identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
7010878EFFA6272CA5F6FCC5CDDCFC05.text	7010878EFFA6272CA5F6FCC5CDDCFC05.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Myloplus aylan Pereira, Ota, Machado, Collins, Andrade, Garcia-Ayala, Jegu, Farias & Hrbek 2024	<div><p>Myloplus aylan Pereira, Ota, Machado, Collins, Ândrade, Garcia-Ayala, Jégu, Farias &amp; Hrbek, new species</p><p>urn:lsid:zoobank.org:act: 2EF3345A-B36F-4BC7-9507-FFECBEB043FC</p><p>(Figs. 2–5; Tab. 3)</p><p>Prosomyleus (Myleus) schomburgkii Géry, 1977:266 [listed, brief description of the subgenus; photo in page 269, above; locality: Alto Solimões (Brazil)].</p><p>Myleus schomburgkii . — Machado-Allison, Fink, 1995:62–63 [cover figure; brief description; illustration, fig. 26:63; locality: Orinoco and Casiquiare rivers (Venezuela)] ―Vari et al., 2009:72 [listed; photo F; locality: Orinoco (Venezuela)].</p><p>Myloplus schomburgkii . — Murrieta-Morey et al., 2019:511–19 [description of a new species of parasite, locality: Rio Nanay basin (Peru)]. — Murrieta-Morey et al., 2021:110 [mortality and water quality; figs. 1C, D; locality: Rio Nanay basin]. — Kolmann et al., 2020:2 [exon-based phylogeny; fig. 1]. — Mateussi et al., 2020:3 [Listed].</p><p>Holotype. INPA 60150, male, 213.01 mm SL, A3742 (GenBank accession OR366877), Brazil, Roraima, Caracaraí municipality, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-60.909&amp;materialsCitation.latitude=1.2595556" title="Search Plazi for locations around (long -60.909/lat 1.2595556)">Baraúna</a>, lago do <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-60.909&amp;materialsCitation.latitude=1.2595556" title="Search Plazi for locations around (long -60.909/lat 1.2595556)">Bento</a>, 01°15’34.4”N 60°54’32.4”W, 17 Jan 2021, M. S. Rocha.</p><p>Paratypes. Brazil: Amazonas: Apuí: INPA 60151, 1, 91.32 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-60.43139&amp;materialsCitation.latitude=-8.711666" title="Search Plazi for locations around (long -60.43139/lat -8.711666)">Guariba</a> tributary of <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-60.43139&amp;materialsCitation.latitude=-8.711666" title="Search Plazi for locations around (long -60.43139/lat -8.711666)">Aripuanã</a> basin, at <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-60.43139&amp;materialsCitation.latitude=-8.711666" title="Search Plazi for locations around (long -60.43139/lat -8.711666)">Reserva Extrativista do Guariba</a>, 08°42’42”S 60°25’53”W, 7 Aug 2008, W. S. Pedroza, W. Ohara, F. R. Ribeiro &amp; T. F. Teixeira. INPA 60153, 1, 81.97 mm SL, rio Guariba at <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-60.43139&amp;materialsCitation.latitude=-8.711666" title="Search Plazi for locations around (long -60.43139/lat -8.711666)">Reserva Extrativista do Guariba</a>, 08°42’42”S 60°25’53”W, 14 Nov 2008, W. S. Pedroza, W. Ohara, F. R. Ribeiro &amp; T. F. Teixeira. Carauari: INPA 60673, 1, 185.0 mm SL, (CTGA 22529), <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-66.964165&amp;materialsCitation.latitude=-2.8444443" title="Search Plazi for locations around (long -66.964165/lat -2.8444443)">Igarapé Pucá</a> tributary of rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-66.964165&amp;materialsCitation.latitude=-2.8444443" title="Search Plazi for locations around (long -66.964165/lat -2.8444443)">Juruá</a>, 02°50’40”S 66°57’51”W, 1 Jul 2022, T. Hrbek. Careiro: INPA 60702, 1, 131.2 mm SL, (CTGA 22278), rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-59.81278&amp;materialsCitation.latitude=-3.705278" title="Search Plazi for locations around (long -59.81278/lat -3.705278)">Juma</a>, interfluve of <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-59.81278&amp;materialsCitation.latitude=-3.705278" title="Search Plazi for locations around (long -59.81278/lat -3.705278)">Madeira-Purus</a>, 03°42’19”S 59°48’46”W, 26 Sep 2021, V. N. Machado. Jutaí: INPA 60672, 1, 178.1 mm SL, (CTGA 22524), rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-66.61833&amp;materialsCitation.latitude=-4.77" title="Search Plazi for locations around (long -66.61833/lat -4.77)">Jutaí</a>, 04°46’12”S 66°37’06”W, 1 Sep 2022, V. N. Machado. INPA 60709, 1, 155.3 mm SL, (CTGA 23316), rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-67.04305&amp;materialsCitation.latitude=-2.9036112" title="Search Plazi for locations around (long -67.04305/lat -2.9036112)">Jutaí</a>, 02°54’13”S 67°02’35”W, 10 Fev 2023, V. N. Machado. BMNH 2024.2.12.1-2, 2, 171.0– 187.1 mm SL, (CTGA 22523, 22525) same collection data as INPA 60672. Presidente Figueiredo: INPA 22192, 2, 275.58– 309.33 mm SL, Balbina, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-59.4725&amp;materialsCitation.latitude=-1.9225001" title="Search Plazi for locations around (long -59.4725/lat -1.9225001)">Uatumã</a>, 01°55’21”S 59°28’21”W, 9 Nov 1985, M. Jégu. Roraima: Caracaraí: INPA 60152, 6, 190.0– 207.7 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-60.909&amp;materialsCitation.latitude=1.2595556" title="Search Plazi for locations around (long -60.909/lat 1.2595556)">Baraúna</a>, lago do <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-60.909&amp;materialsCitation.latitude=1.2595556" title="Search Plazi for locations around (long -60.909/lat 1.2595556)">Bento</a>, 01°15’34.4”N 60°54’32.4”W, 17 Jan 2021, M. S. Rocha. MUBIO 110, 1, 198.70 mm SL, same collection data as INPA 60152 . Peru: Iquitos: Maynas: Loreto: ANSP 180369, 4, 67.68–95.01 mm SL (1 x-ray, 71.3 mm SL), (OR366880), rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-73.34258&amp;materialsCitation.latitude=-3.7824721" title="Search Plazi for locations around (long -73.34258/lat -3.7824721)">Nanay</a>, large sandy beach on downstream end of island upstream from <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-73.34258&amp;materialsCitation.latitude=-3.7824721" title="Search Plazi for locations around (long -73.34258/lat -3.7824721)">Santa Clara</a>, 03°46’56.9”S 73°20’33.3”W, 14 Aug 2003, M. H. Sabaj, N. J. Salcedo &amp; B. Sidlauskas. ANSP 188823, 2, 53.38– 62.73 mm SL, (OR366879), rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-73.34258&amp;materialsCitation.latitude=-3.7824721" title="Search Plazi for locations around (long -73.34258/lat -3.7824721)">Nanay</a>, large sandy beach on downstream end of island upstream from <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-73.34258&amp;materialsCitation.latitude=-3.7824721" title="Search Plazi for locations around (long -73.34258/lat -3.7824721)">Santa Clara</a>, 03°46’56.9”S 73°20’33.3”W, 14 Aug 2003, M. H. Sabaj, N. J. Salcedo &amp; B. Sidlauskas. ANSP 199909, 3, 55.55–61.04 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-73.250275&amp;materialsCitation.latitude=-3.6641667" title="Search Plazi for locations around (long -73.250275/lat -3.6641667)">Nanay</a>, just downstream of sandy beach <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-73.250275&amp;materialsCitation.latitude=-3.6641667" title="Search Plazi for locations around (long -73.250275/lat -3.6641667)">Las Camelias</a>, 7 km from Iquitos, 03°39’51”S 73°15’01”W, 8 Aug 2010, M. H. Sabaj, B. Sidlauskas, C. A. Phillips, J. Tiemann &amp; E. V. Correa Roldán. CIIAP 401, 1, 206.1 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-74.98472&amp;materialsCitation.latitude=-3.3186111" title="Search Plazi for locations around (long -74.98472/lat -3.3186111)">Pucacuro</a>, tributary of rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-74.98472&amp;materialsCitation.latitude=-3.3186111" title="Search Plazi for locations around (long -74.98472/lat -3.3186111)">Tigre</a>, 03°19’07”S 74°59’05”W, 15 May 2003, J. Ruiz. CIIAP 402, 3, 85.2– 8.9 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-73.66603&amp;materialsCitation.latitude=-3.909639" title="Search Plazi for locations around (long -73.66603/lat -3.909639)">Nanay</a>, cocha <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-73.66603&amp;materialsCitation.latitude=-3.909639" title="Search Plazi for locations around (long -73.66603/lat -3.909639)">Anguilla</a>, 03°54’34.7”S 73°39’57.7”W, 18 Jul 2018, C. Chavez. CIIAP 403, 5 (3, 97.0– 113.0 mm SL), rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-73.28361&amp;materialsCitation.latitude=-3.7519445" title="Search Plazi for locations around (long -73.28361/lat -3.7519445)">Nanay</a>, large sandy beach on downstream end of island upstream from <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-73.28361&amp;materialsCitation.latitude=-3.7519445" title="Search Plazi for locations around (long -73.28361/lat -3.7519445)">Panpachica</a>, 03°45’07”S 73°17’01”W, 20 Jan 2019, M. Ruiz-Tafur.</p><p>Diagnosis. Myloplus aylan can be distinguished from all congeners, except M. schomburgkii and M. sauron n. sp. (described below), by the presence of a vertical black bar on the flank commonly extending from the dorsal-fin base to the pelvic-fin distal end (vs. absence of any conspicuous mark on the flank in the rest of the congeners). The new species can be diagnosed from M. schomburgkii and M. sauron by the following characters: parietal bone with dorsal surface markedly concave in lateral view (vs. straight to slightly concave), 82–95 (mode 84) total perforated scales on lateral line [vs. 68–87 (mode 79) in M. schomburgkii and 70–82 (mode 78) in M. sauron]; 40–41 total vertebrae (vs. 36–38), serrae with narrow and long spines (vs. short with wide base); 30–39 prepelvic spines (vs. 17–29 in M. schomburgkii and 20–28 in M. sauron); 38–55 (mode 49) total spines [vs. 27–41 (mode 33) in M. schomburgkii and 29–40 (mode 35) in M. sauron). Also, M. aylan differs from M. schomburgkii and M. sauron by presenting, in juveniles and females, anteroposterior decreasing of anal-fin rays length almost uniform, forming broad lobe, occupying half of the anal-fin extension (vs. abrupt anteroposterior decreasing of anal-fin rays length, forming narrow falcated anal-fin lobe in juveniles and females, restricted to the anterior half of the fin, not reaching the middle portion of anal-fin base length, with conspicuous dark-red to black pigmentation on the entire anal fin (vs. orange to reddish-orange pigmentation along its length, mostly concentrated on anterior rays). Additionally, the new species can be diagnosed from M. schomburgkii by presenting anterior ventral-keel spine at the vertical through pectoral-fin origin or anterior to it (vs. anterior spine of ventral-keel always inserted posterior to the vertical through pectoral-fin origin); and from M. sauron by having greater number of branched dorsal-fin rays (21–25 vs. 17–19), wider dorsal-fin base (31.1–37.1% SL vs. 25.6–29.1%), shorter distance between last branched dorsal-fin ray and the last branched anal-fin ray [23.4–28.6% SL (mean 25.3%) vs. 27.8–32.0% (mean 29.7%)], shorter adipose-fin base [5.0–7.7% SL (mean 6.3%) vs. 7.1–9.7% (mean 8.4%)] and greater adipose-fin height (height 0.7–1.1 times in its base vs. 0.4–0.6).