''Scoloplax'' is the only

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 ...

in the

catfish Catfish (or catfishes; order (biology), order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Catfish are common name, named for their prominent barbel (anatomy), barbels, which resemble a cat's whiskers, though not ...

(

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Siluriformes)

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Scoloplacidae, the spiny dwarf catfishes.

Species

The six currently recognized species in this genus are: * '' Scoloplax baileyi''

Rocha Rocha may refer to: * Rocha (surname), a Portuguese surname * Rocha, Moca, Puerto Rico, a barrio in the municipality of Moca, Puerto Rico * Rocha, Rio de Janeiro, a neighborhood in Rio de Janeiro, Brazil * Rocha, Uruguay, capital city of the R ...

, Lazzarotto & Rapp Py-Daniel, 2012Rocha, R., Lazzarotto, H. & Rapp Py-Daniel, L. (2012): A New Species of ''Scoloplax'' with a Remarkable New Tooth Morphology within Loricarioidea (Siluriformes: Scoloplacidae). ''Copeia, 2012 (4): 670–677.'' * '' Scoloplax baskini''

, de Oliveira & Rapp Py-Daniel, 2008 * '' Scoloplax dicra'' Bailey & Baskin, 1976 * '' Scoloplax distolothrix'' Schaefer, Weitzman & Britski, 1989 * '' Scoloplax dolicholophia'' Schaefer, Weitzman & Britski, 1989 * '' Scoloplax empousa'' Schaefer, Weitzman & Britski, 1989 (Pantanal dwarf catfish)

Distribution

''Scoloplax'' is distributed in

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 ...

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

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 ...

, and

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 ...

. ''S. baskini'' is from the small tributaries of Rio Aripuanã, Rio Madeira drainage, Amazonas State, Brazil. ''S. dicra'' has the largest distribution in the

Amazon basin The Amazon basin is the part of South America drained by the Amazon River and its tributary, tributaries. The Amazon drainage basin covers an area of about , or about 35.5 percent of the South American continent. It is located in the countries ...

, originating from the Amazon and

Paraguay River The Paraguay River (''Ysyry Paraguái'' in Guarani language, Guarani, ''Rio Paraguai'' in Portuguese language, Portuguese, ''Río Paraguay'' in Spanish language, Spanish) is a major river in south-central South America, running through Brazil, Bol ...

basins. ''S. distolothrix'' inhabits the

Tocantins Tocantins () is one of the 26 states of Brazil. It is the newest state, formed in 1988 and encompassing what had formerly been the northern two-fifths of the state of Goiás. Tocantins covers and had an estimated population of 1,496,880 in 2014 ...

- Araguaia, Xingu, and Paraguay River basins. ''S. dolicholophia'' is known from the Rio Negro basin in Brazil, as well as the Lake Amanã. ''S. empousa'' lives in the Amazon and Paraguay-

Paraná River The Paraná River ( ; ; ) is a river in south-central South America, running through Brazil, Paraguay, and Argentina for some ."Parana River". Encyclopædia Britannica. Encyclopædia Britannica Online. Encyclopædia Britannica Inc., 2012. Web. ...

basins.

Description

Species of ''Scoloplax'' are readily distinguishable from other catfishes by the presence of a conspicuous

shield A shield is a piece of personal armour held in the hand, which may or may not be strapped to the wrist or forearm. Shields are used to intercept specific attacks, whether from close-ranged weaponry like spears or long ranged projectiles suc ...

-shaped

rostral Rostral may refer to: Anatomy * Rostral (anatomical term), situated toward the oral or nasal region * Rostral bone, in ceratopsian dinosaurs * Rostral organ, of certain fish * Rostral scale The rostral scale, or rostral, in snakes and other sca ...

plate bearing numerous large and recurved odontodes. These fish have three rows of odontode-bearing plates, two bilateral series and one midventral series. There is also a

plate with many recurved odootodes. The

adipose fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only b ...

is absent. The greatest length reached is about SL. ''Scoloplax'' species have modified

stomach The stomach is a muscular, hollow organ in the upper gastrointestinal tract of Human, humans and many other animals, including several invertebrates. The Ancient Greek name for the stomach is ''gaster'' which is used as ''gastric'' in medical t ...

s that are enlarged, thin-walled, and clear. The

esophagus The esophagus (American English), oesophagus (British English), or œsophagus (Œ, archaic spelling) (American and British English spelling differences#ae and oe, see spelling difference) all ; : ((o)e)(œ)sophagi or ((o)e)(œ)sophaguses), c ...

enters the stomach along the dorsal side just posterior to the anterior margin of the stomach; the intestine exits the stomach ventrally. A small patch of muscular tissue represents the digestive portion of the stomach, located from the entrance of the esophagus to where the intestine exits. This modified stomach may be for

buoyancy Buoyancy (), or upthrust, is the force exerted by a fluid opposing the weight of a partially or fully immersed object (which may be also be a parcel of fluid). In a column of fluid, pressure increases with depth as a result of the weight of t ...

control or for breathing air.

Ecology

''Scoloplax'' species are fairly common among leaf litter in clear and blackwater habitats, including

oxbow lake An oxbow lake is a U-shaped lake or stream pool, pool that forms when a wide meander of a river is meander cutoff, cut off, creating a free-standing body of water. The word "oxbow" can also refer to a U-shaped bend in a river or stream, whether ...

s, backwater pools, and well-vegetated streams.

References

{{Authority control Catfish of South America Taxa named by Reeve Maclaren Bailey Taxa named by Jonathan N. Baskin Fish of the Amazon basin Fish of Bolivia Catfish of Brazil Fish of Paraguay Fish of Peru Catfish genera