taxonID	type	description	language	source
EC4A87C1FFA4E008FEF64AC9FC38D6A9.taxon	description	Four proposed synapomorphies that delimit Archolaemus as monophyletic were identified in our analysis. 1. A free orbital rim. As reported by several authors (e. g. Nijssen & Isbrücker, 1972: 174; Mago-Leccia, 1994: 18; Meunier et al., 2011: 48), all species of the Gymnotiformes, except for Archolaemus and Sternopygus, have the orbit covered by skin, with this surface layer attached to tissues bordering the eye. Juveniles of Archolaemus share this apparently primitive condition of an orbit covered by skin and attached to the surrounding tissues, in some species up to approximately 135 mm TL; however, larger individuals of the genus all have the orbital rim free of the surrounding orbital margin. In the context of present concepts of relationships within the Gymnotiformes, the free orbital rim of Archolaemus and Sternopygus is considered a homoplastic derived character in these two genera. 2. Form of attachment of the teeth to the premaxilla. As in all other sternopygids, the species of Archolaemus bear teeth on the premaxilla (approximately 22 – 35 teeth, depending on the species). The villiform teeth in sternopygids are typically immobile and attached to the ventral surface of the premaxilla. Conversely, in Archolaemus only the anterobasal margins of the teeth of the first tooth row are attached to the dentigerous surface of the premaxilla. As a consequence, these teeth are variably mobile relative to the premaxilla with the range of movement ranging between a few and 90 degrees: an apparent apomorphy for the members of the genus. 3. Association of the posterior margin of the upper lip and the anterior margin of the premaxilla. The anterior margin of the premaxilla lies close to and contacts, or almost contacts, the posterior margin of the upper lip from a ventral view in all species of the Sternopygidae other than for Archolaemus. In contrast, all species of Archolaemus have a pronounced gap equal to approximately one-half the width of the eye between the anterior margin of the premaxilla and the posterior margin of the upper lip (A. blax in Korringa, 1970: fig. 2 A). 4. Morphology of the upper lip. The ventral surface of the upper lip is relatively flat and unelaborated from a ventral view in most members of the Sternopygidae, as well as across the Gymnotiformes. Conversely, the ventral surface of the upper lip is porous and sponge-like with raised papillae and fleshy anteroposteriorly elongate ridges of various extents in all of the species of Archolaemus. Elsewhere within the Sternopygidae this condition was encountered only in some populations of what is now considered to be Eigenmannia trilineata. Within the context of present hypotheses of relationships within the Sternopygidae (see the discussion under character 1), the occurrence of this form of upper lip in some specimens of E. trilineata and the species of Archolaemus would be homoplastic, but with the attribute a synapomorphy for the members of Archolaemus. Two characters previously advanced as autapomorphies for what was then thought to be a monotypic Archolaemus proved not to apply across the expanse of the more species-rich genus in this study. Albert (2001: 71) proposed that a lateral ethmoid contacting four bones was an autapomorphy for A. blax. As such it potentially served as a synapomorphy for the six species of the genus we recognize herein. Our survey shows that the complex lateral ethmoid does not universally contact four bones across the genus. A posterior naris positioned closer to the tip of the snout than to the eye was hypothesized by Albert (2001: 71) to be an autapomorphy for A. blax. Comparisons reveal, however, that the posterior naris is sometimes located approximately in the middle of the snout among several of the previously undescribed species of Archolaemus recognized herein. Relationships within Archolaemus. The data indicate that A. orientalis is the sister group of a clade composed by A. blax, A. ferreirai, A. janeae, A. luciae, and A. santosi. The hypothesis of the monophyly of a clade formed by these five species is supported by three synapomorphies. 1. Presence of a narrow stripe of dark pigmentation along the lateral line. The presence of a narrow stripe of dark pigmentation extending along the lateral line is absent in A. orientalis, and is unique to these five species (see species accounts) among the examined members of the Sternopygidae, other than for also occurring in some species of Eigenmannia such as E. trilineata. What appears as a dark line of pigmentation proximate to the lateral line in A. orientalis is in fact the line of contact between the epaxial and hypaxial musculature. 2. Presence of a band of dusky to dark pigmentation overlying the basal pterygiophores of the anal fin. The presence of a broad band of dusky to distinctly dark pigmentation formed of individual vertical bars paralleling the pterygiophores, with the bars sometimes conjoining in darker specimens to form a variably continuous broad stripe, is limited to the members of this clade (see species accounts). 3. Form of posterodorsal portion of the dentary. Whereas the posterodorsal portion of the dentary is ossified in other sternopygids, this region is occupied by cartilage in these five species. Arratia (1992) made the case that given that the dentary is a dermal bone, the cartilage in the area typically occupied by the posterodorsal portion of the dentary, the ‘ cartilaginous coronoid process’ in her terminology, is at least in some catfishes more likely to be a dorsal extension of Meckel’s cartilage. Within the clade of five species supported by characters 1 – 3, the evidence supports a hypothesis of two clades, each including two species (A. blax plus A. janeae and A. ferreirai plus A. luciae). Those two clades along with A. santosi form an unresolved trichotomy. Archolaemus blax and A. janeae are hypothesized to be sister species based on their common possession of two derived characters. 4. Relative size of the posterior ceratohyal versus ventral hypohyal. In these species, the posterior ceratohyal is approximately 1.5 times the length of the ventral hypohyal versus the two bones being approximately the same size in their congeners and other sternopygids. 5. Number of tooth rows on the posterior portion of dentary. A single tooth row on the posterior portion of the dentary occurs in both of these species, whereas other congeners have two rows of teeth in this area. The remaining sternopygids with teeth present on the posterior portion of the dentary have two or more rows of teeth in that region. The remaining pair of sister species, A. ferreirai and A. luciae, share one hypothesized derived character. 6. Relative size of the coronomeckelian bone versus Meckel’s cartilage. In these two species the elongate coronomeckelian bone extends along a considerable portion of the inner surface of the lower jaw, and corresponds to 50 % or more of the length of Meckel’s cartilage. In other congeners and outgroups the more compact coronomeckelian bone is approximately 20 % or less of the length of Meckel’s cartilage.	en	Vari, Richard P., Santana, Carlos David De, Wosiacki, Wolmar B. (2012): South American electric knifefishes of the genus Archolaemus (Ostariophysi, Gymnotiformes): undetected diversity in a clade of rheophiles. Zoological Journal of the Linnean Society 165 (3): 670-699, DOI: 10.1111/j.1096-3642.2012.00827.x, URL: http://dx.doi.org/10.1111/j.1096-3642.2012.00827.x
