Scleromystax

Taxobox
name = "Scleromystax"
regnum = Animalia
phylum = Chordata
classis = Actinopterygii
ordo = Siluriformes
familia = Callichthyidae
subfamilia = Corydoradinae
tribus = Aspidoradini
genus = "Scleromystax"
genus_authority = Günther, 1864
type_species = "Callichthys barbatus"
type_species_authority = Quoy & Gaimard, 1824
subdivision_ranks = Binomial name
subdivision =
"Scleromystax barbatus"
(Quoy & Gaimard, 1824)"Scleromystax macropterus"
(Regan, 1913)"Scleromystax prionotos"
(Nijssen & Isbrücker, 1980)"Scleromystax salmacis"
Britto & Reis, 2005

"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".cite journal|url=http://silurus.acnatsci.org/ACSI/library/biblios/2007_Ferraris_Catfish_Checklist.pdf|title=Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types|first=Carl J., Jr.|last=Ferraris|journal=Zootaxa|volume=1418|pages=1–628|year=2007|format=PDF]

Taxonomy

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.cite journal|url=http://acd.ufrj.br/ppgzoo/orientadores/dados/Artigos%20Brito/Phylogeny%20Corydoradinae%20(Britto).pdf|title=Phylogeny of the subfamily Corydoradinae Hoedeman, 1952 (Siluriformes: Callichthyidae), with a definition of its genera|first=Marcelo R.|last=Britto|journal=Proceedings of the Academy of Natural Sciences of Philadelphia|volume=153|pages=119–154|date=December 2003|format=PDF|doi=10.1635/0097-3157(2003)153 [0119:POTSCH] 2.0.CO;2|doilabel=10.1635/0097-3157(2003)153[0119:POTSCH]2.0.CO;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.cite journal|url=http://www.ufrgs.br/ni/vol3num4%5CNI_v3n4p481-488lowr.pdf|title=A new "Scleromystax" species (Siluriformes: Callichthyidae) from coastal rivers of Southern Brazil|first=Marcelo R.|last=Britto|coauthors=Reis, Roberto E.|journal=Neotropical Ichthyology|volume=3|issue=4|pages=481–488|year=2005|format=PDF|doi=10.1590/S1679-62252005000400005]

Distribution

"Scleromystax" species are endemic to small tributaries from several coastal river basins draining Brazilian southern and southeastern regions. "S. barbatus" is found in coastal drainages from Rio de Janeiro to Santa Catarina States, Brazil. "S. macropterus" inhabits coastal rivers of Brazil from São Paulo to Santa Catarina States, and some tributaries of the upper Paraná River. "S. prionotos" originates from coastal rivers in southeastern Brazil from Espirito Santo to São Paulo, Brazil. "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.

Description

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. "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". 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. The most conspicuous differences between "S. barbatus" and "S. macropterus" concern young males, recognized as such by the lanceolate genital papillae.

References