Astyanax endy

Astyanax endy Mirande, Aguilera & Azpelicueta 2006

A. endy Mirande, Aguilera & Azpelicueta, 2006 New species > details

List of Freshwater Fishes from Argentina - Update 9.

biology_ecology

Habitat notes: In a series of collections made by the authors during different seasons over a three-year period, this species was very abundant in a broad range of environments, from rather fast-flowing streams to deep pools.

Astyanax endy (Characiformes: Characidae), a new fish species from the upper Río Bermejo basin, northwestern Argentina.

description

Description: Morphometric data for the holotype and 27 paratypes are presented in Table 1. Body rather deep, the maximum depth anterior to dorsal-fin origin. Dorsal profile of body moderate to strongly convex in snout region, straight to supraoccipital tip, convex from this point to dorsal-fin origin; slanted ventrally from dorsal-fin origin to caudal peduncle; gently concave along caudal peduncle to caudal-fin base. Ventral profile of body convex from tip of lower jaw to pelvic-fin origin, straight between pelvic and analfin origins, posterodorsally slanted from anal-fin origin to caudal peduncle, and slightly convex along caudal peduncle. Ventral portion of body between bases of pectoral and pelvic fins transversally rounded; ventral portion of body between origins of pelvic and anal fins more compressed. Dorsal-fin origin usually situated nearer base of caudal-fin rays than snout tip. Pelvic-fin origin located anteriorly to vertical through dorsal-fin origin. Anal-fin origin located posteriorly to vertical through base of last dorsal-fin ray. Tip of pectoral fin reaching pelvic-fin origin, and pelvic fin reaching anal-fin origin in larger mature males. Mouth terminal, placed at

Astyanax endy (Characiformes: Characidae), a new fish species from the upper Río Bermejo basin, northwestern Argentina.

diagnosis

Diagnosis: Astyanax endy is distinguished by the combination of the following characters: a markedly convex snout profile; deep body (36.6 - 42.2 % SL); relatively large orbital diameter (36.0 - 40.9 % HL); relatively short interorbital distance (31.9 - 37.6 % HL); deep caudal peduncle (11.7 - 14.1 % SL); long caudal peduncle (12.6 - 15.9 % SL), short upper-jaw length (34.4 - 40.2 % HL); maxilla scarcely reaching anterior margin of eye; maxilla meeting mouth commissure at an oblique angle; 35 - 37 perforated scales in lateral line; 7 / 6 transverse scales above and below lateral line on body; 17 - 24 branched anal-fin rays; tricuspidate or pentacuspidate teeth on outer premaxillary row; 1 - 2 tricuspidate or pentacuspidate maxillary teeth; 4 gradually decreasing dentary teeth, followed by 1 intermediate and 3 - 6 small tricuspidate or conical teeth; and 19 - 21 gill-rakers in first branchial arch. A detailed comparison of Astyanax endy with the other species of Astyanax appears in the “ Discussion ” section later in this paper.

Astyanax endy (Characiformes: Characidae), a new fish species from the upper Río Bermejo basin, northwestern Argentina.