</p><p>Description. Morphometric data presented in Tab. 3. Body compressed, overall rounded to oval, with highest body depth at dorsal-fin origin. Predorsal and postdorsal length almost equivalent. Head rounded, snout length slightly shorter than postorbital distance. Dorsal profile of head convex from mouth to anterior margin of parietal bone, and straight to slightly concave from this point to base of supraoocipital. Dorsal-fin base straight to slightly convex. Last dorsal-fin ray distal end not reaching adipose-fin origin, when adpressed. Distance between dorsal-fin insertion and adipose-fin origin about two times the adipose-fin base. Adipose fin as long as deep, with straight base. Ventral profile of head and body convex from lower lip to anal-fin origin. Anal-fin base slightly convex. Dorsal and ventral profile of caudal peduncle concave.</p><p>Mouth terminal. Premaxillary teeth in two rows, outer row with 5*(24) molariform teeth, teeth 1–4 almost equal-sized, tooth 5 smaller, all with sharp, convex edges; inner row with 2*(24) equal-sized teeth with sharp, concave edges; in ventral view, contralateral outer rows forming a V-shaped arch with apex anteriorly pointed; contralateral inner rows forming straight line between the 3 rd teeth of outer series, space between rows forming triangular gap. Dentary with 5*(24) molariform teeth, teeth 1–3 substantially bigger than 4–5. Conical symphyseal tooth immediately behind tooth 1 of labial row. Maxilla edentulous.</p><p>Scale cycloid, small. Total of perforated scales on lateral line 82(1), 83(3), 84*(5), 85(3), 86(3), 87(1), 89(4), 90(1), 91(1), 94(1), or 95(1). Dorsal-fin base covered by skin flap bearing one or two scale rows. Scale rows between dorsal-fin origin and lateral-line 41(2), 44(2), 45(2), 46(2), 47(2), 49(1), 50(1), 51(1), 55(1), 56(1), 57*(4), 58(2), 60(1), or 61(1). Scale rows between lateral-line and pelvic-fin origin 43(1), 44(1), 45(2), 46(4), 47(3), 48(1), 49(2), 50(3), 51(1), 52*(3), 53(1), 54(1), or 57(1). Adipose-fin base covered by three or four scale rows. Scale rows between the adipose-fin origin and lateral-line 19(2), 20(5), 21(7), 22(8), 23(1), 24(1), or 25*(1). Anal-fin base covered by four or five scales rows. Circumpeduncular scales 34(4), 35(2), 36(5), 37(2), 38*(4), 40(3), 41(2), 42(1), or 44(1).</p><p>Dorsal-fin origin slightly anterior to vertical through pelvic-fin origin. Dorsal-fin rays ii, iii*, or iv, 21(1), 22(6), 23*(7), 24(10), or 25(1). Adipose-fin square, length, and depth almost equivalent. Pectoral fin feather-shaped, anterior rays longest. Pectoral-fin rays i*, 13(3), 14(4), 15(6), 16*(12), or 17(2). Anterior pelvic-fin rays longest, not reaching vertical through last spines of serrae. Pelvic-fin rays i,7*(25). Last unbranched anal-fin ray most developed (longest and thicker). Anal-fin rays iii or iv*, 29(1), 30(6), 31*(11), 32(4), 33(2), or 34(1). Caudal-fin forked with almost equal-sized lobes.</p><p>Total gill rakers on first branchial arch 27(2), 28(1), 29*(13), 30(5), or 31(2). Upper branch with 12(2), 13*(13), 14(6), or 15(3) rakers; lower branch with 13(1), 14(5), or 15*(17); 1*(23) at cartilage between cerato- and epibranchial.</p><p>Osteology. Dorsal profile of neurocranium convex from premaxilla to the posterior margin of frontal bone, markedly concave at parietal, convex from the base to tip of supraoccipital process. Lateral view of supraoccipital triangular. Supraneurals 5(6) or 6(3). Dorsal-fin pterygiophores 23(1), 24(4), or 25(4). First dorsal-fin pterygiophore inserted between neural spines of 9 th and 10 th (8) or 10 th and 11 th (1) vertebrae, more developed than remaining pterygiophores, with expanded anterior lamella, and bearing forward-oriented predorsal spine. Predorsal spine somewhat similar to scythe, its dorsal surface smooth; almost completely covered by skin. Anal-fin pterygiophores 31(2), 32(4), or 33(4) (Fig. S1).</p><p>Total vertebrae 40(8) or 41(1); Weberian apparatus, 4(10); abdominal 18(6) or 19(3) [Predorsal, 5(7) or 6(2); under dorsal-fin 13(8) or 14(1)]; caudal 17(3) or 18(6) [under dorsal-fin 3(4) or 4(5), posterior to dorsal-fin 14(9)]. Anterior spine of ventral keel never reaching vertical through pectoral-fin origin. Long spines, with an almost uniform width throughout its length, with piercing tips. First prepelvic spines covered by skin. Postpelvic spines more developed than prepelvic spines. Total ventral keel spines 38(1), 40(1), 41(1), 46(2), 47(5), 48(3), 49(7), 51(2), 53(1), or 55*(1). Prepelvic spines 30(2), 31(1), 32(4), 33(4), 35(5), or 39*(1); unpaired post-pelvic spines 10(4), 11*(11), or 12(7); and paired spines around anus 4(16), 5*(7), or 6(1).</p><p>Coloration in alcohol. Ground coloration yellow to pale brown. Brown pigmentation on dorsal portion of head and body. Middle portion of flanks and belly light yellow. Sclera yellow. Bright yellow pigmentation skirting ventral keel extension. High concentration of melanophores form a broad, vertical brown bar extending from the midpoint of dorsal-fin base to midpoint of pelvic-fin length, wider at lateral line. Pectoral, pelvic and caudal fins yellowish hyaline. Dorsal and anal fins yellow, with conspicuous dark-brown pigmentation most concentrated along base and in extension of anterior rays. Adipose-fin yellow, with dark black outlining on its distal margins (Fig. 2).</p><p>Coloration in life. Ground coloration grayish silver. Purplish-silver scales along dorsal region of body, and silvery white scales covering middle portion of flank and belly. Scattered orange-red pigmentation on body, more concentrated on head and pectoral region.Dark vertical bar similar to color in alcohol.Dark olive-yellow pigmentation mostly concentrated on antero-dorsal portion of head. Scattered orangish-red pigmentation on postero-ventral portion of head and pectoral girdle. Sclera white. Paired fins yellowishhyaline. Basal half of dorsal and caudal fins yellow, followed by white area, and distal ends with dark pigmentation. Adipose fin grayish yellow, with subtle dark margins. Anal fin hyaline with black or dark-red pigmentation throughout (Fig. 3).</p><p>Sexual dimorphism. Mature males with two anal-fin lobes; first lobe at anterior rays, less developed; second lobe centered on 13 th or 14 th branched ray, about twice as long as first lobe. Females and juveniles with single, broad lobe, formed by remarkable prolongation of anterior rays, and occupying more than half of fin (i.e., rays decreasing gradually in length from anteriormost rays to middle rays). Breeding males present black pigmentation throughout body, more conspicuous on head, predorsal region and fins, and dark-red pigmentation mostly concentrated on middle portion of flank. Females present grayish-brown pigmentation on antero-dorsal region of head and predorsal region, all fins grayish-hyaline, except for anal fin (which is dark red to black), red to dark-red pigmentation on middle portion of flank and well-marked vertical bar surrounded by light area. Males also differ from females by presenting long filaments extending dorsal-fin branched rays, and stiff hooks on distal-most lepidotrichia segments of anal-fin branched rays.</p><p>Geographical distribution. Myloplus aylan is widespread through Nanay, Tigre (tributary of Marañon), Branco, Juruá, Jutaí, Purus, Madeira, and Uatumã basin, in Peru and Brazil, mostly restricted to the western portion of the Amazon basin. In white water rivers the species is only captured in tributaries with black or clear water (Fig. 4).</p><p>Ecological notes. Myloplus aylan appears to be more abundant in black water rivers such as the Nanay in Peru, Pitinga, and Jutaí rivers in Brazil. In white water rivers such as the Juruá and Madeira, the species was captured in black water lakes. However, it also occurs in clear water rivers such as Água Boa do Univini and Baraúna, tributaries of the Branco River. White water rivers of Andean origin seem to constitute a chemical barrier for this species, since in the Branco, Juruá and Madeira rivers, the species was captured only in black water lakes of these basins. The same distribution pattern was registered to its congener M. nigrolineatus (Ota et al., 2020) . Ríos-Villamizar et al. (2020) classify the black waters of the várzea environments as Intermediate type B, since they present intermediate levels of suspended solids originating from ancient sediments and those recently eroded from the Andes. These characteristics allow the presence of M. aylan in Amazonian floodplain environments.</p><p>Conservation status. This new taxon is threatened by exploitation from commercial fishing (Fig. 5) (upper Solimões River), by pollution, primarily from mining (Branco River) in the environments where it occurs (Nyholt et al., 2022; Vasconcellos et al., 2022), and by the proposed construction of hydroelectric projects in the region of the upper Solimões River (Winemiller et al., 2016; Castello, Macedo, 2016). This species is also exploited to a limited extent by fishing for the ornamental trade, mainly in the upper Solimões region in Peru (García-Dávila et al., 2022), where attempts have already been made to reproduce this species in captivity (Murrieta et al., 2021), without success. Fish farming of M. aylan aims to meet the market demand for ornamental fish and for food consumption, but induced reproduction has not yet been successful. In addition, since 2009 Myloplus aylan is considered a species prohibited from extracting and commercializing, unless it comes from management programs in Peru (PERU, 2009). Although many threats are identified in the range of occurrence of M. aylan, this species has a wide distribution in western Amazonia. Following the IUCN categories and criteria the species can be categorized as Least Concern (LC) (IUCN Standards and Petitions Subcommittee, 2022).</p><p>Etymology. The specific name honors the late Aylan Moraes Andrade, Carine Moraes and Marcelo Andrade’s son, born on December 23, 2022, who passed away prematurely on July 6, 2023. Marcelo is one of the authors of this manuscript and this is a tribute to record all the love and dedication of his parents who will never forget him. A noun in apposition.</p></div>	https://treatment.plazi.org/id/7010878EFFA6272CA5F6FCC5CDDCFC05	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Machado, Valéria N.;Pereira, Victória D.;Ota, Rafaela P.;Collins, Rupert A.;Ândrade, Marcelo;Garcia-Ayala, James R.;Jégu, Michel;Farias, Izeni P.;Hrbek, Tomas	Machado, Valéria N., Pereira, Victória D., Ota, Rafaela P., Collins, Rupert A., Ândrade, Marcelo, Garcia-Ayala, James R., Jégu, Michel, Farias, Izeni P., Hrbek, Tomas (2024): Integrative taxonomy of the black-barred disk pacus (Characiformes: Serrasalmidae), including the redescription of Myloplus schomburgkii and the description of two new species. Neotropical Ichthyology (e 230095) 22 (2): 1-45, DOI: 10.1590/1982-0224-2023-0095, URL: http://dx.doi.org/10.1590/1982-0224-2023-0095