EC4A87C1FFA2E00AFC064EABFE29D61F.taxon	description	In their multifaceted ecological and taxonomic analysis of what they considered to be populations of A. blax, Schwassmann & Carvalho (1985: 236) reported that individuals of the species took refuge during the day ‘ inside crevices and between rocks at places of high current velocities’ at localities in the Rio Xingu (Altamira and Belo Monte) and the Rio Tocantins (Rio Itacaiunas) basins. Our results demonstrate that Schwassmann & Carvalho’s life-history observations were actually of two species, A. janeae (Rio Xingu localities) and A. blax (Rio Tocantins), both of which are clearly rheophiles (those authors did not make life observation in the Rio Araguari system, the home of the third species included in their concept of A. blax). Archolaemus blax also inhabits high water flow subterranean settings within karstic formations in the São Domingos region of the upper Rio Tocantins system (Bichuette & Trajano, 2003). Ferreira, dos Santos & Jégu (1988: 345) reported swift water habitat preferences for A. ferreirai (identified as A. blax in that study) in the rapids of the Rio Mucajaí of the Rio Branco system. Ferreira (1995: 51), in turn, indicated that A. luciae (identified as A. blax in that study) is resident in swiftly moving waters within the Rio Trombetas. Observations of A. luciae in the Rio Tapajós system, A. orientalis at its type locality in the Rio São Francisco, and information on the type locality of A. santosi in the Rio Madeira basin (see Habitat in the accounts for these species) indicate that these three species similarly dwell in high-energy settings. Habitat preference information is unavailable for many of the lots examined of Archolaemus in this study, but it is noteworthy that many of these samples originated at, or proximate to, localities identified as falls (cachoeiras), attesting to the rapid water conditions in those localities. A preference for swiftly flowing waters is clearly an attribute that is general across the species of Archolaemus. Recent advances in the knowledge on the alphataxonomy, habitat preferences, and phylogenetic relationships among Neotropical electric fishes demonstrate that life in shallow waters, including swift water conditions, evolved several times independently across the Gymnotiformes (de Santana & Vari, 2009, 2010 a, b). Crampton (2011) noted that there have been multiple transitions within the Gymnotiformes from deep river habitats to life in high-energy systems, such as rapids, with no apparent reversals in habitat preferences. It is interesting that only two genera in the Gymnotiformes, Archolaemus and Megadontognathus, are composed entirely of rheophiles: species specializing in life in a high-energy aquatic environment. Megadontognathus includes only two species (Camposda-Paz, 1999), which makes Archolaemus, with six species, by far the most species-rich clade of exclusively rheophlic species in the Gymnotiformes. Rheophily, the behaviour of inhabiting high-energy aquatic environments, such as occurs in all species of Archolaemus, is a phenomenon that is widespread among freshwater fishes, albeit limited to a small subset of the total number of species in the geographically extensive ichthyofaunas encompassing such swift water specialist species (Kullander, 1988; Lima & Zuanon, 2004; de Santana & Vari, 2010 a). Adaptations for rheophily are myriad, but in some instances are apparently limited to behavioural strategies, or at least would seem to be so restricted based on externally obvious morphological adaptations. The observations by Schwassmann & Carvalho (1985: 237) document that behaviour undoubtedly contributes to the utilization of rapid flowing waters by A. blax in the Rio Itacaiunas and A. janeae in the Rio Xingu. Behavioural adaptations are supplemented in many rheophilic species by, sometimes manifold, morphological specializations for life in rapids and proximate to waterfalls. One of these specializations, the possession of a subconical downwardly oriented snout (Kullander, 1988), characterizes the species of Archolaemus, but many of the other specializations common in other rheophiles (e. g. dorsoventrally flattened head and body) are not feasible within the body plan of the Sternopygidae.	en	Vari, Richard P., Santana, Carlos David De, Wosiacki, Wolmar B. (2012): South American electric knifefishes of the genus Archolaemus (Ostariophysi, Gymnotiformes): undetected diversity in a clade of rheophiles. Zoological Journal of the Linnean Society 165 (3): 670-699, DOI: 10.1111/j.1096-3642.2012.00827.x, URL: http://dx.doi.org/10.1111/j.1096-3642.2012.00827.x
EC4A87C1FFA1E005FEB34A1EFBECD702.taxon	diagnosis	Diagnosis: Archolaemus is diagnosed by the synapomorphies described and discussed above, and distinguished from all remaining genera of the Sternopygidae by a pronounced gap between the anterior margin of the premaxilla and the posterior margin of the upper lip, with this separation equal to approximately one-half the width of the eye. It is further separated from Distocyclus, Eigenmannia, Japigny, and Rhabdolichops by the possession of a free orbital rim in adults (a feature uniquely shared with Sternopygus within the Gymnotiformes). Archolaemus is distinguished from Sternopygus by various features, with those of particular note being the possession of a postcleithrum (versus the absence of that ossification), the presence of a foramen in the scapula (versus the absence of that aperture), and the presence of some branched anal-fin rays (versus all anal-fin rays unbranched). One of the attributes that Korringa (1970) used to delimit Archolaemus from Sternopygus was the relative orbital diameter. The subsequent description of S. astrabes by Mago-Leccia (1994), with a relatively large eye (13.8 – 19.5 % HL; Hulen et al., 2005), resulted in an overlap of the range of orbital diameters in the species of Sternopygus, with values for this feature sitting among the range of values found in species of Archolaemus (Tables 1 and 2). Dentition: Jaw dentition of all species of Archolaemus consists of small, needle-like teeth embedded in the fleshy jaws. Consequently, details of the number of teeth and their exact distribution in each jaw are difficult to ascertain other than in cleared and counterstained specimens. Korringa (1970: fig. 2) provides a good illustration of the general dentition pattern (see, however, our comment concerning the dentary dentition in the next paragraph), with the dentary dentition consisting of bands of small teeth extending for varying distances posteriorly along the dorsal margin of the bone. Premaxillary dentition consists of two rounded to anteroposteriorly elongate patches that correspond to the form of the overlying premaxillae, and are separated from each other medially. Korringa (1970: 267) reported that larger specimens of A. blax have ‘ a number of dentary teeth outside the mouth and project forward in larger specimens. ’ Schwassmann & Carvalho (1985: 232) were unable to confirm this condition: an observation that is in line with our results. Some larger specimens of Archolaemus can have the dentary dentition somewhat more prominent anteriorly, but not projecting forwards. Distribution: Species of Archolaemus are known from the Rio Branco, Rio Madeira, Rio Tapajós, and Rio Xingu catchments within the Amazon basin, and outside that system in the Rio Tocantins, the easterly flowing Rio Araguari in the state of Amapá, Brazil, and the Rio São Francisco system of eastern Brazil (see species accounts). Secondary sexual dimorphism: Secondary sexual dimorphism is manifest in several features among the species of Archolaemus. These include the distinctly darker overall pigmentation of the head and body in mature males, relative to the condition in females and juveniles, in A. ferreirai, the pronounced elongation of the snout in mature males of A. luciae, versus the condition in females and immatures, and the presence of teeth on the upper lip of large males of A. ferreirai, compared with the absence of such dentition in mature females. Limited samples of many species and the absence of mature males for others make it impossible to determine the generality of these features across the genus. This limitation notwithstanding, these modifications represent the first reported instances of secondary sexual dimorphism in the Sternopygidae. N, number of specimens; H, holotype; range includes holotype of species. N, number of specimens; H, holotype; range includes holotype of species. Remarks: In their description of Japigny, Meunier et al. (2011) differentiated that genus from Archolaemus on the basis of pigmentation patterns and the total number of anal-fin rays. Their concept of Archolaemus was based on samples from the Rio Xingu, which presumably represent what we consider to be A. janeae, the only member of the genus known from that river system. Archolaemus orientalis described in this paper, however, has a range of total anal-fin rays (164 – 186) overlapping, albeit barely, with the values in Japigny (132 – 164), and lacks the pattern of longitudinal dark and light pigmentation common to the other species of Archolaemus. As such, the characters originally proposed to distinguish the two genera are no longer applicable. Archolaemus and Japigny differ in the association of the eye with the