Two new species of thicklip thornycats, Genus Rhinodoras (Teleostei: Siluriformes: Doradidae)

Abstract

Rhinodoras is newly diagnosed within Doradidae by its unique combination of coloration (sides darkly mottled, usually with wide dark bars, light midlateral stripe absent) and lip morphology (labial tissue thick, fleshy, considerably expanded at corners of mouth forming rounded flap-like extensions with entire margins, all surfaces rugose with low, rounded, and tightly spaced papillae, and distal margin of lower lip draped over bases of outer and inner jaw barbels, at times nearly encircling the latter). Three previously described species are considered valid, R. thomersoni (Lake Maracaibo basin), R. boehlkei (Amazonas), and R. dorbignyi (Paraguay-Paraná), and two new species are described. Rhinodoras armbrusteri from the Branco/Essequibo basins is diagnosed by having ventral surfaces with dark pigment, anterior midlateral plates moderately deep with dorsal and ventral wings subequal in depth, sum of midlateral plates 57-60, midlateral plates anterior to vertical through pelvic-fin origin usually five, tympanal portion of lateral-line canal moderately ossified with three distinct plates, postcleithral process moderately short and broad, adipose eyelid moderate to large, pectoral-fin rays usually eight, and one-part gas bladder. Rhinodoras gallagheri from the Orinoco basin is diagnosed by having ventral surfaces pale, anterior midlateral plates shallow to moderately deep with dorsal and ventral wings about equal in depth, midlateral plates anterior to vertical through pelvic-fin origin usually five, tympanal portion of lateral-line canal weakly ossified with two to three emergent plates, postcleithral process moderately long and narrow, adipose eyelid moderate to large, pectoral-fin rays usually eight, and one-part gas bladder. Rhinodoras is the only doradid genus with extant species in both trans- and cis-Andean drainages. © 2008 by the American Society of Ichthyologists and Herpetologists.