''Megalancistrus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of large suckermouth armored catfishes native to

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...

Species

There are currently two recognized species in this genus: * '' Megalancistrus barrae'' ( Steindachner, 1910) * '' Megalancistrus parananus'' ( W. K. H. Peters, 1881)

Distribution

The genus ''Megalancistrus'' are found in the

Río de la Plata The Río de la Plata (, "river of silver"), also called the River Plate or La Plata River in English, is the estuary formed by the confluence of the Uruguay River and the Paraná River at Punta Gorda. It empties into the Atlantic Ocean and fo ...

and São Francisco River basins.

Description

''Megalancistrus'' species are large and spiny and generally have 10 dorsal-fin rays. The color on the sides and the abdomen is dark brown with very large spots on the head, sides, and fins or with light vermicualtions. The abdomen is completely plated in adults. The

caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

is forked, but without filaments. Cheek

odontode Odontodes, or dermal teeth, are hard structures found on the external surfaces of animals or near internal openings. They consist of a soft pulp surrounded by dentine and covered by a mineralized substance such as enamel, a structure similar to th ...

s, as in '' Acanthicus'', are thin but numerous. The plates on the body are well keeled with rows of odontodes above and below the keel rows incomplete in specimens up to at least .

Ecology

''Megalancistrus'' species are live in large rivers. These fish eat freshwater

sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate throug ...

s and probably other

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s. They have been found with a lot of wood in the gut, but it appears as if this was consumed accidentally.

References

Ancistrini Fish of South America Fish of the Amazon basin Fauna of Brazil Catfish genera Taxa named by Isaäc J. H. Isbrücker {{Loricariidae-stub