| Scleromystax | |
|---|---|
| Schleromystax barbatus, male (above) and female | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Siluriformes |
| Family: | Callichthyidae |
| Subfamily: | Corydoradinae |
| Tribe: | Aspidoradini |
| Genus: | Scleromystax Günther, 1864 |
| Type species | |
| Callichthys barbatus Quoy & Gaimard, 1824 |
|
| Species | |
Scleromystax is a genus of catfishes (order Siluriformes) of the family Callichthyidae. It includes several species including, S. barbatus, S. macropterus, S. prionotos, and S. salmacis.[1]
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The species of Scleromystax were previously classified within the genus Corydoras. However, Scleromystax species are now thought to be more closely related to Aspidoras in a tribe called Aspidoradini.[2] Although the monophyly of Scleromystax has been demonstrated, phylogenetic relationships of its species remains obscure. In addition, the taxonomic status of its species are only partially resolved.[3]
Scleromystax species are endemic to small tributaries from several coastal river basins draining Brazilian southern and southeastern regions.[3] S. barbatus is found in coastal drainages from Rio de Janeiro to Santa Catarina States, Brazil.[1] S. macropterus inhabits coastal rivers of Brazil from São Paulo to Santa Catarina States, and some tributaries of the upper Paraná River.[1] S. prionotos originates from coastal rivers in southeastern Brazil from Espirito Santo to São Paulo, Brazil.[1] S. salmacis has the southernmost distribution in the genus. It is known from the Mampituba River and Araranguá River basins in southern Santa Catarina State of Brazil, and the Ratones River, a small coastal river drainage in Florianópolis.[3]
Most of the species of Scleromystax are highly sexually dimorphic species; males have developed odontodes inserted in fleshy papillae on the preopercular-opercular region, and the dorsal and pectoral fins are 2–3 times as long as those of females.[3] S. salmacis is an exception, as its sexually dimorphic features are subtle and non-remarkable. In fact, S. salmacis was named for Salmacis of Ovid's tale; this is an allusion to the slight difference between males and females when compared to other Scleromystax.[3] In S. barbatus, the dorsal and pectoral fins of males reach, or almost reach, the caudal peduncle, and well-developed odontodes are inserted in fleshy tissue on a large area on the sides of the snout in fully grown males. Although S. macropterus can have dorsal and pectoral fins proportionally longer than those of S. barbatus, odontodes on the sides of the snout are much smaller, scattered, and cover a smaller area.[3] The most conspicuous differences between S. barbatus and S. macropterus concern young males, recognized as such by the lanceolate genital papillae.[3]