Tetragonopterus chalceus Agassiz, in Spix & Agassiz, 1829

Silva, Gabriel S. C., Melo, Bruno F., Oliveira, Claudio & Benine, Ricardo C., 2016, Revision of the South American genus Tetragonopterus Cuvier, 1816 (Teleostei: Characidae) with description of four new species, Zootaxa 4200 (1), pp. 1-46 : 15-18

Tetragonopterus chalceus Agassiz, in Spix & Agassiz, 1829

( Fig. 4 , Table 3)

Tetragonopterus chalceus Agassiz, in Spix & Agassiz, 1829: 70 , pl. 33 (original description; type locality: Brasiliae aequinoctialis fluviis); Günther, 1864: 320 (description; British Guyana, Essequibo; Amazonas, Porto do Moz, Ambyiacu); Eigenmann & Eigenmann, 1891: 52 (citation; Suriname, Essequibo, Amazonas); Fowler, 1906: 440 (description); Eigenmann, 1910: 438 (citation; Guianas; Amazonas); Eigenmann, 1917: 59 -62 (citation; Brazil, Guianas, Amazonas and São Francisco rivers); Fowler, 1943: 233 (description; Florência, Colombia); Géry, 1964a: 5 (citation; Peruvian Amazon); Géry, 1964b: 431 (description; ilha do Bananal, Rio Araguaia); Ortega & Vari, 1986: 436: 10 (citation; Amazonas, Peru; common name, "mojarra"); Stewart et al., 1987: 29 (citation; Río Napo, eastern Ecuador); Kottelat, 1988: 79 (authorship, holotype); Géry et al., 1991: 58 (description; Camopi river, French Guyana); Reis, 2003: 212 (list of species in Tetragonopterinae ).

Tetragonopterus gibbosus Steindachner, 1877: 562 , pl. 1 (original description; type locality: “Rio Parahyba [Parnaíba] Brazil).

Diagnosis. Tetragonopterus chalceus is distinguished from T. anostomus , T. denticulatus , T. juruena , and T. kuluene by the presence of 4 principal teeth on dentary (vs. 5–6), and by having larger and more robust teeth (vs. thinner and sharper teeth). Tetragonopterus chalceus differs from T. anostomus and T. araguaiensis by having 11–14 gill-rakers on lower limb of the first gill arch (vs. 17–20). Tetragonopterus chalceus differs from T. carvalhoi by the presence of a rounded dark mark on the caudal peduncle (vs. lozenge-shaped dark mark on caudal peduncle). Tetragonopterus chalceus differs from T. anostomus by having a terminal mouth (vs. subsuperior mouth) and from T. anostomus and T. kuluene by having two conspicuous humeral marks (vs. only one humeral mark). Tetragonopterus chalceus differs from T. argenteus by having 7–9 predorsal scales (vs. 11–17); it also differs from T. franciscoensis by the presence of 20–40 olfactory lamellae (vs. 11–17) and by having more robust teeth on dentary (vs. thinner and sharper teeth). Tetragonopterus chalceus differs from T. denticulatus by having humeral marks separated by a single vertical scale row (vs. humeral marks separated by three vertical scale rows). Tetragonopterus chalceus differs from T. rarus by the lack of longitudinal dark stripes on the trunk (vs. presence of such stripes); it differs from both T. rarus and T. georgiae by having 3.5 scale rows between lateral line and pelvicfin origin (vs. 4.5–5.5). Finally, T. chalceus differs from T. ommatus by having 1–4 teeth on the maxilla (vs. 7–8) and by the presence of a conspicuous dark mark on the caudal peduncle (vs. inconspicuous mark limited to the posterior portion of the caudal peduncle).

TABLE ³. Morphometric for Tetragonopterus chalceus from đistinct South American basins separateđ accorđing to the COI tree resolution ( Fig. 1 ).

