© Martins et al.

A new loricariid catfish from the upper rio Paraná basin, Brazil has been described.

Microlepidogaster arachas Martins, Calegari & Langeani, sp. nov is a member of the subfamily Hypoptopomatinae and can be distinguished from all congeners except M. perforatus) primarily by having the anterior portion of the compound supraneural plus the first dorsal-fin proximal radial contacting the neural spine of the ninth vertebra.

It can be told apart from M. perforatus by possessing 18–29 dentary teeth (vs. 11–15), a complete series of median lateral plates  reaching the caudal peduncle base, and a continuous lateral line (vs. median series of lateral plates terminating two plates before the end  of the caudal peduncle, with non-perforated and missing plates in the middle of the series); and 20–24 mid-dorsal plates (vs. 9-13).

There also exist a combination of osteological differences between members of the genus.

The new species is known only from tributaries to the rios Araguari, Perdizes and Dourados, all within the rio Paranaíba drainage, upper rio Paraná basin, and is named for the native Arachás people who once inhabited the rio Parnaíba watershed but were exterminated by the Caiapós, another indigenous group, in the 1750s.

For further information download the full, open access paper: Martins, F. O., B. B. Calegari and F. Langeani. 2013. Microlepidogaster arachas, a new species of hypoptopomatine catfish (Siluriformes: Loricariidae) from the upper rio Paraná basin, Brazil. Zootaxa 3608(5): 379-388