''Eurycheilichthys'' 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 armored catfishes native to

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 ...

Taxonomy

''Eurycheilus pantherinus'' was first described in 1992 by

Roberto Esser dos Reis Roberto Esser dos Reis, is a Brazilian ichthyologist, professor and Curator of Fishes at the Pontifical Catholic University of Rio Grande do Sul. Among other duties, Reis has been working at the University of São Paulo, Brazil, the University o ...

and Scott A. Schaefer. However, ''Eurycheilus'' was preoccupied in

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

cephalopods, and therefore was replaced by ''Eurycheilichthys'' in 1993. ''E. limulus'' was described in 1998. ''Eurycheilichthys'' together with ''

Pseudotocinclus ''Pseudotocinclus'' is a genus of armored catfishes native to South America. Species There are currently three recognized species in this genus: * '' Pseudotocinclus juquiae'' Takako, Oliveira & Oyakawa, 2005 * '' Pseudotocinclus parahybae'' ...

'', '' Microlepidogaster'', '' Schizolecis'', '' Otothyris'' and '' Pseudotothyris'' form a clade whose sister group is '' Epactionotus''.

Species

There are currently two recognized species in this genus: * '' Eurycheilichthys limulus''

Reis Reis may refer to : * Reis (surname), a Portuguese and German surname *Reis (military rank), an Ottoman military rank and obscure Lebanese/Syrian noble title Currency * Portuguese Indian rupia (subdivided into ''réis''), the currency of Portugu ...

Schaefer Schaefer is an alternative spelling and cognate for the German word ''schäfer'', meaning 'shepherd', which itself descends from the Old High German '' scāphare''. Variants "Shaefer", "Schäfer" (a standardized spelling in many German-speaking ...

, 1998 * '' Eurycheilichthys pantherinus'' (

, 1992)

Distribution

Both species in this genus are

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 else ...

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 ...

Description

The two species of ''Eurycheilichthys'' are similar. The trunk and

caudal peduncle 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 see ...

are round in

cross section Cross section may refer to: * Cross section (geometry) ** Cross-sectional views in architecture & engineering 3D *Cross section (geology) * Cross section (electronics) * Radar cross section, measure of detectability * Cross section (physics) **Abs ...

. Males have a fleshy flap along the posterior margin of the thickened first pelvic fin ray. They lack a

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 ...

locking mechanism. Both species lack an

adipose 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 se ...

. Their bodies are almost entirely covered by plates. The body and head lack crests. The head and body plates are covered with

odontode Odontodes, or dermal teeth, are hard structures found on the external surfaces of animals or near internal openings. They consist of a soft pulp surrounded by dentine and covered by a mineralized substance such as enamel, a structure similar to th ...

s; these are larger on the ventral face of pelvic 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 ...

spines. Odontodes on the head and trunk are otherwise of uniform size and distribution, and not arranged in conspicuous rows. The lips are roundish, wide and

papillose This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary o ...

. The maxillary barbels are short. ''E. limulus'' shares with ''E. pantherinus'' a single

synapomorphy In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to hav ...

: the derived presence of seven branched

rays. ''E. limulus'' is distinguished from ''E. pantherinus'' by a more narrow body, head and dorsal trunk with series of longitudinal light stripes (versus scattered dark blotches), and presence of an accessory ceratobranchial flange and filamentous

gill raker Gill rakers in fish are bony or cartilaginous processes that project from the branchial arch (gill arch) and are involved with suspension feeding tiny prey. They are not to be confused with the gill filaments that compose the fleshy part of the ...

s (versus absence of those features in ''E. pantherinus'').

Ecology

''E. pantherinus'' inhabits shady, fast-flowing, shallow water, ranging from approximately 200–500 metres in

elevation The elevation of a geographic location is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface (see Geodetic datum § Ver ...

. The substratum is predominantly stones, with little or no macrophytes. The habitat at the type locality of ''E. limulus'' is a small river about 3–5 metres wide with moderate water current, bottom comprising some rocks but mostly sand and a large amount of marginal vegetation. These fishes live among leaves and stalks.

References

{{Taxonbar, from=Q5034408 Otothyrinae Fish of South America Catfish genera Taxa named by Roberto Esser dos Reis Taxa named by Scott Allen Schaefer Freshwater fish genera