Hemipsilichthys papillatus, PEREIRA, OLIVEIRA & OYAKAWA

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 : 284-286

HEMIPSILICHTHYS PAPILLATUS PEREIRA, OLIVEIRA & OYAKAWA ( FIG. 6 )

Hemipsilichthys papillatus Pereira, Oliveira & Oyakawa, 2000: 378 : fig. 1 [type locality: Ribeirão Santana, tributary of Rio Preto, at Rio Preto ( approximately 22°02′S 43°47′W) Rio Paraíba do Sul drainage, Minas Gerais, Brazil ].

Specimens examined: Brazil: Minas Gerais: Holotype : MZUSP 53085 (91.8 mm SL), male, Ribeirão Santana, tributary of Rio Preto, at Rio Preto, Rio Paraíba do Sul drainage (approximately 22°02′S 43°47′W), 22 July 1997 . Paratypes: all collected with the holotype: MCP 21423 (2 + 1 c&s, 70.6–77.2 mm SL) , MZUSP 53086 (1, 60.0 mm SL) , UFJF 0378 (5 + 1 c&s, 26.1–85.9 mm SL) , UFJF 0379 (3, 65.2–75.3 mm SL) and USNM 352350 (1, 60.4 mm SL) . Other specimens: MCP 27982 (2, 26.8–36.7 mm SL), Ribeirão Santa Rita, tributary of Ribeirão Santana, itself a tributary of Rio Preto, Rio Preto , 29 July 1997 . MCP 27983 (6, 26.3–45.3 mm SL), Ribeirão Santana, tributary of Rio Preto, Rio Preto , 27 September 1996 .

Diagnosis: Hemipsilichthys papillatus is diagnosed by an autapomorphic mesial bend of the ventral portion of both preopercle and quadrate, forming a concave fossa where strong facial odontodes are implanted ( Fig. 7 ), and by the absence of a dorsal-fin spinelet. It can also be distinguished from H. gobio and H. nimius by having no plates in the dorsal series between the dorsal-fin origin and the end of the adipose fin (vs. dorsal series of plates complete but plates not reaching the mid-dorsal line). H. papillatus can be further distinguished from its congeners by its smaller orbital diameter (8.6–11.8% HL vs. 12.0–14.7% in H. gobio and 15.3–16.9% in H. nimius ).

Description: This species was recently described and illustrated by Pereira et al. (2000) and the description will not be repeated here. Morphometric data, however, are presented in Table 1 for comparative purposes.

Distribution: Hemipsilichthys papillatus is known only from two localities in a tributary of the Rio Preto, Rio Paraíba do Sul basin, Minas Gerais, Brazil ( Fig. 5 ).

Ecology: The type specimens were collected in a small, shallow river, with clear water, moderate to strong current, and a substrate of rocks, loose stones, and gravel.

Figures

Figure 5. Geographical distribution of the species of Delturus and Hemipsilichthys in south-eastern Brazil.

Figure 6. Hemipsilichthys papillatus, holotype, MZUSP 53085, 91.8 mm standard length, male, Ribeirão Santana, Rio Paraíba do Sul drainage, Minas Gerais.

Figure 7. Hemipsilichthys papillatus, MCP 21423, ventral (mesial) view of suspensorium. Scale bar 2 mm. AA, angulo-articular; CP, canal plate; HY, hyomandibula; MP, metapterygoid; POP, preopercle; Q, quadrate.