Megalechis is a small genus of freshwater catfish in the Callichthyinae subfamily of the armored catfish family.
The name is derived from the Greek megas, meaning "great", and the Greek lekis, meaning "plate".
No uniquely derived features are known for Megalechis.
A change in the synonymy of the species of Megalechis occurred in 2005. It is especially confusing because the name M. thoracata remains valid, but applies to the species formerly known as M. personata, which becomes a new junior synonym of M. thoracata. On the other hand, the species formerly known as M. thoracata is now named M. picta.
There are currently two recognized species in this genus:
Both species of Megalechis are distributed east of the Andes in the northern portion of South America, including the Amazonas and Orinoco rivers, as well as the coastal drainages of the Guyanas.
M. thoracata is distinguished from M. picta by a comparatively shorter dorsal fin spine, the anal fin with six (rarely five) branched rays instead of an anal fin with five, rarely four, branched rays, and the caudal fin dotted or dusky often with a clearer band at the base of rays versus a caudal fin with a conspicuous transverse dark band and dark distal border. Megalechis species grow to about 12–15 centimetres SL.
Reproductive males have an extremely developed pectoral fin spine, like that of Hoplosternum littorale. In M. thoracata, males are also larger than females.
^ a b Froese, Rainer and Pauly, Daniel, eds. (2011). Species of Megalechis in FishBase. December 2011 version.
^ a b c Reis, Roberto E. (22 April 1997). "Megalechis". Tree of Life Web Project. Retrieved 2007-07-12.
^ a b Reis, Roberto E.; Le Bail, Pierre-Yves; Mol, Jan H. A (2005). Armbruster, J. W. (ed.). "New Arrangement in the Synonymy of Megalechis Reis, 1997 (Siluriformes: Callichthyidae)". Copeia. 2005 (3): 678–682. doi:10.1643/CI-04-353R.
^ Froese, Rainer; Pauly, Daniel (eds.) (2007). "Megalechis picta" in FishBase. July 2007 version.
^ Froese, Rainer; Pauly, Daniel (eds.) (2007). "Megalechis thoracata" in FishBase. July 2007 version.
^ Pruzsinszky, Inge; Ladich, Friedrich (October 1998). "Sound production and reproductive behaviour of the armoured catfish Corydoras paleatus (Callichthyidae)". Journal Environmental Biology of Fishes. 53 (2): 183–191. doi:10.1023/A:1007413108550.