Bryconops piracolina

description

Description. Morphometric data summarized in Table 1. Largest specimen 71.3 mm SL. Body shape compressed, greatest body depth located just anterior to dorsal-fin origin. Dorsal body profile convex from margin of upper lip to region near nares; straight from that point to end of supraoccipital spine; convex from this point to dorsal-fin origin. Straight and posteroventrally-aligned along dorsal-fin base; straight and convex from end of dorsal-fin base to adipose fin and concave from that point to insertion of dorsal procurrent caudal-fin rays. Ventral body profile convex from lower jaw to pelvic-fin origin; straight from this point to anal-fin origin. Straight and posterodorsally-aligned along anal-fin base; concave from posterior end of anal-fin base to ventral procurrent caudal-fin rays. Caudal peduncle slightly longer than deep. Dorsal-fin origin situated anterior to vertical through pelvic-fin origin and near middle of body. Cheek area between second and third infraorbitals naked ventrally; third infraorbital moderately developed, not reaching preopercle ventrally or at angle. Supraorbital bone present. Eyes large than shout length. Adipose ocular membrane well developed. Maxill

A new species of Bryconops (Teleostei: Characidae) from the rio Madeira basin, Northern Brazil

diagnosis

Diagnosis. Bryconops piracolina belongs to the subgenus Bryconops in having no teeth or rarely one tooth on the maxilla and a naked area on the cheek between the second and third infraorbitals. It is distinguished from all species of this subgenus by the pigmentation of the dorsal fin with a large black blotch extending from near the dorsal-fin base distally for approximately one half the length of most dorsal-fin rays, in contrast to the dorsal fins of congeneres that are slightly pigmented with scattered chromatophores. Bryconops piracolina furthermore is distinguished from all congeners, except B. inpai Knöppel, Junk & Géry, 1968, by possessing an entirely black adipose fin. It differs from B. inpai by its lack of humeral spots. It further differs from all species of the subgenus Bryconops, except for B. caudomaculatus (Günther, 1864), by having the last scales of the longitudinal series of scales that bears the lateral line series not pored beyond the end of the hypural plate. Bryconops piracolina differs from B. caudomaculatus by the number of pored lateral line scales (31 - 36, mean 34.6, n = 8, vs. 37 - 43, mean = 40.6, n = 101, respectively).

A new species of Bryconops (Teleostei: Characidae) from the rio Madeira basin, Northern Brazil

distribution

Distribution. Bryconops piracolina is known from its type locality, Igarapé Piracolina, a tributary to the rio Madeira, rio Amazonas drainage, about 6 km west of Vilhena, Rondônia, Brazil (Fig. 5).

A new species of Bryconops (Teleostei: Characidae) from the rio Madeira basin, Northern Brazil

etymology

Etymology. The specific epithet name piracolina is given in allusion to its type locality, Igarapé Piracolina. A noun in apposition.

A new species of Bryconops (Teleostei: Characidae) from the rio Madeira basin, Northern Brazil