7010878EFFAE2737A51CFF25CCE9FBB5.text	7010878EFFAE2737A51CFF25CCE9FBB5.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Myloplus sauron Pereira, Ota, Machado, Collins, Andrade, Garcia-Ayala, Jegu, Farias & Hrbek 2024	<div><p>Myloplus sauron Pereira, Ota, Machado, Collins, Ândrade, Garcia-Ayala, Jégu, Farias &amp; Hrbek, new species</p><p>urn:lsid:zoobank.org:act: ADA03DE2-2F3D-42B0-8860-67BEDC5B7A33</p><p>(Figs. 6–8; Tab. 4)</p><p>Holotype: INPA 40824, male, 166.39 mm SL, Brazil, Pará, Anapu municipality, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.613888&amp;materialsCitation.latitude=-3.1299999" title="Search Plazi for locations around (long -51.613888/lat -3.1299999)">Xingu</a>, below the <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.613888&amp;materialsCitation.latitude=-3.1299999" title="Search Plazi for locations around (long -51.613888/lat -3.1299999)">Tamaracá</a> waterfall, entrance on the right bank of the river, parallel to BR-230, 03°07’48”S 51°36’50”W, 1 Oct 2013, M. H. Sabaj Pérez, L. M. Sousa, A. Gonçalves, N. K. Lujan, D. B. Fitzgerald &amp; P. M. Ito.</p><p>Paratypes. All from Brazil: Pará: rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-52.210278&amp;materialsCitation.latitude=-3.3038888" title="Search Plazi for locations around (long -52.210278/lat -3.3038888)">Xingu</a> basin. Altamira: INPA 4151, 1, 71.64 mm SL, ilha de <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-52.210278&amp;materialsCitation.latitude=-3.3038888" title="Search Plazi for locations around (long -52.210278/lat -3.3038888)">Babaquara</a>, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-52.210278&amp;materialsCitation.latitude=-3.3038888" title="Search Plazi for locations around (long -52.210278/lat -3.3038888)">Xingu</a>, 03°18’14”S 52°12’37”W, 4 Oct 1990, L. H. R. Py-Daniel &amp; J. Zuanon. INPA 30884, 2, 56.56–67.06 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-52.619164&amp;materialsCitation.latitude=-3.815" title="Search Plazi for locations around (long -52.619164/lat -3.815)">Iriri</a>, close to its mouth in rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-52.619164&amp;materialsCitation.latitude=-3.815" title="Search Plazi for locations around (long -52.619164/lat -3.815)">Xingu</a>, 03°48’54”S 52°37’09”W, 15 Aug 2008, H. Lopez-Fernandez. INPA 31160, 1, 106.63 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-53.409447&amp;materialsCitation.latitude=-4.237222" title="Search Plazi for locations around (long -53.409447/lat -4.237222)">Iriri</a>, down stream from mouth of rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-53.409447&amp;materialsCitation.latitude=-4.237222" title="Search Plazi for locations around (long -53.409447/lat -4.237222)">Novo</a>, 04°14’14”S 53°24’34”W, 22 Aug 2008, H. Lopez-Fernandez. MZUSP 105723, 1, 110.48 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.876915&amp;materialsCitation.latitude=-3.5621943" title="Search Plazi for locations around (long -51.876915/lat -3.5621943)">Xingu</a>, 03°33’43.9”S 51°52’36.9”W, 6 Nov 2000, Eq. Ictiologia UFPA. MNRJ 35028, 1, 158.7 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-55.01611&amp;materialsCitation.latitude=-8.109722" title="Search Plazi for locations around (long -55.01611/lat -8.109722)">Curuá</a>, northeast of Castelo dos Sonhos (22 km via BR plus 18 km via secondary road), 08°06’35”S 55°00’58” W, 30 Sep 2008, P. A. Buckup, J. Maldonado &amp; C. Zawadzki. Anapú: INPA 40279, 1 (x-ray), 109.97 mm SL, (OR366896), rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.709724&amp;materialsCitation.latitude=-3.5194445" title="Search Plazi for locations around (long -51.709724/lat -3.5194445)">Bacajá</a>, 03°31’10”S 51°42’35”W, 15 Sep 2013, M. H. Sabaj. INPA 060148, 1, 138.8 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.613888&amp;materialsCitation.latitude=-3.1299999" title="Search Plazi for locations around (long -51.613888/lat -3.1299999)">Xingu</a>, downstream of the <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.613888&amp;materialsCitation.latitude=-3.1299999" title="Search Plazi for locations around (long -51.613888/lat -3.1299999)">Tamaracá</a> waterfall, 03°07’48”S 51°36’50”W, 1 Oct 2013, M. H. Sabaj. MUBIO 109, 1, 163.51 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.7175&amp;materialsCitation.latitude=-3.4080555" title="Search Plazi for locations around (long -51.7175/lat -3.4080555)">Xingu</a>, 3.5 km upstream from <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.7175&amp;materialsCitation.latitude=-3.4080555" title="Search Plazi for locations around (long -51.7175/lat -3.4080555)">Praia do Caju</a>, 03°24’29”S 51°43’03”W, 8 Nov 2014, M. H. Sabaj. Medicilândia: MZUSP 36827, 2 of 4, 60.85–125.06 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-52.533306&amp;materialsCitation.latitude=-3.8" title="Search Plazi for locations around (long -52.533306/lat -3.8)">Xingu</a> at cachoeira do <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-52.533306&amp;materialsCitation.latitude=-3.8" title="Search Plazi for locations around (long -52.533306/lat -3.8)">Espelho</a>, 03°48’00”S 52°31’59.9”W, 23 Oct 1986, P. E. V. Vanzolini. Senador José Porfírio: INPA 47142, 4 of 6, 38.6–62.77 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.766666&amp;materialsCitation.latitude=-3.5869443" title="Search Plazi for locations around (long -51.766666/lat -3.5869443)">Bacajaí</a>, tributaryof rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.766666&amp;materialsCitation.latitude=-3.5869443" title="Search Plazi for locations around (long -51.766666/lat -3.5869443)">Xingu</a>, 03°35’13”S 51°46’00”W, 9 Nov 2014, M. H. Sabaj. Uruará: INPA 31820, 1, 110.8 mm SL, Maia community, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.75111&amp;materialsCitation.latitude=-3.526389" title="Search Plazi for locations around (long -51.75111/lat -3.526389)">Xingu</a>, canal do <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.75111&amp;materialsCitation.latitude=-3.526389" title="Search Plazi for locations around (long -51.75111/lat -3.526389)">Paletó</a>, 03°31’35”S 51°45’04”W, 9 Nov 2008, L. H. R. Py-Daniel. Mato Grosso: Paranatinga: LBP 25971, 1, 129.3 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-53.260834&amp;materialsCitation.latitude=-13.846666" title="Search Plazi for locations around (long -53.260834/lat -13.846666)">Culuene</a>, 13°50’48”S 53°15’39”W, 25 Jan 2018, N. Falusino Junior, N. Estevão &amp; F. A. Machado.</p><p>Non-types. All from Brazil, Pará, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.855553&amp;materialsCitation.latitude=-3.5630555" title="Search Plazi for locations around (long -51.855553/lat -3.5630555)">Xingu</a> basin. Altamira: INPA 4273, 2, ilha de <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.855553&amp;materialsCitation.latitude=-3.5630555" title="Search Plazi for locations around (long -51.855553/lat -3.5630555)">Kaituka</a>, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.855553&amp;materialsCitation.latitude=-3.5630555" title="Search Plazi for locations around (long -51.855553/lat -3.5630555)">Xingu</a>, 03°33’47”S 51°51’20”W, 8 Oct 1990, L. H. R. Py-Daniel &amp; J. Zuanon. INPA 43638, 1, 48.75 mm SL, rio Xingu, 03°33’18”S 52°21’24”W, 18 Mar 2014, I. M. Soares. INPA 47088, 1, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-52.349167&amp;materialsCitation.latitude=-3.6094444" title="Search Plazi for locations around (long -52.349167/lat -3.6094444)">Xingu</a>, 03°36’34”S 52°20’57”W, 4 Nov 2014, M. H. Sabaj. INPA 47284, 1, 47.38 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.73639&amp;materialsCitation.latitude=-3.048889" title="Search Plazi for locations around (long -51.73639/lat -3.048889)">Xingu</a>, praia do <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.73639&amp;materialsCitation.latitude=-3.048889" title="Search Plazi for locations around (long -51.73639/lat -3.048889)">Caju</a>, 03°02’56”S 51°44’11”W, 7 Nov 2014, I. M. Soares. INPA 47568, 6, ilha de <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-52.35611&amp;materialsCitation.latitude=-3.5622222" title="Search Plazi for locations around (long -52.35611/lat -3.5622222)">Boa Esperança</a>, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-52.35611&amp;materialsCitation.latitude=-3.5622222" title="Search Plazi for locations around (long -52.35611/lat -3.5622222)">Xingu</a>, 03°33’44”S 52°21’22”W, 3 Nov 2014, M. H. Sabaj. INPA 47587, 9, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-52.34861&amp;materialsCitation.latitude=-3.607222" title="Search Plazi for locations around (long -52.34861/lat -3.607222)">Xingu</a>, praia <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-52.34861&amp;materialsCitation.latitude=-3.607222" title="Search Plazi for locations around (long -52.34861/lat -3.607222)">Itapuama</a>, 03°36’26”S 52°20’55”W, 3 Nov 2014, M. H. Sabaj. INPA 47793, 5, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.82083&amp;materialsCitation.latitude=-3.6208334" title="Search Plazi for locations around (long -51.82083/lat -3.6208334)">Itatá</a>, tributarity of rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.82083&amp;materialsCitation.latitude=-3.6208334" title="Search Plazi for locations around (long -51.82083/lat -3.6208334)">Xingu</a>, 03°37’15”S 51°49’15”W, 10 Nov 2014, M. H. Sabaj. Anapú: INPA 4076, 1, 140.7 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.60611&amp;materialsCitation.latitude=-3.1511111" title="Search Plazi for locations around (long -51.60611/lat -3.1511111)">Xingu</a>, downstream from <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.60611&amp;materialsCitation.latitude=-3.1511111" title="Search Plazi for locations around (long -51.60611/lat -3.1511111)">Volta Grande</a>, 03°09’04”S 51°36’22”W, 28 Aug 2013, J. Zuanon. INPA 40363, 1, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.765556&amp;materialsCitation.latitude=-3.5916667" title="Search Plazi for locations around (long -51.765556/lat -3.5916667)">Bacajaí</a>, upstream to its mouth in rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-51.765556&amp;materialsCitation.latitude=-3.5916667" title="Search Plazi for locations around (long -51.765556/lat -3.5916667)">Xingu</a>, 03°35’30” S 51°45’56”W, 16 Sep 2013, M. H. Sabaj.