surrounding regions (free versus attached) and pigmentation pattern (dark pigmentation either absent or, when present, in the form of a dark stripe along the lateral line and a broad dusky to dark band over the basal pterygiophores of the anal fin versus wide alternatively dark and light vertical bars along the body). In their analysis of Archolaemus blax, Schwassmann & Carvalho (1985) detailed the apparent pronounced variation in head form between populations within what they considered to be that species. In part, this variation was a consequence of ontogenetic modifications in snout and overall head morphology, as reflected in differences in the head profile from a lateral view. Supplementing these intraspecific ontogenetic alterations are alternative degrees of snout development across the species in Archolaemus, four of which (A. blax, A. ferreirai, A. janeae, and A. luciae) were encompassed within A. blax as delimited by Schwassmann & Carvalho (1985). Of note is the particularly elongate and broader snout of A. luciae, more so in mature males (Fig. 7). This factor contributes significantly to the range of snout profiles within what those authors considered to be A. blax. Conservation status: The rapids and waterfalls patchily distributed across the gradients of the Brazilian and Guiana shields (Lima & Ribeiro, 2011; Lujan & Armbruster, 2011) are home to a number of specialized communities of plants and animals, including rheophilic fishes. Such high-energy settings significantly hinder the sampling of these communities, and as such our knowledge of the ichthyofaunas in these settings is often deficient, even within the context of the still inadequate overall understanding of the Neotropical freshwater fish fauna (Vari & Malabarba, 1998). At the same time the high-energy conditions that complicate the thorough sampling of these habitats provide the attributes that are ideal for hydroelectric facilities. The development of hydroelectric generating capacity is accelerating across the Neotropics, with the consequent submergence under reservoirs of multiple habits preferentially occupied by rheophiles. Moreover, proposed impoundments (i. e. the Belo Monte project on the lower Rio Xingu; Fearnside, 2006) threaten many as yet undeveloped high-energy settings. It is likely that various rheophilic species have been extirpated from their type localities by hydroelectric developments. Within the Gymnotiformes, this eventuality probably applies both in Archolaemus (e. g. A. santosi from the Rio Jamari at Usina Hidroelétrica Samuel in Rondônia) and Sternarchorhynchus (e. g. Sternarchorhynchus britskii in the upper Rio Paraná; Camposda-Paz, 2005: 399). The same is likely to befall many of the locations inhabited by the species of Archolaemus and other rheophiles.	en	Vari, Richard P., Santana, Carlos David De, Wosiacki, Wolmar B. (2012): South American electric knifefishes of the genus Archolaemus (Ostariophysi, Gymnotiformes): undetected diversity in a clade of rheophiles. Zoological Journal of the Linnean Society 165 (3): 670-699, DOI: 10.1111/j.1096-3642.2012.00827.x, URL: http://dx.doi.org/10.1111/j.1096-3642.2012.00827.x
EC4A87C1FFAAE01CFF5E4F3BFD83D1D0.taxon	description	(FIGS 3, 4; TABLE 1)	en	Vari, Richard P., Santana, Carlos David De, Wosiacki, Wolmar B. (2012): South American electric knifefishes of the genus Archolaemus (Ostariophysi, Gymnotiformes): undetected diversity in a clade of rheophiles. Zoological Journal of the Linnean Society 165 (3): 670-699, DOI: 10.1111/j.1096-3642.2012.00827.x, URL: http://dx.doi.org/10.1111/j.1096-3642.2012.00827.x
EC4A87C1FFAAE01CFF5E4F3BFD83D1D0.taxon	diagnosis	Diagnosis: Archolaemus ferreirai is diagnosed from A. blax by the length of the gape (the rictus falling short of the vertical through the posterior naris versus extending beyond that line), the length of the coronomeckelian bone (50 % or more the length of Meckel’s cartilage versus less than 20 % the length of Meckel’s cartilage) and the length of the posterior ceratohyal (approximately the same length as the ventral hypohyal versus 1.5 times the length of the ventral hypohyal). Archolaemus ferreirai is diagnosed from A. janeae in the number of scales above the lateral line at the midbody (10 – 14 versus 15 – 17), by the form of the premaxilla (the anteroposterior length greater than the transverse width versus the anteroposterior length equal to the transverse width), the distribution of the teeth on the dentary (dentition restricted to anterior one-half or slightly more of the dorsal margin versus occupying most of the dorsal margin), the length of the coronomeckelian bone (50 % or more the length of Meckel’s cartilage versus less than 20 % the length of Meckel’s cartilage), and the length of the posterior ceratohyal (approximately the same length as the ventral hypohyal versus 1.5 times the length of the ventral hypohyal). Archolaemus ferreirai is diagnosed from A. luciae by the length of the gape (the rictus not extending posteriorly beyond the vertical through the posterior naris versus extending beyond that line) and the distribution of the teeth on the internal surface of the endopterygoid (five or six teeth arranged in single row versus between seven and ten irregularly distributed teeth). Archolaemus ferreirai is diagnosed from A. orientalis in the pigmentation pattern (the presence of a narrow dark stripe along the lateral line and a broad band of dusky to dark pigmentation overlying the basal pterygiophores of the anal fin, versus the lack of such dark pigmentation), the total number of pectoral-fin rays (18 – 21 versus 16), the total number of anal-fin rays (190 – 222 versus 164 – 186), the form of the premaxilla (the anteroposterior length greater than the transverse width versus the anteroposterior length equal to the transverse width), and the length of the coronomeckelian bone (50 % or more of the length of Meckel’s cartilage versus less than 20 % the length of Meckel’s cartilage). Archolaemus ferreirai is diagnosed from A. santosi in the form of the premaxilla (the anteroposterior length greater than the transverse width versus the anteroposterior length equal to the transverse width) and the length of the coronomeckelian bone (50 % or more the length of Meckel’s cartilage versus less than 20 % the length of Meckel’s cartilage). Description: Morphometric data for the examined specimens of A. ferreirai are presented in Table 1. Body elongate and laterally compressed. Greatest body depth located along abdominal cavity. Body profile gently convex from rear of head for approximately anterior one-third of body, and then gradually angled posteroventrally along progressively tapering body and caudal filament. Ventral profile of body slightly convex anteriorly along anterior half of abdominal cavity, and then gradually angled posterodorsally along base of anal fin and caudal filament. Anterior most perforated lateral line scale located at vertical approximately at origin of pectoral fin. Lateral line continuous, extending from immediately after vertical through origin of pectoral fin to end of caudal filament. Head laterally compressed, widest at opercular region and deepest at nape. Head profile nearly straight dorsally. Ventral profile of head straight and posteroventrally aligned. Snout subconical and anteroventrally directed. Eye small and located laterally on dorsal half of head. Orbital rim covered by membrane and partially free of surface tissues of adjoining region of head in specimens of up to approximately 119 mm TL, but rim totally free and without membranous attachment in larger examined individuals. Anterior naris located at end of short tube and positioned short distance posterior of tip of snout, but distant from anterior margin of eye. Posterior naris elliptical, without tube and located nearer tip of snout than to anterior margin of eye. Mouth distinctly inferior, with upper jaw clearly longer than, and overlapping, lower jaw. Gape relatively short and in adults falling short posteriorly of vertical through posterior margin of posterior naris. Branchial opening moderately elongate; located along posterior margin of opercle and immediately anterior to anterior margin of pectoral-fin origin. Branchial membranes joined at isthmus and extending posteriorly to under pectoral-fin base. Anus proximate to elongate urogenital papilla, and both structures positioned approximately ventral of orbit. Position of anus and