Scientists have described two new species of loricariid catfish from the genus Parotocinclus.
The two new catfish were discovered in the Rio Paraiba do Sul basin in Brazil and have been named Parotocinclus bidentatus and P. muriaensis in a paper in the journal Neotropical Ichthyology.
The fishes, which are members of the loricariid subfamily Hypoptopomatinae were discovered by Marco Gauger and Paulo Buckup during an inventory of hypoptopomine catfishes in the collections of Rio de Janeiro's Museu Nacional (MNRJ).
Both species are unusual among Parotocinclus in that they lack the fully developed adipose fin seen in most other species. The two fishes also have quite unusual dentition, with each fish possessing an extra set of accessory unicuspid teeth.
Accessory teeth are also known in a number of other hypoptopomines including Parotocinclus collinsae and some members of the Epactionotus, Eurycheilichthys and Niblichthys genera.
The first of the new catfishes, Parotocinclus bidentatus, is known from a number of localities around Rio de Janeiro, including the Rio Pirapetinga, a left bank tributary of the Rio Paraiba do Sul.
The species appears to reach a size of around 3-4cm/2" and is brown in colour with a yellowish belly.
Parotocinclus muriaensis is known only from its type locality, near Itaperuna in the Rio Muriae, a left tributary of the Rio Paraiba do Sul basin, Rio de Janeiro, Brazil.
The lack of adipose fin sets the two species apart from most other members of the Parotocinclus genus, with the exception of P. spilurus in which some specimens occassionally lack the fin.
For more information on the new tropical fish species see the paper: Gauger, M and P, Buckup (2005) - Two new species of Hypoptopomatinae from the rio Paraba do Sul basin, with comments on the monophyly of Parotocinclus and the Otothyrini (Siluriformes: Loricariidae). Neotropical Ichthyology, 3(4): 509-518, 2005.