Hemipsilichthys, EIGENMANN & EIGENMANN, 1889

Reis, Roberto E., Pereira, Edson H. L. & Armbruster, Jonathan W., 2006, Delturinae, a new loricariid catfish subfamily (Teleostei, Siluriformes), with revisions of Delturus and Hemipsilichthys, Zoological Journal of the Linnean Society 147 (2), pp. 277-299 : 280-281

HEMIPSILICHTHYS EIGENMANN & EIGENMANN

Xenomystus Lütken (1874) : 217 (type species: Xenomystus gobio Lütken, 1874 by original designation. Name preoccupied in fishes by Xenomystus Günther, 1868 as a subgenus of Notopterus ).

Hemipsilichthys Eigenmann & Eigenmann, 1889: 46 (type species: Xenomystus gobio Lütken, 1874 ; name in substitution to Xenomystus Lütken, 1874 ).

Upsilodus Miranda Ribeiro, 1924: 365 (type species: Upsilodus victori Miranda Ribeiro, 1924 by monotypy).

Diagnosis: No uniquely derived features were found to diagnose Hemipsilichthys . The following features are derived for Hemipsilichthys but are shared with a number of other loricariid groups: (1) anterior and posterior edges of hyohyal bone concave, making it spindle-shaped (character 21–0); (2) some of the bifid neural spines under the dorsal fin are perforated above the spinal cord (character 126–1); (3) adductor fossa of the pectoral girdle displaced laterally by the development of anterior and posterior rims of the fossa

KEY TO GENERA OF DELTURINAE

1. Adults with body strong and massive, usually attaining large sizes around 200 mm SL (but D. brevis smaller); eye large (orbital diameter 18.0–24.5% HL); dorsal-fin membrane extended posteriorly and contacting first preadipose plate ................................................................................................................ Delturus

1′. Adults with body slender and elongate, usually attaining sizes smaller than 100 mm SL; eye small (orbital diameter 8.6–16.9% HL); dorsal-fin membrane not or slightly extended posteriorly but never in contact with first preadipose plate ...................................................................................... Hemipsilichthys

(character 152–1); and (4) ventral ridge of the pelvic basipterygium tall (a reversion, character 172–0).

In addition, Hemipsilichthys can be easily recognized by the combination of a high preadipose keel, formed by the azygous preadipose plates, almost symmetrically bifid teeth ( Fig. 2 ) on premaxilla and dentary, small eye (orbital diameter 8.6–16.9% HL), and dorsal-fin membrane not or slightly extended posteriorly but never in contact with the first preadipose plate.

Figures

Figure 2. Teeth of the Delturinae. A, right premaxilary tooth of Delturus angulicauda, USNM 318180, lateral view. Scale bar 1 mm. B–H, dorsal view of right premaxillary tooth crown. B, D. parahybae, MCZ 7726. C, D. angulicauda, USNM 318180. D, D. carinotus, MCP 28039. E, D. brevis, MZUSP 69858. F, Hemipsilichthys papillatus, MCP 21423. G, H. nimius, MCP 31990. H, H. gobio, MCP 19780. Scale bar 250 µm.