''Megalechis'' is a small

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 freshwater

catfish Catfish (or catfishes; order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the three largest species alive ...

in the Callichthyinae subfamily of the armored catfish family.

Taxonomy

The name is derived from the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

''megas'', meaning "great", and the Greek ''lekis'', meaning "plate". No uniquely derived features are known for ''Megalechis''. A change in the

synonymy A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

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''.

Species

There are currently two recognized species in this genus: * '' Megalechis picta'' ( J. P. Müller & Troschel, 1849) (Spotted hoplo) * '' Megalechis thoracata'' (

Valenciennes Valenciennes (, also , , ; nl, label=also Dutch, Valencijn; pcd, Valincyinnes or ; la, Valentianae) is a commune in the Nord department, Hauts-de-France, France. It lies on the Scheldt () river. Although the city and region experienced a ...

, 1840)

Distribution

Both species of ''Megalechis'' are distributed east of the

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

in the northern portion of

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 ...

, including the Amazonas and Orinoco rivers, as well as the coastal drainages of the

Guyanas The Guianas, sometimes called by the Spanish loan-word ''Guayanas'' (''Las Guayanas''), is a region in north-eastern South America which includes the following three territories: * French Guiana, an overseas department and region of France * G ...

Description

''M. thoracata'' is distinguished from ''M. picta'' by a comparatively shorter

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through c ...

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 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 ...

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

centimetre 330px, Different lengths as in respect to the Electromagnetic spectrum, measured by the Metre and its deriveds scales. The Microwave are in-between 1 meter to 1 millimeter. A centimetre (international spelling) or centimeter (American spellin ...

s SL. Reproductive males have an extremely developed

pectoral 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 ...

spine, like that of '' Hoplosternum littorale''. In ''M. thoracata'', males are also larger than females.

References

{{Taxonbar, from=Q837223 Callichthyidae Fish of South America Catfish genera Taxa named by Roberto Esser dos Reis Freshwater fish genera