Cyanocharax macropinna Malabarba & Weitzman 2003, new species
Creators: name: Malabarba, Luiz R.
name: Weitzman, Stanley H.
Publisher: name: Zenodo
Year: 2003
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Characiformes
Characidae
Cyanocharax
Cyanocharax macropinna

description: Cyanocharax macropinna Malabarba & Weitzman, new species
(Figs. 1, 5, 8, 16, 45-49, Table 7)
Diagnosis. The presence in C. macropinna of an anal fin sheath of scales covering all, or nearly all, of the anal fin base (versus anal-fin sheath of scales covering base of a maximum of 18 branched rays in all other species), and the high number of anal-fin rays (28-35, mostly 29-33, mean = 31.0, n = 120) diagnoses that species from all congeners (C. itaimbe, 21 -27; C. dicropotamicus, 22-28; C. tipiaia, 21-23; C. lepiclastus, 24-29; C. alegretensis, 23-30; C. alburnus, 20-23).
Description. Morphometric data given in Table 7. Body moderately elongated, compressed. Dorsal head profile nearly straight to slightly convex, with a concavity at nape in larger specimens. Dorsal body profile from nape to dorsal-fin origin convex, and nearly straight between dorsal-fin origin and adipose fin, with a concavity at last dorsal-fin ray base. Ventral body profile convex from lower jaw to pelvic-fin origin, and slightly concave from pelvic-insertion to anal-fin origin. Ventral body profile along anal-fin base nearly straight in young and females to deeply convex in mature males. Dorsal and ventral profiles of the caudal peduncle nearly straight to slightly concave.
Head small (20.7-25.9 % of SL). Eyes relatively large (38.1 -45.0 % of HL). Maxilla large positioned at an angle of 45 degrees relative to long body axis. Posterior tip of maxilla usually reaching or crossing vertical line through anterior border of pupil.
Two series of premaxillary teeth. Teeth of outer series usually tricuspid, smaller than those of inner series, numbering 4 to 5. Four teeth with 5 to 7 cusps in inner series. Four to seven maxillary teeth usually with 3 or 5 cusps. Three large dentary teeth with 5 or 7 cusps, followed by a medium size tooth usually with 3 cusps and a series of 8 to 10 much smaller ones, ranging from 3 cusps to conical, from anteriormost to posteriormost teeth. Second dentary tooth inserted at a lower position in jaws, in such a way that tip of its longest cusp reaches only as high as tip of second largest cusp of first and third dentary teeth (Fig. 49).
Dorsal-fin rays ii,8 (n = 28). Dorsal-fin origin near middle of body length. Adipose fin dorsal to posterior anal-fin ray insertion.
Anal-fin rays iv-vi, 29-35 (x̄= 31.0, n = 120, one specimen from MCP 11340 numbering 26). Anal-fin origin nearly ventral to dorsal-fin origin at middle of body length. Anal-fin distal border nearly straight in females. Anal-fin distal border deeply convex in mature males, with the anal-fin rays of the posterior half of anal fin longer. Anal-fin rays of males with small retrorse bony hooks, present in largest unbranched ray and along most anal fin in well developed males (Fig. 8). Hooks usually present on posterior branches and posterior border of lepidotrichia. Usually one pair of hooks per bony ray segment.
Pectoral-fin rays i, 9 - 11 (x̄ = 9.9, n = 28). Distal end of longest rays extend posterior to pelvic-fin insertion in both males and females. Pelvic-fin rays i, 6 (x̄ = 6.0, n = 36, one specimen with i, 5). Pelvic-fin origin anterior to dorsal-fin origin. Distal end of longest rays reach anal-fin origin. Pelvic fins with ventromedial, usually unpaired retrorse bony hooks on first unbranched and all branched rays in sexually mature males (Fig. 5). Principal caudal rays 10/9.
Scales cycloid. Lateral line incomplete, with 8- 12 (x̄ = 9.7, n = 26) perforated scales. Seven of 26 specimens with alternated series of 8- 12 perforated, 16-23 non-perforated, 3-9 perforated and 1 -4 non-perforated scales. Total number of scales in the lateral line series 36-38 (x̄ = 37.2, n = 19). Scale rows between lateral line and dorsal-fin origin, 5 -7 (x̄ = 6.0, n = 26). Scale rows between lateral line and pelvic-fin origin, 4-5 (x̄ = 4.6, n = 25). Predorsal scales, 11 - 14 (x̄= 12.4, n = 16), usually in an irregular series. Males and females with a sheath of scales on anal-fin base, consisting of one row with 20-30 small scales, covering bases of unbranched rays and at least anterior 22 branched rays, to all anal-fin base.
Vertebrae 36-37 (x̄= 36.2, n = 19), including Weberian apparatus and posterior half centrum (counts taken from x-ray negatives from MCP 14291 and 15092).
Color in alcohol. Figs. 45-46. Body pale brownish yellow. Lateral body stripe black, broad, and diffuse along borders in specimens preserved in formalin long enough to destroy guanine. Specimens retaining guanine with lateral body stripe dark silvery and much broader in males than females. Dark humeral spot small. Exposed borders of scales of dorsal portion of body delineated by dark chromatophores. Caudal fin without perceptible marks except for slightly dark pigmentation that extends along entire length of middle caudal-fin rays in some specimens. Dorsal darkly pigmented except at its tip. Anal fin slightly darkly pigmented, more so along distal border (their pigmentation not obvious in the black and white photos; Figs. 45-46). Adipose fin slightly pigmented. Head black to gray dorsally, especially dark at nape. Sides of head whitish yellow or silvery where guanine still present.
