two medial anal plates (vs. single medial anal plate in all other species of Hypoptopoma) (fig. 9 C).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFA5F50BFD31904A5C6B6A0C.taxon	description	DESCRIPTION: Morphometric and meristic data presented in table 10. Body robust, stocky, greatest body depth at dorsal-fin origin, least depth at caudal peduncle. Dorsal profile of head and body straight from tip of snout to posterior tip of supraoccipital, smoothly convex at level of predorsal plates. Dorsal profile of trunk straight from dorsalfin origin to caudal procurrent rays. Ventral profile of head and abdomen straight to slightly convex from snout tip to caudal-fin procurrent rays (not apparent in lateral view of head profile). Head moderately depressed, slightly acute, smoothly concave anterior to naris. Posterior surface of bony pit of nasal organ gradually inclined. Lateral process of lateral ethmoid bone slightly visible in dorsal view of head. Trunk cross section ovoid to progressively compressed posterior to dorsal fin. Eyes moderately large, positioned slightly closer to posterior tip of compound pterotic than to tip of snout. Ventral margin of orbit close to ventral margin of head. Dorsal interorbital distance roughly equal to ventral interorbital distance. Total plates in medial series 22. Dorsal series plates 19; middorsal series plates 3 – 4 (4); midventral series plates 12 – 13 (13), three plates anterior to first ventral series plate; ventral series plates 19. Second plate of midventral series contacting two plates of medial series. Abdomen covered by paired series of lateral sickle-shaped plates, with unequal number of plates between left and right series, 4 – 6; anterior azygous plate present; lateral series make contact along midline in fully developed individuals. Presence of two medial anal plates positioned along longitudinal axis of body, between pelvic fins laterally, abdominal plates anteriorly, TABLE 10 Morphometric and Meristic Data of Hypoptopoma bianale Holotype: FMNH 105177. Paratypes: FMNH 117745; AMNH 243576. Nontypes: MNHG 2390.25; MZUSP 27624, 36203, 36206, 36207, 36208, 36211; SU 33272. and anus posteriorly; anterior plate larger than posterior plate (fig. 9 C). Thoracic plates present, 4 – 5. Canal in preopercle present, semicircular; anteriormost pore located between ventral canal-bearing plate and fourth infraorbital, framed by notch at posterolateral margin of canal-bearing plate and lateral margin of fourth infraorbital. Small odontodes evenly distributed on head. Odontodes on rostral margin of snout enlarged and arranged in irregular lines, without odontode-free discontinuity between dorsal and ventral margins. Lamina of trunk plates with odontodes arranged in longitudinal rows; plates progressively smoother in ontogeny; marginal odontodes present in mature adults. Anterior margin of pectoralfin spine and ventral surface of pelvic-fin spine with enlarged odontodes. Total vertebrae 26. Premaxillary teeth 21 – 29 (25), dentary teeth 20 – 27 (23). Maxillary barbels extending slightly beyond anterior margin of ventral canal-bearing plate. Dorsal-fin origin located at vertical through pelvic-fin origin; depressed dorsal fin reaching almost to vertical through posterior tip of anal fin. Pectoral fin reaching to vertical through posterior tip of pelvic fin. Pectoral spine serrae along entire posterior margin, except for short basal segment; individual serrae oriented oblique to spine shaft. Pelvic fin short, unbranched and first branched rays equal in length; when depressed reaching to plate anterior to anal-fin spine. Caudal-fin margin concave. Adipose fin absent. COLOR IN ALCOHOL: Overall body pigmentation relatively uniform, ground color tan to pale ochre. Melanophores variably light brown, slightly more concentrated along base of plates, dorsal portions of head, lateral border of compound pterotic, cleithral process, opercle, and base of dorsal fin. No lateral stripe on trunk. Ventral surface of body mostly unpigmented. Scattered dark melanophores present on anterior surface of lip. Fins with pale brown bands (dorsal fin 4 – 6; caudal fin 4 – 5). Triangular spot of dark brown melanophores at base of caudal-fin branched rays, mostly extended over basal plates and lower lobe, progressively widening toward lower marginal ray; caudal-fin bars mainly visible on marginal rays and outer most branched rays. SEXUAL DIMORPHISM: Male urogenital papilla short, half-length of flaplike anus, which totally covers and joins base of papilla. Males with patch of tightly arranged small odontodes on second through fourth plates of ventral series, lateral to urogenital papilla. Female anus tubular, without separate urogenital papilla. In females, size and arrangement of odontodes on plates lateral to anus similar to adjacent plates, without distinct patch of differentially arranged odontodes.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFA5F50BFD31904A5C6B6A0C.taxon	distribution	DISTRIBUTION: Rio Solimões in Brazil and Río Ucayali in Peru (fig. 32).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFA5F50BFD31904A5C6B6A0C.taxon	etymology	ETYMOLOGY: The specific epithet bianale is a reference to the presence of two anal plates (Lt. bi, meaning ‘‘ two’ ’; Lt. analis, from anal (adaptation from modern Latin; Oxford English Dictionary: ‘‘ Of or pertaining to the anus, or excretory opening’ ’).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFDFF575FD23942F5C446A03.taxon	materials_examined	HOLOTYPE: INPA 7240 (♀, 95.4 mm SL) Brazil: Pará, Rio Tapajos, Itaituba; collected by L. Rapp Py-Daniel and J. Zuanon, 18 October 1991. PARATYPES: INPA 29657 (32 ♀ + 26 ³, 2 cs, 62.7 – 102.7 mm SL) (collected with holotype).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFDFF575FD23942F5C446A03.taxon	description	OTHER MATERIAL EXAMINED: BRAZIL, Pará: CAS 6748 (1 ♀, 93.2 mm SL) Santarem market; INPA 5405 (6 ♀, 93.0 – 96.2 mm SL) Rio Trombetas, Cach. Porteira a jusante da cachoeira; INPA 5406 (1 ♀, TABLE 12 Morphometric and Meristic Data for Hypoptopoma elongatum Holotype: INPA 7240. Paratype: INPA 29657. Nontype: MZUSP 38187. 101.4 mm SL) Rio Trombetas, Lago Tapagem; INPA 5570 (3 ♀, 88.4 – 104.2 mm SL) Rio Trombetas, R. Cumina, Lago Salgado; INPA 7130 (1 ♀ + 2 ³, 90.6 – 94.1 mm SL) Rio Cupari, afluente do Rio Tapajos (próximo a boca); INPA 7131 (3 ♀ + 1 ³, 88.8 – 94.3 mm SL) Rio Cupari, afluente do Rio Tapajos (próximo a boca); INPA 7213 (2 ♀, 88.2 – 9.2 mm SL) Rio Cupari, afluente do Rio Tapajos; MZUSP 34193 (8 ♀ + 3 ³, 87.9 – 97.0 mm SL) Rio Tapajos, beira do rio, entre Itaituba e São Luis; MZUSP 36187 (2 ♀ + 2 ³, 79.9 – 89.5 mm SL) Rio Tapajos, ihla confrontando Monte Cristo; MZUSP 36220 (1 ♀, 77.0 mm SL) Rio Tapajos, Igarape Jacare, margen dereita do Rio Tapajos, perto de Boim.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFDFF575FD23942F5C446A03.taxon	diagnosis	DIAGNOSIS: Hypoptopoma elongatum is distinguished from all congeners by having a nonpigmented band on the head positioned parallel to the ventral margin of the rostral and lateral snout plates, with the margin between pigmented and nonpigmented plates very well defined (fig. 35 C) (vs. absence of a distinct pigmented band). Hypoptopoma elongatum can be further distinguished from congeners, except for H. inexspectatum, by having the ventral surface of the anterior rostral plate as wide as the ventral surface of the first lateral rostral plates (vs. ventral surface gradually widening from anterior rostral to lateral rostral plates). Hypoptopoma elongatum is readily distinguished from H. inexspectatum by having a greater number of plates along the trunk medial series (23 vs. 20 – 21 (21 )), by having the snout appearing pointed in dorsal view due to a slight concavity between rostral plate and first infraorbital (fig. 35 A) (vs. snout typically spatulate), and by having, if present, a distinct series of odontodes along dorsal and ventral rostral margin of snout restricted to the anterior rostral plate (vs. series of odontodes along dorsal and ventral rostral margin of snout extended laterally to include second and third infraorbitals).