Megalechis

Megalechis
Megalechis thoracata
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Siluriformes
Family:	Callichthyidae
Subfamily:	Callichthyinae
Genus:	Megalechis Reis, 1997
Species
Megalechis picta Megalechis thoracata

Megalechis thoracata

Megalechis is a small genus of freshwater catfish in the Callichthyinae subfamily of the armored catfish family, and consists of 2 species.^[1]

Taxonomy

The type species for this genus is Callichthys thoracatus. The name is derived from the Greek megas, meaning "great", and the Greek echis, meaning "viper".^[2]

No uniquely derived features are known for Megalechis.^[3]

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.^[4]

Distribution

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.^[3] M. picta occurs east of the Andes in the Amazon, Orinoco, and upper Essequibo River basins, and coastal rivers of northern Brazil.^[4] M. thoracata is found east of the Andes in the Amazon, Orinoco, and upper Paraguay River basins, as well as in the coastal rivers of the Guianas and northern Brazil. Recent introductions were recorded in the upper Paraná River drainage.^[4]

Description

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.^[4] Megalechis species grow to about 12–15 centimetres SL.^[5][6]

Reproductive males have an extremely developed pectoral fin spine, like that of Hoplosternum littorale.^[3] In M. thoracata, males are also larger than females.^[7]

Ecology

M. thoracata has been observed to produce sounds during territorial behavior in males at their nest sites and especially during spawning, and during aggressive behavior in both sexes. M. thoracata males aggressively defend territories against intruders.^[7]

References

1. ^ Ferraris, Carl J., Jr. (2007). "Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types" (PDF). Zootaxa 1418: 1–628. http://silurus.acnatsci.org/ACSI/library/biblios/2007_Ferraris_Catfish_Checklist.pdf. 
2. ^ Froese, Rainer, and Daniel Pauly, eds. (2006). Species of Megalechis in FishBase. March 2006 version.
3. ^ ^{a b c} Reis, Roberto E. (22 April 1997). "Megalechis". Tree of Life Web Project. http://www.tolweb.org/Megalechis/15338. Retrieved 2007-07-12. 
4. ^ ^{a b c d} 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. 
5. ^ Froese, Rainer, and Daniel Pauly, eds. (2007). "Megalechis picta" in FishBase. July 2007 version.
6. ^ Froese, Rainer, and Daniel Pauly, eds. (2007). "Megalechis thoracata" in FishBase. July 2007 version.
7. ^ ^{a b} 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.