</p><p>Diagnosis. Myloplus sauron can be readily distinguished from all congeners, except M. schomburgkii and M. aylan, by the presence of a vertical black bar on the flank commonly extending from the dorsal-fin base to the pelvic-fin distal end (vs. absence of any conspicuous mark on the flank in the rest of the congeners). The new species can be diagnosed from M. schomburgkii and M. aylan by having fewer branched dorsal-fin rays (17–19 vs. 20–25 in M. schomburgkii and 21–25 in M. aylan), shorter dorsal-fin base (25.6–29.1% SL vs. 29.2–36.7% in M. schomburgkii and 31.1–37.1% in M. aylan), greater dorsal-fin end to anal-fin end distance [27.8–32.0% SL (mean 29.7%) vs. 21.7–28.8% (mean 25.8%) in M. schomburgkii and 23.4–28.6% (mean 25.3%) in M. aylan], longer adipose-fin base (7.1–9.7% SL (mean 8.4%) vs. 4.6–7.2% (mean 6.0%) in M. schomburgkii and 5.0–7.7% (mean 6.3%) in M. aylan) and lower adipose-fin height (height 0.4–0.6 times in its base, vs. 0.5–1.0 in M. schomburgkii and 0.7–1.1 in M. aylan). Additionally, the new species can be diagnosed from M. schomburgkii by presenting anterior ventral-keel spine at the vertical through pectoral-fin origin or anterior to it (vs. anterior spine of ventral-keel always inserted posterior to the vertical through pectoral-fin origin). Further, M. sauron differs from M. aylan by having 70–82 total of perforated scales on lateral line (vs. 82–95); fewer prepelvic (20–28 vs. 30–39) and total spines (29–40 vs. 38–55); 36–37 total vertebrae (vs. 40–41); serrae composed by short spines with wide bases (vs. long and with narrow bases); dorsal surface of parietal bone straight to slightly concave in lateral view (vs. markedly concave) and by abrupt anteroposterior decreasing of anal-fin rays length, forming narrow falcated anal-fin lobe in juveniles and females, restricted to the anterior half of the fin, not reaching the middle portion of anal-fin base length (see Sexual dimorphism) (vs. anteroposterior decreasing of anal-fin rays length almost uniform, forming broad lobe, occupying half of the anal-fin extension), with orange to reddish-orange pigmentation along its length, mostly concentrated on anterior rays (vs. conspicuous dark-red to black pigmentation on the entire anal fin).</p><p>Description. Morphometric data presented in Tab. 4. Body compressed, overall shape with highest body depth at dorsal-fin origin. Predorsal length slightly longer than postdorsal length. Head rounded, eye at the center of the head. Snout short. Dorsal profile of head convex from mouth to horizontal through dorsal margin of the eye, and straight from this point to base of supraoocipital. Dorsal profile between supraoocipital base and dorsal-fin origin convex. Dorsal-fin base straight to slightly convex. Last dorsal-fin ray distal end not reaching adipose-fin origin when adpressed. Dorsal profile between dorsal-fin insertion and adipose-fin origin straight. Adipose fin longer than deep, with straight base. Dorsal and ventral profile of caudal peduncle concave. Ventral profile of head and body convex from lower lip to anal-fin origin. Anal-fin base straight to slightly convex.</p><p>Mouth terminal. Premaxillary teeth in two rows, outer row with 5*(50) molariform teeth, teeth 1–4 almost equal-sized, tooth 5 smaller, all with sharp, convex edges; inner row with 2*(50) equal-sized teeth with sharp, concave edges; in ventral view, contralateral outer rows forming a V-shaped arch with apex anteriorly pointed; contralateral inner rows forming straight line between the 3 rd teeth of outer series, space between rows forming triangular gap. Dentary with 5*(50) molariform teeth, teeth 1–3 substantially bigger than 4–5. Conical symphyseal tooth immediately behind tooth 1 of labial row. Maxilla edentulous.</p><p>Scales cycloid, small. Total of perforated scales on lateral line 70(1), 72(3), 73(2), 74(1), 75(6), 76(5), 77(5), 78(7), 79(3), 80(1), 81(1), or 82*(4). Dorsal-fin base covered by skin flap bearing one or two scale rows. Scale rows between dorsal-fin origin and lateral line 44(2), 46(2), 47(1), 48(4), 49(3), 50(6), 51(2), 52(3), 53(3), 54(3), 55*(2), 56(2), 57(2), or 59(2). Scale rows between lateral line and pelvic-fin origin 41(1), 42(2), 43(2), 44*(3), 45(5), 46(8), 47(2), 48(3), 49(3), 50(1), 51(4), 54(1), or 55(2). Adipose-fin base covered by five or six scale rows. Scales between adipose-fin origin and lateral line 18(1), 19(1), 21(4), 22(4), 23(5), 24*(14), 25(4), 26(1), or 27(3). Anal-fin base covered by five or six scales rows. Circumpeduncular scales 33(5), 34(5), 35(3), 36(6), 37*(3), 38(5), or 40(3).</p><p>Dorsal-fin origin slightly anterior to vertical through pelvic-fin origin. Dorsal-fin rays ii-iii, 17(6), 18*(32), or 19(11). Adipose fin rectangular. Pectoral-fin feather-shaped, anterior rays longest. Pectoral-fin rays i, 14(6), 15*(30), 16(5), or 17(3). Anterior pelvic-fin rays longest, not reaching vertical through last spines of serrae. Pelvic-fin rays i,7*(40). Last unbranched anal-fin ray most developed (longest and thicker). Anal-fin rays iii or iv, 30(1), 31*(6), 32(13), 33(15), 34(1), 35(4), or 36(1). Caudal-fin forked, with almost equal-sized lobes. Total gill rakers on first branchial arch 27(1), 28(6), 29*(12), 30(9), 31(7), or 32(2). Upper branch with 12(1), 13(3), 14*(16), 15(9), or 16(5) rakers; lower branch with 12(1), 13(4), 14*(21), or 15(11) rakers; 1*(38) at cartilage between cerato- and epibranchial.</p><p>Osteology. Dorsal profile of neurocranium convex from premaxillae to posterior margin of frontal bone, slightly concave to straight at parietal, convex from base to the tip of supraoccipital process. Lateral view of supraoccipital triangular. Supraneurals 4(1) or 5(9). Dorsal-fin pterygiophores 18(1), 19(1), or 20(8). First dorsal-fin pterygiophore inserted between neural spines of 9 th and 10 th (7) or 10 th and 11 th (3) vertebrae, more developed than remaining pterygiophores, with expanded anterior lamella, and bearing a forward-oriented Predorsal-spine. Predorsal spine somewhat similar to scythe, dorsal surface smooth; almost completely covered by skin. Anal-fin pterygiophores 32(1), 33(1), 34(4), 35(3), or 36(1) (Fig. S2).</p><p>Total vertebrae 36(2) or 37(8); Weberian apparatus, 4(10); abdominal 14(1), 15(7), or 16(2) [pre-dorsal, 5(7) or 6(3); under dorsal-fin 9(2) or 10(8)]; caudal 17(3) or 18(7) [under dorsal-fin 3(4) or 4(6), posterior to dorsal-fin 13(1), 14(7), or 15(2)]. Anteriormost spine of ventral keel never reaching vertical through pectoral-fin origin. Short spines, with wide base and thin piercing tips. First prepelvic spines covered by skin. Postpelvic spines more developed than prepelvic spines. Total ventral keel spines 29(2), 32(4), 33(2), 34(6), 35*(10), 36(5), 37(5), 38(1), 39(1), or 40(1). Prepelvic spines 20(1), 21(3), 22(7), 23(10), 24*(7), 25(5), 26(3), or 28(1); unpaired post-pelvic spines 6(1), 7*(20), 8(11), or 9(4); and paired spines around anus 3(2), 4*(25), or 5(8).</p><p>Coloration in alcohol. Ground coloration light grayish brown dorsally, grading to light-yellow ventrally. Narrow, vertical, brown to dark-brown bar on middle of flanks, extending from region near dorsal-fin base to region near ventral-fin distal end, wider on medial portion, narrowing toward its distal ends (Fig. 6). Inconspicuous plumbeous blot on humeral region above lateral line (most common in males). Head brownish gray antero-dorsally and light yellow postero-ventrally. Bright yellow sclera. Pectoral fins dark yellowish hyaline. Pelvic fins light yellow. Dorsal, anal and caudal fins overall yellowish hyaline. Caudal and adipose fins with diffuse brown pigmentation on basal portion. Anal and adipose fins presenting subtle dark line skirting its margins.</p><p>Coloration in life. Ground coloration silvery white. Iridescent bluish-green scales on dorsal portion of body, most concentrated above head. Subtle spot of melanophores on humeral region. Scattered patches of light orange-yellow pigmentation around head, covering markedly opercle, interopercle, branchiostegal membrane, and pectoral girdle. Dark vertical bar on flank similar to color in alcohol. Breeding females present a white area around the vertical dark bar. Vertical dark bar inconspicuous in dimorphic males (see Sexual dimorphism). Paired fins light yellowish hyaline. Dorsal and caudal fins overall yellowish orange, with diffuse dark pigmentation on interradial membranes from base to about two thirds of their length, resulting in an orange bar on their margins. Filaments extending dorsal-fin branched rays of breeding males, when present, dark brown. Anal-fin overall orange-yellow and somewhat hyaline, with subtle dark pigmentation along its length in adults; striking orange, with dark distal margins in juvenile (Fig. 7). Adipose-fin orange-yellow and somewhat hyaline.</p><p>Sexual dimorphism. Mature males with two anal-fin lobes; first lobe at anterior rays, less developed; second lobe centered on 13 th or 14 th branched ray, about twice as long as first lobe. Females and juveniles present single falcate lobe, formed by remarkable prolongation of anterior rays. Mature males with long filaments extending dorsal-fin branched rays. Breeding males might present inconspicuous vertical black bar. Breeding females present well-marked bar surrounded by light area. Stiff hooks on distal-most lepidotrichia segment of anal-fin branched rays not observed (Fig. 8).</p><p>Geographical distribution. Myloplus sauron is known only from the Xingu basin where it is widely distributed, also occurring in its main tributaries such as the Culuene, Iriri, and Bacajá rivers (Fig. 4). However, this species has not yet been recorded below Volta Grande do Xingu rapids.