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFDFF575FD23942F5C446A03.taxon	description	DESCRIPTION: Morphometric and meristic data presented in table 12. Body robust; greatest body depth at dorsal-fin origin. Dorsal profile of head and body straight from snout tip to dorsal-fin origin, slightly elevated at posterior tip of supraoccipital; straight from dorsal-fin origin to anteriormost procurrent caudal-fin ray. Ventral profile of head and body straight to slightly concave from snout tip to anteriormost procurrent caudal-fin ray. Head moderately depressed, almost as wide as cleithral width; lateral process of lateral ethmoid bone visible dorsally. Anterior snout margin acute; slightly concave anterior to naris. Posterior surface of bony pit of nasal organ sharply inclined. Trunk cross section slightly triangular between pectoral- and pelvic-fin origins, ovoid to progressively round posterior to dorsal fin, caudal peduncle posterior to adipose-fin base progressively compressed. Eyes relatively large, positioned closer to posterior tip of compound pterotic than to tip of snout. Ventral margin of orbit located on ventral side of head. Dorsal interorbital distance greater than ventral interorbital distance. Total plates in medial series typically 23. Dorsal series plates 20; middorsal series plates 4; midventral series plates 12 – 13 (13), three plates anterior to first ventral series plate; ventral series plates 20. Second plate of midventral series contacting two plates of medial series. Abdomen covered by paired series of lateral sickle-shaped plates, with unequal number of plates between left and right series, 4 – 7 each; anterior azygous plate usually present. Single anal plate. Thoracic plates present, 2 – 6. Preopercular canal in preopercle present, semicircular; anteriormost pore located between ventral canal-bearing plate and fourth infraorbital; framed by notch at posterolateral margin of canal-bearing plate and ventral margin of fourth infraorbital. Small odontodes evenly distributed on head; odontodes on rostral margin not arranged in well-defined series, without odontode-free discontinuity. Odontodes on ventral surface of rostral plate variably enlarged. Lamina of trunk plates with odontodes arranged in longitudinal rows, becoming progressively smoother ontogenetically; marginal odontodes present in mature adults. Anterior margin of pectoral-fin spine and ventral surface of pelvic-fin spine with enlarged odontodes. Total vertebrae 27. Premaxillary teeth 16 – 23 (21); dentary teeth 14 – 22 (18). Maxillary barbels short, only reaching to anterior margin of ventral canal-bearing plate. Dorsal-fin origin located slightly posterior to vertical through pelvic-fin origin. Depressed dorsal fin reaching to or surpassing vertical through posterior half of anal-fin base. Depressed pectoral fin reaching to anus. Pectoral spine serrae typically along middle three-fifths of spine length, involving less of spine shaft with growth; individual serrae oriented oblique to spine shaft. Pelvic fin short, unbranched and first branched rays of equal length. Depressed pelvic fin reaching to anus, not reaching analfin origin. Caudal-fin margin markedly forked; upper and lower lobes equal. Adipose fin variably present; when present, small and membranous. COLOR IN ALCOHOL: Ground color tan and pale ochre. Light to dark brown melanophores clustered on trunk and at base of plates, yielding mottled appearance. Melanophores slightly more concentrated on narrow area along compound pterotic, between cleithral process and opercle, and at base of both dorsal and pectoral fins. Well-defined nonpigmented band parallel to ventral surface of snout plates, including two plates lateral to barbel; margin between pigmented and nonpigmented plates distinct. Deep-lying melanophores arranged in series of blotches posterior to dorsal-fin base; butterfly-shaped blotch anterior to dorsal-fin origin, centered at anteriormost predorsal plate, anterior arms lateral to supraoccipital. Trunk lateral stripe involving medial plate series. Ventral surface of body mostly unpigmented except for scattered melanophores on posterior portion of trunk and anterior surface of lip. Paired and unpaired fins with few dark brown bands. Dorsal fin typically with faint bar at base followed by one dark bar roughly orthogonal to rays and closer to tip than to base of fin, with one or two additional faint bars intervening. Caudal-fin rays with melanophores arranged in parallel V-shaped pigmented bands, typically fainter on medial branched rays; anterior band located at base of branched rays, typically lighter than posterior band; posterior band located near posteror fin margin; unbranched rays and tip of median caudal-fin branched rays light. Lanceolate plates at base of caudal fin light brown, variably connected with basal faint vertical band. SEXUAL DIMORPHISM: Male urogenital papilla well developed, pointed, joined at base to anterior flaplike anus. Patch of tightly arranged small odontodes on second, third, and fourth plates of ventral series, lateral to urogenital papilla. Males with softtissue flap along posterior margin of pelvic spine and along basal one-third to two-thirds of spine. Female anus tubular, without separate urogenital papilla. In females, size and arrangement of odontodes on plates lateral to anus similar to adjacent plates, without distinct patch of differentially arranged odontodes.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFDFF575FD23942F5C446A03.taxon	distribution	DISTRIBUTION: Lower Rio Tapajos and lower Rio Trombetas (fig. 32).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFDFF575FD23942F5C446A03.taxon	etymology	ETYMOLOGY: The specific epithet elongatum (Lt. elongatus, meaning ‘‘ prolonged’ ’) is a reference to the elongated general shape of the body, particularly marked at the tip of snout, caudal peduncle, and caudal fin.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFD8F57BFD0992705C8A687A.taxon	materials_examined	HOLOTYPE: AMNH 39759, 85.01 mm SL, female, Bolivia: Beni, Río Itenez, opposite to Costa Marques; collected by R. M. Bailey and R. Ramos, 1 – 3 September 1964. PARATYPES (collected with holotype): AMNH 241976, 6 females and 13 males, 2 cs, 76.6 – 94.1 mm SL. UMMZ 204339, 8 females and 8 males, 3 cs, 79.56 – 95.03 mm SL.