Scientists from USA and Venezuela have described two new species of thicklip thorny catfishes of the genus Rhinodoras.
Publishing the descriptions in the latest issue of the journal Copeia, Mark Sabaj, Donald Taphorn and Otto Castillo have named the two new species Rhinodoras armbrusteri and Rhinodoras gallagheri.
Rhinodoras is a genus of doradid catfishes distinguished by a 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).
There are three previously described species: Rhinodoras thomersoni (Lake Maracaibo basin), R. boehlkei (Amazon River drainage), and R. dorbignyi (Paraguay"Paran river drainages).
Rhinodoras armbrusteriThis species is distinguished from other members of the genus in having a combination of: heavily pigmented ventral surfaces with many dark speckles or larger spots on belly usually extending onto chin region; moderately deep anterior midlateral plates, the depth of the fifth plate 26.3"29% of the corresponding body depth, the depth of the dorsal wing slightly less than twice that of the ventral; sum of midlateral plates 57"60, usually five midlateral plates anterior to the vertical through the pelvic-fin origin; tympanal portion of the lateral-line canal moderately ossified with two or three distinct plates, posteriormost plate largest with a low medial ridge or thorn and moderately developed wings with serrated margins; moderately short and broad postcleithral process, depth 36.8"44.3% of length; moderate to large adipose eyelid, horizontal diameter 11.4"14.2% of head length; pectoral fin usually with 8 branched rays; and a single-chambered gas bladder with small and fused terminal diverticula.
Rhinodoras armbrusteri is named after loricariid expert Jonathan Armbruster (who led the expedition that resulted in the discovery of this species), and is only known from Takutu and Rupununi rivers in Guyana.
Given the common name of Dirty Thicklip Thornycat, this species was found hiding in cavities in lateritic boulders submerged in less than three metres of water during the day.
Rhinodoras gallagheri by Mark Sabaj.
Rhinodoras gallagheriGiven the common name of Orinoco Thicklip Thornycat, this species is distinguished from other members of the genus in having a combination of: pale ventral surfaces, largely without dark pigmentation; shallow to moderately deep anterior midlateral plates, the depth of the fifth plate 16.6"26.2% of the corresponding body depth; the depths of the dorsal and ventral wings of the anterior plates about equal; usually five midlateral plates anterior to the vertical through the pelvic-fin origin; the tympanal portion of the lateral-line canal weakly ossified with two to three plates, posteriormost plate largest with a low medial ridge or procumbent thorn; moderately long and narrow postcleithral process, depth 23.9"34.5% of length; moderate to large adipose eyelid, horizontal diameter 10.9"14.6% of head length; pectoral fin usually with 8 branched rays; and a single-chambered gas bladder with small and fused terminal diverticula.
Rhinodoras gallagheri is known from the Orinoco River drainage, and is named after Francis Richard Gallagher, mailroom supervisor at The Academy of Natural Sciences of Philadelphia, for 37 years of dedicated service to the global community of taxonomists and systematists via the shipping and receiving of countless loans of biological specimens.
For more information, see the paper: Sabaj, MH, DC Taphorn and OE Catillo G (2008) Two new species of Thicklip Thornycats, genus Rhinodoras (Teleostei: Siluriformes: Doradidae). Copeia 2008, pp. 209"226.