urogenital papilla shifting anteriorly ontogenetically from posterior of vertical through posterior margin of orbit to position along, or anterior of, vertical through anterior margin of orbit in larger specimens. Scales small, cycloid, and present from immediately posterior of head to end of caudal filament. Scales along lateral line 136 to 150 (145) (N = 25). Scales above lateral line at midbody 10 to 14 (12) (N = 50). Scales absent on head. Pectoral fin long, approximately two-thirds of head length, broad, and distally pointed with lateral rays longer. Pectoral-fin rays between ii, 16 and ii, 19 (18) (N = 50). Anal-fin elongate, extending from vertical through base of pectoral-fin base along most of length of body. Fin margin gently convex anteriorly and then straight, but with rays becoming progressively shorter posteriorly. Anal fin with 24 – 33 (28) unbranched rays (N = 30) and 190 – 222 (197) total fin rays (N = 30). Caudal filament of moderate length. Coloration in alcohol: Overall body coloration ranging from tan to light brown, with lightly coloured specimens demonstrating a less intense version of pigmentation pattern characteristic of darker individuals. Overall brown pigmentation more developed dorsally, with narrow dark stripe extending along lateral line from vertical through tip of pectoral fin, or slightly posterior of that line to end of caudal filament. Band less apparent, but still obvious in very darkly pigmented adult male specimens. Skin overlying basal pterygiophores of anal fin with pterygiophores outlined by very narrow dark bars on body surface. Bars cumulatively form dusky to dark, broad, band running along ventral portion of body, with height of band gradually decreasing posteriorly. Dark pigmentation along centre of band often less intense, with resultant darker dorsal and ventral components to band. Dark stripe along lateral line and ventral band above anal fin separated by more lightly pigmented, broad, midlateral stripe. Lighter midlateral stripe less obvious in some overall more darkly pigmented individuals, and obscured to significant degree by overall dark pigmentation in the single examined large male specimen. Head ranging from tan ventrally and dark dorsally to dark brown over all surfaces, other than for narrow lightly coloured midventral stripe. Lips of darkly pigmented specimens distinctly lighter than proximate areas. Region anteroventral and posteroventral of pectoral-fin base more darkly pigmented than adjoining regions. Pigmentation of pectoral and anal fins ranging from tan in more lightly coloured specimens to quite dusky with dark pigmentation overlying fin rays in more intensely pigmented individuals. Distribution: Archolaemus ferreirai is known from north-eastern portions of the Amazon basin in the Rio Mucajaí at Cachoeira Paredão 2 and the Rio Uraricoera at Ilha de Maracá, both in Roraima, Brazil (Fig. 4). Secondary sexual dimorphism: The only examined mature male of Archolaemus ferreirai (INPA 3757) has an overall body coloration (Fig. 3 B) much darker than in the juveniles and females (Fig. 3 A) captured at the same time. This darker pigmentation largely obscures the lighter longitudinal band present in mature females and juveniles between the dark stripe along the lateral line and the dark band overlying the basal pterygiophores of the anal fin. The upper lip of this large male is also notable in bearing some teeth, contrary to the absence of such dentition in mature females and juveniles. Habitat: Ferreira et al. (1988: 342) reported the type region of Archolaemus ferreirai, the Rio Mucajaí at Cachoeira Paredão 2, as characterized by rapidly flowing waters and a 20 m high waterfall. The sample of A. ferreirai (reported as A. blax in that paper) was captured above these falls, in an area with many rapids and no still backwaters. Etymology: The species name, Archolaemus ferreirai sp. nov., is in honor of Efrem Ferreira of the Instituto Nacional de Pesquisas da Amazônia, one of the collectors of the type series, in recognition of his many contributions to our understanding of the Amazonian fish fauna. Material examined Holotype: BRAZIL. Roraima: Rio Mucajaí, Cachoeira Paredão 2 (approximately 02 ° 57 ′ N, 061 ° 27 ′ W), collected by E. G. Ferreira & M. Jégu, 19 February 1987; INPA 3757 (183). Paratypes: BRAZIL. Roraima: collected with holotype; INPA 36379, 21 (119 – 342; 1 CS); MPEG 21683, 1 (286); MZUSP 110183, 1 (150); USNM 404354, 1 (172). Rio Mucajaí, mouth of Igarapé Traira (approximately 02 ° 57 ′ N, 061 ° 27 ′ W), collected by E. G. Ferreira & M. Jégu, 21 February 1987; INPA 6422, 12 (131 – 269; 4 CS). Non-type specimens: BRAZIL. Roraima: Rio Uraricoera, Ilha Maracá, Furo Santa Rosa (approximately 03 ° 22 ′ N, 061 ° 22 ′ W); INPA 2038, 6 (122 – 176). Rio Uraricoera, Ilha Maracá, below Furo Santa Rosa (approximately 03 ° 22 ′ N, 061 ° 22 ′ W); INPA 2054, 4 (135 – 184). Rio Uraricoera, Ilha Maracá (approximately 03 ° 22 ′ N, 061 ° 22 ′ W); INPA 2675, 1 (54). Rio Uraricoera, Ilha Maracá, below Furo Santa Rosa (approximately 03 ° 22 ′ N, 061 ° 22 ′ W); INPA 3747, 1 (60). Rio Mucajaí, station Fé-Esperança; INPA 3758, 3 (83 – 145). Rio Mucajaí, 2 km above Cachoeira Paredão (approximately 02 ° 57 ′ N, 061 ° 27 ′ W); INPA 6423, 1 (338). Rio Mucajaí, 2 km above Cachoeira Paredão, mouth of igarapé (approximately 02 ° 57 ′ N, 061 ° 27 ′ W); INPA 6495, 1 (136); INPA 6500, 7 (115 – 223). Rio Mucajaí, near Cachoeira Paredão (approximately 02 ° 57 ′ N, 061 ° 27 ′ W); INPA 6496, 11 (69 – 196). Rio Mucajaí, above Cachoeira Paredão (approximately 02 ° 57 ′ N, 061 ° 27 ′ W); INPA 6499, 1 (192).	en	Vari, Richard P., Santana, Carlos David De, Wosiacki, Wolmar B. (2012): South American electric knifefishes of the genus Archolaemus (Ostariophysi, Gymnotiformes): undetected diversity in a clade of rheophiles. Zoological Journal of the Linnean Society 165 (3): 670-699, DOI: 10.1111/j.1096-3642.2012.00827.x, URL: http://dx.doi.org/10.1111/j.1096-3642.2012.00827.x
EC4A87C1FFB7E01FFEB74A78FF38D4D3.taxon	description	(FIGS 5, 6; TABLE 1)	en	Vari, Richard P., Santana, Carlos David De, Wosiacki, Wolmar B. (2012): South American electric knifefishes of the genus Archolaemus (Ostariophysi, Gymnotiformes): undetected diversity in a clade of rheophiles. Zoological Journal of the Linnean Society 165 (3): 670-699, DOI: 10.1111/j.1096-3642.2012.00827.x, URL: http://dx.doi.org/10.1111/j.1096-3642.2012.00827.x
EC4A87C1FFB7E01FFEB74A78FF38D4D3.taxon	diagnosis	Diagnosis: Archolaemus janeae is diagnosed from A. blax in the length of the gape (the rictus falling short posteriorly of the vertical through the posterior naris versus extending beyond that line), the form of the premaxilla (the anteroposterior length equal to the transverse width versus the anteroposterior length greater than the transverse width), the distribution of the teeth on the dentary (dentition occupying most of the dorsal margin versus restricted to the anterior one-half or slightly more of the margin), and the number and arrangement of teeth on the internal surface of the endopterygoid (two or three teeth arranged in a single row versus six irregularly distributed teeth). Archolaemus janeae is diagnosed from A. ferreirai by the number of scales above the lateral line at the midbody (15 – 17 versus 10 – 14), the form of the premaxilla (the anteroposterior length equal to the transverse width versus the anteroposterior length greater than the transverse width), the distribution of the teeth on the dentary (dentition occupying most of the dorsal margin versus restricted to the anterior one-half or slightly more of the margin), the length of the coronomeckelian bone (less than 20 % the length of Meckel’s cartilage versus 50 % or more of length of Meckel’s cartilage), and the length of the posterior ceratohyal (1.5 times the length of the ventral hypohyal versus approximately the same size as the ventral hypohyal). Archolaemus janeae is diagnosed from A. luciae in the length of the gape (the rictus falling short posteriorly of the vertical through the posterior naris versus extending beyond that line), the length of the caudal filament (16.0 – 25.7 % LEA versus 28.6 – 46.1 % LEA), the depth of the caudal filament (5.6 – 11.2 % CL versus 3.3 – 4.8 % CL), the form of the premaxilla (the anteroposterior length equal to the transverse width versus the anteroposterior length greater than the transverse width), the distribution of the teeth on the dentary (dentition occupying most of the dorsal margin versus restricted to the anterior one-half or slightly more of the margin), the length of the coronomeckelian bone (less than 20 % the length of Meckel’s cartilage versus 50 % or more of the length of Meckel’s cartilage), and the length of the posterior ceratohyal (1.5 times the length of the ventral hypohyal versus approximately the same size as the ventral hypohyal). Archolaemus janeae is diagnosed from A. orientalis by the pigmentation pattern (the presence of a narrow dark stripe along the lateral line and a broad band of dusky to dark pigmentation overlying the basal pterygiophores of the anal fin, versus the lack of such dark pigmentation), the total number of pectoral-fin rays (19 – 21 versus 16), the total number of anal-fin rays (205 – 228 versus 164 – 186), the distribution of the teeth on the dentary (dentition occupying most of the dorsal margin versus restricted to the anterior one-half or slightly more of the margin), and the length of the posterior ceratohyal (1.5 times the length of the ventral hypohyal versus approximately the same size as the ventral hypohyal). Archolaemus janeae is diagnosed from A. santosi by the pigmentation pattern (the presence of a narrow dark stripe along the lateral line and a broad band of dusky to dark pigmentation overlying the basal pterygiophores of the anal fin, versus the lack of such dark pigmentation), the head length at the opercle (13.5 – 14.7 % LEA versus 15.0 – 16.3 % LEA), the distribution of the teeth on the dentary (dentition occupying most of the dorsal margin versus restricted to the anterior one-half or slightly more of the margin), and the length of the posterior ceratohyal (1.5 times the length of the ventral hypohyal versus approximately the same size as the ventral hypohyal). Description: Morphometric data for examined specimens of A. janeae are presented in Table 1. Body elongate and laterally compressed. Greatest body depth located along abdominal cavity or slightly posterior to that region. Body profile very gently convex from rear of head for approximately anterior one-third of body, and then gradually angled posteroventrally along progressively tapering body and caudal filament. Ventral profile of body distinctly convex anteriorly below anterior one-half to twothirds of abdominal cavity, more so in specimens with distended abdomens, and then gradually angled posterodorsally along base of anal fin and caudal filament. Anteriormost perforated lateral line scale located at vertical situated approximately at origin of pectoral fin. Lateral line continuous, extending from immediately after vertical through origin of pectoral fin to end of caudal filament. Head laterally compressed, widest at opercular region and deepest at nape. Head profile ranging from nearly straight to slightly concave from tip of snout to vertical through orbit, and then straight from that area to rear of head. Ventral profile straight and posteroventrally aligned. Snout subconical, anteroventrally directed and moderately developed. Eye small and located laterally on dorsal one-half of head. Orbital rim partially attached to surface tissues of adjoining region of head in examined specimen of approximately 105 mm TL, but rim totally free and without membrane in larger individuals. Anterior naris located at end of short tube and positioned short distance posterior of tip of snout, but distant from anterior margin of eye. Posterior naris elliptical, without tube and located nearer to tip of snout than to anterior margin of eye. Mouth distinctly inferior, with upper jaw clearly longer than, and overlapping, lower jaw. Gape relatively long, and extending posteriorly beyond vertical through posterior margin of posterior naris. Branchial opening moderately elongate; located along posterior margin of opercle and immediately anterior to anterior margin of pectoralfin origin. Branchial membranes joined at isthmus and extending posteriorly to under pectoral-fin base. Anus proximate to elongate urogenital papilla, and both structures positioned approximately ventral of orbit. Position of anus and urogenital papilla shifting ontogenetically from posterior of vertical through posterior margin of orbit to more anterior position. Scales small, cycloid, and present from immediately posterior of head to end of caudal filament. Scales along lateral line 146 to 161 (155) (N = 15). Scales above lateral line at midbody 15 to 17 (15) (N = 15). Scales absent on head. Pectoral fin long, approximately two-thirds of head length, broad, and distally pointed with lateral rays longer. Pectoral-fin rays ii, 19 to ii, 21 (19) rays (N = 15). Anal-fin elongate, extending from vertical through base of pectoral-fin base along most of length of body. Fin margin gently convex anteriorly and then straight for length of fin, but with rays becoming progressively shorter posteriorly. Anal fin with 22 – 33 (33) unbranched rays (N = 15) and 205 – 228 total fin rays (220) (N = 9). Caudal filament of moderate length. Coloration in alcohol: Overall ground body coloration ranging from tan to dark brown. More lightly coloured specimens with pigmentation pattern characteristic of darker specimens less pronounced. More intensely pigmented individuals with overall brown pigmentation more developed dorsally, and narrow dark stripe extending over lateral line from vertical through tip of pectoral fin or slightly posterior of that line to end of caudal filament. Stripe particularly dark in intensely pigmented specimens, such that it stands out even against an overall dark anterior portion of body. Area overlying anal-fin basal pterygiophores with ossifications outlined by variably dark bars on body surface. Bars narrow, distinct, and dusky in overall more lightly coloured specimens, in which they cumulatively form dusky band along ventral portion of body with height of band gradually decreasing posteriorly. More darkly pigmented band in dark specimens quite intense, and individual narrow bars sometimes merge into continuous dark broad band running along ventral portion of body. Dark stripe along lateral line and ventral band overlying basal pterygiophores separated in most specimens by more lightly pigmented, broad midlateral stripe. Lighter stripe less obvious in overall very lightly coloured specimens, and obscured anteriorly in some overall more darkly pigmented individuals. Head ranging from tan ventrally and dusky dorsally in lightly coloured individuals to totally dark brown in large, dark specimens. Smaller darkly pigmented specimens sometimes with lightly coloured area on ventral surface of head. Fleshy covering of branchial opening lightly pigmented, even in dark specimens. Larger specimens in some samples with dark pigmentation patch present immediately anterior to base of pectoral fin. Pectoral and anal fins ranging from hyaline in smaller individuals to dusky in larger specimens. Coloration in life: (Based on photograph of recently captured specimen from São Felix do Xingu along the Rio Xingu.) Dark coloration overall quite intense, with head, portion of body dorsal of lateral line, and region overlying basal pterygiophores of anal fin nearly black. Rays of anal fin overlain by black pigmentation. Pectoral fin black. Midlateral more lightly pigmented stripe present in most preserved specimens, obscured anteriorly by darker pigmentation that gradually becomes more diffuse posteriorly. Distribution: Archolaemus janeae is known from the upper and lower portions of the Rio Xingu basin at the Rio Iriri, the Cachoeira de Kaituká at Município de Altamira, and localities in the Rio Culuene, as well as the upper Rio Tapajós basin, where it was collected in the Rio Jamanxim at the Município do Novo Progresso, Brazil (Fig. 6). Remarks: Two specimens of A. janeae from the Rio Xingu listed by Schwassmann & Carvalho (1985: 233; cited therein as A. blax) as MPEG 1370 are now registered as MZUSP 31491. Etymology: The species name, Archolaemus janeae, is in honor of Jane Mertens of Humboldt Universität zu Berlin for her assistance to the second author. Habitat: The holotype and a portion of the paratype series of A. janeae were collected between 21: 00 and 23: 00 h in the Rio Iriri, just upriver of a sandbank that separated the tributary from the mainstream Rio Xingu. In this area the river had a pronounced current that was faster towards the centre of the channel, with the substrate in the sampled