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFD8F57BFD0992705C8A687A.taxon	description	OTHER MATERIAL EXAMINED: BOLIVIA, Beni: AMNH 40039 (1 ³, 85.4 mm SL) Río Baures, above mouth 6 km SW Costa Marques, Brazil; AMNH 77403 (1 ³, 72.1 mm SL) Río Mamore´, ca. 10 km west of San Pedro; AMNH 77467 (2 ♀ + 1 ³, 43.5 – 57.3 mm SL) Río Mamore´, Puerto Siles; CAS 77140 (1 ³, 56.7 mm SL) Cachuela Esperanza, first falls of the Beni; CBF 1323 (5 ♀, 53.1 – 78.9 mm SL) Ballivian, Espíritu, Arroyo Carnaval, Río Yacuma, Mamore´, Madeira; USNM 305596 (2 ♀, 47.2 – 49.2 mm SL) Río Matos / Apere / Mamore´; Prov. Ballivia, Río Matos below road x-ing, 48 km E San Borja. Pando: FMNH 107001 (2 ♀, 48.0 – 62.3 mm SL) 100 m de la boca del Nareuda en el Tahuamanu; FMNH 107002 (2 ♀, 36.4 – 39.1 mm SL) Río Nareuda, río arriba de la desembocadura en el Tahuamanu; FMNH 107003 (7 ♀, 41.8 – 71.1 mm SL) Río Manuripi, + / 2 12 km río arriba de Puerto Rico; FMNH 107004 (2 ♀ + 2 ³, 54.5 – 71.5 mm SL) Río Manuripi, + / 2 20 km río arriba de Puerto Rico; FMNH 107007 (1 ♀, 71.3 mm SL) Brazo del Manuripi, + / 2 1 km río arriba del campamento; FMNH 107008 (8 ♀, 50.2 – 70.6 mm SL) Río Manuripi above camp; FMNH 107009 (3 ♀ + 2 ³, 52.8 – 82.1 mm SL) Río Manuripi at playa, 5.78 km from camp, 9.23 from Puerto Rico; FMNH 107010 (2 ♀ + 2 ³, 65.1 – 73.6 mm SL) Río Manuripi at playa outside, 6.76 km above camp and 9.78 above Puerto Rico; FMNH 107011 (1 ♀, 34.6 mm SL) Rio Manuripi at island 0.76 km above camp and 4.20 above Puerto Rico. Santa Cruz: CBF 2862 (1 ♀, 53.9 mm SL) Guarayos, Perseverancia, Río Negro cerca de Las Naranjas; CBF 10110 (1 ♀, 51.1 mm SL) Guarayos, Perseverancia, TABLE 13 Morphometric Data for Hypoptopoma incognitum Holotype: AMNH 39759. Paratype: AMNH 241976. Nontypes: CAS 6736, 6748, 56723; FMNH 117743; INPA 2798, 6039; MUSM 7520, 10521; MZUSP 4978; UMMZ 202339; USNM 177706, 177707, 308093. Río Negro. BRAZIL, Acre: MZUSP 49782 (3 ♀ + 1 ³, 45.5 – 46.9 mm SL) Rio Acre, entre Seringal Paraiso y Lago Amapa; MZUSP 49795 (1 ♀ + 1 ³, 75.2 – 85.7 mm SL) Lago Amapa. Amazonas: CAS 56723 (1 ♀, 74.0 mm SL) Igarapé Chibareno, 30 km E of Manaus on south shore of Rio Negro, about 0.3 mi. S of its entrance into Rio Amazonas; INPA 127 (4, 51.3 – 70.4 mm SL) Lago Janauaca, Rio Solimões; INPA 807 (1 ♀, 84.0 mm SL) Flutuante do Tarumã Açu; INPA 2798 (9 ♀ + 4 ³, 2 cs, 58.9 – 88.3 mm SL) Ihla da Marchantaria, Rio Solimões; INPA 2800 (1, 74.1 mm SL) Lago Janauaca, Rio Solimões; INPA 6035 (3 ♀, 82.0 – 85.6 mm SL) Rio Amazonas, Ihla do Careiro, Lago do Pedro; INPA 6082 (1 ³, 78.8 mm SL) Rio Solimões, Boca do Paraná do Janauacá; INPA 6088 (1 juvenile, 58.8 mm SL) Río Madeira, Igarapé Aramaguara; INPA 14017 (1 ³, 76.2 mm SL) Rio Solimões, Parana do Rei; MZUSP 6723 (1 ♀, 74.1 mm SL) Rio Negro, Manaus; MZUSP 7557 (1 ♀ + 1 ³, 64.9 – 68.2 mm SL) Parana do Urucura, mun. de Urucura; MZUSP 7654 (1 ♀, 75.5 mm SL) Boca do lago José Açu, Parintins; MZUSP 6598 (1 ♀, 74.4 mm SL) Lago Manacupuru; MZUSP 27607 (1 ♀, 67.0 mm SL) Paraná de Capacete, Rio Solimões, mun. de Benjamin Constant; MZUSP 36198 (1 ♀, 90.0 mm SL) Lago Janauaca e arrededores, Rio Solimões; MZUSP 36227 (1 juvenile, 43.3 mm SL) Ihla Marchantaria, perto de Manaus; USNM 177706 (1 ♀, 62.3 mm SL) Amazonas, Rio Urubu; USNM 177707 (1 ♀, 65.95 mm SL) Amazonas, Rio Urubu; USNM 306963 (2 juveniles, 37.3 – 41.0 mm SL) ressaca da Ilha de Marchantaria; USNM 306991 (1 juvenile, 41.8 mm SL) ressaca da Ilha de Marchantaria; USNM 307056 (1 ³, 62.24 mm SL) Amazonas, Paraná de Janauaca, entrada do Lago Castanho; USNM 308093 (1 ³, 82.9 mm SL) Amazonas, entrada de Janauari, entre Furo de Paracuuba e Lago Terra Preta; USNM 308244 (1 ³, 83.2 mm SL) near Manaus, entrance of lago Janauari, between furo (channel) de Paracuuba and lago Terra Preta; USNM 308303 (1 ³, 79.0 mm SL) Amazonas, Lago Terra Preta, Janauari. Goiás: MZUSP 4881 (11, 39.2 – 71.0 mm SL) Rio Araguaia, Aruana. Maranhão: MNRJ 17720 (8) Rio Mearim em Arari; MNRJ 17725 (4) Rio Mearim; MNRJ 17726 (1) Lago Malhada Grande. Mato Grosso: MZUSP 36222 (1 juvenile, 47.6 mm SL) Río Araguaia, Santa Terezinha. Pará: CAS 6736 (1 ♀, 70.3 mm SL) Amazonas, Santarém market; CAS 6748 (1 ♀, 92.4 mm SL) Amazonas, Santarém market; FMNH 59622 (3 ♀, 47.0 – 55.6 mm SL) Santarém; FMNH 117743 (13 ♀ + 2 ³, 41.6 – 72.3 mm) Santarém; INPA 558 (2) Rio Tocantins, Ig. Arapari, Breu Branco; INPA 6028 (1) Rio Tocantins, Breu Branco; INPA 6029 (1) Rio Tocantins, Poco do Paulo; INPA 6030 (1) Rio Tocantins, Breu Branco, Igarape Arapari; INPA 6031 (2) Rio Tocantins, Breu Branco, Igarape Canoal; INPA 6032 (1) Rio Tocantins, Breu Branco, Igarape Arapari; INPA 6033 (3) Rio Tocantins, Itupiranga; INPA 6036 (5) Rio Tocantins, a jusante da represa; INPA 6037 (1) Rio Tocantins, Breu Branco, Igarape Canoal; INPA 6039 (13) Rio Tocantins, Itupiranga; INPA 6053 (9) Rio Tocantins, Igarape Arapari, Breu Branco; INPA 6054 (1) Rio Tocantins, Icangui; INPA 6055 (2) Rio Tocantins, Capuerana; INPA 6057 (1) Rio Tocantins, Tucurui, Igarape Vallentim; INPA 6058 (1) Rio Tocantins, Itupiranga; INPA 6059 (1) Rio Tocantins, Breu Branco, Igarape Canoal; MHNG 2538 12 (1 ♀, 48.1 mm SL) Ig. Azul, Ilha do Cameta, face a Santarém; MHNG 2708.060 (1 ³, 71.7 mm SL) Amazon river, side arm with lagos along right shore, about 10 km downriver of Santarém; MZUSP 5657 (6 juveniles, 19.1 – 39.8 mm SL) Lago Paru, Oriximiná; MZUSP 7850 (3 ♀, 63.5 – 69.7 mm SL) Parana Jacare´, Mun. Faro; MZUSP 8539 (1 ♀, 76.7 mm SL) Rio Tapajos, Santarém; MZUSP 34194 (1 ♀, 89.6 mm SL) Tocantins, Tucurui; MZUSP 36185 (1 ♀, 71.7 mm SL) Rio Arari, Cachoeira de Arari, Ilha de Marajo; MZUSP 36186 (2 ♀, 57.2 – 80.4 mm SL) Lagoa marginal do Rio Tocantins, perto de Baiao; MZUSP 36188 (1 ♀, 64.9 mm SL) Oriximiná. Rondonia: INPA 456 (16 ♀ + 9 ³, 63.0 – 75.0 mm SL) Río Madeira, Varza de calama, Lago de Repartimento; INPA 2237 (1 ♀, 70.0 mm SL) Río Madeira, Calama Flechal. Roraima: INPA 49 (1 ♀, 86.1 mm SL) Paraná do Rio Branco. PERU, Madre de Dios: ANSP 144008 (1 ♀, 65.9 mm SL) NW of Puerto Maldonado, Lago Tupuhumaro, oxbow lake E bank of Madre de Dios, above junction with Río de las Piedras; MUSM 2474 (5 ♀, 40.6 – 66.6 mm SL) Manú, Parque Nacional, Pakitza, Cocha Salvador; MUSM 7520 (1 ♀ + 5 ³, 33.2 – 65.8 mm SL) Tambopata, Río Madre de Dios, Lago Valencia; MUSM 7960 (1 ♀, 55.1 mm SL) Tambopata, Río Madre de Dios, Lago Valencia; MUSM 8123 (3 ♀, 60.2 – 65.2 mm SL) Tambopata, Candamo, Río Tambopata, Río Chuncho; USNM 263910 (3 ♀, 46.4 – 69.6 mm SL) Reserva Natural de Tambopata, Laguna Cocococha, 5.1 km to E of explorers inn; USNM 264046 (2 juveniles, 35.9 – 44.5 mm SL) Reserva Natural de Tambopata, Laguna Chica, end opposite boat dock (farthest from trail leading to lodge); USNM 302696 (6 ♀ + 1 ³, 2 cs, 40.3 – 68.1 mm SL) Prov. Manú, Coche Salvador, and oxbow lake off Río Manú about 1 hr. downriver from Pakitsa; USNM 327324 (3 ♀, 50.0 – 56.5 mm SL) Prov. Manú, Parque Nacional Manú, Cocha Salvador; USNM 327333 (1 ♀ + 1 ³, 49.4 – 71.2 mm SL) Prov. Manú, Parque Nacional Manú, Cocha Nueva; USNM 327334 (2, 58.3 – 63.5 mm SL) Prov. Manú, Parque Nacional Manú, Río Manú, Cocha Juárez; USNM 327340 (1 ♀ + 1 ³, 48.8 – 55.0 mm SL) Prov. Manú, Parque Nacional Manú, Cocha Nueva. Ucayali: MHNG 2407.97 (2 ♀, 68.8 – 76.0 mm SL) Bagazan, Río Ucayali, Pucallpa; MUSM 10476 (2 ♀, 44.6 – 47.6 mm SL) Purús, Río Purús, Cocha Zapote; MUSM 10521 (10 ♀ + 5 ³, 44.7 – 77.1 mm SL) Purús, Río Purús, Cocha Bola de Oro; USNM 384194 (1 ♀, 44.8 mm SL) Río Purús.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFD8F57BFD0992705C8A687A.taxon	diagnosis	DIAGNOSIS: Hypoptopoma incognitum is distinguished from all congeners, with the exception of H. elongatum, by the presence of a patch of odontodes on the anterolateral surface of the cleithrum at the opening to the branchial chamber. Hypoptopoma incognitum is distinguished from H. elongatum by having a shorter caudal peduncle (caudal-peduncle length 26.0 – 36.0 (32.0) vs. 32.3 – 36.3 (34.4); ttest, p, 0.001) (fig. 37); by a deeper, more robust caudal peduncle (caudal-peduncle depth 8.8 – 11.0 (10.1) vs. 7.9 – 8.8 (8.4); t-test, p, 0.001); by the round to slightly acute snout (vs. snout appearing pointed due to slight lateral inflexion between rostral plate and first infraorbital); by fewer plates along medial series (21 – 22 (22) vs. 23); by having caudal-fin lobes light brown (vs. caudal-fin lobes dark).