A leading taxonomist has described two new species of glyptosternine catfish from Nepal and China which have adhesive apparatus on their bellies.
Heok Hee Ng of the University of Michigan described the two new sisorid catfishes as Pseudecheneis stenura and P. eddsi in a recent paper in the systematics journal Zootaxa.
The fish were discovered during a study of Pseudecheneis sulcata, a species previously believed to be the most widely distributed member of the Glyptosterninae subfamily, with a reported distribution extending from the Ganges, Brahmaputra, Salween and Irrawaddy to the Mekong.
However, Ng's analyses found that what was previously believed to be a single fish, was actually a complex of several closely related Pseudecheneis species, with the real P. sulcata being restricted to the Brahmaputra drainage, where Ng says it appears to be the only species. He redescribes Pseudecheneis sulcata in the paper.
The first of the two new fishes, Pseudecheneis eddsi, is known from tributaries of the Ganges River in Nepal, and is named in honour of the ichthyologist David Edds. "Externally", says Ng, "P. eddsi is very similar to both P. sulcata, being distinguished by the pelvic fin".
P. stenura comes from the Irrawaddy Drainage in southwestern China and is diagnosed by a number of characters including a prominent bony spur on the anterodorsal surface of the first dorsal-fin pterygiophore, various other osteological features and the presence of pale spots on the body.
The new fish species are members of the sisorid subfamily Glyptosterninae and have a special adhesive sucker on their undersides, just between the bases of the pectoral fins, to help them stick to rocks in fast-flowing water.
The thoracic adhesive apparatus seen in Pseudecheneis consists of a disc containing transverse ridges called laminae, each separated by a groove called a sulca. The apparatus is believed to work rather like the adhesive apparatus on the feet of geckos.
For more details on the new catfishes see the paper: Ng HH (2006) - The identity of Pseudecheneis sulcata (M'Clelland, 1842), with descriptions of two new species of rheophilic catfish (Teleostei: Sisoridae) from Nepal and China. Zootaxa 1254: 45-68 (2006).