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 n ...
of
fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% ...
in the
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
Callichthyidae
Callichthyidae is a family of catfishes (order Siluriformes), called armored catfishes due to the two rows of bony plates (or scutes) along the lengths of their bodies. It contains some of the most popular freshwater aquarium fish, such as many s ...
endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found els ...
to small
tributaries
A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drainage ...
from several coastal
river
A river is a natural flowing watercourse, usually freshwater
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the ...
Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
. Most of the
species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...
of ''Scleromystax'' are highly
sexually dimorphic
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...
dorsal
Dorsal (from Latin ''dorsum'' ‘back’) may refer to:
* Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism
* Dorsal, positioned on top of an aircraft's fuselage
* Dorsal co ...
and
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 ...
s 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.
Taxonomy
The species of ''Scleromystax'' were previously classified within the genus ''
Corydoras
''Corydoras'' is a genus of freshwater catfish in the family Callichthyidae and subfamily Corydoradinae. The species usually have more restricted areas of endemism than other callichthyids, but the area of distribution of the entire genus almos ...
monophyly
In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gr ...
of ''Scleromystax'' has been demonstrated,
phylogenetic
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...
Gaimard
Joseph Paul Gaimard (31 January 1793 – 10 December 1858) was a French naval surgeon
A naval surgeon, or less commonly ship's doctor, is the person responsible for the health of the ship's company aboard a warship. The term appears often ...
Regan
The family name Regan, along with its cognates O'Regan, O Regan, Reagan, and O'Reagan, is an Anglicized form of the Irish surname Ó Riagáin or Ó Ríogáin, from Ua Riagáin. The meaning is likely to have originated in ancient Gaelic ''ri' ...
Nijssen Nijssen is a Dutch patronymic surname originating from the given name "Denijs" (DenisPeople with this surname include:
;
;Nijssen
* Han Nijssen (1935–2013), Dutch ichthyologist
* Sjir Nijssen (born 1938), Dutch computer scientist known for Nij ...
Scleromystax salmacis
''Scleromystax salmacis'' is a species of catfish of the family Callichthyidae. ''S. salmacis'' has the southernmost distribution of its genus. It is known from the Mampituba River and Araranguá River basins in southern Santa Catarina State ...