</p><p>Ecological notes. Myloplus sauron is a rheophilic species only known from the Xingu River basin. The species feeds most on plant material being categorized as herbivore (Andrade et al., 2019).</p><p>Etymology. The specific name sauron alludes to the Eye of Sauron, from J. R. R. Tolkien’s “The Lord of the Rings”. The elliptical body of Myloplus sauron, marked with a vertical, black bar tapering toward both ends, resembles the famous vertical-pupilled eye from the novel. A noun in apposition.</p><p>Conservation status. Myloplus sauron is a rheophilic species, restricted to the Xingu River basin and, together with its congener M. schomburgkii, is commercially exploited to a limited extent by fishing for the ornamental trade (Prang, 2007; Isaac et al., 2015). Like most rheophilic fish in this basin, M. sauron may be seriously threatened by changes in its habitat caused by alterations in the course of the Xingu River after the construction of the Belo Monte hydroelectric plant, as the flow of the river changed in some stretches (Fitzgerald et al., 2017, 2018). However, the species has a wide distribution within this basin, also occurring in tributaries less affected by the Belo Monte dam, such as the Iriri and Culuene rivers. Although some threats are detected in its range, M. sauron can be categorized as Least Concern (LC) according to IUCN categories and criteria (IUCN Standards and Petitions Subcommittee, 2022).</p></div>	https://treatment.plazi.org/id/7010878EFFAE2737A51CFF25CCE9FBB5	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Machado, Valéria N.;Pereira, Victória D.;Ota, Rafaela P.;Collins, Rupert A.;Ândrade, Marcelo;Garcia-Ayala, James R.;Jégu, Michel;Farias, Izeni P.;Hrbek, Tomas	Machado, Valéria N., Pereira, Victória D., Ota, Rafaela P., Collins, Rupert A., Ândrade, Marcelo, Garcia-Ayala, James R., Jégu, Michel, Farias, Izeni P., Hrbek, Tomas (2024): Integrative taxonomy of the black-barred disk pacus (Characiformes: Serrasalmidae), including the redescription of Myloplus schomburgkii and the description of two new species. Neotropical Ichthyology (e 230095) 22 (2): 1-45, DOI: 10.1590/1982-0224-2023-0095, URL: http://dx.doi.org/10.1590/1982-0224-2023-0095
7010878EFFB42700A584FB12CCABF868.text	7010878EFFB42700A584FB12CCABF868.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Myloplus schomburgkii (Jardine 1841)	<div><p>Myloplus schomburgkii (Jardine, 1841)</p><p>(Figs. 9–14; Tab. 5)</p><p>Tetragonopterus schomburgkii Jardine, 1841:243 – 44 [original description; plate XXII, Schomburk’s drawing N. 63; type-locality: “ Rio Negro ” (Guyana), without a type designation].</p><p>Myletes schomburgkii Müller, Troschel, 1844:97 [new combination for Tetragonopterus schomburgkii Jardine, 1841]. ― Müller, Troschel, 1845:23, 37 – 38 [redescription based on specimens from “ Guyana, Essequibo ”]. ― Valenciennes, 1850:213 – 14 [description as a new species similar to Tetragonopterus schomburgkii, without considering the new generic arrangement; type-locality: Surinam]. ― Steindachner, 1876:134 – 35 [additional description; comments on sexual dimorphism].</p><p>Myletes palometa Valenciennes, 1850:214 – 15 [original description, type-locality: “Upper Orinoco” (Venezuela)]. ― Steindachner, 1876:134 – 35 [considered a junior synonym of Myletes schomburgkii].</p><p>Myleus schomburgkii Eigenmann, 1910:443 [listed; new combination for Tetragonopterus schomburgkii Jardine, 1841; locality: Essequibo]. ― Gosline, 1951:40 [Listed]. ―Wallace in Ragazzo, 2002:170–75 [listed; Wallace’s plate 29, 96 and 146; locality: Rio Negro (Brazil)].</p><p>Mylophus schomburgkii Eigenmann, 1912:391–92 [spelling error; new combination; additional description].</p><p>Myloplus schomburgkii Eigenmann, 1915:271 [brief description; plates LVI and LVII, locality: ‘Manaos’ (=Manaus, Amazonas, Brazil) and Santarem (Pará, Brazil)].― Norman,1929:824 [listed; locality:rio Madeira (Amazonas, Brazil)]. ― Ohara et al., 2017:135 [brief description; photo; locality: Teles Pires (Brazil)]. ― Machado et al., 2018:8 [species delimitation using the mitochondrial gene cytochrome c oxidase subunit I (COI) recovered four lineages identified as M. schomburgkii; figs. 3e,f showing morphological variation of individuals from Nhamundá and Tapajós rivers, respectively]. ― Kolmann et al., 2020:2 [exon-based phylogeny]. ― Silvano et al., 2020:176 [Listed; brief description; fig. 4.179].</p><p>Myleus (Prosomyleus) schomburgkii Géry, 1977:266 [listed; brief description of the subgenus; photo on page 269, below; locality: Rio Araguaia (Brazil)]. ― Géry, 1979:470–71 [description; plate III, above, dentition].</p><p>Diagnosis. Myloplus schomburgkii can be easily distinguished from all congeners, except M. aylan and M. sauron, by the presence of a vertical black bar on the flank commonly extending from the dorsal-fin base to the pelvic-fin distal tip (vs. absence). The species can be diagnosed from the aforementioned species by presenting anterior spine of ventral-keel posterior to the vertical through pectoral-fin origin (vs. anterior ventral-keel spine at the vertical through pectoral-fin origin or anterior to this point). Additionally, M. schomburgkii can be distinguished from M. sauron by having greater number of branched dorsal-fin rays (20–25 vs. 17–19), greater dorsal-fin base (29.7– 36.7% SL vs. 25.6–29.1%), shorter dorsal-fin end to anal-fin end distance [21.7–28.8% SL (mean 25.8%) vs. 27.8–32.0% (mean 29.7%)], and shorter adipose-fin base [4.6– 7.2% SL (mean 6.0%) vs. 7.1–9.7% (mean 8.4%)]. Myloplus schomburgkii can be readily diagnosed from M. aylan by possessing dorsal surface of parietal bone straight to slightly concave in lateral view (vs. parietal bone markedly concave), 68–87 (mode 79) total perforated lateral-line scales [vs. 82–95 (mode 84)], 37–38 total vertebrae (vs. 40–41), fewer prepelvic (17–29 vs. 30–39) and total ventral-keel spines [27–41 (mode 33) vs. 38– 55 (mode 49)], and serrae composed by short spines with wide bases (vs. long and with narrow bases). Also M. schomburgkii differs from M. aylan by abrupt anteroposterior decreasing of anal-fin rays length, forming narrow falcated anal-fin lobe in juveniles and females, restricted to the anterior half of the fin, not reaching the middle portion of anal-fin base length (see Sexual dimorphism) (vs. anteroposterior decreasing of anal-fin rays length almost uniform, forming broad lobe, occupying half of the anal-fin extension), with orange to reddish-orange pigmentation along its length, mostly concentrated on anterior rays (vs. conspicuous dark-red to black pigmentation on the entire anal fin).</p><p>Description. Morphometric data presented in Tab. 5. Body compressed, overall body shape oval, with highest body depth at dorsal-fin origin. Predorsal and postdorsal length almost equivalent. Head rounded, eye at center of the head. Dorsal profile of head convex from mouth to horizontal through dorsal margin of eye, and straight to slightly concave from this point to base of supraoccipital. Dorsal profile between supraoccipital base and dorsal-fin origin convex. Dorsal-fin base slightly convex. Last dorsal-fin ray distal end not reaching adipose-fin origin when adpressed. Dorsal profile between dorsal-fin insertion and adipose-fin origin straight. Adipose-fin deeper than long, with straight base. Ventral profile of head and body convex from lower lip to anal-fin origin. Anal-fin base slightly convex. Dorsal and ventral profile of caudal peduncle concave.</p><p>Mouth terminal. Premaxillary teeth in two rows, outer row with 5*(91) molariform teeth, teeth 1–4 almost equal-sized, tooth 5 smaller, all with sharp, convex edges; inner row with 2*(91) equal-sized teeth with sharp, concave edges; in ventral view, contralateral outer rows forming a V-shaped arch with apex anteriorly pointed; contralateral inner rows forming straight line between 3rd tooth of outer series, space between rows forming a triangular gap. Dentary with 5*(91) molariform teeth, teeth 1–3 substantially bigger than 4–5. Conical symphyseal tooth immediately behind tooth 1 of labial row. Maxilla edentulous.</p><p>Scales cycloid, small. Perforated scales on lateral line 68(1), 69(2), 71(2), 72(2), 73(5), 74(7), 75(3), 76(7), 77(5), 78(6), 79*(10), 80(4), 81(8), 82(7), 83(4), 84(3), 86(7), or 87(1). Dorsal-fin base covered by skin flap bearing one or two scale rows. Scale rows between dorsal-fin origin and lateral line 38(1), 39(1), 40(2), 41(3), 42(3), 43(6), 44(6), 45*(6), 46(6), 47(7), 48(8), 49(5), 50(2), 51(3), 52(3), 53(5), 54(1), 55(4), 57(2), or 58(1). Scale rows between lateral line and pelvic-fin origin 36(1), 37(3), 38(5), 39(5), 40(10), 41(7), 42*(10), 43(2), 44(4), 45(7), 46(5), 47(2), 48(2), 49(1), 50(1), 51(3), 52(5), 53(1), 54(1), 55(1), or 58(1). Adipose-fin base covered by three or four scale rows. Scale rows between adipose-fin origin and lateral line 15(2), 16(5), 17*(14), 18(18), 19(21), 20(6), 21(10), 22(3), 23(1), or 27(1). Anal-fin base covered by five or six scale rows. Circumpeduncular scales 28(1), 31(3), 32(6), 33(3), 34(13), 35(8), 36(8), 37(12), 38*(10), 39(2), 40(3), or 45(1).</p><p>Dorsal-fin origin slightly anterior to vertical through pelvic-fin origin. Dorsal-fin rays ii-iii, 20(11), 21*(36), 22(30), 23(9), 24(3), or 25(1). Adipose-fin square, length and depth almost equivalent. Pectoral fin feather-shaped, anterior rays longest. Pectoral-fin rays i, 12(1), 14(9), 15*(58), 16(21), or 17(7). Anterior pelvic-fin rays longest, not reaching vertical through last spines of serrae. Pelvic-fin rays i, 6(1) or 7*(97). Last unbranched anal-fin ray most developed (longest and thicker). Anal-fin rays iii or iv, 29(1), 30(1), 31(12), 32(37), 33*(30), 34(4), 35(6), or 36(1). Caudal-fin forked, with almost equal-sized lobes. Total gill rakers on first branchial arch 27(9), 28*(22), 29(19), 30(9) or 31(6). Upper branch with 12(12), 13(32), 14*(15) or 15(7) rakers; lower branch with 13*(7), 14(26), 15(32), or 16(1) rakers; 1*(66) raker at cartilage between cerato- and epibranchial.</p><p>Osteology. Dorsal profile of neurocranium convex from premaxilla to posterior margin of frontal bone, slightly concave to straight at parietal, convex from base to tip of supraoccipital process. Lateral view of supraoccipital triangular. Supraneurals 5(15). Dorsal-fin pterygiophores 22(3), 23(5), 24(4) or 25(2). First dorsal-fin pterygiophore inserted between neural spines of 8 th and 9 th (11) or 9 th and 10 th (4) vertebrae, more developed than remaining pterygiophores, with expanded anterior lamella, and bearing forward-oriented predorsal spine. Predorsal spine somewhat similar to scythe, dorsal surface smooth; almost completely covered by skin. Anal-fin pterygiophores 30(1), 31(1), 32(3), 33(6), or 34(1) (Fig. S3).