Description. Morphometric data summarized in Table 3. Body shape compressed, moderately deep. Greatest body depth at dorsal-fin origin. Dorsal profile convex from snout tip to vertical through middle of orbit; slightly concave from this point to end of occipital process; convex from this point to dorsal-fin origin, straight along dorsalfin base until eighth or ninth branched ray, then smoothly convex from end of dorsal-fin base to terminus of adiposefin base. Ventral profile of body slightly convex from lower lip to slightly behind vertical through pectoral-fin origin; straight or somewhat convex from that point to anal-fin origin; straight along base of anal fin. Prepelvic region transversely flattened with distinct, longitudinally aligned lateral keels. Caudal peduncle with dorsal and ventral profiles slightly concave.

Olfactory lamellae 18 (3), 19 (4), 20 (7), 21 (4), 22 (4), 23 (4), 24 (7), 25 (12), 26 (12), 27 (16), 28 (13), 29 (8), 30 (7), 31 (7), 32 (7), 33 (6), 34 (6), 35 (2) or 40 (3). Snout length smaller than orbital diameter. Mouth terminal. Upper and lower jaws of similar size. Premaxillary teeth in two rows, relatively robust. Outer row with 3 (2), 4 (37), 5 (146), 6 (41) or 7 (3) teeth with three cusps, central cusp longest. Inner row with 4 (3), 5 (232) or 6 (1) teeth with three or five cusps, central cusps twice as long as the lateral cusps. Maxilla with 1 (3), 2 (56), 3 (145) or 4 (29) conic or tricuspidate teeth. Dentary bearing 4 (235) anteriormost teeth with 3 to 5 cusps, followed by one (8 c&s) smaller tooth with three cusps and then 7–12 (8 c&s) small conical teeth of similar size.

Dorsal-fin rays ii,9 (271). First unbranched ray shorter than second one. Dorsal-fin origin anterior to middle of body in SL. Anal-fin rays v,26 (4), v,27 (10), v,28 (31), v,29 (47), v,30 (67), v,31 (40), v,32 (23) or v,33 (8); posterior unbranched and anterior branched rays usually slightly longer than posterior rays. Anal-fin origin at vertical through base of ninth branched dorsal-fin ray. Pelvic-fin rays i,7 (269); its origin situated anterior to vertical line through dorsal-fin origin; tip of adpressed pelvic fin reaching first unbranched anal-fin ray. Pectoral-fin rays i,11 (12) i,12 (44), i,13 (143), i,14 (43) or i,15 (6). Caudal fin forked. Principal caudal-fin rays i,17,1 or i,18,1 (8 c&s). Dorsal procurrent rays 12–13 (8 c&s) and ventral procurrent rays 8–9 (8 c&s).

Scales large and cycloid. Lateral line complete and distinctly curved downward anteriorly. Longitudinal scales 30 (10), 31 (24), 32 (87), 33 (94) or 34 (22). Scale rows between lateral line and dorsal-fin origin 6 (7) or 7 (259). Scale rows between lateral line and pelvic-fin origin 3.5 (268). Predorsal scales 7 to 9. Scale rows around caudal peduncle 12 (4), 13 (67) or 14 (114). Anal-fin base covered by a single row of small scales. Some specimens presenting a high concentration of scales covering both lobes of the caudal fin; such scales smaller than those covering lateral surface of body.

First gill arch with 8 (27), 9 (47), 10 (45) or 11 (5) gill rakers on upper limb and 11 (14), 12 (51), 13 (56) or 14 (3) gill rakers on lower limb. Total vertebrae 30 or 31, precaudal vertebrae 12, intermediate vertebrae 2 and caudal vertebrae 16–17 (8 c&s). Supraneurals 3 (8 c&s).

Color in alcohol. General body color yellowish. Dorsal portions of head and body darkly pigmented. Dorsolateral portion of body with scattered small chromatophores along distal margin of scales; scales of ventrolateral portion of body unpigmented. Opercular and infraorbital bones silvery, with few scattered large chromatophores. Two conspicuous vertical dark humeral marks separated by one scale, anterior mark more evident. Anterior humeral mark extending over four horizontal scale rows above and one or two horizontal scale rows below lateral line. Posterior humeral mark located over three horizontal scales rows above lateral line. Caudal peduncle with a distinctly rounded dark mark covering posterior most regular scales of body and anterior most portion of middle rays of the caudal fin. Midlateral silvery stripe broad, extending from supracleithrum to caudal peduncle. Anal, pelvic, and dorsal fins hyaline, outlined by small chromatophores at distal portions of the rays. Adipose fin hyaline with small chromatophores at distal margins. ( Fig. 4 a).

