A new rheophilic sisorid catfish from the Glyptothorax genus has been described from Borneo.
Heok Hee Ng of the University of Michigan and Ike Rachmatika of the Indonesian Institute of Sciences recently named the new species in a paper in The Raffles Bulletin of Zoology.
The discovery was made after Ng and Rachmatika compared the Glyptothorax platypogonoides they collected in the Kapuas River drainage in Borneo to specimens of G. platypogonoides Ng had collected with Heok Hui Tan in Sumatra; the fish from Borneo actually turned out to be an undescribed species, which Ng and Rachmatika have named Glyptothorax exodon.
The new fish has a deeper caudal peduncle than platypogonoides, and more of the premaxillary teeth are visible when the catfish has its mouth closed.
The catfish was found in swift-flowing, clear streams with a substrate of gravel, pebbles and large rocks. It shares its habitat with a number of species including the Flying fox, Epalzeorhynchos kalopterus; the bagrid catfish Hemibagrus cf nemurus; the loach Gastromyzon contractus and a puffer called Auriglobus amabilis.
Glyptothorax catfishes are members of the family Sisoridae and typically live in large, fast-flowing waters. They have flattened bodies with a thoracic adhesive organ, which allows them to stick to rocks and maintain their position in turbulent waters.
The Glyptothorax genus is currently being revised by Heok Hee Ng and Maurice Kottelat and currently contains 87 nominal species, which are widely distributed across Asia.
Ng and Rachmatika say that although Glyptothorax are more diverse than the current literature suggests, lots of names have been misapplied, so Ng and Kottelat's forthcoming revision is likely to lead to major changes in the knowledge of the taxonomy of these catfishes.
For more details on the new Glyptothorax see the paper: Ng HH and I Rachmatika (2005) - Glyptothorax exodon, a new species of rheophilic catfish from Borneo (Teleostei: Sisoridae). The Raffles Bulletin of Zoology, 53(2): 251-255.