</p><p>Total vertebrae 37(12) or 38(1); Weberian apparatus 4(15); abdominal 15(3), 16(9), or 17(1) [pre-dorsal, 4(11) or 5(4); under dorsal-fin 11(5), 12(7), or 13(1)]; caudal 16(1), 17(8) or 18(4) [under dorsal-fin 3(5), 4(7), or 5(1); posterior to dorsal-fin 13(6), or 14(7)]. Anteriormost spine of ventral keel never reaching vertical through pectoral-fin origin. Spines overall thin, with wide base and piercing tips. First prepelvic spines covered by skin. Post pelvic spines more developed than prepelvic spines. Total ventral keel spines 29(3), 30(2), 31(5), 32(9), 33(13), 34(12), 35*(13), 36(4), 37(2), 38(2), 39(2), or 40(2). Composed by prepelvic spines 17(2), 18(3), 19(14), 20(9), 21(14), 22(9), 23(7), 24*(4), 25(2), 26(4), 27(2), or 29(1); postpelvic spines 7(11), 8*(34), or 9(26); and paired spines around anus 3*(6), 4(40), or 5(24).</p><p>Coloration in alcohol. Ground coloration light brown dorsally, grading to light-yellow ventrally. Sclera light yellow. Great concentration of melanophores form a wide, well-marked vertical bar extending from region near dorsal-fin base to region near ventral-fin distal end. Numerous scattered, irregular, light brown to dark-brown blots of variable sizes on the entire body including head and fins, mostly concentrated on dorsal regions of body and head. Paired fins yellowish hyaline. Dorsal, anal, and caudal fins yellowish hyaline with inconspicuous dark pigmentation along its distal margins. Adipose fin yellow to light brown (Fig. 9).</p><p>Coloration in life. Based on the Neotype and similar specimens (Fig. 10). Ground coloration grayish silver. Whitish-silver iridescent scales on dorsal region of body. Vertical dark bar and scattered dark blots similar of color in alcohol. Scattered striking red pigmentation mostly concentrated along anterior portion of body (including head), becoming less perceptible at posterior portion (see Sexual dimorphism). Different colors of blots confer a rust appearance to specimens. White sclera, in occasional specimens presenting subtle orange-red pigmentation. Paired fins grayish hyaline, with dark pigmentation concentrated along anterior rays. Dorsal, anal, and caudal fins grayish hyaline, with diffuse dark pigmentation along interradial membranes. Adipose fin grayish brown.</p><p>Sexual dimorphism. Mature males with two anal-fin lobes; first lobe at anterior rays, less developed; second lobe centered on 12 th or 14 th branched ray, about twice as long as first lobe (Fig. 10A). Females and juveniles present single falcate lobe, formed by remarkable prolongation of anterior rays (Fig. 10B). On breeding period male specimens present abundant, striking red pigmentation covering most of head and anterior portion of body, spreading through posterior portion less conspicuously, as scattered spots. Females present orangish-red spots of variable sizes, also more concentrated on head and anterior portion of body, but not covering great uninterrupted areas. Though both sexes present scattered, irregular, dark brown to black blots of variable sizes on entire body including head and fins, in females those are less evident. Males present filaments extending dorsal-fin branched rays, and stiff hooks on distal-most lepidotrichia segment of anal-fin branched rays.</p><p>Geographical distribution. Myloplus schomburgkii is widespread through the Orinoco and Amazon river basins, occurring in the Casiquiare, Branco, Negro, Aripuanã, Nhamundá, Uatumã, Pitinga, Trombetas, Tapajós, Teles Pires, Xingu and Araguaia, rivers in Venezuela and Brazil. In white water river basins, the species is only captured in tributaries with black or clear water (Fig. 4).</p><p>Geographic variation. The species displays three different, well recognizable types of vertical bar on the flanks, which vary in length and shape according to the area of occurrence. In the left bank tributaries of the Amazon River, draining the Guiana shield, the specimens present a well-developed bar (Fig. 11A), extending from near the dorsal-fin base to near the pelvic-fin insertion, always conspicuous below lateral line, presenting regular width throughout its length. Conversely, specimens collected on the right bank of the Amazon River basin (Tapajós, Teles Pires, Xingu and Tocantins rivers) present a shorter bar. Specimens from Teles Pires river basin have the portion of the midlateral bar immediately dorsal to the lateral line much more conspicuous, with the appearance of a well-defined, round to vertically oval black spot (Fig. 12); in some specimens, the portion of the midlateral bar ventral to the lateral line is very faint, although still perceptible; in other specimens, it is unrecognizable (Fig. 13). Besides these two different well-defined types of bars, an intermediary type is observed in specimens from Tapajós, Xingu and Tocantins river basins, in which the midlateral bar is much more conspicuous immediately dorsal to lateral line, with rectangular appearance, while the portion ventral to lateral line is very faint (Fig. 11B). Although these populations present this color pattern variation, they were recovered as a single lineage in molecular analysis, with low intraspecific variance.</p><p>Ecological notes. The species inhabits slow-flowing environments in clear and black water rivers that drain the Guiana and Brazilian Shields. It feeds mainly on aquatic plants (Goulding, 1980), but aquatic insects are also part of its diet (Dary et al., 2017). Although it has been described for the Rio Negro basin, a river with acidic waters (Sioli, 1984; Venticinque et al., 2016), M. schomburgkii occurs mainly in rivers with clear waters that have low concentrations of sediments and humic compounds (Sioli, 1984; Ríos-Villamizar et al., 2014; Venticinque et al., 2016) such as the Aripuanã, Branco, Nhamundá, Trombetas, Tapajós and Tocantins-Araguaia rivers. White water river basins of Andean origin seem to constitute a chemical barrier for this species, since in the Branco, Purus and Madeira rivers, the species was captured only in black water lakes of these basins. The same distribution pattern was registered to its congener M. nigrolineatus (Ota et al., 2020) . Ríos-Villamizar et al. (2020) classify the black waters of the várzea environments as Intermediate type B, since they present intermediate levels of suspended solids originating from ancient sediments and those recently eroded from the Andes. These characteristics allow the presence of M. schomburgkii in Amazonian floodplain environments.</p><p>Etymology. Myloplus schomburgkii was described in honor of Robert H. Schomburgk, who, during an expedition to English Guyana, collected individuals of the species, took notes, and illustrated (Fig. 14) the specimen used by Jardine (1841) to describe the new species. A genitive noun.</p><p>Remarks. Taxonomic history. Jardine (1841) described several species of Neotropical fishes based on illustrations and commentaries provided by Robert H. Schomburgk from his expedition to Guyana, French Guyana, Surinam, and northern Brazil. Among those species, Jardine (1841) described Tetragonopterus schomburgkii (= Myloplus schomburgkii) based on the plate XXII (illustration 68 of Schomburgk; Fig. 14), from “Rio Negro”, without mentioning the precise type-locality or the existence of a preserved type specimen. Although Jardine (1841) did not designate a holotype, according to Art. 73.1.2. of ICZN (International Commission on Zoological Nomenclature) the holotype was fixed by monotypy, once it is possible to deduce that the author based the description on a single specimen. Furthermore, Art. 73.1.4. states that the “Designation of an illustration of a single specimen as a holotype is to be treated as designation of the specimen illustrated; the fact that the specimen no longer exists or cannot be traced does not of itself invalidate the designation”. Thus, the specimen on which Schomburgk based his illustration (see Jardine, 1841: plate XXII) and meristic data is the holotype.</p><p>Müller, Troschel (1844:97) placed Tetragonopterus schomburgkii in Myletes . Subsequently, Müller, Troschel (1845:37–38) provided a complementary description based on a specimen from “ Guiana, in Essequibo ” collected by Richard Schomburgk (Robert Schomburgk’s brother) and deposited in the Zoological Museum of Berlin (ZMB). Zarske (2012) found at ZMB three lots identified as Myletes schomburgkii: ZMB 3638, from Guyana collected by Robert Schomburgk, and ZMB 3639–3640 from Surinam, collected by Stegelich. Jégu, Santos (2002) identified the specimens of lots ZMB 3639 and 3640 as Myleus setiger Müller &amp; Troschel, 1844 in the species redescription, based on teeth arrangement (two premaxillary teeth rows in contact) and on color pattern, with no evidence of a vertical dark bar on the flank, the main diagnostic feature of M. schomburgkii . But the authors did not consider them as typeseries of Myleus setiger because they were collected in Surinam, and its type-locality is Guyana. As Zarske (2012) also provided a figure, x-ray, and a brief description of ZMB 3639, we corroborate here the identification of Jégu, Santos (2002). Another important fact is that they were collected by Stegelich, could not correspond to the specimens used by Müller, Troschel (1845) to redescribe M. schomburgkii .</p><p>Eigenmann, during a visit to ZMB in 1910, identified ZMB 3638 as Myleus setiger, and Zarske (2012) suggested it could be Myleus planquettei . However, Jégu, Santos (2002) mentioned the presence of a gap between the two premaxillary teeth rows, and at the symphysis in this specimen, a character currently used to diagnose Myloplus from Myleus . The authors could not identify this specimen at a specific level. The specimen cataloged as ZMB 3638 is a female (184 mm SL), with 25 total dorsal-fin rays; 39 total anal-fin rays (MJ, pers. obs.). Although it could represent the specimen used by Müller, Troschel (1845) to redescribe M. schomburgkii, it does not fit the original description and is not the holotype of Tetragonopterus schomburgkii Jardine, 1841, once it was collected in Guyana (vs. T. schomburgkii type-locality Rio Negro). Therefore, none of the lots deposited in ZMB could represent the holotype, and the designation of a neotype is necessary (see designation of neotype below).