Sexual dimorphism. Adult males with up to eight bony hooks on the first eight branched rays of anal fin.

Distribution. Tetragonopterus chalceus is distributed in the Amazon basin (including rio Tocantins), Orinoco and the Atlantic drainages of the Guianas such as the Essequibo, Corantijn and Marowijne river basins ( Fig. 2 b).

Remarks. Tetragonopterus chalceus was described by Agassiz, in Spix & Agassiz (1829) based on material collected during the expedition of Martius and Spix to Brazil (1817 to 1820), which explored the São Francisco and the Amazon river basins ( Kottelat 1988). Therefore, the potential holotype of T. chalceus (MHNN 785), as implied by Jacques Géry (see Kottelat 1988) was, thus, provenient from one of the two aforementioned basins. Agassiz (1829) mentioned T. chalceus ’s type locality simply as Habitat in Brasiliae aequinociales (habitat in equinoctial Brazil). Considering the additional species described from equinoctial Brazil [e.g. Hypophtalmus edentatus, Hypophtalmus nuchalis (= Auchenipterus nuchalis ), Cetopsis candiru, Anodus latior (= Potamorhina latior ), Leporinus novemfasiatus (= Leporinus fasciatus ), Pimelodus pirinampu (= Pinirampus pirinampu ), Pimelodus ctenodus (= Calophysus macropterus ), Platystoma planiceps (= Sorubimichthys planiceps ), Platystoma truncatum (= Pseudoplatystoma tigrinum ), Serrasalmus aureus (= Pristobrycon aureus ), Serrasalmus nigricans , Myletes aureus (= Mylossoma aureum )], it is clear that it corresponds to the Amazon basin. Likewise, Agassiz’s species from “Habitat in fluvial S. Francisci [e.g. Rhinelepis aspera, Pimelodus rigidus , Platystoma corruscans (= Pseudoplatystoma corruscans ), Prochilodus argenteus and Serrasalmus piranha (= Pygocentrus piraya )], or Habitat in Brasiliae septentrionalis fluviis [e.g. Hypostoma etentaculatum (= Pterygoplichthys etentaculatus )] correspond unequivocally to the Rio São Francisco basin.

