''Otothyris'' is a

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

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 ...

Species

There are currently four recognized species in this genus: * '' Otothyris juquiae'' Garavello, Britski &

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 * '' Otothyris lophophanes'' (

Eigenmann Eigenmann is a surname. Notable persons with that surname include: * Andi Eigenmann (born 1990), Filipino actress * Carl H. Eigenmann (1863–1927), German–American ichthyologist, husband of Rosa Eigenmann * Eduardo de Mesa Eigenmann, birth name ...

, 1889) * '' Otothyris rostrata'' Garavello, Britski &

, 1998 * '' Otothyris travassosi'' Garavello, Britski &

, 1998

Distribution

The genus ''Otothyris'' is distributed along the

Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...

coast of

between Barra do Ribeira,

Guaíba River Guaíba is a city located in the Metropolitan Porto Alegre of Porto Alegre, in the Brazilian state of Rio Grande do Sul. The city is on the shores of the Guaíba Lake. History In the current territory of the municipality of Guaíba there have ...

Basin of Rio Grande do Sul State in the south to the

Jequitinhonha River The Jequitinhonha River () flows mainly through the Brazilian state of Minas Gerais. Its source lies near Diamantina in the Espinhaço Mountains at an elevation of , after which it flows northward and then east-northeastward across the uplands. ...

Basin of

Bahia Bahia ( , , ; meaning "bay") is one of the 26 states of Brazil, located in the Northeast Region of the country. It is the fourth-largest Brazilian state by population (after São Paulo, Minas Gerais, and Rio de Janeiro) and the 5th-largest b ...

State in the north. The species are apparently restricted to the lowland sections of these river systems near the coast and have not been collected further to the west in higher elevation or headwater streams.

Description

''Otothyris'' species have a laterally-placed eye that does not have an iris diverticulum. The head and margin of the snout have enlarged

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 arranged in dorsal and lateral series. The pectoral skeleton is completely exposed from below and bears strong odontodes. The supraoccipital has paired anterior odontode crests and a posterior midline crest. Immature specimens of ''Otothyris'' species, as in most species of the Hypoptopomatinae, exhibit salient crests or ridges of enlarged odontodes on the posterodorsal region of the supraoccipital and pterotic-supracleithrum bones. In ''O. lophophanes'', ''O. juquiae, and ''O. rostrata, these odontode crests are retained in adults and the regions of the head between crests form deep depressions with growth. Within Otothyris, ''O. lophophanes'', ''O. juquiae'', and ''O. rostrata'' have larger and more extensive odontode crests, more pronounced odontode ridges, larger swimbladder capsule, and larger pterotic fenestrae, in comparison with ''O. travassosi'', which has smaller, shorter odontode crests and less pronounced ridges, a relatively small swimbladder capsule, and smaller pterotic fenestrae. ''Otothyris lophophanes'' has a single series of downturned rostral odontodes separated from a series of upturned odontodes along the dorsal rostral margin by a distinct, broad linear discontinuity, which extends laterally to a line through the anterior nares; however, in all other members of the genus, the ventral downturned odontodes comprise more than one series and are not separated from the dorsal odontodes by a broad linear discontinuity. ''Otothyris'' species also differ in tooth counts, lateral line and abdominal plates, and

morphometrics Morphometrics (from Greek μορϕή ''morphe'', "shape, form", and -μετρία ''metria'', "measurement") or morphometry refers to the quantitative analysis of ''form'', a concept that encompasses size and shape. Morphometric analyses are co ...

References

{{Taxonbar, from=Q5028146 Otothyrinae Fish of South America Fauna of Brazil Endemic fauna of Brazil Catfish genera Taxa named by George S. Myers Freshwater fish genera