Meeting Abstract

58.5  Saturday, Jan. 5  Monotypic genera: two unique armored catfish species (Siluriformes: Loricariidae), with naked snouts. SALCEDO, N. J.; College of Charleston, Charleston salcedon@cofc.edu

Although the external morphology of a new species of armored catfish suggested it could be closely related to the genus Chaetostoma, the lack of nuchal plate and dorsal spinelet suggested it could be closely related to Lithogenes or Hemipsilichthys; and the narrow anterior process of its basipterygia suggested it could be closely related to Ancistrus. To determine the taxonomy of the new species based on phylogetic relationships, the new species and Lipoterichthys carrioni (a monotypic genus considered a synonym of Chaetostoma) were included in a published matrix of morphological traits (153 taxa and 215 characters). The results of the phylogenetic analysis retrieved 16123 most parsimonious trees (length 1558; CI=0.18; RI=0.76). The new species was retrieved as sister to Lipopterichthys carrioni, this relationship is supported by nine unambiguously changing characters. Furthermore, the new species and Lipopterichthys carrioni exhibit 11 and 18 unambiguosly changing characters, respectively, but all these characters are homoplasies (CI<0.5). The decision was to describe the new species in a new genus, based on the unique morphology of its evertible cheek odontodes and on its intermediate characters, such as: a slightly projected anguloarticular, and narrow lateral anterior process of the basipterygia, almost in contact with the medial anterior process of the basipterygia.