Pseudomystus

Heok Hee Ng & Darrell J. Siebert, 2005, Pseudomystus stenogrammus, a new species of bagrid catfish from Borneo (Teleostei, Bagridae)., Zootaxa 813, pp. 1-7 : 1-2

[[ Genus Pseudomystus ]]

Pseudomystus (Jayaram) is a genus of bagrid catfishes with about 14 recognised species (depending on synonymy), commonly found in swamps and rivers throughout Southeast Asia. Jayaram (1968) originally described it as a subgenus of Leiocassis Bleeker , for those Leiocassis species with a relatively short snout and subterminal mouth as opposed to those species with a snout produced beyond an inferior mouth. Mo (1991), in a study of the anatomy and systematics of bagrids, elevated Pseudomystus to generic rank based on four putative synapomorphies: 1) a posterior fontanelle absent or reduced to a small hole enclosed entirely in the supraoccipital; 2) the cranial roof elements largely observable through the skin; 3) the pterotic cephalic sensory canal by-passing the extrascapular on way to posttemporal (sensory canal not incorporated into extrascapular); and 4) a hypertrophied nuchal plate (unique among bagrids). Mo’s results also indicate that, although Pseudomystus was proposed originally as a subgenus of Leiocassis , Pseudomystus probably is not closely related to Leiocassis . Instead Pseudomystus is the sister group to a large group of bagrinine genera, of which Leiocassis is a member.

Ten of the recognised Pseudomystus species were described in the period from 1840- 1913. From 1913 until 1959 no new Pseudomystus species were described that are considered valid now, but beginning in 1959 three species were described from Borneo ( Pseudomystus robustus (Inger & Chin , 1959), Pseudomystus myersi (Roberts , 1989), and Pseudomystus flavipinnis Ng & Rachmatika , 1999) and one from Lao PDR ( Pseudomystus bomboides Kottelat , 2000).

Many Pseudomystus species are beautiful fishes with colour patterns of striking contrast, with light bands and/or blotches on a dark background on the body and fins, with the pattern reversed on some fins in some species. Even some species that were described as having uniformly coloured bodies, e.g. P. inornatus (Boulenger , 1894) and P. robustus , have blotches and bands when juvenile (Lim & Wong, 1994; Ng & Rachmatika, 1999). Pseudomystus mahakamensis (Vaillant , 1902) lacks any blotches or bands on the body, instead possessing a clearly defined midlateral stripe on a dark background.