Abstract
Neblinichthys brevibracchium and N. echinasus are new sympatric species from upland tributaries of the Mazaruni River (Essequibo River basin) of Guyana. These two new species are the first Neblinichthys reported from Guyana. Adult males of both new species have short pectoral-fin spines and several series of hypertrophied odontodes covering the entire dorsal surface and along the entire edge of the snout. They are distinguished from each other by dorsal-fin base length/standard length (18.1-22.8% in N. brevibracchium vs. 24.3-27.0% in N. echinasus), dorsal-anal distance/SL (13.7-18.3% in N. brevibracchium vs. 11.9-12.5% in N. echinasus), by having the snout decreasing in steep arc just anterior to eyes and then flattening in area anterior of nares in N. brevibracchium vs. the snout tapering shallowly and continuously from eyes to snout tip in N. echinasus); and by having the adpressed dorsal fin reaching the anterior preadipose plate in N. brevibracchium (vs. not reaching anterior preadipose plate in N. echinasus). They are distinguished from all congeners by lacking odontodes on the opercle (vs. odontodes present); and by completely lacking an iris operculum (vs. congeners with small iris operculum present or at least dorsal portion of iris flat instead of rounded). Neblinichthys echinasus and N. brevibracchium differ from all congeners by having a spotted or vermiculated pigment pattern on the abdomen (vs. abdomen plain); in N. echinasus the abdomen is darkly pigmented with bold white spots and in Neblinichthys brevibracchium the abdomen is light-colored with gray spots and vermiculations. Neblinichthys brevibracchium and N. echinasus differ from N. roraima by having one to two preadipose plates (vs. four or more). New observations revealed Neblinichthys roraima and N. yaravi to be distinct, with N. roraima having four or more preadipose plates and N. yaravi having one or two. Both are present in the upper río Caroní, an Orinoco tributary that drains the slopes of Mount Roraima and other mountains of the Pacaraima Range in Venezuela and interdigitates with headwaters of the Mazaruni River.
Highlights
Material and MethodsFerraris et al (1986) described Neblinichthys pilosus, a new genus and species of loricariid catfish in the subfamily Hypostominae, tribe Ancistrini
These two new species are the first Neblinichthys reported from Guyana. Adult males of both new species have short pectoral-fin spines and several series of hypertrophied odontodes covering the entire dorsal surface and along the entire edge of the snout. They are distinguished from each other by dorsal-fin base length/standard length (18.1-22.8% in N. brevibracchium vs. 24.3-27.0% in N. echinasus), dorsal-anal distance/SL (13.7-18.3% in N. brevibracchium vs. 11.9-12.5% in N. echinasus), by having the snout decreasing in steep arc just anterior to eyes and flattening in area anterior of nares in N. brevibracchium vs. the snout tapering shallowly and continuously from eyes to snout tip in N. echinasus); and by having the adpressed dorsal fin reaching the anterior preadipose plate in N. brevibracchium
Neblinichthys echinasus and N. brevibracchium differ from all congeners by having a spotted or vermiculated pigment pattern on the abdomen; in N. echinasus the abdomen is darkly pigmented with bold white spots and in Neblinichthys brevibracchium the abdomen is light-colored with gray spots and vermiculations
Summary
Ferraris et al (1986) described Neblinichthys pilosus, a new genus and species of loricariid catfish in the subfamily Hypostominae, tribe Ancistrini (sensu Armbruster, 2004a). A second species, Neblinichthys roraima, was described from the upper Caroní River, a tributary of the Orinoco River draining the tepui region of the Gran Sabana in southeastern Venezuela (Provenzano et al, 1995) This species was thought to be a synonym of N. yaravi (Steindachner, 1915), (Ferraris, 2007; Armbruster, 2008). We have discovered two new species of Neblinichthys in the upper Mazaruni River, Essequibo River drainage, Guyana These two species differ from all other Neblinichthys by lacking odontodes on the opercle, and by having most of the odontodes arranged along the anterior and lateral margins of the snout in a pattern similar to that of some other ancistrins (like Pseudancistrus and Lasiancistrus) in addition to having slightly shorter odontodes directed dorsally on the snout. Sex was presumed based on the presence of hypertrophied odontodes on the snout being present or developing; some ancistrins have both males and females with hypertrophied snout odontodes (Armbruster & Provenzano, 2000)
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