Aphyocheirodon hemigrammus

description

Body elongated; greatest body depth contained 2.3 to 3.1 and caudal peduncle depth 9.2 to 10.0 times in SL; head length 3.5 to 4.2, predorsal distance 1.8 to 2.0 and caudal peduncle length 6.6 to 8.8 in SL; snout length 3.7 to 4.4, horizontal orbital diameter 2.8 to 3.2 and least interorbital width 3.0 to 3.4 in HL. Mouth terminal; premaxilla with 8 - 11 teeth, dentary with 20 to 26 teeth and expanded tips, and maxilla with 3 - 5 teeth. Lateral line incomplete, with 6 - 9 pored scales; longitudinal series with 34 - 36 scales; transverse series above lateral line with 5 or 6 scale rows and below with 3 or 4 scale rows. Dorsal fin with 10 or 11 rays, pectoral fin with 11 or 12 rays, pelvic fin with 8 or 9 rays, anal fin with 25 - 27 rays and caudal fin with 19 rays. Ground color pale yellow; dark-brown longitudinal stripe on flank, from pseudotympanum to caudal peduncle; darkbrown blotch occupying whole caudal peduncle depth and caudal-fin base; dark-brown stripe along anal-fin base. Maximum standard length. 37.7 mm. Biological data. Lives in creeks and lagoons (Agostinho et al., 1995).

Peixes da planície de inundação do alto rio Paraná e áreas adjacentes: revised, annotated and updated

discussion

Remarks. Some specimens of A. hemigrammus were identified as Serrapinnus sp. 1 by Graça, Pavanelli (2007). Both species occur in the upper rio Paraná floodplain, where A. hemigrammus has been captured since 2004. Aphyocheirodon hemigrammus can be distinguished by having the central cusp of dentary teeth of same size and with straight edge, and the anal fin of mature males without bony hooks (vs. central cusp of dentary teeth much longer than lateral ones, and anal fin of mature males with bony hooks, in Serrapinnus sp. 1). Some specimens of A. hemigrammus do not present predorsal series of scales, whereas other specimens only present scales next to dorsal fin. Eigenmann (1915) described that species from the rio Grande, upper rio Paraná basin in Minas Gerais State, Brazil, and stated that the species has “ predorsal area rounded, with a median series of about twelve scales ”. As no other distinguishing characters were observed, the specimens analyzed herein was considered as belonging to the same species, despite the apparently disrupted distribution of the species.

Peixes da planície de inundação do alto rio Paraná e áreas adjacentes: revised, annotated and updated