areas formed by pebbly sand. The depth of the fishing effort varied between <10 cm and about 120 cm, and water parameters at that location were: pH = 5.5; T = 31.1 ° C at night and 31.9 ° C during the day; dissolved oxygen (D. O.) = 5.9 mg L- 1; conductivity 32.9 uScm- 1; and Secchi depth = 187 cm (H. López- Fernández, pers. comm.). Some non-type specimens of A. janeae that originated in the Rio Xingu were captured in the main stream of shallow rapids and small waterfalls, always over a rocky bottom (J. L. O. Birindelli, pers. comm.). Material examined Holotype: BRAZIL. Pará: Rio Iriri, just upriver of its mouth into Rio Xingu, Município de Altamira (03 ° 48 ′ 54 ″ S, 052 ° 37 ′ 09 ″ W), collected by H. López- Fernández, G. Ortí, N. Meliciana, and C. Röepke, 15 August 2008; INPA 30832 (160). Paratypes: BRAZIL. Pará: collected with holotype, INPA 36380, 16 (136 – 225; 2 CS); MPEG 21684, 1 (141); USNM 404355, 1 (191). Rio Xingu near cachoeira, collected by M. Goulding, 14 October 1983; MZUSP 31491, 2 (115 – 206). Non-type specimens: BRAZIL. Pará: Rio Xingu, Cachoeira de Kaituká, Altamira (03 ° 33 ′ 47 ″ S, 51 ° 51 ′ 20 ′ W); MZUSP 3930, 13 (113 – 340). Rio Xingu, Furo da Mirandolina (approximately 03 ° 12 ′ 43 ″ S, 052 ° 12 ′ 12 ″ W); INPA 4131, 1 (221). Rio Jamanxim, Rio Tapajós basin, Novo Progresso near Vila Mil (07 ° 43 ′ 51 ″ S, 055 ° 16 ′ 36 ″ W); MZUSP 97383, 10 (197 – 402). Rio Jamanxim, Rio Tapajós basin, small beach near Novo Progresso (09 ° 17 ′ 59 ′ S, 054 ° 50 ′ 00 ′ W); MZUSP 97514, 9 (213 – 222). Rio Iriri (03 ° 48 ′ 49 ″ S, 052 ° 38 ′ 06 ″ W), MZUSP 105843, 1 (300). Rio Xingu, above Belo Monte (approximately 03 ° 17 ′ S, 052 ° 12 ′ W); MZUSP 106054, 1 (341). Rio Xingu at Altamira, near Kaituká (03 ° 33 ′ 48 ″ S, 051 ° 51 ′ 49 ″ W); MZUSP 106223, 1 (372). Rio Xingu, Boa Esperança (03 ° 33 ′ 44 ″ S, 052 ° 20 ′ 59 ″ W); MZUSP 106287, 1 (only anterior half of specimen). Rio Xingu, Arroz Crú, Altamira (03 ° 22 ′ 05 ′ S, 051 ° 58 ′ 02 ′ W); MZUSP 106290, 1 (209); MZUSP 106049, 1 (230). Mato Grosso: Rio Xingu basin, Rio Culuene, Paranatinga, cachoeira at site of Pequenia Centrais Hidreléctica Paranatinga II (13 ° 51 ′ 08 ′ S, 053 ° 15 ′ 22 ″ W); MZUSP 89741, 3 (191 – 232). Rio Xingu basin, Rio Culuene, Paranantinga, cofferdam of Pequena Centrais Hidreléctica 2 (13 ° 49 ′ 00 ″ S, 053 ° 15 ′ 00 ″ W); MZUSP 94909, 6 (253 – 368).	en	Vari, Richard P., Santana, Carlos David De, Wosiacki, Wolmar B. (2012): South American electric knifefishes of the genus Archolaemus (Ostariophysi, Gymnotiformes): undetected diversity in a clade of rheophiles. Zoological Journal of the Linnean Society 165 (3): 670-699, DOI: 10.1111/j.1096-3642.2012.00827.x, URL: http://dx.doi.org/10.1111/j.1096-3642.2012.00827.x
EC4A87C1FFB4E01AFF3C4979FA70D6E8.taxon	diagnosis	Diagnosis: Archolaemus luciae is diagnosed from A. blax by the depth of the caudal filament (3.3 – 4.8 % CL versus 5.0 – 6.5 % CL), the length of the coronomeckelian bone (50 % or more the length of Meckel’s cartilage versus less than 20 % the length of Meckel’s cartilage), and the length of the posterior ceratohyal (approximately the same length as the ventral hypohyal versus 1.5 times the length of the ventral hypohyal). Archolaemus luciae is diagnosed from A. ferreirai in the length of the gape (the rictus extending posteriorly beyond the vertical through the posterior naris versus falling short of that line) and the distribution of teeth on the internal surface of the endopterygoid (between seven and ten irregularly distributed teeth versus five or six teeth arranged in a single row). Archolaemus luciae is diagnosed from A. janeae in the length of the gape (the rictus extending posteriorly beyond the vertical through the posterior naris versus falling short of that line), the length of the caudal filament (28.6 – 46.1 % LEA versus 16.0 – 25.7 % LEA), the depth of the caudal filament (3.3 – 4.8 % CL versus 5.6 – 11.2 % CL), the form of the premaxilla (the anteroposterior length greater than the transverse width versus the anteroposterior length equal to the transverse width), the distribution of the teeth on the dentary (dentition restricted to the anterior one-half or slightly more of the dorsal margin versus occupying most of the dorsal margin), the length of the coronomeckelian bone (50 % or more of the length of Meckel’s cartilage versus less than 20 % of the length of Meckel’s cartilage), and the length of the posterior ceratohyal (approximately the same length as the ventral hypohyal versus 1.5 times the length of the ventral hypohyal). Archolaemus luciae is diagnosed from A. orientalis by the pigmentation pattern (the presence of a narrow dark stripe along the lateral line and a broad band of dusky to dark pigmentation overlying the basal pterygiophores of the anal fin, versus the lack of such dark pigmentation), the length of the gape (the rictus extending posteriorly beyond the vertical through the posterior naris versus falling short of that line), the total number of pectoral-fin rays (19 – 21 versus 16), the total number of anal-fin rays (192 – 213 versus 164 – 186), the form of the premaxilla (the anteroposterior length greater than the transverse width versus the anteroposterior length equal to the transverse width), and the length of the coronomeckelian bone (50 % or more the length of Meckel’s cartilage versus less than 20 % the length of Meckel’s cartilage). Archolaemus luciae is diagnosed from A. santosi by the pigmentation pattern (the presence of a narrow dark stripe along the lateral line and a broad band of dusky to dark pigmentation overlying the basal pterygiophores of the anal fin versus the lack of such dark pigmentation), the length of the gape (the rictus extending posteriorly beyond the vertical through the posterior naris versus falling short of that line), the length of the caudal filament (28.6 – 46.1 % of LEA versus 14.4 – 27.0 %), the depth of the caudal filament (3.3 – 4.8 % of CL versus 6.7 – 9.1 %), and the length of the coronomeckelian bone (50 % or more of the length of Meckel’s cartilage versus less than 20 % the length of Meckel’s cartilage). Description: Morphometric data for the examined specimens of A. luciae are presented in in Table 2. Body elongate and laterally compressed. Greatest body depth located along abdominal cavity or slightly posterior to that region. Body profile gently convex from rear of head for approximately anterior one-third of body, and then gradually angled posteroventrally along progressively tapering body and caudal filament. Ventral profile of body distinctly convex anteriorly along anterior half of abdominal cavity, and then gradually angled posterodorsally along base of anal fin and caudal filament. Anteriormost perforated lateral line scale located approximately at vertical through origin of pectoral fin. Lateral line continuous, extending from immediately posterior of vertical through origin of pectoral fin to end of caudal filament. Head laterally compressed, widest at opercular region and deepest at nape. Dorsal profile of head varying from nearly straight to slightly concave along antorbital region, and then from straight to slightly convex from that point to rear of head. Ventral profile of head straight and posteroventrally aligned. Snout subconical, anteroventrally directed, and moderately developed to elongate with elongation particularly pronounced in largest examined specimen (INPA 6767; 497 mm TL). Eye small and located laterally on dorsal half of head. Orbital rim covered by membrane and attached to surface tissues of adjoining region of head in six specimens of approximately 97 – 135 mm TL, partially free on one side in two specimens of approximately 96 – 97 mm TL, and without membrane and unattached in individuals larger than 135 mm TL. Anterior naris located at end of short tube and positioned short distance posterior of tip of snout, but distant from anterior margin of eye. Posterior naris elliptical, without tube, and located nearer tip of snout than anterior margin of eye. Mouth distinctly inferior, with upper jaw clearly longer than, and overlapping, lower jaw. Gape relatively long and extending posteriorly beyond vertical through posterior margin of posterior nares. Branchial opening moderately elongate, located along posterior margin of opercle and immediately anterior to anterior margin of pectoral-fin origin. Branchial membranes joined at isthmus, and extending posteriorly to under pectoral-fin