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFD8F57BFD0992705C8A687A.taxon	description	DESCRIPTION: Morphometric and meristic data presented in table 13. Body robust; greatest body depth at dorsal-fin origin. Dorsal profile of head and body straight from tip of snout to dorsal-fin origin, slightly elevated at posterior supraoccipital tip; straight from dorsal-fin origin to anteriormost procurrent caudal-fin ray. Ventral profile slightly convex from tip of snout to anteriormost procurrent caudal-fin ray. Head moderately depressed, almost as wide as cleithral width; lateral process of lateral ethmoid bone visible dorsally. Snout rounded to slightly acute in dorsal view; dorsally, slightly concave anterior to naris. Posterior surface of bony pit of nasal organ sharply inclined. Trunk cross section between pectoral- and pelvic-fin origin slightly triangular, ovoid to progressively rounded posterior to dorsal fin, progressively compressed posteri- or to adipose-fin base. Eyes relatively large, positioned closer to posterior tip of compound pterotic than to tip of snout. Ventral margin of orbit located on ventral surface of head. Dorsal interorbital distance / ventral interorbital distance ratio changing from, 1 to. 1 during ontogeny. Total plates in lateral medial series 21 – 22 (22). Dorsal series plates 19; middorsal series plates 4; midventral series plates 12 – 14 (13), three plates anterior to first ventral series plate; ventral series plates 19. Second plate of midventral series contacting two plates of medial series. Abdomen covered by paired series of lateral sickle-shaped plates, with unequal number of plates between left and right sides, 4 – 8 each; anterior azygous plate usually present; medial abdominal plates, if present, not forming well-defined series. Single anal plate present. Thoracic plates present, 2 – 6 (4). Preopercular canal in preopercle present, semicircular; anteriormost pore opening between ventral canal-bearing plate and fourth infraorbital; framed by notch at posterolateral margin of canal-bearing plate and ventral margin of fourth infraorbital. Small odontodes evenly distributed on head. Odontodes along anterior snout margin not arranged in well-defined series, without odontode-free discontinuity between ventrad and dorsad odontodes. Odontodes along dorsal snout margin small, slightly larger than those on dorsal surface of head. Lamina of trunk plates with odontodes arranged in longitudinal rows, becoming progressively smoother ontogenetically; marginal odontodes present in mature adults. Patch of odontodes on anterolateral surface of cleithrum, at opening to branchial chamber, visible upon retraction of branchiostegal membrane. Odontode patch variably developed, from few odontodes to elevated patch of closely arranged odontodes; expression of patch often bilaterally variable. Total vertebrae 26. Premaxillary teeth 18 – 23 (21); dentary teeth 17 – 20 (18). Maxillary barbels short, extended slightly beyond anterior margin of ventral canal-bearing plate in adults. Dorsal-fin origin located slightly posterior to vertical through pelvic-fin origin. Depressed pectoral fin reaching to anus; pectoral-fin spine with serrae along posterior margin, individual serrae oriented orthogonal to spine shaft. Extension of serrae along pectoral spine margin reduced ontogenetically from proximal two-thirds in smaller specimens to middle third in larger specimens. Pectoral fin reaching to vertical through midpoint between pelvic-fin tip and anal-fin origin. Pelvic fin short with unbranched and first branched rays equal in length. Depressed fin reaching beyond anus, not reaching to anal-fin origin. Caudal-fin margin concave to forked; upper and lower lobes equal. Adipose fin present or absent; when present, composed of bony spine shaft and membrane; when absent, small platelike scar visible. COLOR IN ALCOHOL: Ground color tan and pale ochre. Melanophores light to dark brown on trunk; melanophores on head and trunk varying from uniformerly distributed to clustered in beanlike spots; melanophores slightly more concentrated along narrow area between compound pterotic, cleithral process, and anterior margin of opercle, at base of dorsal and pectoral fins, and on anterior surface of lip. Deep-lying melanophores arranged in series of blotches posterior to dorsal-fin base. Midlateral stripe situated mostly along medial plates series. Ventral surface of body mostly unpigmented except for scattered melanophores on posterior portion of trunk, anterolateral margin of cleithra, cleithral process, canal-bearing plates, and lateral portions of lateral abdominal series. Paired, dorsal and anal fins with dark brown bands. Dorsal fin with dark triangular spot extended over base of anterior 3 – 4 branched rays. Series of lanceolate plates at caudal-fin base darkened by black melanophores. Basal triangular spot on caudal fin variably present, typically absent. Caudal fin pigmentation pattern typically composed of three broad bands, with distal tip of lobes light brown. Juveniles up to around 60 mm SL with slightly different caudal-fin pigmentation, having a small triangular spot at base of lower lobe, followed by darker broad bar and darker tips of dorsal and ventral lobes. SEXUAL DIMORPHISM: Male urogenital papilla well developed, pointed, joined at base to anterior flaplike anus. Males with patch of tightly arranged small odontodes oriented as a swirl, variably covering first to fourth plates of ventral series, lateral to urogenital papilla. Female anus tubular, without separate urogenital papilla. In females, size and arrangement of odontodes on plates lateral to anus similar to adjacent plates, without distinct patch of differentially arranged odontodes. COMPARISONS: The overall pattern of morphometric variation between Hypoptopoma incognitum and H. elongatum is summarized by the results of a sheared principal component analysis on 20 morphometric characters (fig. 38; table 14). The second and third components represent 35.1 % and 1.6 % of the variation of the morphometric data, respectively; the separation between species is complete along PC 2. The analysis shows that the morphometric variance is expressed mostly by variables related to the elongation of the body (trunk and caudal peduncle length, caudal-peduncle depth, and snout length).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFD8F57BFD0992705C8A687A.taxon	distribution	DISTRIBUTION: Broadest distribution among species of Hypoptopoma across the central and lower Rio Amazonas basin. It is found in the Rio Tocantins basin and is the only species known for northeastern coastal rivers (fig. 39).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFD8F57BFD0992705C8A687A.taxon	etymology	ETYMOLOGY: The specific epithet incognitum (Lt. incognitus, meaning ‘‘ unknown, strange’ ’) is a reference to the fact that speci- mens of the species have long been misidentified with other species of Hypoptopoma.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFCFF568FCCF95FD5A6B6CB1.taxon	description	Eschmeyer and Ferraris, 1998: 691 (catalog of fishes). — Bistoni et al., 1992: 108 (Argentina: occurrence in Río Dulce, Córdoba; misidentification). — Isbrücker, 2002: 28 (list of loricariid species). — Schaefer, 2003: 323 (list of hypoptopomatine species). — Bogotá-Gregory and Maldonado-Ocampo, 2006: 76 (list of fishes of the Amazon basin in Colombia). — Ferraris, 2007: 250 (list of catfish species).