New records of Pimelodella (Siluriformes, Heptapteridae) from Colombia for the Amazon River basin, and redescription of P. serrata.

We recorded Pimelodella bockmanni and P. serrata for the first time for Colombia, based on specimens collected in tributaries from the main channel of the Amazonas River, in the so-called Trapecio Amazónico, in the southernmost region of this country. We also present morphometric, meristic, and osteological data of the examined material, and provide a complementary morphological description of the poorly known P.

A new cryptic species of Imparfinis (Siluriformes: Heptapteridae) from the Orinoco River basin, revealed by an iterative approach.

An iterative analysis of Imparfinis, combining phylogenetic analysis based on cytochrome oxidase gene and multivariate morphometrics, revealed a new cryptic species from the Andean tributaries of the Orinoco River basin, which is described here. The new species is sister to a clade constituted by Imparfinis hasemani and Imparfinis pijpersi, both from the river basins of the Guiana Shield, being also the most geographically proximate species. Nonetheless, the new species is most similar in general appearance to Imparfinis guttatus from the Madeira and Paraguay River drainages, being almost undistinguishable by conventional characters of external morphology, differing only by morphometric attributes overall.

A new species of Pimelodella Eigenmann amp; Eigenmann, 1888 (Siluriformes: Heptapteridae) from the Orinoco River basin.

A new species of Pimelodella is described from western Andean tributaries of the Orinoco River basin. The new species differs from all congeners by a unique set of characters that includes long maxillary barbel, surpassing the dorsal lobe of the caudal fin; relatively short adipose fin (32.8-36.