base. Anus situated proximate to elongate urogenital papilla, and both structures positioned approximately ventral of orbit. Position of anus and urogenital papilla shifting ontogenetically from posterior of vertical through posterior margin of orbit to under or slightly anterior of orbit. Scales small, cycloid, and present from immediately posterior of head to end of caudal filament. Between 127 and 148 (127) scales along lateral line (N = 15). Between 13 and 16 scales above lateral line at midbody (14) (N = 29). Scales absent on head. Pectoral fin long, approximately two-thirds of head length, broad and distally pointed, with rounded margin, and lateral rays longer overall. Pectoral-fin rays between ii, 17 and ii, 19 (19) (N = 29). Anal-fin elongate, extending from vertical through base of pectoral-fin base along most of length of body. Fin margin gently convex anteriorly, and then straight for length of fin, but with rays becoming progressively shorter posteriorly. Anal fin with 22 – 32 (24) unbranched rays (N = 29) and 192 to 213 (192) total fin rays (N = 29). Caudal filament long, with elongation particularly pronounced in largest examined specimen (INPA 6767; 497 mm TL). Coloration in alcohol: Available specimens somewhat faded compared with obvious coloration in live specimens (see Coloration in life). Overall ground head and body coloration tan. Body with obvious but not dark, narrow stripe along lateral line. Extent of stripe variable anteriorly, even in specimens of comparable size, with anterior limit ranging from above centre of pectoral fin to point slightly posterior to vertical through tip of pectoral fin. Body pigmentation darker than overall ground pigmentation along dorsal portion of body. Area overlying basal anal-fin pterygiophores with pterygiophores outlined by very narrow dark surface bars that cumulatively form dusky broad band running along ventral portion of body, with depth of band gradually decreasing posteriorly. Dusky stripe along lateral line and dark ventral band above anal fin separated by more lightly pigmented, broad midlateral stripe. Head lightly coloured ventrally, and somewhat darker on opercle and above horizontal between tip of snout and areas somewhat below orbit. Pectoral and anal fins hyaline. Coloration in life: (Based on recently collected specimens from Rio Teles Pires, Rio Tapajós basin.) Head dark overall, more so dorsal of horizontal between mouth and base of pectoral fin. Body dark from lateral line dorsally, with lateral line more intensely pigmented. Basal portions of anal-fin basal pterygiophores outlined by dark bars on body surface; pigmentation cumulatively forming dark band above base of fin, with height of band gradually decreasing posteriorly. Pigmentation overlying distal portions of basal pterygiophores less intense than that near base of fin, resulting in faint dusky band variably separate, other than anteriorly, from dark band along ventral margin of body. Pectoral fin dusky. Anal fin with rays outlined by dark pigmentation and dusky overall. Distribution: Archolaemus luciae is known within the Amazon basin from the Rio Trombetas basin at Cachoeira Porteira, Cachoeira Vira-Mundo, and the Rio Mapuera, all in the state of Pará, as well as the Rio Tapajós basin, where it has been collected in the Rio Jamanxim and Rio Teles Pires in the state of Mato Grosso. In the state of Amapá, north of the lower Amazon, it has been collected in the Rio Jari that empties into the Amazon and the Rio Araguari that drains independently into the Atlantic Ocean (Fig. 6). Secondary sexual dimorphism: Archolaemus luciae demonstrates pronounced sexual dimorphism in the form of the snout in mature individuals (Fig. 7). Whereas the snout in mature females of the species is overall comparable with that in mature males and females of various congeners, the snout in the large male of A. luciae is distinctly lengthened and more massive anteriorly. Habitat: Ferreira (1995: 51) reported A. luciae (as A. blax) from swift-flowing water habitats around Cachoeira Porteira and Cachoeira Vira-Mundo in the Rio Trombetas basin. Some of the non-type specimens of the species that originated in the Rio Tapajós were captured in the main stream of shallow rapids and small waterfalls, always over a rocky bottom (J. L. O. Birindelli, pers. comm.). Etymology: The species name, Archolaemus luciae, is in honor of Lucia Py-Daniel of the Instituto Nacional de Pesquisas da Amazônia, in recognition of her many contributions to the knowledge of the fishes of the Amazon and her assistance to the authors over the years. Material examined Holotype: BRAZIL. Pará: Rio Trombetas, Cachoeira Porteira, below Furo nas Pedras (approximately 01 ° 05 ′ S, 057 ° 02 ′ W), collected by Equipe de Ictiologia do INPA, 19 April 1985; INPA 20960 (267). Paratypes: BRAZIL. Collected with holotype: INPA 36381, 3 (137 – 276); Rio Trombetas, Cachoeira Porteira (approximately 01 ° 05 ′ S, 057 ° 02 ′ W), collected by Equipe de Ictiologia do INPA, 19 April 1985; INPA 20962, 23 (40 – 202); INPA 20964, 12 (110 – 210; 4 CS); MPEG 21685, 1 (138); MZUSP 110184 (135); USNM 404356 (158). Rio Mapuera, Cachoeira Porteira (approximately 01 ° 05 ′ S, 057 ° 02 ′ W); collected by E. Ferreira & M. Jegú; INPA 20961, 2 (130 – 180). Non-type specimens: BRAZIL. Amapá: Rio Cupixi, Rio Araguari basin, bridge on road to Serra do Navio, in channel of river (approximately 00 ° 53 ′ 45 ″ N, 052 ° 00 ′ 07 ′ W); MZUSP 34920, 1 (238). Rio Iratapuru, left bank tributary of Rio Jari, Laranjal do Jari, at Cachoeira de São Raimundo, above Cachoeira de Santo Antonio (00 ° 33 ′ 59 ″ S, 052 ° 34 ′ 40 ″ W); MZUSP 103446, 1 (206). Pará: Rio Trombetas, Oriximiná, above Cachoeira Porteira (approximately 01 ° 03 ′ S, 057 ° 01 ′ W); INPA 3289, 1 (210). Rio Trombetas, Oriximiná, near igarapé Caxipacoré (approximately 01 ° 03 ′ S, 057 ° 01 ′ W); INPA 3354, 1 (173); INPA 3386, 1 (160). Rio Trombetas, Oriximiná, above Cachoeira Vira-Mundo (approximately 01 ° 03 ′ S, 057 ° 01 ′ W); INPA 3356, 3 (230 – 269); INPA 3378, 1 (250). Rio Mapuera, Cachoeira Porteira (approximately 01 ° 05 ′ S, 057 ° 02 ′ W); INPA 4371, 10 (140 – 235); INPA 20957, 2 (130 – 141). Rio Trombetas, Cachoeira Porteira (approximately 01 ° 05 ′ S, 057 ° 02 ′ W); INPA 4372, 1 (102); INPA 19989, 1 (275); INPA 19990, 1 (181); INPA 20965, 1 (60). Trombetas, Oriximiná, Cachoeira Vira-Mundo (approximately 01 ° 05 ′ S, 057 ° 02 ′ W); INPA 5081, 1 (220); INPA 5082, 1 (180). Rio Jamanxim, Rio Tapajós basin, Ilha Terra Preta (05 ° 27 ′ 04 ″ S, 055 ° 52 ′ 40 ″ W); INPA 6767, 1 (497); INPA 6812, 6 (92 – 130). Rio Tapajós, São Luis do Tapajós (approximately 04 ° 25 ′ S, 056 ° 13 ′ W); MZUSP 24268, 1 (400). Rio Tapajós basin, Jacareacanga, rapids along Rio Teles Pires, below Sete Quedas (approximately 06 ° 13 ′ 20 ′ S, 057 ° 45 ′ 10 ″ W); MZUSP 96130, 1 (229). Mato Grosso: Rio Tapajós, Paranaíta, Rio Teles Pires, near ferry crossing of rodovia MT- 416; MZUSP 95630, 4 (148 – 186). Rio Peixoto de Azevedo, Município do Peixoto de Azevedo, tributary of Rio Teles Pires near Peixoto de Azevedo (approximately 10 ° 10 ′ S, 054 ° 50 ′ W); MZUSP 96618, 1 (203). Rio Teles Pires, Itaúba, below mouth of Rio Renato (approximately 11 ° 03 ′ 43 ″ S, 055 ° 16 ′ 33 ″ W); MZUSP 99362, 2 (363 – 445). Rio Tapajós, Itaúba, Rio Teles Pires (approximately 11 ° 39 ′ 11 ″ S, 055 ° 42 ′ 14 ″ W); MZUSP 95909, 1 (409). Rio Braço Norte, Novo Mundo, above Pequena Centrais Hidreléctica Braço Norte IV (approximately 09 ° 47 ′ S, 054 ° 54 ′ W); MZUSP 106461, 1 (292). Rio Teles Pires, Município da Paranatinga, Fazenda do Antônio Bezerra (approximately 10 ° 20 ′ S, 054 ° 45 ′ W); MZUSP 107923, 1 (447). ARCHOLAEMUS ORIENTALIS SP. NOV. STEWART,	en	Vari, Richard P., Santana, Carlos David De, Wosiacki, Wolmar B. (2012): South American electric knifefishes of the genus Archolaemus (Ostariophysi, Gymnotiformes): undetected diversity in a clade of rheophiles. Zoological Journal of the Linnean Society 165 (3): 670-699, DOI: 10.1111/j.1096-3642.2012.00827.x, URL: http://dx.doi.org/10.1111/j.1096-3642.2012.00827.x