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFCFF568FCCF95FD5A6B6CB1.taxon	materials_examined	HOLOTYPE: ANSP 21477, 81.9 mm SL, ³, Peru: Loreto, Peruvian Amazonia, Río Marañón; collected by J. Orton, 1877. OTHER MATERIAL EXAMINED: PERU, Amazonas: LACM 36333 - 3 (1 ♀ + 1 ³, 55.1 – 63.1 mm SL) Quebrada Caterpiza. Loreto: CAS 77138 (1 ♀, 76.7 mm SL) Ucayali, Lago Cashiboya, a cutoff lake of Río Ucayali above Contamana; CAS 77139 (1 ♀, 56.2 mm SL) Río Pacaya, at the mouth, Bretaña; FMNH 92883 (1 ♀, 78.3 mm SL) Yanamono creek and the small tributary behind Travelrama lodge; FMNH 92884 (1 ♀, 66.1 mm SL) swampy area in the interior of small island in the Río Amazonas; FMNH 108759 (19 ♀ + 10 ³, 58.9 – 80.9 mm SL) Río Marañón dr., Caño Abico, tributary to Río Samiría, ca. 6 – 7 km from mouth in Río Marañón; FMNH 108760 (1 ♀, 33.6 mm SL) Río Marañón dr., Punto Caño ca. 7 km above mouth of Río Chambira in Río Marañón; INHS 40008 (1 ♀, 70.4 mm SL) Río Amazonas dr., Río Orosa, Caño Zapatilla, ca. 10 min. upstream by boat from Río Orosa, 76.4 mi E Iquitos; INHS 40216 (5 ³, 75.7 – 87.0 mm SL) Río Itaya dr., Quebrada Mazama, ca. 1 km upstream from confluence with Río Itaya, S of Belem (Iquitos); INHS 44124 (2 ♀, 52.2 – 58.5 mm SL) Río Amazonas dr., Río Napo and Quebrada Mazán, 33.3 km NE Iquitos; INHS 52027 (1 ♀, 53.1 mm SL) Río Amazonas dr., Río Itaya, Moena caño near confluence with Ullpa caño and lower Ullpa caño, SE of Iquitos; INHS 53742 (2 ♀ + 1 ³, 71.6 – 88.1 mm SL) Río Amazonas dr., Río Pampa Chica, 4.5 km W center of Iquitos; INHS 53845 (2 ♀ + 2 ³, 76.7 – 105.0 mm SL) Río Amazonas dr., Río Napo, opposite Mazán, N channel Río Napo, N of Isla Milagro; INHS 101387 (63 ♀ + 47 ³, 46.8 – 88.4 mm SL) Río Amazonas dr., Río Yamashi, Yamashi, 69.8 mi. E Iquitos; INHS 101390 (2 ³, 68.5 – 81.0 mm SL) Río Amazonas dr., Río Orosa, mouth of Tonche Caño, Madre Selva II field station, 69.4 mi E Iquitos; MHNG 2390.25 (1 ♀, 44.5 mm SL) Río Ucayali, San Antonio; MUSM 2673 (12 ♀ + 2 ³, 63.9 – 79.8 mm SL) Maynas, Iquitos, Cocha Aguajal; MUSM 7298 (1 ♀, 37.4 mm SL) Alto Amazonas, Río Pastaza, Lago Rimachi, Quebrada Chapuli; MZUSP 15308 (1 ♀, 86.2 mm SL) Río Corrientes; MZUSP 36206 (1 ³, 43.2 mm SL) Río Ucayali; MZUSP 36208 (1 ♀, 43.0 mm SL) Río Ucayali, Sgto. Lores; SIUC 28113 (1 ♀, 39.0 mm SL) Río Napo, confluence with Río Mazán, ca. 2 – 3 km N town of Mazán; SU 33272 (1 ³, 42.6 mm SL) Río Ampiyacu; NRM 17988 (2 ♀, 31.5 – 78.4 mm SL) Río Napo dr., Cayapoza, small laguna on left bank island; NRM 47513 (3 ♀, 45.7 – 48.7 mm SL) Río Samiria dr., caño Atún; NRM 57231 (13 ♀ + 4 ³, 2 cs, 59.6 – 85.5 mm SL) Río Tahuayo dr., Caño Huayti; SIUC 26798 (1 ♀ + 1 ³, 57.6 – 82.1 mm SL) Prov. Fernando Lores, Lago Aguajal, Lucero Pata (between Iquitos and Nauta); SIUC 29198 (2 ³, 85.1 – 88.8 mm SL) Prov. Maynas, Río Itaya, upriver of Belén, approx. 4.5 km; SIUC 29363 (1 ♀, 51.5 mm SL) Río Napo, Mazán, 33.3 km from center of Iquitos; SIUC 29422 (2 ♀, 60.1 – 71.9 mm SL) Itaya dr., Ushpa caño, ca. 100 yrs. uptream from confluence with caño Moena; SIUC 29646 (1 ♀, 71.3 mm SL) Río Nanay, Pampachica beach, 4.5 km from Iquitos center; SIUC 29664 (1 ³, 76.9 mm SL) Río Napo, backwater playa behind Isla Milagro, 1.03 km from Mazán; SIUC 30062 (1 ♀, 60.2 mm SL) Prov. Maynas, Río Itaya and Quebrada Mazán, 11 km from Iquitos center; SIUC 67364 (2 ♀, 40.3 – 59.4 mm SL) Río Napo, confluence with Río Mazán, ca. 2 – 3 km N (town of) Mazán; SU 34253 (1 ♀, 89.6 mm SL) Río Ampiyacu near Pebas. Ucayali: FMNH 42963 (2 ♀, 63.5 – 77.9 mm SL) Yarinacocha, Río Ucayali dr., Pucallpa. MHNG 2618.88 (2 ♀, 60.2 – 72.6 mm SL) Pucallpa, Tapistica Alejandria; MHNG 2389 – 60 (1 ♀ + 1 ³, 74.1 – 76.5 mm SL) Pucallpa, Río Ucayali, Romainecocha; MHNG 2389 - 62 (3 ♀, 56.6 – 72.9 mm SL) Pucallpa, Río Ucayali, Yarinacocha; MHNG 2618.86 (1 ♀, 70.0 mm SL) Pucallpa, San Antonio, Río Ucayali; MHNG 2618.87 (2 ♀, 68.8 – 76.0 mm SL) Pucallpa, Bagazán, Río Ucayali; MUSM 1845 (10 ♀ + 2 ³, 57.28 – 77.10 mm SL) Pucallpa, Coronel Portillo, Tapistica Alejandria; MUSM 4183 (7 ♀ + 1 ³, 55.7 – 80.0 mm SL) Pucallpa, Coronel Portillo, Río Ucayali, Cocha Tacshitea; MZUSP 36195 (21 ♀ + 3 ³, 55.2 – 77.4 mm SL) Pucallpa, Río Ucayali; MZUSP 36196 (2 ♀, 52.9 – 61.0 mm SL) Pucallpa, Río Ucayali; MZUSP 36199 (4 ♀ + 8 ³, 58.0 – 76.9 mm SL) Pucallpa, Cocha Romaine, Río Ucayali; MZUSP 36200 (1 ³, 70.7 mm SL) Pucallpa, Laguna Yarinacocha; MZUSP 36201 (1 ³, 69.4 mm SL) Laguna Yarinacocha, Río Ucayali, close to Pucallpa; MZUSP 36202 (1 unsexed, 55.1 mm SL) Pucallpa, Río Ucayali; MZUSP 36207 (1 ♀, 42.03 mm SL) Laguna Yarinacocha, Río Ucayali; MZUSP 36229 (2 ♀, 54.5 – 59.6 mm SL) Utuquinia, Río Ucayali; USNM 284866 (10 ♀, 48.9 – 60.8 mm SL) Coronel Portillo, Yarinacocha, side caño. BRAZIL, Acre: MZUSP 50368 (1 ♀, 70.0 mm SL) Lago do Breu, Ponto 7, Rio Jurúa. Amazonas: INPA 2420 (17 ♀ + 9 ³, 62.2 – 85.6 mm SL) Paraná Jaraná, Río Japurá; INPA 2489 (1 ♀, 78.8 mm SL) Lago do Reis; MNHN A- 1966 (73.7 mm SL) (holotype of Otocinclus joberti Vaillant 1880) Calderon; MZUSP 36209 (6 ♀ + 6 ³, 55.1 – 72.9 mm SL) Lago Supiá, in front of Codajás. COLOMBIA, Amazonas: NRM 16561 (1 ♀ + 2 ³, 77.9 – 82.5 mm SL) Leticia, lagos de Leticia.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFCFF568FCCF95FD5A6B6CB1.taxon	diagnosis	DIAGNOSIS: Hypoptopoma gulare is distinguished from all congeners, with the exception of H. machadoi, by the presence of a single paranasal plate separating the lateral process of the lateral ethmoid from the second infraorbital and the nasal organ (fig. 7 B). In contrast, in all other species of Hypoptopoma, except H. steindachneri, the paranasal plates are absent and the lateral process of the lateral ethmoid contacts the second infraorbital (fig. 7 A). In H. steindachneri, there are two or more paranasal plates. Hypoptopoma gulare is distinguished from H. machadoi by a slender caudal peduncle (caudal-peduncle depth 7.2 – 9.1 (8.3) vs. 9.0 – 12.0 (10.3); t (16.298), p, 0.001); by fewer premaxillary (12 – 16 (14) vs. 16 – 25 (20); t (12,675), p, 0.001) and dentary teeth (10 – 14 (12) vs. 14 – 21 (17); t (12,068), p, 0.001); by lanceolate plates at the base of the caudal fin with dark spot, asymmetrically shaped and slightly more extended over lower-lobe branched rays, followed by two V-shaped bars pointing forward, with the anterior bar variably developed on the upper lobe but always connected at its angle with the basal spot (vs. the lanceolate plates at the base of the caudal fin with a light brown spot, symmetrically shaped and shortly extended over the branched rays, typically followed by three vertical bands variably defined, with the anterior band not continuous in the middle with the basal spot); by dorsal fin with dark brown, roughly triangular spot extended over base of anterior 3 – 4 branched rays, followed typically by 2 – 3 bars (vs. dorsal fin without triangular spot at base; dorsal fin typically with 4 – 7 bars).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFCFF568FCCF95FD5A6B6CB1.taxon	description	DESCRIPTION: Morphometric and meristic data presented in table 16. Body robust; greatest body depth at dorsal-fin origin. Dorsal profile of head and body straight from tip of snout to dorsal-fin origin, slightly angled dorsally at posterior tip of supraoccipital; straight from dorsal-fin origin to anteriormost procurrent caudal-fin ray. Ventral profile straight from tip of snout to anteriormost procurrent caudal-fin ray. Head moderately depressed, almost as wide as cleithral width; lateral process of lateral ethmoid visible dorsally. Snout rounded to slightly acute in dorsal view; slightly concave dorsally anterior to naris. Posterior surface of bony pit of nasal organ sharply inclined. Trunk cross section between pectoral- and pelvic-fin origins slightly triangular, ovoid to progressively rounded posterior to dorsal fin, progressively compressed posterior to adipose-fin base. Eyes relatively large, positioned closer to posterior tip of compound pterotic than to tip of snout. Ventral margin of orbit located on ventral surface of head. Dorsal interorbital