American ichthyologists Richard Vari and Carl Ferraris have described a new whale catfish from the Takutu River drainage of southwestern Guyana in a recent issue of the journal Neotropical Ichthyology.
Naming the new catfish Cetopsidium soniae after Swiss ichthyologist Sonia Fisch-Muller, the authors distinguish the new species from congeners in details of pigmentation, the length of the pelvic fin, the form of the first rays of the dorsal and pectoral fins in mature males, the relative alignment of the dorsal and ventral profiles of the postdorsal portion of the body, the position of the anus, and the depth of the body.
At the time of collection, the type locality was 1.5 m deep, with the substrate consisting of sand, gravel, and woody debris.
For more information, see the paper: Vari, RP and CJ Ferraris Jr (2009) New species of Cetopsidium (Siluriformes: Cetopsidae: Cetopsinae) from the upper rio Branco system in Guyana. Neotropical Ichthyology 7, pp. 289"293.