Color in life. Described from photos of a male taken just after formalin fixation (Fig. 47). Sides of head and belly silvery white. Dorsal portion of body dark brown. Midlateral body stripe very broad and light blue from head to caudal-fin base, diffuse in humeral area. Humeral spot present and clearly discernible. Median caudal-fin rays slightly darkly pigmented. Caudal, dorsal, and anal fins light reddish, except for a distinct unpigmented area at tip of dorsal fin. Narrow distal border of anal fin intensely pigmented.
Sexual dimorphism. Males of C. macropinna have a deeply convex distal border of anal-fin instead of the nearly straight profile in females. Males also have anal and pelvic-fin hooks, and longer pelvic and dorsal-fins (Table 7).
Etymology. Macro is from the Greek makros meaning long and pinna is from the Greek pinna meaning fin, in reference to its long anal fin base.
Ecological notes. Eleven lots of MCP were collected in clear to slightly turbid waters, usually in low to moderate velocity water current. All localities had rocks and stones on the bottom and with alternating areas of sand and mud in four of these locations.
Distribution. Cyanocharax macropinna is known from the middle tributaries of rio Uruguay, in the Brazil, Argentina and Uruguay border regions, and from the headwaters of rio Negro along the Uruguay and Brazil borders. No samples of Cyanocharax are available from lower portions of rio Uruguay and rio Negro (Fig. 1).
Holotype. MCP 25973, arroio Pai-Passo, on road Santana do Livramento - Alegrete (RS 183), Quaraí, Rio Grande do Sul, Brazil; 12 Nov 1986.
Paratypes. Rio Uruguay basin. Misiones, Argentina: MCP 13350 (8), arroio Santa Maria, 8 km from Santa Maria, between Santa Maria and Itacaruare, Santa Maria, Missiones; 28 Jun 1989. Rio Grande do Sul, Brazil: MCP 12622 (125, 22.1 -43.7 mm SL), MZUSP 82261 (25), MNRJ 23844 (25, 26.7-35.9 mm SL), USNM 319750 (50), arroio Canoin, on road Pirapó- São Nicolau, Sao Nicolau; 2 Nov 1988. MCP 15092 (9, 24.5 - 38.2 mm SL), collected with holotype. MCP 11340 (33, 20.3-42.7 mm SL), arroio Quaraí-Mirim, on road Quaraí-Alegrete, Quaraí; 12 Nov 1986. MCP 11341 (4, 23.8-36.2 mm SL), creek flowing into arroio Garupá, Quaraí; 12 Nov 1986. MCP 11401 (2, 30.2-30.3 mm SL), arroio Garupá, border between Quaraí and Uruguaiana, Quaraí; 11 - 12 Nov 1986. MCP 15081 (4, 22.9-29.6 mm SL), arroio Garupá, limit between Quaraí and Uruguaiana, Quaraí; 22 Jul 1986. MCP 15099 (5, 22.5 -36.4 mm SL), rio Cati, on road Quaraí-Santana do Livramento, Santana do Livramento; 23 Jul 1986. MCP 16382 (16: 4 c&s, 36.5-46.4 mm SL), MCP 16384 (10: 2 c&s, 26.2-38.8 mm SL), rio Sarandi III, on road Santana do Livramento to Quaraí; 10 Dec 1992. Rio Negro basin, Rio Grande do Sul, Brazil: MCP 9057 (2, 26.9-31.6 mm SL), arroio Valente, BR 153, on road Bagé-Aceguá, Bagé; 25 Oct 1982. MCP 14291 (11; 7c, 27.6-35.0 mm SL), rio Negro, on road Bagé - Aceguá, Bagé; 14 Dec 1989. MCP 14589 (19; 7c, 25.0- 34.9 mm SL), rio Negro, on road Bagé - Pinheiro Machado; 22 Dec 1982.
Non-types: rio Uruguay basin: Misiones, Argentina: MCP 13350 (8, 12.5-37.2 mm SL), 8 km from Santa Maria, between Santa Maria and Itacaruare, Santa Maria, Misiones; 28 Jun 1989. Rio Grande do Sul, Brazil: MCP 25752 (185 collected with MCP 12622), arroio Canoin, on road Pirapó- São Nicolau, São Nicolau; 2 Nov 1988. MCP 16385 (86), arroio Ximbocuzinho, on road São Luiz Gonzaga to Boçoroca, 4 km from access to São Luiz Gonzaga; 11 Dec 1992. MCP 22685, arroio Sarandi, on road Santana do Livramento to Quaraí; 6 Apr 1999. Rio Negro basin, Rio Grande do Sul, Brazil: MCP 16383 (43), rio Piraizinho on road Bagé - Dom Pedrito; 9 Dec 1992. MCP 16380 (8), rio Negro, on road from Bagé to Aceguá, 14 km from Bagé, 9 Dec 1992.
description: Published as part of Malabarba, Luiz R. & Weitzman, Stanley H., 2003, Description Of A New Genus With Six New Species From Southern Brazil, Uruguay And Argentina, With A Discussion Of A Putative Characid Clade (Teleostei: Characiformes: Characidae), pp. 67-151 in Comun. Mus. Ciênc. Tecnol. PUCRS 16 (1) on pages 134-140, DOI: 10.5281/zenodo.10813265