distance / ventral interorbital distance ratio changing from, 1 to. 1 during ontogeny. Total plates in medial series 22 – 23 (22). Dorsal series plates 19 – 20 (19); middorsal series plates 4; midventral series plates 12 – 13 (13), three plates anterior to first ventral series plate; ventral series plates 19 – 20 (19). Second plate of midventral series contacting two plates of medial series. Abdomen covered by paired series of lateral sickle-shaped plates, with unequal number of plates between left and right sides, 4 – 8 each; anterior azygous plate usually present; medial abdominal plates, if present (22 % of 132 individuals examined), not forming well-defined series. Single anal plate present. Thoracic plates present, 2 – 6. Preopercular canal present and semicircular; anteriormost pore opening between ventral canal-bearing plate and fourth infraorbital; posterolateral margin of canal-bearing plate and lateral margin of fourth infraorbital smooth, framed by notch at posterolateral margin of canal-bearing plate and ventral margin of fourth infraorbital. Small odontodes evenly distributed on head. Odontodes along snout margin not arranged in well-defined series, without odontode-free discontinuity between ventrad and dorsad odontodes. Odontodes on dorsal snout margin small, slightly larger than those on dorsal surface of head. Lamina of trunk plates with odontodes arranged in longitudinal rows, becoming progressively smoother ontogenetically; marginal odontodes present in mature adults. Total vertebrae 26. Premaxillary teeth 12 – 16 (10); dentary teeth 10 – 14 (10). Maxillary barbels short, reaching slightly beyond anterior margin of canal-bearing plate in adults. Dorsal-fin origin located slightly posterior to vertical through pelvic-fin origin. De- pressed dorsal fin reaching to vertical through midpoint of anal-fin base. Pectoral fin reaching to vertical through midpoint between pelvic-fin tip and anal-fin origin. Pectoral spine serrae present, oriented orthogonal to spine shaft. Extension of serrae along pectoral spine margin reduced ontogenetically from proximal two-thirds in smaller specimens to middle third in larger specimens. Pelvic fin short, unbranched and first branched rays of equal length. Depressed fin reaching anus, not reaching anal-fin origin. Caudal-fin margin concave to forked; upper and lower lobes equal. Adipose fin present. COLOR IN ALCOHOL: Ground color tan and pale ochre. Melanophores light to dark brown on trunk and particularly clustered at base of plates, resulting in mottled appearance; melanophores on head more uniformly distributed; melanophores slightly more concentrated along narrow area among compound pterotic, cleithral process, and opercle, at base of dorsal and pectoral fins, and on anterior surface of lip. Deep-lying melanophores arranged in series of blotches posterior of dorsal-fin base. Midlateral stripe situated mostly along medial series of trunk plates. Ventral surface of body mostly unpigmented except for scattered melanophores on posterior portion of trunk, anterolateral margin of cleithra and posterior tip of cleithral processes, ventral canal-bearing plates, and lateral portions of lateral abdominal series. Paired dorsal and anal fins with dark brown bars, roughly orthogonal to rays. Dorsal fin with dark brown, roughly triangular spot extended over base of anterior 3 – 4 branched rays. Series of lanceolate plates at base of caudal fin darkened by black melanophores. Basal triangular dark spot over caudal-fin lower lobe determined by lower-lobe arm of most anterior V-shaped bar variably merging with spot at lanceolate plates. Upper-lobe arm of same bar light brown to absent, clearly separated from spot at lanceolate plates. One or two following, nearly complete V-shaped bars pointing forward and 1 – 3 incomplete bars along posterior half of upper and lower lobes; tip of branched rays usually light (fig. 17 D). SEXUAL DIMORPHISM: Males with urogenital papilla well developed, pointed; joined at base to anterior flaplike anus. Males with patch of tightly arranged small odontodes oriented as a swirl, variably covering from first to fourth plates of ventral series, lateral to urogenital papilla and narrow band along posterior border of anal plate. Female anus tubular, without separate urogenital papilla. In females, size and arrangement of odontodes on plates lateral to anus similar to adjacent plates, without distinct patch of differentially arranged odontodes.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFCFF568FCCF95FD5A6B6CB1.taxon	distribution	DISTRIBUTION: Upper Amazon River in Brazil; lower and upper Río Ucayali (fig. 39). TAXONOMIC REMARKS: Cope (1878) described Hypoptopoma gulare based on a single specimen collected in 1877 near Pebas by Orton. Cope compared the new species with H. bilobatum Cope (1870) and distinguished H. gulare by having a more robust body, a lower number of lateral plates, presence of thoracic plates, and the absence of a medial series of abdominal plates. Vaillant (1880) described the new species Otocinclus joberti based on the examination of a single specimen collected by Jobert in Calderón (Rio Amazonas, Manaus region). The genus Otocinclus had been established by Cope (1871) (for a historical review, see Schaefer, 1997). Vaillant failed to recognize the similarity between his specimen and previously described Hypoptopoma species (H. thoracatum in 1868, H. bilobatum in 1870, and H. gulare in 1878). Berg (1898) properly reassigned Vaillant’s species to the genus Hypoptopoma. Gosline (1945) proposed H. joberti as a junior synonym of H. gulare, an opinion shared by Fowler (1954); however, neither of these authors provided argumentation for that nomenclatural act. Our examination of the type specimens and additional comparative material confirm the synonymy of H. joberti and H. gulare.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFC5F56DFF6594BE5C5B6F0F.taxon	materials_examined	HOLOTYPE: MBUCV V- 35362 (♀, 46.2 mm SL) Venezuela: San Fernando de Apure, swamps on south bank of Río Apure, ca. 3 km west of Fisheries Station; collected by Apure Fisheries Station technicians, 21 January 1983. PARATYPES: AMNH 77794, 23 females, 42.1 – 53.7 mm SL (collected with holotype).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFC5F56DFF6594BE5C5B6F0F.taxon	description	OTHER MATERIAL EXAMINED: COLOM- BIA, Meta: ANSP 128569 (1 ³, 48.3 mm SL) Hacienda Mozambique, N. shore at main house; ANSP 128955 (9 ♀ + 3 ³, 45.8 – 61.7 mm SL) Río Negro, just downstream from where it passes under the main Villavicencio, Puerto López highway at La Balsa (W side of river); ANSP 128956 (6 ♀ + 3 ³, 50.4 – 69.3 mm SL) Río Negrito midway between La Argelia and La Balsa (Plancha 267 – Río Guayuriba); ANSP 128960 (16 ♀ + 2 ³, 47.5 – 66.5 mm SL) Río Negro, just downstream from where it passes under the main Villavicencio, Puerto López highway at La Balsa; ANSP 131666 (5 ♀ + 1 ³, 45.6 – 61.9 mm SL) Río Negrito downstream bridge at La Balsa; ANSP 134438 (18 ♀ + 3 ³, 2 cs, 39.8 – 53.2 mm SL) tributary caño La Raya (first caño N de La Siberia); ANSP 139463 (3 juveniles, 25.5 – 31.0 mm SL) canal y laguna Aerotas, S. side of Río Metica, entrance on Metica, ca. 2 km. SW (upstream) of entrance to Lake Mozambique; FMNH 84005 (1 ³ + 2 juveniles, 24.3 – 51.3 mm SL) Caño Venturosa, at 1 km N Puerto López. VENEZUELA, Amazonas: MCNG 6306 (4 ♀, 43.7 – 59.7 mm SL). Anzoátegui: ANSP 166734 (2 ♀, 54.9 – 57.8 mm SL) Río Orinoco basin, Soledad, L. Terecaya. Apure: ANSP 130028 (1 ♀, 41.7 mm SL) Camaguán swamp, on W side of Hwy to San Fernando de Apure, about 2 km N of Camaguán; ANSP 130040 (12 ♀, 1 cs; 38.2 – 50.5 mm SL) S bank