Psilorhynchus robustus

Conway, Kevin W., 2011, Osteology of the South Asian Genus Psilorhynchus McClelland, 1839 (Teleostei: Ostariophysi: Psilorhynchidae), with investigation of its phylogenetic relationships within the order Cypriniformes, Zoological Journal of the Linnean Society 163 (5), pp. 50-154 : 65

E. Psilorhynchus robustus F. Psilorhynchus pseudecheneis the interopercle. There is no mandibular sensory canal.

Comparisons

The hyopalatine arch and opercular series of the other species of Psilorhynchus examined are similar in most respects to that described for P. sucatio , with slight differences in the shape of individual bones and the extent of the preopercular–mandibular sensory canal ( Figs 7B–F, 8B–F ). In P. pseudecheneis and P. breviminor the preopercular sensory canal is a short, threepored canal, restricted to the posteroventral edge of the preopercle ( Fig. 8C, F ). In all other species examined the preopercular sensory canal exhibits four or five pores, and extends along the entire length of the preopercle ( Fig. 8B, D, E ). Psilorhynchus gracilis , P. robustus , and P. melissa are the only members of the genus examined that possess a mandibular sensory canal, which is present as a short tube-like ossification along the ventrolateral edge of the anguloarticular ( Figs 7D, E, 8D, E ). Like P. sucatio , all other species of Psilorhynchus exhibit an interopercular–preopercular articulation (Fig. 9A, B). The articular heads of the interopercular–preopercular articulation are particularly well developed in P. robustus , and exhibit an irregular surface (Fig. 9D).

Interestingly, P. sucatio is the only species of Psilorhynchus examined in possession of a large, dorsally directed spine-like process on the lateral face of the quadrate.

Figures

Figure 8. Hyopalatine arch and opercular series of Psilorhynchus, right side in lateral (i) and medial (ii) view. Anterior to left (images reversed). A, Psilorhynchus sucatio, CAS 50289, 39.6-mm SL. B, Psilorhynchus balitora, UMMZ 244782, 31.2-mm SL. C, Psilorhynchus breviminor, ZRC 43452, paratype, 32.0-mm SL. D, Psilorhynchus gracilis, UMMZ 205345, paratype, 39.1-mm SL. E, Psilorhynchus robustus, CMK 17941, paratype, 58.1-mm SL. F, Psilorhynchus pseudecheneis, KU 29517, 41.5-mm SL. Cartilage highlighted in grey. Abbreviations: Ana, anguloarticular; Apa, autopalatine; Cm, coronomeckelian; De, dentary; Ecpt, ectopterygoid; Enpt, endopterygoid; Hy, hyomandibular; Iop, interopercle; MC, Meckel’s cartilage; Mpt, metapterygoid; Mx, maxilla; Op, opercle; Pmx, premaxilla; Pop, preopercle; Q, quadrate; Ra, retroarticular; Sop, subopercle; Sy, symplectic.