''Scleronema'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of pencil catfishes native to

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. They are a member of the subfamily

Trichomycterinae The Trichomycterinae are a subfamily of catfishes (order Siluriformes) of the family Trichomycteridae. It includes six genera, '' Bullockia'', '' Hatcheria'', '' Rhizosomichthys'', and '' Eremophilus'', all monotypic, '' Silvinichthys'' with seve ...

. Species of Scleronema are geographically distributed in the

La Plata basin LA most frequently refers to Los Angeles, the second most populous city in the United States of America. La, LA, or L.A. may also refer to: Arts and entertainment Music *La (musical note), or A, the sixth note *"L.A.", a song by Elliott Smit ...

and Atlantic coastal drainages from

Southern Brazil The South Region of Brazil ( ) is one of the five regions of Brazil. It includes the states of Paraná, Rio Grande do Sul, and Santa Catarina, and covers , being the smallest region of the country, occupying only about 6.76% of the territory of ...

, Southern

Paraguay Paraguay, officially the Republic of Paraguay, is a landlocked country in South America. It is bordered by Argentina to the Argentina–Paraguay border, south and southwest, Brazil to the Brazil–Paraguay border, east and northeast, and Boli ...

, Northeastern

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

and

Uruguay Uruguay, officially the Oriental Republic of Uruguay, is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast, while bordering the Río de la Plata to the south and the A ...

. They inhabit rivers or streams with sand or gravel-bottoms across the Pampa grasslands. In Greek, Scleronema means "hard filament."

Species

There are currently three recognized species in this genus: * '' Scleronema angustirostre'' ( Devincenzi, 1942) * '' Scleronema minutum'' ( Boulenger, 1891) * '' Scleronema operculatum'' C. H. Eigenmann, 1917 ''S. minutum'' and ''S. operculatum'' both originate from

Rio Grande do Sul Rio Grande do Sul (, ; ; "Great River of the South") is a Federative units of Brazil, state in the South Region, Brazil, southern region of Brazil. It is the Federative units of Brazil#List, fifth-most populous state and the List of Brazilian s ...

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

; ''S. minutum'' 4.0 cm (1.6 in) SL and ''S. operculatum'' 8.0 cm (3.1 in). ''S. minutum'' and '' S. operculatum'' usually live in a freshwater, tropical environment. '' S. operculatum'' are harmless to humans.

''Scleronema angustirostre''

As of 2017, ''S. angustirostre'' has been deemed a prohibited nonnative species in Florida, meaning the species is a danger to the ecology, health, and/or welfare of Florida and its residents. Like other species of Scleronema, ''S. angustirostre'' thrive in a freshwater environment and are benthopelagic, meaning that they either live at the surface or bottom of a body of water.

References

Trichomycteridae Pencil catfish of Brazil Catfish genera Freshwater fish genera Taxa named by Carl H. Eigenmann {{Trichomycteridae-stub