Scleromystax
Encyclopedia
Scleromystax is a genus
of catfish
es (order
Siluriformes) of the family
Callichthyidae
. It includes several species
including, S. barbatus, S. macropterus, S. prionotos, and S. salmacis.
. However, Scleromystax species are now thought to be more closely related to Aspidoras
in a tribe called Aspidoradini. 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.
ian 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
.
species; males have developed odontode
s inserted in fleshy papilla
e 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.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of catfish
Catfish
Catfishes 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 heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...
es (order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Siluriformes) of the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Callichthyidae
Callichthyidae
Callichthyidae is a family of catfishes , called armored catfishes due to the two rows of bony plates running down the length of the body. This family contains some of the most popular freshwater aquarium fish, such as the Corydoras.-Taxonomy:The family derives its name from the Greek words kallis...
. It includes several species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
including, S. barbatus, S. macropterus, S. prionotos, and S. salmacis.
Taxonomy
The species of Scleromystax were previously classified within the genus CorydorasCorydoras
Members of the South American Corydoras genus are freshwater temperate and tropical catfish in the armored catfish family , and are commonly referred to as corydorases, cories, or cory catfish.-Taxonomy:...
. However, Scleromystax species are now thought to be more closely related to Aspidoras
Aspidoras
Aspidoras is a genus of catfishes of the family Callichthyidae.-Taxonomy:The type species for this genus is Aspidoras rochai...
in a tribe called Aspidoradini. Although the monophyly
Monophyly
In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group. The term is synonymous with the uncommon term holophyly...
of Scleromystax has been demonstrated, phylogenetic
Phylogenetics
In biology, phylogenetics is the study of evolutionary relatedness among groups of organisms , which is discovered through molecular sequencing data and morphological data matrices...
relationships of its species remains obscure. In addition, the taxonomic status of its species are only partially resolved.
Distribution
Scleromystax species are endemic to small tributaries from several coastal river basins draining BrazilBrazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
ian southern and southeastern regions. S. barbatus is found in coastal drainages from Rio de Janeiro
Rio de Janeiro
Rio de Janeiro , commonly referred to simply as Rio, is the capital city of the State of Rio de Janeiro, the second largest city of Brazil, and the third largest metropolitan area and agglomeration in South America, boasting approximately 6.3 million people within the city proper, making it the 6th...
to Santa Catarina
Santa Catarina (state)
Santa Catarina is a state in southern Brazil with one of the highest standards of living in Latin America. Its capital is Florianópolis, which mostly lies on the Santa Catarina Island. Neighbouring states are Rio Grande do Sul to the south and Paraná to the north. It is bounded on the east by...
States, Brazil. S. macropterus inhabits coastal rivers of Brazil from São Paulo
São Paulo
São Paulo is the largest city in Brazil, the largest city in the southern hemisphere and South America, and the world's seventh largest city by population. The metropolis is anchor to the São Paulo metropolitan area, ranked as the second-most populous metropolitan area in the Americas and among...
to Santa Catarina States, and some tributaries of the upper Paraná River
Paraná River
The Paraná River is a river in south Central South America, running through Brazil, Paraguay and Argentina for some . It is second in length only to the Amazon River among South American rivers. The name Paraná is an abbreviation of the phrase "para rehe onáva", which comes from the Tupi language...
. S. prionotos originates from coastal rivers in southeastern Brazil from Espirito Santo
Espírito Santo
Espírito Santo is one of the states of southeastern Brazil, often referred to by the abbreviation "ES". Its capital is Vitória and the largest city is Vila Velha. The name of the state means literally "holy spirit" after the Holy Ghost of Christianity...
to São Paulo, Brazil. S. salmacis has the southernmost distribution in the genus. It is known from the Mampituba River
Mampituba River
The Mampituba River is a river forming part of the boundary between Santa Catarina and Rio Grande do Sul states in southeastern Brazil.-References:* ] map]...
and Araranguá River
Araranguá River
The Araranguá River is a river of Santa Catarina state in southeastern Brazil.-References:* ] map]...
basins in southern Santa Catarina State of Brazil, and the Ratones River
Ratones River
The Ratones River is a river of Santa Catarina state in southeastern Brazil.-References:* ] map]...
, a small coastal river drainage in Florianópolis
Florianópolis
-Climate:Florianópolis experiences a warm humid subtropical climate, falling just short of a true tropical climate. The seasons of the year are distinct, with a well-defined summer and winter, and characteristic weather for autumn and spring. Frost is infrequent, but occurs occasionally in the winter...
.
Description
Most of the species of Scleromystax are highly sexually dimorphicSexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
species; males have developed odontode
Odontode
Odontodes, or dermal teeth, are hard structures found on the external surfaces of animals or near internal openings. They comprise a soft pulp surrounded by dentine and covered by a mineralized substance such as enamel, a structure similar to that of teeth. They generally do not have the same...
s inserted in fleshy papilla
Papilla (fish mouth structure)
The papilla, in certain kinds of fish, particularly rays, sharks, and catfish, are small lumps of dermal tissue found in the mouth, where they are "distributed uniformly on the tongue, palate, and pharynx"...
e on the preopercular-opercular region, and the dorsal
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
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
Salmacis
In Greek mythology, Salmacis was an atypical naiad who rejected the ways of the virginal Greek goddess Artemis in favour of vanity and idleness. Her attempted rape of Hermaphroditus places her as the only nymph rapist in the Greek mythological canon ."There dwelt a Nymph, not up for hunting or...
of Ovid
Ovid
Publius Ovidius Naso , known as Ovid in the English-speaking world, was a Roman poet who is best known as the author of the three major collections of erotic poetry: Heroides, Amores, and Ars Amatoria...
'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.
Species
- Scleromystax barbatus, banded corydoras - Quoy & Gaimard, 1824
- Scleromystax macropterusScleromystax macropterusScleromystax macropterus is a species of catfish of the family Callichthyidae....
- (Regan, 1913) - Scleromystax prionotosScleromystax prionotosScleromystax prionotos is a tropical freshwater catfish belonging to the Corydoradinae sub-family of the Callichthyidae family. It originates in inland waters in South America, and is found in coastal rivers in southeastern Brazil from Espírito Santo to São Paulo. It was originally described by...
- Nijssen & Isbrücker, 1980 - Scleromystax salmacisScleromystax salmacisScleromystax salmacis is a species of catfish of the family Callichthyidae....
- Britto & Reis, 2005