and backwater areas pm downstream side of bridge at San Fernando de Apure; ANSP 165843 (4 ♀ + 3 ³, 53.6 – 69.0 mm SL) Río Cunaviche, ca. 20 km SW of Cunaviche on San Fernando de Apure – Puerto Paez Hwy; ANSP 165844 (1 ♀, 38.8 mm SL) Río Matiyure, at Achaguas; ANSP 166433 (2 ♀, 31.4 – 44.9 mm SL) Caño Caicara, 10 – 12 km W of Montecal; CAS 64271 (3 ♀, 44.0 – 58.1 mm SL) pool just S of Bruzual alongside dyke that parallels highway behind bull run; CAS 64283 (59 ♀ + 4 ³, 35.6 – 62.2 mm SL) Caño first creek S of Bruzual at red steel bridge; FMNH 85814 (35 ♀ + 3 ³, 33.9 – 53.4 mm SL) River 24 km S Biruaca on road to San Juan de Apayara; FMNH 85826 (10 ♀ + 1 ³, 31.2 – 47.2 mm SL) Río Aruaca, 32.5 Km S Biruaca; INHS 29809 (13 ♀, 40.7 – 53.2 mm SL) tributary caño Setento, 10 km. S Bruzual; INHS 30098 (34 ♀, 27.9 – 45.4 mm SL) Caño Guaritico (5 caño Maporal) (Río Apure drainage), 58 km SSW Bruzual; MCNG 6104 (7 ♀, 37.1 – 44.3 mm SL); MCNG 9369 (8 ♀ + 4 ³, 42.5 – 49.3 mm SL); MZUSP 27973 (51 ♀, 32.3 – 51.0 mm SL) caño 1 km ao sul passagem de balsa, na altura da estrada de San Fernando de Apure; USNM 257971 (2 ♀, 43.3 – 44.2 mm SL) Río Apure West of town center; USNM 257972 (68 ♀ + 1 ³, 35.1 – 49.7 mm SL) Caño Caicará, where crossed by bridge on road from Montecal; USNM 257975 (2 ♀, 46.8 – 50.6 mm SL) Río Apure ca. 2 km East of bridge at San Fernando de Apure; USNM 260193 (52 ♀ + 2 ³, 32.7 – 66.1 mm SL) side channel of Río Apure ca. 5 km West of San Fernando de Apure. Barinas: FMNH 105985 (2 ♀, 36.7 – 42.9 mm SL) Río Suripa ca. 10 min. by boat above confluence with Río Carapo; FMNH 105986 (1 ♀, 62.5 mm SL) Río Anaro ca. 10 min. from mouth in Río Suripa, small island and collected small arms of river; FMNH 105987 (27 ♀ + 4 juveniles, 30.7 – 49.2 mm SL) Caño La Indiecita near mouth TABLE 17 Morphometric and Meristic Data for Hypoptopoma machadoi Holotype: MBUCV V- 35362. Paratype: AMMH 77794. Nontypes: ANSP 165843; CAS 64283; FMNH 85814, 85826; LACM 43204 - 4; MCNG 9369. in Río Suripa ca. 35 min. up river from boat launch in Hato Mercedes; FMNH 105988 (3 ♀, 42.7 – 48.1 mm SL) Caño Socopo ca. 3.5 hours upstream from boat launch of Hato Mercedes in Río Suripa.; FMNH 108762 (1 ♀, 48.3 mm SL) Río Orinoco drainage, Caño Caigua ca. 20 min. by boat from boat launch at Hato Las Mercedes; INHS 28696 (20 ♀, 47.1 – 56.0 mm SL) Río Santo Domingo (Río Apure drainage) in Torunos, hacienda La Isla; MCNG 21329 (7 ♀, 42.2 – 53.3 mm SL); MCNG 26277 (6 ♀ + 1 ³, 41.9 – 55.9 mm SL). Bolívar: ANSP 135631 (11 ♀ + 7 ³, 42.1 – 63.1 mm SL) Caño Chuapo ca. 20 min. downstream from Jabillal (opposite bank) on Río Caura; ANSP 135678 (20 ♀ + 1 ³, 36.8 – 57.1 mm SL) mouth of caño Chuapo ca. 20 min. downstream from Javillal (opposite bank) on Río Caura; ANSP 139521 (1 ♀, 39.9 mm SL) Quebrada Cuchivero (Cuchiverito), tributary of Río Mato (right bank); ANSP 139620 (12 ♀ + 1 ³, 40.0 – 61.2 mm SL) Sandbar along Río Mato; ANSP 160863 (1 ♀, 42.2 mm SL) Río Cuchivero at Cuchivero ferry crossing; FMNH 97050 (1 ♀, 40.8 mm SL) Río Orinoco, cove West end of islote Fejardo, 182 naut. mi. upstream from sea buoy; FMNH 108767 (1 ♀, 43.4 mm SL) Río Orinoco basin, S bank of Río Orinoco at mouth of Río Orocopiche, in mouth and along Orinoco; FMNH 108768 (4 ♀, 38.2 – 55.0 m SL) Río Orinoco basin, Río Orinoco just above bridge at Ciudad Bolívar; MCNG 6658 (3 ♀ + 1 ³, 47.4 – 70.8 mm SL); SU 48664 (9 ♀ + 1 ³, 40.6 – 48.9 mm SL) Río Orinoco at Caicará; USNM 265696 (1 ♀, 41.5 mm SL) Río Orinoco, Cove, Islote de Fajardo, 182 naut. mi. upstream from sea buoy; USNM 265963 (1 ♀, 47.6 mm SL) small caño connecting with Río Orinoco immediately South of El Burro. Cojedes: MCNG 13770 (1 ♀ + 6 juveniles, 20.6 – 45.0 mm SL). Delta Amacuro: AMNH 47955 (6 ♀, 38.6 – 48.0 mm SL) lagoon at caño Araguaíto, ca. Km 130, Río Orinoco; ANSP 152860 (9 ♀, 1 cs, 36.7 – 47.1 mm SL) ca. Km. 65, small caño near mouth of caño Fiscal, Río Orinoco; FMNH 97051 (1 ♀, 36.3 mm SL) backwater caño Araguao, 112 naut. mi. upstream from sea buoy; FMNH 97052 (4 ♀, 44.4 – 49.7 mm SL) Río Orinoco, cave on sand bar near E end of Isla Portuguesa, 117 naut. mi. upstream from sea buoy; FMNH 97066 (14 ♀, 37.9 – 53.5 mm SL) Río Orinoco, first small caño on W side of caño Paloma 100 m above its mouth, 92 naut. mi. upstream from sea buoy; FMNH 108765 (1 ♀, 43.4 mm SL) Río Orinoco at plays on North side; FMNH 108766 (2 ♀, 44.7 – 48.3 mm SL) Río Santa Clara at first tributary on East side ca. 0.5 hour above mouth; LACM 43016 - 2 (1 ♀, 48.2 mm SL) N bank – beach across from Los Castillos; 160 NM upstream from sea buoy; LACM 43151 - 16 (69 ♀ + 1 ³, 32.9 – 54.1 mm SL) Río Orinoco, inlet; 82 NM upstream from sea buoy; LACM 43204 - 4 (30 ♀ + 3 ³, 35.2 – 66.8 mm SL) Río Orinoco, shallow lagoon on N side of river, W of caño Araguarito; LACM 43297 - 2 (15 ♀ + 1 juvenile, 25.3 – 46.5 mm SL) Teda, caño Paloma system; USNM 265682 (1 ♀, 44.3 mm SL) Río Orinoco, first small caño on W side of caño Paloma 100 m above its mouth, 92 naut. mi. upstream of sea buoy; USNM 265708 (5 ♀, 38.3 – 50.6 mm SL) Río Orinoco, small caño near mouth of caño Socoroco, 111 naut. mi. upstream from sea buoy. Guárico: ANSP 166732 (19 ♀, 38.9 – 48.8 mm SL) Río Orinoco basin, Cabruta, Laguna Larga II; ANSP 166733 (1 ♀ + 1 ³, 37.4 – 62.7 mm SL) Río Orinoco basin, Cabruta, Laguna Larga II; FMNH 85807 (1 ♀, 39.9 mm SL) pond by river at 8 km E of Camaguán on road to Uvenito; INHS 62063 (43 ♀, 33.9 – 47.1 mm SL) caño (Río Guariquito – Río Orinoco drainage) 100 air km E San Fernando; MCNG 15072 (10 ♀, 37.8 – 48.7 mm SL); USNM 257969 (7 ♀, 32.8 – 43.4 mm SL) Caño Falcon ca. 5 km north of RPV 83 - 4; Río Portuguesa drainage basin; USNM 257973 (16 ♀, 36.2 – 48.3 mm SL) Caño to West of highway from Calabozo to San Fernando about 35 km South of Fundo Masaguaral, Caño Falcon; USNM 257976 (1 ♀, 45.6 mm SL) Río Guárico at Flores, Moradas ranch ca. 3 – 4 km East of road from Calabozo to San Fernando. Monagas: CAS 58157 (5 ♀, 47.0 – 54.8 mm SL) Río Orinoco, small caño 0.75 miles upstream from mouth of caño Guarguapo, near Barrancas; LACM 43382 - 29 (7 ♀, 43.0 – 54.9 mm SL) Río Orinoco, secondary caño about 500 m from its mouth in caño Guarguapo; LACM 43423 - 4 (31 ♀ + 1 ³, 35.1 – 50.7 mm SL) Río Orinoco, S shore of Isla Noina, 51 – 52 NM from sea buoy; USNM 163172 (1 ♀, 53.0 mm SL) Caicará, Río Guarapiche; USNM 265718 (17 ♀, 3 cs, 36.3 – 48.3 mm SL) Río Orinoco, 161 naut. mi. upstream from sea buoy, laguna Tapatapa on Isla Tapatapa near downstream end of caño de Limón. Portuguesa: MCNG 1179 (4 ♀ + 3 ³, 39.0 – 55.5 mm SL); TNHC 12513 (6, 43.6 – 53.3 mm SL) Caño Maraca at Urriolas ranch, 35 km SE Guanare´; TNHC 12766 (10 ♀, 35.6 – 39.8 mm SL) Caño Maraca at Urriolas ranch, 35 km SE Guanare´; USNM 348681 (12 ♀, 38.2 – 57.8 mm SL) Guanaré-Guanarito, road at road km 60; caño Igues – Río Portuguesa (Caño Maraca).