EC4A87C1FFBEE017FEAD4DCEFAABD3BB.taxon	description	(FIGS 10, 11; TABLE 2) Diagnosis: Archolaemus santosi is diagnosed from A. blax in the length of the gape (the rictus falling short of the vertical through the posterior border of the posterior naris versus extending beyond that line), the depth of the caudal filament (6.7 – 9.1 % CL versus 5.0 – 6.5 % CL), the form of the premaxilla (the anteroposterior length equal to the transverse width versus the anteroposterior length greater than the transverse width), and the length of the posterior ceratohyal (approximately the same length as the ventral hypohyal versus 1.5 times the length of the ventral hypohyal). Archolaemus santosi is diagnosed from A. ferreirai in the form of the premaxilla (the anteroposterior length equal to the transverse width versus the anteroposterior length greater than the transverse width) and the length of the coronomeckelian bone (less than 20 % the length of Meckel’s cartilage versus 50 % or more the length of Meckel’s cartilage). Archolaemus santosi is diagnosed from A. janeae by the head length to the rear of the opercle (15.0 – 16.3 % LEA versus 13.5 – 14.7 % LEA), the mouth width (7.0 – 10.3 % HL versus 11.0 – 19.1 % HL), the form of the premaxilla (the anteroposterior length equal to the transverse width versus the anteroposterior length greater than the transverse width), the distribution of the teeth on the dentary (dentition restricted to the anterior one-half or slightly more of the dorsal margin versus occupying most of the dorsal margin), and the length of the posterior ceratohyal (approximately the same length as the ventral hypohyal versus 1.5 times the length of the ventral hypohyal). Archolaemus santosi is diagnosed from A. luciae in the length of the gape (the rictus falling short of the vertical through the posterior border of the posterior nares versus extending beyond that line), the length of the caudal filament (14.4 – 27.0 % LEA versus 28.6 – 46.1 % LEA), the depth of the caudal filament (6.7 – 9.1 % CL versus 3.3 – 4.8 % CL), the form of the premaxilla (the anteroposterior length equal to the transverse width versus the anteroposterior length greater than the transverse width), and the length of the coronomeckelian bone (less than 20 % the length of Meckel’s cartilage versus 50 % or more of the length of Meckel’s cartilage). Archolaemus santosi is diagnosed from A. orientalis by the pigmentation pattern (the presence of a narrow dark stripe along the lateral line and a broad band of dusky to dark pigmentation overlying the basal pterygiophores of the anal fin versus the lack of such dark pigmentation), the total number of pectoral-fin rays (19 – 21 versus 16), and the total number of anal-fin rays (204 – 221 versus 164 – 186). Description: Morphometric data for the examined specimens of A. santosi are presented in Table 2. Body elongate and laterally compressed. Greatest body depth located along abdominal cavity in specimens of all sizes. Body profile gently convex from rear of head for approximately anterior one-third of body, and then gradually angled posteroventrally along progressively tapering body and caudal filament. Ventral profile of body straight and posteroventrally aligned in juveniles and convex anteriorly along anterior half of abdominal cavity in larger individuals, and then gradually angled posterodorsally along base of anal fin and caudal filament. Anteriormost perforated lateralline scale located at vertical situated approximately at origin of pectoral fin. Lateral line continuous, extending from immediately posterior of vertical through origin of pectoral fin to end of caudal filament. Head laterally compressed, widest at opercular region and deepest at nape. Head profile convex anteriorly from margin of upper lip in specimens of all sizes, then convex to varying degrees along antorbital region, with concavity more pronounced in larger specimens, and then straight to slightly convex from that point to rear of head in specimens of all sizes. Ventral profile straight and posteroventrally aligned. Snout subconical and anteroventrally directed, moderately elongate in smaller specimens to elongate in larger individuals. Eye small and located laterally on dorsal half of head. Orbital rim covered by membrane and attached to surface tissues of adjoining region of head in two specimens of approximately 73 – 104 mm TL, partially free on one side in an individual of 103 mm TL, and completely free in larger examined specimens. Anterior naris located at end of short tube and positioned short distance posterior of tip of snout, but distant from anterior margin of eye. Posterior naris elliptical, without tube, and located nearer to tip of snout than to anterior margin of eye in adults. Mouth distinctly inferior, with upper jaw clearly longer than, and overlapping, lower jaw. Gape short in adults, not extending posteriorly to vertical through anterior margin of posterior naris. Branchial opening moderately elongate, located along posterior margin of opercle and immediately anterior to anterior margin of pectoral-fin origin. Branchial membranes joined at isthmus and extending posteriorly to under pectoral-fin base. Anus situated proximate to elongate urogenital papilla, and both structures positioned approximately ventral of orbit. Position of anus and urogenital papilla shifting ontogenetically from distinctly posterior of vertical through posterior margin of orbit in juveniles, to along vertical through eye in largest specimens. Scales small, cycloid, and present from immediately posterior of head to end of caudal filament. Scales along lateral line 132 to 147 (147) (N = 10). Scales above lateral line at midbody 14 to 17 (17) (N = 12). Scales absent on head. Pectoral fin long, approximately two-thirds of head length, broad, and distally pointed, with lateral rays longer. Pectoral-fin rays between ii, 19 and ii, 21 (21) (N = 12). Anal-fin elongate, extending from vertical through base of pectoral fin along most of length of body. Fin convex anteriorly, and then straight for length of fin, but with rays becoming progressively shorter posteriorly. Anal fin with 26 – 35 unbranched rays (26) (N = 12) and 204 – 221 total fin rays (208) (N = 12). Caudal filament of moderate length. Coloration in alcohol: Overall ground body coloration ranging from tan to brown. Head more lightly pigmented ventrally in specimens across all intensities of dark coloration, with dorsal two-thirds of head together with most of opercle distinctly darker in largest examined specimen. Narrow, dark stripe overlying lateral line for varying distances. Dark pigmentation along lateral line starts posterior of vertical through tip of pectoral fin in very small individuals, but extends anteriorly to beginning of lateral line in larger specimens. Basal anal-fin pterygiophores outlined on body surface by very narrow dark bars that cumulatively form dusky broad band running along ventral portion of body, with height of band gradually decreasing posteriorly. Surface bars along pterygiophore margins expand ontogenetically and coalesce to varying degrees to form solid dark band in larger specimens. Dark stripe along lateral line and dark ventral band separated by more lightly pigmented, broad midlateral stripe. Some specimens with ventral surface of the head tan, but most often with head dark over all surfaces. Pectoral fin hyaline overall, with scattered dark chromatophores. Anal fin hyaline. Distribution: Archolaemus santosi is only known from the type locality at the Rio Jamari in Rondônia, Brazil (Fig. 11). Habitat: The area of the type locality of A. santosi was reported by Santos (1996: 249) as being rapids (= corredeira), indicative of the rapid water flow conditions at the site. Remarks: Archolaemus santosi is only known from juveniles and mature females. Etymology: The species name, Archolaemus santosi, is in honor of Geraldo Mendes dos Santos of the Instituto Nacional de Pesquisas da Amazônia, the collector of the type series, in recognition of his many contributions to our knowledge of the Amazonian fish fauna. Material examined Holotype: BRAZIL. Rondônia, Rio Jamari, above site of Usina Hidroelétrica Samuel (approximately 08 ° 27 ′ S, 063 ° 30 ′ W), station Polo 666, collected by G. M. Santos, 4 April 1985; INPA 20966 (197). Paratypes: BRAZIL. Collected with holotype, INPA 36382, 9 (73 – 212; 3 CS); MPEG 21686, 1 (100); MZUSP 110185, 1 (132); USNM 404357, 1 (100).	en	Vari, Richard P., Santana, Carlos David De, Wosiacki, Wolmar B. (2012): South American electric knifefishes of the genus Archolaemus (Ostariophysi, Gymnotiformes): undetected diversity in a clade of rheophiles. Zoological Journal of the Linnean Society 165 (3): 670-699, DOI: 10.1111/j.1096-3642.2012.00827.x, URL: http://dx.doi.org/10.1111/j.1096-3642.2012.00827.x
