[Ichthyology • 2017] Hoplomyzon cardosoi • A New Species of Hoplomyzon (Siluriformes: Aspredinidae) from Maracaibo Basin, Venezuela: Osteological Description Using High-resolution Computed Microtomography of A Miniature Species

Hoplomyzon cardosoi Carvalho, Reis & Friel, 2017

Fig. 1 Hoplomyzon cardosoi, holotype, MCNG 375, 18.5 mm SL, Caño La Raya, Zulia, Venezuela.  Dorsal, left side lateral and ventral views.

DOI: 10.1590/1982-0224-20160143 

ABSTRACT

A new miniature species of banjo catfish of the genus Hoplomyzon is described from the Lake Maracaibo Basin in Venezuela. The new species is distinguished from all its congeners by the straight anterior margin of the mesethmoid (vs. a medial notch); a smooth and straight ventral surface of the premaxilla (vs. presence of bony knobs on the ventral surface of premaxilla); absence of teeth on dentary (vs. teeth present on dentary); configuration of ventral vertebral processes anterior to anal fin, which are composed of single processes anterior to anal-fin pterygiophore (vs. paired process); presence of several filamentous barbel-like structures on the ventral surface of head of adults (vs. small papillous structures in the ventral surface of head of adults); and 8 anal-fin rays (vs. 6 or 7). An extensive osteological description is made of the holotype using high-resolution x-ray computed microtomography (HRXCT).

Keywords: Endemism; Ernstichthys intonsus; Miniaturization; Synapomorphy; Taxonomy

Distribution and habitat. Known from three tributaries, which drain southwestern portions of Lake Maracaibo Basin in Zulia State, Venezuela. The Caño raya at type locality is a medium size stream (~12m wide) with mostly slow flowing white waters running over sand intercalated with riffles of fast flowing waters over pebbles; little marginal and floating vegetation.

Etymology. Hoplomyzon cardosoi is named in honor and memory of a dear colleague who prematurely passed away, Alexandre Rodrigues Cardoso, for his humbleness, positive attitude, and dedicated friendship, and furthermore for his contributions to the taxonomy of Neotropical fishes, including the family Aspredinidae.

Tiago P. Carvalho, Roberto E. Reis and John P. Friel. 2017.  A New Species of Hoplomyzon (Siluriformes: Aspredinidae) from Maracaibo Basin, Venezuela: Osteological Description Using High-resolution Computed Microtomography of A Miniature Species.   Neotropical Ichthyology. 15(1);  DOI: 10.1590/1982-0224-20160143