</p><p>Valenciennes (1850), in a comprehensive study of the ichthyofauna from Surinam, described Myletes schomburgkii based on a specimen collected by H. H. Dieperink (erroneously spelled Diepering) and deposited in Rijksmuseum van Natuurlijke Historie in Leiden by C. J. Temminck (the director of the Museum). Posteriorly, this material was donated to MNHN (Muséum National d’Histoire Naturelle), in Paris (Boeseman, 1972). This lot was not found (MJ, pers. obs). On the other hand, the possibility of ZMB 3638 and 3639 being syntypes of Myletes schomburgkii, raised by Fricke et al. (2023), certainly can be ruled out. In the description, despite mentioning it as a new species, Valenciennes (1850:212–13) highlighted that the new species “seems to be an extremely close species to Tetragonopterus schomburgkii ”; and cited parts of the original description of T. schomburgkii, without providing a diagnosis between the two species.</p><p>Subsequently, Valenciennes (1850:214–15) described Myletes palometa from “upper Orinoco” River, based on the observations made by Mr. Humboldt. He stated that M. palometa had a color pattern very similar to T. schomburgkii but described it as a different species because it was collected from another river basin. He did not establish a type specimen for M. palometa . Finally, in the same manuscript, Valenciennes (1850:215–16) described Myletes divaricatus, a species with similar body shape, but with a second anal-fin lobe, indicating it was a male. The author did not mention the presence of a vertical bar on the middle of the flanks.</p><p>Kner (1860:23–24) examined specimens from Rio Branco (Brazil) that had a second anal-fin lobe. However, they had the typical color pattern of T. schomburgkii (i. e., dark vertical bar on the middle of the flank). Thus, the author suggested that the second anal-fin lobe might consist of a secondary sexual character. By the analysis of the gonads, Steindachner (1876:134–35) confirmed that the presence of a second anal-fin lobe is present exclusively in males, corroborating this feature as a secondary sexual character of Myletes schomburgkii . Furthermore, he considered Myletes schomburgkii the senior synonym of Myletes palometa Valenciennes, 1850 and M. divaricatus . Posteriorly, M. divaricatus was considered a junior synonym of Myleus setiger by Jégu, Santos (2002:51, fig. 10a), and M. palometa a junior synonym of T. schomburgkii by Jégu (2003). According to our molecular results, specimens from Rio Orinoco were recovered within the M. schomburgkii clade, corroborating the synonymy proposed by Steindachner (1876) and Jégu (2003).</p><p>Neotype designation. We provide the designation of a neotype, to better define Myloplus schomburgkii, and set a precise type-locality to facilitate the comparison among the congeners described herein [See taxonomic history for explanation about lots ZMB 3638–3939 pointed by Fricke et al., 2023 as possible syntypes of Myletes schomburgkii]. Although the specimen illustrated was a female, considering the presence of solely an anterior lobe on anal fin (vs. two lobes in males), we chose a male specimen as the neotype, considering it was better preserved and exhibited secondary dimorphism of the species. We also restricted the species type-locality to Rio Negro, Barcelos (INPA 60149) (Fig. 9).</p><p>In the original description, Jardine (1841) provided information on general morphology of the body; color pattern, highlighting the presence of a vertical dark bar on the middle of flank; and counts of total fin rays (dorsal-fin rays 25; pectoral-fin rays 15; total pelvic-fin rays 8; total anal-fin rays 39; caudal-fin rays 27); branchiostegal rays (4); ribs (13); and vertebrae (34). Even though the remarkable color pattern of the species was considered until now an autapomorphy, herein we describe two additional species previously identified as M. schomburgkii, that also present a vertical mark on the middle of the flank. Thus, a brief commentary is necessary to explain how we deduced which specimens were conspecific with the holotype and how we based our choice of the neotype.</p><p>Myloplus schomburgkii can be promptly distinguished from M. aylan by the anal-fin lobe extension, dark vertical bar shape, and total vertebrae counts provided by Jardine (1841). In M. aylan the anteriormost anal-fin rays length decreases gradually, forming a broad lobe, occupying half of the anal-fin base length (vs. anal-fin rays length decreasing abruptly, forming a narrow falcated anal-fin lobe in juveniles and females, restricted to the anterior third of the fin or slightly posterior to that point, not reaching the middle portion of anal-fin base in M. schomburgkii). The figure of the holotype in the original description (Jardine, 1841: plate XXII) clearly illustrates the narrow anal-fin lobe. The vertical dark bar is also different in the two congeners, with a uniform width in M. schomburgkii and wider in the central portion in M. aylan . Furthermore, the original description mentions a total of 34 vertebrae (without Weberian apparatus), whereas M. aylan has at least 36 total vertebrae (without Weberian apparatus).</p><p>The Myloplus sauron is from Xingu River basin and has a color pattern that resembles Schomburgk’s illustration (i.e., bluish-green scales mostly concentrated at dorsal region of the body and vertical mark on the flanks tapering toward both ends). Nonetheless, Jardine cited the presence of 25 total dorsal-fin rays, and the greatest count known for M. sauron is 22. Myloplus sauron also differs from the specimen illustrated by having a long adipose-fin base (vs. short). Finally, M. sauron is restricted to Xingu River basin and its occurrence at Negro River basin is unlikely.</p><p>In addition, in the species delimitation analysis, the species were recovered as distinct lineages in all methods. The interspecific genetic distance between M. schomburgkii and M. aylan was 7.9%; and M. schomburgkii and M. sauron was 9.7%. For further detailed comparison between M. schomburgkii and all congeners see Diagnosis and Molecular Results.</p><p>Material examined. Neotype (Present designation). INPA 60149, male, 203.9 mm SL, CTGA 12333 (GenBank accession MG752391.1), Brazil, Amazonas, Barcelos municipality, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-62.928974&amp;materialsCitation.latitude=-0.94905555" title="Search Plazi for locations around (long -62.928974/lat -0.94905555)">Negro</a>, 00°56’56.6”S 62°55’44.3”W, 20 Feb 2013, V. N. Machado. Brazil: Amazonas: Barcelos: INPA 52507, 2, 170.8– 197.1 mm SL, CTGA 12274 (MG752389), 12335 (MG752393), rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-62.928974&amp;materialsCitation.latitude=-0.94905555" title="Search Plazi for locations around (long -62.928974/lat -0.94905555)">Negro</a>, 00°56’56.6”S 62°55’44.3”W, 20 Feb 2013, V. N. Machado. MZUSP 91456, 1, 208.16 mm SL, Tapera community, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-64.066666&amp;materialsCitation.latitude=0.2" title="Search Plazi for locations around (long -64.066666/lat 0.2)">Negro</a>, 00°12’00”N 64°04’00”W, 1 Nov 1972, Expedição Permanente à Amazônia. Apuí: INPA 33610, 76.0 mm SL (x-ray), Amazonas, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-60.43139&amp;materialsCitation.latitude=-8.711666" title="Search Plazi for locations around (long -60.43139/lat -8.711666)">Guariba</a> at <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-60.43139&amp;materialsCitation.latitude=-8.711666" title="Search Plazi for locations around (long -60.43139/lat -8.711666)">Reserva Extrativista do Guariba</a>, 08°42’42”S 60°25’53”W, 14 Nov 2008, W. S. Pedroza, W. Ohara, F. R. Ribeiro &amp; T. F. Teixeira. INPA 36251, 197.5 mm SL, Amazonas, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-60.43139&amp;materialsCitation.latitude=-8.711666" title="Search Plazi for locations around (long -60.43139/lat -8.711666)">Guariba</a> at <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-60.43139&amp;materialsCitation.latitude=-8.711666" title="Search Plazi for locations around (long -60.43139/lat -8.711666)">Reserva Extrativista do Guariba</a>, 08°42’42”S 60°25’53”W, 7 Nov 2008, W. S. Pedroza, W. Ohara, F. R. Ribeiro &amp; T. F. Teixeira. Nhamundá: INPA 46309, 2, 162.8– 175.3 mm SL, CTGA 14526 (MG752395), 14527 (MG752396), rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-57.036667&amp;materialsCitation.latitude=-1.9975001" title="Search Plazi for locations around (long -57.036667/lat -1.9975001)">Paracatu</a>, tributary of rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-57.036667&amp;materialsCitation.latitude=-1.9975001" title="Search Plazi for locations around (long -57.036667/lat -1.9975001)">Nhamundá</a>, 01°59’51”S 57°2’12”W, 10 Nov 2013, V. N. Machado &amp; R. A. Collins. INPA 46311, 1, 62.9 mm SL, CTGA 14479 (MG752394), rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-57.422195&amp;materialsCitation.latitude=1.6908057" title="Search Plazi for locations around (long -57.422195/lat 1.6908057)">Nhamundá</a>, 01°41’26.9”N 57°25’19.9”W, 11 Nov 2013, V. N. Machado. INPA 46312, 2, 138.5– 173.7 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-57.073303&amp;materialsCitation.latitude=-1.8319166" title="Search Plazi for locations around (long -57.073303/lat -1.8319166)">Nhamundá</a>, 01°49’54.9”S 57°04’23.9”W, 12 Nov 2013, V. N. Machado &amp; R. A. Collins . Novo Airão: INPA 30716, 1, 144.4 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-61.543304&amp;materialsCitation.latitude=-2.0235834" title="Search Plazi for locations around (long -61.543304/lat -2.0235834)">Carabinani</a>, 02°01’24.9”S 61°32’35.9”W, 25 Oct 2004, L. N. Carvalho. INPA 39024, 1, 170.5 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-61.272194&amp;materialsCitation.latitude=-1.7155555" title="Search Plazi for locations around (long -61.272194/lat -1.7155555)">Jauaperi</a>, close to its mouth in rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-61.272194&amp;materialsCitation.latitude=-1.7155555" title="Search Plazi for locations around (long -61.272194/lat -1.7155555)">Negro</a>, 01°42’56”S 61°16’19.9”W, 20 Sep 2011, R. P. Ota. INPA 46062, 3, 151.7– 183.4 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-60.81278&amp;materialsCitation.latitude=-2.6027777" title="Search Plazi for locations around (long -60.81278/lat -2.6027777)">Negro</a>, Arquipélago de Anavilhanas, 02°36’10”S 60°48’46”W, 7 Nov 1996, V. Garcia . Novo Aripuanã: INPA 35586, 2, 194.6– 223.7 mm SL, São Miguel community, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-60.193306&amp;materialsCitation.latitude=-5.9944167" title="Search