Lasiancistrus plecs revised

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The loricariid catfish genus Lasiancistrus has been revised and two new species have been described.

The work, which was undertaken by leading suckermouth catfish expert Dr Jon Armbruster, has just been published in the journal Neotropical Ichthyology and lists 16 species in the genus, but classes only four of these as valid.

Armbruster studied the morphology of all fishes believed to be members of the Lasiancistrus genus (a member of the loricariid subfamily Ancistrini) and found that the genus is diagnosed by the presence of a unique ventral strut of the pterotic and the presence of whiskery odontodes (bristles) on the snout.

Only four of the 16 species previously believed to be species of Lasiancistrus (schomburgkii, heteracanthus, caucanus and guachorote) were found to have these characteristic features so the other dozen will need to be moved into other genera and renamed.

Synonyms and invalid speciesQuite a few of the species in Lasiancistrus which were going under different species names were found to be members of the same species.

Lasiancistrus pictus, for example, along with L. caquetae, L. castelnaui, L. scolymus and L. multispinis, are all actually Lasiancistrus schomburgkii.

L. maracaiboensis and L. mystacinus are both the same fish as Lasiancistrus guacharote, and L. planiceps, mayoloi and volcanensis are all synonyms of L. caucanus.

One of the other fish, L. nationi, was found to be an Ancistrus, and the unusual L. trinitatus couldn't be confidently placed in any genus at the moment so it's been termed incertae cedis, which means that it is of uncertain taxonomic postition.

Two new plecsThe revision also includes descriptions of two new species of Lasiancistrus, L. tentaculatus and L. saetiger, which bring the total number of valid species in the genus to six.

The first of the new plecos, L. tentaculatus, was found in the Rio Orinoco basin, while saetiger was discovered in the Rio Guama.

Says Armbruster: "The species can largely be told apart via color (L. schomburgkii has no or white spots on the fins, L. saetiger has entirely gray fins, and the rest have black spots in the fins), the presence of abdominal plates (L. caucanus, L. saetiger, and L. tentaculatus have naked abdomens, L. guacharote has a few small plates near the insertion of the pectoral fin, L. heteracanthus has a large patch of small plates, and L. schomburgkii is variable), and nuptial male condition (L. tentaculatus has small tentacles along the edge of the snout and the other species have a patch of whiskerlike odontodes at the corners of the snout)."

For more details on the members of the Lasiancistrus genus see the paper: Armbruster, J. (2005) - The loricariid catfish genus Lasiancistrus (Siluriformes)

with descriptions of two new species. Neotropical Ichthyology, 3(4):549-569, 2005.