A new Gladioglanis catfish has been described from the Aripuan River in central Brazil.
Named Gladioglanis anacanthus by Marcelo Rocha, Renildo de Oliveira and Lcia Py-Daniel in the latest issue of the journal Neotropical Ichthyology, the new heptapterid species can be distinguished from congeners by the absence of a dorsal spine and spinelet, a flexible, unbranched first dorsal-fin ray (homologous to spine), followed by five branched dorsal-fin rays, pectoral spine 5.8-6.1% of standard length, five serrations on the front and four serrations on the dentations on the rear edge of the pectoral spine, 22"25 anal-fin rays, round profile of the head in dorsal view, first pterygiophore of the dorsal fin in contact with the neural spine of the eighth vertebra, both caudal-fin lobes with 13 rays and 60 total vertebrae.
Picture kindly supplied by Leandro Sousa
The type locality of G. anacanthus is a large lake, inside an island located in the middle portion of the Aripuan River (which is part of the Madeira River subsystem of the Amazon River drainage).
The new Gladioglanis species, named after its lack of a dorsal spine (from the Greek an, meaning without and akantha, meaning thorn), was found in the flooded forest (igap) on the border of the lake, in a shallow (up to 0.5 m) marginal area on a deep mat of leaf litter as substrate.
For more information, see the paper: Rocha, MS, RR de Oliveira and LHR Py-Daniel (2008) A new species of Gladioglanis Ferraris and Mago-Leccia from rio Aripuan, Amazonas, Brazil (Siluriformes: Heptapteridae). Neotropical Ichthyology 6, pp. 433"438.