Plazi for locations around (long -60.193306/lat -5.9944167)">Aripuanã</a>, 05°59’39.9”S 60°11’35.9”W, 12 Set 2004, L. H. R. Py-Daniel . Presidente Figueiredo: INPA 22192, 1, 236.8 mm SL, vila de Balbina, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-59.4725&amp;materialsCitation.latitude=-1.9225001" title="Search Plazi for locations around (long -59.4725/lat -1.9225001)">Uatumã</a>, 01°55’21”S 59°28’21”W, 9 Nov 1985, M. Jégu. INPA 22193, 1, 214.81 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-59.47167&amp;materialsCitation.latitude=-1.908611" title="Search Plazi for locations around (long -59.47167/lat -1.908611)">Uatumã</a>, igarapé do <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-59.47167&amp;materialsCitation.latitude=-1.908611" title="Search Plazi for locations around (long -59.47167/lat -1.908611)">Arraia</a>, 01°54’31”S 59°28’18”W, 1 Nov 1985, M. Jégu. INPA 46055, 3, 150–203.9 mm SL, vila de Balbina, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-59.583305&amp;materialsCitation.latitude=-1.1499722" title="Search Plazi for locations around (long -59.583305/lat -1.1499722)">Pitinga</a> at <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-59.583305&amp;materialsCitation.latitude=-1.1499722" title="Search Plazi for locations around (long -59.583305/lat -1.1499722)">Cachoeira 40 ilhas</a>, 01°08’59.9”S 59°34’59.9”W, 14 Oct 1996, V. Garcia. São Sebastião do Uatumã: INPA 46059, 3 of 4, 207.83– 178.24 mm SL, Santa Maria community, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-58.582775&amp;materialsCitation.latitude=-1.716389" title="Search Plazi for locations around (long -58.582775/lat -1.716389)">Capucapu</a>, close to its mouth in rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-58.582775&amp;materialsCitation.latitude=-1.716389" title="Search Plazi for locations around (long -58.582775/lat -1.716389)">Jatapú</a>, cachoeira das <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-58.582775&amp;materialsCitation.latitude=-1.716389" title="Search Plazi for locations around (long -58.582775/lat -1.716389)">Garças</a>, 01°42’59”S 58°34’58”W, 25 Sep 1995, V. Garcia . Mato Grosso: Paranaíta: INPA 44790, 1, 66.7 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-56.708305&amp;materialsCitation.latitude=-9.509167" title="Search Plazi for locations around (long -56.708305/lat -9.509167)">Teles Pires</a> 09°30’33”S 56°42’29.9”W, 9 Oct 209, R. R. de Oliveira. INPA 45456, 5, 58.1–107.4 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-56.711945&amp;materialsCitation.latitude=-9.3747225" title="Search Plazi for locations around (long -56.711945/lat -9.3747225)">Teles Pires</a>, <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-56.711945&amp;materialsCitation.latitude=-9.3747225" title="Search Plazi for locations around (long -56.711945/lat -9.3747225)">Inventário CHTP</a>, 09°22’29”S 56°42’43”W, 15 Dec 2021, Solange, Reginaldo &amp; Rosalvo. INPA 59651, 1, 156.8 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-56.711945&amp;materialsCitation.latitude=-9.375" title="Search Plazi for locations around (long -56.711945/lat -9.375)">Teles Pires</a>, 09°22’30”S 56°42’43”W, L. N. Carvalho. MZUSP 99863, 5 of 13, 46.2– 45.7 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-56.779694&amp;materialsCitation.latitude=-9.3116665" title="Search Plazi for locations around (long -56.779694/lat -9.3116665)">Teles Pires</a>, 09°18’42”S 56°46’46.9”W, 9 Mar 2008, L. Netto-Ferreira . Carlinda: MZUSP 68215, 1, 93.3 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-55.56333&amp;materialsCitation.latitude=-9.990278" title="Search Plazi for locations around (long -55.56333/lat -9.990278)">Teles Pires</a>, 09°59’25”S 55°33’48”W, 29 Sep 2007, F. A. Machado . Paranatinga: MZUSP 94072, 5, 110.38– 134.54 mm SL, rio Culuene at cachoeira do Adelino, 13°53’55’S 53°19’17”W, 20 May 2007, F. C. T. Lima, F. A. Machado &amp; J. Birindelli. MZUSP 98124, 3, 121.34– 144.82 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-53.25&amp;materialsCitation.latitude=-13.833305" title="Search Plazi for locations around (long -53.25/lat -13.833305)">Culuene</a>, 13°49’59.9”S 53°15’00”W, 2 Oct 2007, F. C. T. Lima, F. A. Machado, A. C. Ribeiro &amp; C. L. R. Moreira . Peixoto de Azevedo: MZUSP 97639, 5, 152.7– 200.9 mm SL, (OR366886), rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-54.849167&amp;materialsCitation.latitude=-10.287195" title="Search Plazi for locations around (long -54.849167/lat -10.287195)">Peixoto de Azevedo</a>, tributary of rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-54.849167&amp;materialsCitation.latitude=-10.287195" title="Search Plazi for locations around (long -54.849167/lat -10.287195)">Teles Pires</a>, 10°17’13.9”S 54°50’57”W, 17 Oct 2007, J. Birindelli, L. Netto-Ferreira, M. H. Sabaj &amp; N. Lujan . Pará: Oriximiná: MZUSP 15656, 1, 208.9 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-56.616665&amp;materialsCitation.latitude=-1.4166666" title="Search Plazi for locations around (long -56.616665/lat -1.4166666)">Trombetas</a> at <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-56.616665&amp;materialsCitation.latitude=-1.4166666" title="Search Plazi for locations around (long -56.616665/lat -1.4166666)">Reserva Biológica do Trombetas</a>, 01°25’00”S 56° 37’00”W, 23 Jul 1979, M. Goulding. Roraima: Atauba: INPA 46280, 2, 152.3– 198.8 mm SL, CTGA 12199 (MG752387), 12200 (MG752388), left bank of rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-61.85&amp;materialsCitation.latitude=-1.0605555" title="Search Plazi for locations around (long -61.85/lat -1.0605555)">Branco</a>, 01°03’38”S 61°51’00”W, 10 Dec 2013, V. N. Machado &amp; R. A. Collins . Caracaraí: INPA 23398, 1, 174.53 mm SL, CTGA 14611 (MG752398), rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-61.92806&amp;materialsCitation.latitude=1.1" title="Search Plazi for locations around (long -61.92806/lat 1.1)">Capivara</a>, tributary of rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-61.92806&amp;materialsCitation.latitude=1.1" title="Search Plazi for locations around (long -61.92806/lat 1.1)">Branco</a>, 01°06’00”N 61°55’41”W, 10 Dec 2013. V. N. Machado. MZUSP 79209, 2, 131.6– 168.7 mm SL, rio <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-61.266666&amp;materialsCitation.latitude=1.5" title="Search Plazi for locations around (long -61.266666/lat 1.5)">Branco</a>, 01°30’00”N 61°16’00”W, 28 Oct 1979, M. Goulding. MZUSP 79210, 2, 161.7– 194.7 mm SL, <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-61.866665&amp;materialsCitation.latitude=-1.1666666" title="Search Plazi for locations around (long -61.866665/lat -1.1666666)">rio Branco</a>, 01°10’00”S 61°52’00”W, 9 May 1979, M. Goulding. Venezuela: ANSP 192193, 1, 110.7 mm SL, caño Yurebita, tributaryof <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-66.423744&amp;materialsCitation.latitude=4.218789" title="Search Plazi for locations around (long -66.423744/lat 4.218789)">rio Ventuari</a>, 04°13’07.64”N 66°25’25.5”W, 15 Apr 2010, N. K. Lujan, J. Birindelli &amp; V. Meza.</p><p>Molecular differentiation. We obtained sequence data for representatives of 10 of the 12 recognized species of Myloplus: M. arnoldi, M. asterias, M. levis (Eigenmann &amp; McAtee, 1907), M. lobatus, M. lucienae, M. rubripinnis, M. schomburgkii, M. tiete (Eigenmann &amp; Norris, 1900), M. nigrolineatus and M. zorroi Andrade, Jégu &amp; Giarrizzo, 2016 . No tissues or sequences of M. tumukumak Andrade, Jégu &amp; Gama, 2018 and M. torquatus were available. Nineteen additional nominal Myleini species were also used in the analysis (Fig. 15). A total of 89 sequences initially identified as “ Myloplus schomburgkii ” were obtained, with 40 of these newly generated. These “ M. schomburgkii ” sequences represent 36 haplotypes and 32 unique localities from six major tributaries of the Amazon basin in Brazil (Negro, Branco, Nhamundá, Madeira, Tapajós, Xingu), as well as the Nanay River in Peru, Orinoco basin, and Tocantins-Araguaia system.</p><p>The full nucleotide dataset represented 564 sequences of a median sequence length of 612 bp (range 312–621 bp). After dereplication, 209 sequences of length 621 bp remained (range 405–621 bp). Species discovery using mPTP on the maximum clade credibility consensus of MrBayes trees partitioned the haplotype dataset into 48 putative species clusters (Fig. 15). Within “ M. schomburgkii ” a total of six geographicallystructured species clusters were estimated, comprising: a taxon from the Xingu River corresponding to M. sauron (BPP = 0.97); a taxon from the upper Amazon, Madeira and Branco rivers corresponding to M. aylan (BPP = 0.96); M. schomburgkii from Brazilian Shield rivers including Lower Xingu, Tapajós and Araguaia (BPP = 0.16); M. schomburgkii from Guiana Shield rivers including Negro, Branco and Nhamundá (BPP = 0.26); M. schomburgkii from Orinoco and Casiquiare rivers (BPP = 0.32); and M. schomburgkii from Teles Pires River (BPP = 0.14). Due to the uncertainty within the M. schomburgkii Brazilian and Guiana Shield delimitations with low posterior support, a full range of alternative candidate species is provided in Tab. 6. Among these delimitations, a unified M. schomburgkii cluster from the Brazilian and Guiana Shield had the greatest support (BPP = 0.54). Individuals of M. sauron, M. aylan, and the Brazilian and Guiana Shield M. schomburgkii were all monophyletic with posterior clade support value of 1 (Fig. 15). Smallest interspecific genetic distances (Tab. 6) were 0.097 ( M. sauron vs. M. schomburgkii) and 0.079 ( M. aylan vs. M. schomburgkii). The distance between M. sauron and M. aylan was 0.11 (data not shown).</p></div>	https://treatment.plazi.org/id/7010878EFFB42700A584FB12CCABF868	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Machado, Valéria N.;Pereira, Victória D.;Ota, Rafaela P.;Collins, Rupert A.;Ândrade, Marcelo;Garcia-Ayala, James R.;Jégu, Michel;Farias, Izeni P.;Hrbek, Tomas	Machado, Valéria N., Pereira, Victória D., Ota, Rafaela P., Collins, Rupert A., Ândrade, Marcelo, Garcia-Ayala, James R., Jégu, Michel, Farias, Izeni P., Hrbek, Tomas (2024): Integrative taxonomy of the black-barred disk pacus (Characiformes: Serrasalmidae), including the redescription of Myloplus schomburgkii and the description of two new species. Neotropical Ichthyology (e 230095) 22 (2): 1-45, DOI: 10.1590/1982-0224-2023-0095, URL: http://dx.doi.org/10.1590/1982-0224-2023-0095
