Two new species of catfish have been described following a revision of the genus Pseudotocinclus.
Prior to the study, Pseudotocinclus held a single species, P. tietensis, but recent collections in Ribeira do Iguape and the Rio Paraiba do Sul basin revealed two previously unseen plecs that appeared to represent totally new species distinct from tietensis.
The revision, which was undertaken by Adriana Kazue Takako, Claudio Oliveira and Osvaldo Takeshi Oyakawa studied all of the species in the hypoptopomine loricariid genus Pseudotocinclus and described the two new fish as P. parahybae and P. juquiae.
Pseudotocinclus parahybae was collected in the Rio Paraiba do Sul basin near Sao Paulo, Brazil, and reaches a size of around 6cm/2" in length. The fish was caught in clear, fast flowing streams among beds of stones and shared its habitat with a couple of Astyanax species, a Characidium, and the catfish Imparfinus minutus, Neoplecostomus microps and Harttia carvalhoi.
P. juquiae was collected from the Rio Juquitiba in Sao Paulo, and also reaches a size of around 5-6cm/2". This fish was collected in several clear, slow-flowing stream habitats over substrates ranging from mud to sand.
Both juquiae and parahybae have tiny platelets on the snout, which are absent in tietensis. P. juquiae has a very prominent ring around its eye, which makes it one of the easiest in the genus to identify. P. parahybae has no ring around its eye, and only three dark brown bands on the back, rather than the four seen in tietensis.
The revision also updates the diagnosis of characters a fish needs to be placed within the Pseudotocinclus genus: "The genus Pseudotocinclus can be diagnosed from other Hypoptomatinae by the presence of a caudal peduncle that is nearly square in cross section from the posterior base of the dorsal fin to the caudal fin, and the following combination of characters: 26 or more plates along the lateral line, a dorsally positoned eye, an exposed preopercle, and an abdomen covered with numerous small platelets."
Pseudotocinclus are herbivorous plecs and spend their time near the water surface where they feed upon algae attached to overhanging branches and terrestrial grasses.
For more details on the new species see the revision: Takako AK, Oliveira C and Oyakawa OT (2005) - Revision of the genus Pseudotocinclus (Siluriformes: Loricariidae: Hypoptomatinae), with descriptions of two new species. Neotropical Ichthyology,, 3(4): 499-508.