Megalancistrus
Megalancistrus is a genus of large suckermouth armored catfishes native to South America. Species. There are currently two recognized species in this genus: Distribution. The genus "Megalancistrus" are found in the Río de la Plata 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 is forked, but without filaments. Cheek odontodes, 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 sponges and probably other invertebrates. They have been found with a lot of wood in the gut, but it appears as if this was consumed accidentally.