Two new Ancistrus described

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A team of scientists has described two new species of catfish from the genus Ancistrus.

The plecs, which have been named Ancistrus verecundus and A. parecis, were described by Sonia Fisch-Muller, Alexandre Cardosa, Jose da Silva and Vinicius Bertaco in a paper in the latest issue of the journal Neotropical Ichthyology.

Ancistrus verecundus was discovered in the Rio Madeira basin, while A. parecis was discovered in both the upper Rio Juruena and Rio Tapajos in Brazil.

No adipose finThe two new species are unusual among Ancistrus in that they lack an adipose fin.

This fatty fin is seen in the majority of catfish species, but in the two new species, and in the closely related Ancistrus A. jataiensis, A. reisi, and A. tombador, the adipose consists of a tiny ridge made up of median platelets.

The scientists say that a number of other morphological features help to distinguish the new catfishes from existing Ancistrus:

"Ancistrus verecundus is further distinguished from these species, except A. tombador by the broad naked margin of the snout and reduced tentacle development.

"Ancistrus verecundus differs from A. tombador in various morphometric features, and in having the base of the first anal-fin pterygiophore covered by skin (vs. base of the first anal-fin pterygiophore exposed and forming a platelet-like element).

"Ancistrus verecundus and A. tombador have two or more dermal plates of the dorsal plate series between the end of the postdorsal ridge and the origin of the first plate-like procurrent caudal-fin ray, whereas the other species of the genus that lack an adipose fin, including A. parecis, have one or none.

"Ancistrus parecis is further distinguished from A. tombador and A. verecundus by the presence of tentacles in adults. It also differs from A. tombador in morphometric and meristic features and from A. jataiensis and A. reisi in the length of the mandibular tooth row, the number of teeth on dentary and premaxillary, and the caudal-peduncle depth."

The paper includes a key for the identification of species of Ancistrus lacking an adipose fin.

For more details on the new plecos see the paper: Fisch-Muller, S; Cardoso, AR; da Silva, JFP and VA Bertaco (2005) - Two new Amazonian species of armored catfishes (Siluriformes: Loricariidae): Ancistrus verecundus and Ancistrus parecis. Neotropical Ichthyology, 3(4):525-532, 2005.