Material examined. Ecuador: ANSP 195250, 6 , 42.7–78.2 mm SL, Rio Lagartococha . Peru: ANSP 136862, 6 , 45.1–51.0 mm SL, Loreto, Iquitos, Río Nanay. LBP 12581, 1, 53.5 mm SL , Loreto, Nauta, Rio Maranõn , 4°18’13.6”S 73°31’16.1”W. OS 18751, 1, 59.5 mm SL , Loreto, Maynas, Río Nanay, 3°49’48.5”S 73°20’13.4”W. Venezuela: ANSP 135695, 1 , 49.2 mm SL, Jabillau, Río Caura , Caño Chuapo . ANSP 135916, 2, 40.5–41.8 mm SL, Bolivar, Rio Caura. LBP 3059, 1, 51.9 mm SL, Caicara del Orinoco , Río Orinoco , 7°38’11.6”N 66°19’04.2”W. Guyana: ANSP 175635, 1 , 60 mm SL, Siparuni river . ANSP 176965, 2 , 64.9–65.0 mm SL, Demerara, Burro, Burro River , 4°39’53”N 58°50’28”W . ANSP 190536, 1, 41.0 mm SL, Rupununi, Essequibo river. OS 18468, 3, 49.8–61.0 mm SL, Essequibo basin, Cuyuni River, 6°52’28.7”N 60°14’54.5”W. OS 18532, 1, 54.8 mm SL; OS 18580, 1, 62.4 mm SL Essequibo basin, Cuyuni River, 6°50’49.9”N 60°8’10.6”W. OS 18550, 1, 60.3 mm SL, Cuyuni River , Essequibo basin, 6°50’41.6”N 60°7’47.6”W. OS 18616, 13, 49.1–68.2 mm SL , Essequibo basin, Cuyuni River, 6°48’35.3”N 59°47’55.1”W. OS 18638, 1, 47.9 mm SL, Cuyuni River , Essequibo basin, 6°41’30.7”N 59°34’38”W . Suriname: ANSP 189627, 1 , 85.4 mm SL, Sipaliwini , Marowijne basin, Lawa river . MHNG 2716.089, 2 , 55.7–57.2 mm SL , Sipaliwini, Tapanahony river. MHNG 2717.036, 3 , 54.7–112.6 mm SL, Wayu camp, Tapanahony river . MZUSP 65485, 2 , 38.2–46.1 mm SL, Brokopondo, Mindrineti river . Brazil: Amazonas: MZUSP 7037 , 57.0– 64.6 mm SL, Jutaí, Rio Canumã , 2°59’00”S 66°58’00”W . MZUSP 17555, 17 , 62.1–98.0 mm SL, Rio Içá, Igarapé Boa Vista . MZUSP 29817, 2 , 44.9–47.1 mm SL, Rio Negro . MZUSP 29820, 26 , 46.0– 75.2 mm SL, Rio Negro basin, Rio Marauiá , 0°24’00”S 65°12’00”W . MZUSP 92214, 6 , 49.5–70.2 mm SL, Rio Tiquié, Pirarara-Poço village , 0°08’40”N 69°12’48”W . Amapá: MZUSP 35008, 6 , 59.3–95.4 mm SL, Amazon basin, Rio Cupuxi , 0°40’00”S 51°40’00”W . MZUSP 101472, 10 , 71.4–79.9 mm SL, Vitória do Jari, Rio Jari , 0°38’35”S 52°30’31”W . MZUSP 101714, 13 , 67.7–84.2 mm SL, Vitória do Jari, Rio Jari , 0°39’42”S 52°30’54”W . Goiás: LBP 17193, 1, 77.5 mm SL, Britânia, Araguaia basin, Rio Vermelho , 15°10’23.2”S 51°09’27.1”W . MZUSP 54091, 4 , 59.6–62.9 mm SL, Minaçu, Rio Tocantins . MZUSP ex 89295, 4, 45.8–53.6 mm SL, Nova Crixás, Araguaia basin, Rio Preto , 14°22’18”S 50°39’13”W . MZUSP 91160, 1, 50.9 mm SL, Aruanã, Araguaia basin, 14°24’11”S 50°59’27”W. Maranhão: MZUSP 87313, 2 , 68.3–69.7 mm SL, Estreito , Tocantins basin, 6°35’18”S 47°12’31”W . Mato Grosso: LBP 3981, 2, 42.1–44.8 mm SL, São Félix do Araguaia, Araguaia basin, 11°38’57.3”S 50°50’59”W. LBP 4011, 2, 58.4–59.4 mm SL; LBP 7770, 1, 71.4 mm SL; LBP 7792, 2, 32.8–35.3 mm SL; Cocalinho, Rio Araguaia basin, 11°40’09”W 50°01’03”W. LBP 7687, 4, 69.8–73.6 mm SL, marginal lagoon of the Rio Araguaia . LBP 8773, 1, 54.1 mm SL, Cocalinho, Araguaia basin, 13°19’22.8”S 50°37’20.7”W. LBP 8857, 1, 56.2 mm SL, Cocalinho, Rio Araguaia basin, 13°22’36.1”S 50°40’08.4”W . LBP 15922, 2, 62.4–68.3 mm SL, Canarana, Rio Xingu, Rio Culuene , 13°31’02.8”S 53°04’41.8”W . LBP 15961, 2, 42.5–44.3 mm SL, Canarana, Rio Xingu, Rio Culuene , 13°29’41.8”S 53°04’57.7”W . LBP 16911, 1, Ribeirão Cascalheira, Rio Xingu, Rio Suiá-Missu , 13°09’13.6”S 51°55’18.7”W . MZUSP 62868, 2 , 50.2–85.6 mm SL, Juruena , Rio Arinos , 10°27’S 58°17’W . MZUSP 63032, 1 , 81.9 mm SL, Vila Bela da Santíssima Trindade, Rio Guaporé , Madeira basin, 15°01’17”S 59°57’90”W . MZUSP 89182, 5, 37.5–47.6 mm SL, Cocalinho, Araguaia basin, 14°25’33”S 50°59’40”W. MZUSP 115276, 30 , 42.5–76.5 mm SL, Paranatinga, Xingu basin, Rio Culuene , 13°49’00”S 53°15’00”W . MZUSP 95855, 9 , 76.1–93.2 mm SL, Itaúba, Rio Tapajós, Rio Teles Pires , 10°58’30”S 55°44’03”W . MZUSP 99121 , 80.0– 93.8 mm SL, Itaúba, Rio Tapajós basin, 11°04’24”S 55°14’35”W . MZUSP 100583, 3 , 57.0– 84.8 mm SL, Aripuanã, Rio Madeira , 10°10’06”S 59°26’50”W . MZUSP 101045, 11 , 68.0– 90.2 mm SL, Aripuanã, Madeira basin, Rio Aripuanã , 10°12’33”S 59°27’39”W . MZUSP 107792, 4 , 71.1–79.3 mm SL, Novo Mundo, Rio Tapajós. Pará: LBP 13832, 2, 49.3–53.0 mm SL, Itaituba, Rio Tapajós , 4°33’09.7”S 56°17’59”W . LBP 13946, 2, 55.6–66.4 mm SL, Itaituba, Rio Tapajós , 4°16’49.5”S 59°59’26”W . LBP 13947, 1, 67.1 mm SL, Itaituba, Rio Tapajós , 4°16’49.5”S 59°59’26.1”W . LBP 16208, 2, 74.5–91.8 mm SL, Itaituba, Rio Tapajós , 4°28’11”S 56°17’01”W . LBP 16663, 7, 34.2–59.9 mm SL, Altamira, Rio Xingu , 3°30’14.3”S 52°02’19.9”W . MZUSP 5449, 3 , 65.1–75.3 mm SL, Oriximiná, Rio Trombetas , 1°46’00”S 55°52’00”W . MZUSP 18106, 1, 57.2 mm SL, Igarapé Muru, downstream Tucuruí. MZUSP 35006, 8 , 48.4–54.7 mm SL, Itaituba, Rio Tapajós . MZUSP 35017, 5 , 47.9–82.3 mm SL, São Luiz, Rio Tapajós , 4°27’00”S 56°15’00”W . MZUSP 92777, 5 , 70.3–100.0 mm SL, Santarém, Lago do Maiacas, Rio Amazonas, 2°27’54”S 54°39’31”W . MZUSP 99499, 11 , 67.1–78.2 mm SL, Jacareacanga, Rio Teles Pires, Rio Tapajós , 9o20’24”S 56o46’33”W. – NUP 8310, 4, 55.2–63.5 mm SL, São Geraldo do Araguaia, 6°19’37.7”S 48°32’15.03”W . Roraima: MZUSP 35004, 36 , 43.1–85.6 mm SL, Rio Branco . Tocantins: LBP 17366, 1, 64.4 mm SL, Rio Tocantins, Palmas, 10°07’59.6”S 48°18’53.0”W . MZUSP 40819, 8 , 46.0–71.0 mm SL, Arraias, Rio Tocantins, 13°05’00”S 46°55’00”W . MZUSP 97933, 6 , 57.2–78.4 mm SL, Alta do Tocantins , Tocantins basin, Rio do Sono, 10°15’40”S 46°53’13”W. NUP 8202, 8, 34.4–53.3 mm SL, Ananás, Rio Tocantins basin . NUP 9034, 1, 54.5 mm SL, Ananás, Rio Tocantins .

Figures

FIGURE 1. Maximum likelihood tree of Tetragonopterus based on partial sequences of cytochrome oxidase c subunit I. Black circles represent bootstrap support ± 80 %; grey circles represent bootstrap support between 50 % and 79 %; values <50 % are not shown. Voucher numbers are represented after species names.

FIGURE 4. Tetragonopterus chalceus. a) MZUSP 115276, Paranatinga, Rio Culuene, Xingu basin; b) Brazil, Goiás, Brejinho de Nazaré, Rio Crixás, Rio Tocantins. Photo (b) by M. Taylor.