''Megalancistrus'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

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 considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

Species

There are currently two recognized species in this genus: * '' Megalancistrus barrae'' (

Steindachner Franz Steindachner (11 November 1834 in Vienna – 10 December 1919 in Vienna) was an Austrian zoologist, ichthyologist, and herpetologist. He published over 200 papers on fishes and over 50 papers on reptiles and amphibians. Steindachner descri ...

, 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 (; ), 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, Colonia, Punta Gorda. It empties into the Atlantic Ocean and ...

and

São Francisco River The São Francisco River (, ) is a large Rivers of Brazil, river in Brazil. With a length of , it is the longest river that runs entirely in Brazilian territory, and the fourth longest in South America and overall in Brazil (after the Amazon R ...

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 moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

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 t ...

s, as in ''

Acanthicus ''Acanthicus'' is a genus of large, South American Loricariidae, suckermouth armored catfishes native to the Amazon basin, Amazon and Orinoco basins, and possibly in Guyana. The name ''Acanthicus'' is derived from the Greek language, Greek, ''aka ...

'', 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 or sea sponges are primarily marine invertebrates of the animal phylum Porifera (; meaning 'pore bearer'), a basal clade and a sister taxon of the diploblasts. They are sessile filter feeders that are bound to the seabed, and a ...

s and probably other

invertebrate Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...

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 the Amazon basin Suckermouth catfish of Brazil Catfish genera Taxa named by Isaäc J. H. Isbrücker {{Hypostominae-stub