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFC5F56DFF6594BE5C5B6F0F.taxon	diagnosis	DIAGNOSIS: Hypoptopoma machadoi is distinguished from all congeners, with the exception of H. gulare, by the presence of a single paranasal plate separating the lateral process of the lateral ethmoid from the second infraorbital and the nasal organ (fig. 7 B). In contrast, in all other species of Hypoptopoma, except H. steindachneri, the paranasal plates are absent and the lateral process of the lateral ethmoid contacts the second infraorbital (fig. 7 A). In H. steindachneri, there are two or more paranasal plates (fig. 7 C). Hypoptopoma machadoi is distinguished from H. gulare by its deeper caudal peduncle (caudal-peduncle depth 9.0 – 12.0 (10.2) vs. 7.2 – 9.1 (8.7); t (16.298), p, 0.001); by its greater number of premaxillary (16 – 25 (20) vs. 12 – 16 (14); t (16.298), p, 0.001) and dentary teeth (14 – 21 (17) vs. 10 – 14 (12); t, p, 0.001); by having lanceolate plates at caudal-fin base with light brown spot, symmetrically shaped, shortly extended over branched rays; spot followed by three vertical bands variably defined, with anterior band not continuous along midline with the basal spot (vs. lanceolate plates at caudal-fin base with dark spot, asymmetrically shaped, slightly more extended over lower-lobe branched rays; this spot is followed by two V-shaped bars, anterior bar variably developed on the upper lobe but always connected with basal spot) (fig. 17 B); and by having the dorsal fin with typically three bars, without triangular spot at base (vs. dorsal fin with roughly triangular dark brown spot extended over base of anterior 3 – 4 branched rays, followed typically by 3 – 4 bars) (fig. 17 G).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFC5F56DFF6594BE5C5B6F0F.taxon	description	Hypoptopoma machadoi is distinguished from H. steindachneri by having a single paranasal plate (vs. presence of two or more paranasal plates) (fig. 7 B – C), second infraorbital in contact with nasal and pararostral plates (vs. second infraorbital entirely separated from nasal and pararostral plates), and ventral canal-bearing plate undivided (vs. canal-bearing plate typically subdivided) (fig. 5 A – B). DESCRIPTION: Morphometric and meristic data presented in table 17. Body robust; greatest body depth at dorsal-fin origin. Dorsal profile of head and body straight from tip of snout to dorsal-fin origin, slightly angled dorsally at posterior tip of supraoccipital; straight from dorsal-fin origin to anteriormost procurrent caudal-fin ray. Head moderately depressed, almost as wide as cleithral width; lateral process of lateral ethmoid bone visible dorsally. Snout rounded in dorsal view; dorsally, slightly concave anterior to naris. Posterior surface of bony pit of nasal organ sharply inclined. Trunk cross section between pectoral-fin and pelvicfin origins slightly triangular, ovoid to progressively rounded posterior to dorsal fin, progressively compressed posterior to adipose-fin base. Eyes relatively large, positioned closer to posterior tip of compound pterotic than to tip of snout. Ventral margin of orbit located on ventral surface of head. Dorsal interorbital distance / ventral interorbital distance ratio changing from, 1 to. 1 during ontogeny. (12,068) Total plates in lateral medial series typically 21 – 22 (22). Dorsal series plates 18 – 19 (19); middorsal series plates 3 – 4 (4); midventral series plates 12 – 13 (13), three plates anterior to first ventral series plate; ventral series plates 18 – 19 (19). Second plate of midventral series contacting two plates of medial series. Abdomen covered by paired series of lateral sickle-shaped plates, with unequal number of plates between left and right series, 3 – 10 each; anterior azygous plate usually present; medial series of plates, if present (47 % of 316 individuals examined), not forming well-defined series. Single anal plate present. Thoracic plates present, 2 – 6. Preopercular canal present, semicircular; anteriormost pore located between ventral canal-bearing plate and fourth infraorbital; posterolateral margin of canal-bearing plate and lateral margin of fourth infraorbital variably developed, framed by notch at posterolateral margin of canal-bearing plate and ventral margin of fourth infraorbital. Small odontodes evenly distributed on head. Odontodes along rostral margin of snout not arranged in well-defined series, without odontode-free discontinuity between ventrad and dorsad odontodes. Odontodes dorsal to tip of snout small, slightly larger than those on dorsal surface of head. Lamina of trunk plates with odontodes arranged in longitudinal rows, becoming progressively smoother ontogenetically; marginal odontodes present in mature adults. Total vertebrae 26. Premaxillary teeth 16 – 25 (20); dentary teeth 14 – 21 (17). Maxillary barbels short; in adults, slightly surpassing anterior margin of ventral canal-bearing plate. Dorsal-fin origin located slightly posterior to vertical through pelvic-fin origin. Depressed dorsal fin reaching to vertical through distal half of anal-fin base. Pectoral fin reaching to vertical through midpoint between anus and anal-fin origin. Pectoral spine with serrae along posterior margin, individual serrae oriented orthogonal to spine shaft. Extension of serrae along pectoral spine margin reduced ontogenetically from proximal two-thirds in smaller specimens to middle third in larger specimens. Depressed pelvic fin not reaching to anal-fin origin; unbranched and first branched rays of equal length. Caudal-fin margin concave; upper and lower lobes equal. Adipose fin present. COLOR IN ALCOHOL: Ground color tan and light brown. Melanophores light to dark brown, clustered on trunk and at base of plates, yielding mottled appearance. Pigmentation slightly more concentrated dorsally on head, along narrow area betweeen compound pterotic, cleithral process and opercle, at base of dorsal and pectoral fins, and on anterior surface of lip. Deep-lying melanophores arranged as series of blotches posterior to dorsal-fin base. Midlateral stripe mostly along trunk medial series of plates. Ventral surface of body mostly unpigmented except for scattered melanophores on posterior portion of trunk, anterolateral margin of cleithra and posterior tip of cleithral process, lateral border of canal-bearing plates, and lateral portions of lateral abdominal series. Paired dorsal and anal fins with dark brown bars, aligned roughly orthogonal to the rays. Basal dark spot on anterior dorsal-fin branched rays typically not developed; if present, spot poorly defined. Lanceolate plates at base of caudal fin with light brown spot, symmetrically shaped and shortly extended over branched rays, followed by typically three vertical bands variably defined, with anterior one not continuous in the middle with basal spot; tips of lobes variably pigmented (fig. 17 G). SEXUAL DIMORPHISM: Males with genital papilla small, not clearly separated from tubelike anal papilla. Males without patch (or patch poorly developed) of tightly arranged small odontodes oriented as a swirl on plates lateral to anal region. Female anus tubular, without separate urogenital papilla. In females, size and arrangement of odontodes on plates lateral to anus similar to adjacent plates, without distinct patch of differentially arranged odontodes.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFC5F56DFF6594BE5C5B6F0F.taxon	distribution	DISTRIBUTION: Known for the Rio Orinoco basin in Venezuela, including the Rio Meta drainage in Colombia (fig. 39).	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFC5F56DFF6594BE5C5B6F0F.taxon	discussion	REMARKS: Specimens collected in the Río Meta drainage and in localities along the southern tributaries of the Río Orinoco are slightly more slender and with fewer caudalfin bars than specimens that originated in localities from northern tributaries to the Río Orinoco.	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
03F9BE50FFC5F56DFF6594BE5C5B6F0F.taxon	etymology	ETYMOLOGY: The specific epithet machadoi is a patronymic honoring Antonio Machado-Allison, in recognition of his lifelong dedication and contributions to Neotropical ichthyology. PHYLOGENETIC ANALYSIS Character Descriptions and Coding	en	Aquino, Adriana E. (2010): Systematics Of The Genus Hypoptopoma Günther, 1868 (Siluriformes, Loricariidae). Bulletin of the American Museum of Natural History 2010 (336): 1-110, DOI: 10.1206/336.1, URL: http://www.bioone.org/doi/abs/10.1206/336.1
