''Leptodoras'' 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 n ...

of thorny 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 souther ...

Taxonomy

''Leptodoras'' is a

monophyletic 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 ...

genus based on the single unique characteristic: presence of an infranuchal scute. This scute is the first in a series of well-developed midlateral scutes characteristic of most doradids. It is one of the most

derived Derive may refer to: * Derive (computer algebra system), a commercial system made by Texas Instruments * ''Dérive'' (magazine), an Austrian science magazine on urbanism *Dérive, a psychogeographical concept See also * *Derivation (disambiguatio ...

genera within the clade of fimbriate-barbel doradids. The most closely related genus to ''Leptodoras'' is '' Anduzedoras''. This genus includes eleven species, making it the largest doradid genus. There has been taxonomic confusion due to similarities of some species with each other and members of other genera. Misunderstood distributions and identities of some species added to this confusion. Most species were described from small geographic areas without information on their potential distributions. Also, specimens have been rare in museums until recently. An assessment in 2005 diagnosed ''Leptodoras'' and its seven species while describing three new species.

Species

There are currently 12 recognized species in this genus: * ''

Leptodoras acipenserinus ''Leptodoras'' is a genus of thorny catfishes native to South America. Taxonomy ''Leptodoras'' is a monophyletic genus based on the single unique characteristic: presence of an infranuchal scute. This scute is the first in a series of well-devel ...

'' ( Günther, 1868) * ''

Leptodoras cataniai ''Leptodoras'' is a genus of thorny catfishes native to South America. Taxonomy ''Leptodoras'' is a monophyletic genus based on the single unique characteristic: presence of an infranuchal scute. This scute is the first in a series of well-devel ...

'' Sabaj Pérez, 2005 * ''

Leptodoras copei ''Leptodoras'' is a genus of thorny catfishes native to South America. Taxonomy ''Leptodoras'' is a monophyletic genus based on the single unique characteristic: presence of an infranuchal scute. This scute is the first in a series of well-devel ...

'' ( Fernández-Yépez, 1968) * ''

Leptodoras hasemani ''Leptodoras'' is a genus of thorny catfishes native to South America. Taxonomy ''Leptodoras'' is a monophyletic genus based on the single unique characteristic: presence of an infranuchal scute. This scute is the first in a series of well-devel ...

'' (

Steindachner Franz Steindachner (11 November 1834 in Vienna – 10 December 1919 in Vienna) was an Austrian zoologist, ichthyologist, and herpetologist. He published over 200 papers on fishes and over 50 papers on reptiles and amphibians. Steindachner describ ...

, 1915) * ''

Leptodoras juruensis ''Leptodoras'' is a genus of thorny catfishes native to South America. Taxonomy ''Leptodoras'' is a monophyletic genus based on the single unique characteristic: presence of an infranuchal scute. This scute is the first in a series of well-devel ...

'' Boulenger, 1898 * ''

Leptodoras linnelli ''Leptodoras'' is a genus of thorny catfishes native to South America. Taxonomy ''Leptodoras'' is a monophyletic genus based on the single unique characteristic: presence of an infranuchal scute. This scute is the first in a series of well-devel ...

'' C. H. Eigenmann, 1912 * ''

Leptodoras marki ''Leptodoras'' is a genus of thorny catfishes native to South America. Taxonomy ''Leptodoras'' is a monophyletic genus based on the single unique characteristic: presence of an infranuchal scute. This scute is the first in a series of well-devel ...

'' Birindelli & Sousa, 2010 * ''

Leptodoras myersi ''Leptodoras'' is a genus of thorny catfishes native to South America. Taxonomy ''Leptodoras'' is a monophyletic genus based on the single unique characteristic: presence of an infranuchal scute. This scute is the first in a series of well-devel ...

'' J. E. Böhlke, 1970 * ''

Leptodoras nelsoni ''Leptodoras'' is a genus of thorny catfishes native to South America. Taxonomy ''Leptodoras'' is a monophyletic genus based on the single unique characteristic: presence of an infranuchal scute. This scute is the first in a series of well-devel ...

'' Sabaj Pérez, 2005 * ''

Leptodoras oyakawai ''Leptodoras'' is a genus of thorny catfishes native to South America. Taxonomy ''Leptodoras'' is a monophyletic genus based on the single unique characteristic: presence of an infranuchal scute. This scute is the first in a series of well-devel ...

'' Birindelli, Sousa & Sabaj Pérez, 2008 * ''

Leptodoras praelongus ''Leptodoras'' is a genus of thorny catfishes native to South America. Taxonomy ''Leptodoras'' is a monophyletic genus based on the single unique characteristic: presence of an infranuchal scute. This scute is the first in a series of well-devel ...

'' ( G. S. Myers & S. H. Weitzman, 1956) * ''

Leptodoras rogersae ''Leptodoras'' is a genus of thorny catfishes native to South America. Taxonomy ''Leptodoras'' is a monophyletic genus based on the single unique characteristic: presence of an infranuchal scute. This scute is the first in a series of well-devel ...

'' Sabaj Pérez, 2005

Distribution

''Leptodoras'' species are distributed in large, predominantly lowland rivers east of the

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

throughout the northern half of

. Species are distributed throughout lowlands in the

Orinoco The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers , with 76.3 percent of it in Venezuela and the remainder in Colombia. It is the fourth largest river in the wo ...

Amazon Amazon most often refers to: * Amazons, a tribe of female warriors in Greek mythology * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon River, in South America * Amazon (company), an American multinational technolog ...

, and

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 2 ...

basins and several coastal river systems that enter 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 ...

between the mouths of the Orinoco and Amazon. ''Leptodoras'' is not known from west-Andean drainages or Atlantic-slope drainages south of the Tocantins.

Description

''Leptodoras'' is easily recognized by its long conical snout and well-developed ''oral hood'' formed by the membranous union of maxillary barbels, paired jaw barbels on the chin, and

lip The lips are the visible body part at the mouth of many animals, including humans. Lips are soft, movable, and serve as the opening for food intake and in the articulation of sound and speech. Human lips are a tactile sensory organ, and can be ...

structures. It has fimbriate barbels.

Ecology

Most species of ''Leptodoras'' are truly

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

and typically inhabit the deep swift-flowing waters of large rivers. Many species of ''Leptodoras'' migrate at dusk into shallow waters near shore to forage over beaches and shoals of sand or silt. Other species, such as ''L. juruensis'' and ''L. myersi'', appear more restricted to deep channel habitats. ''Leptodoras'' species are not known from

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 § ...

s exceeding 500 metres (1600 ft) above

sea level Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardise ...

and most records are from below 200 m (660 ft). The oral hood found in ''Leptodoras'' species presumably facilitates the detection and

suction Suction is the colloquial term to describe the air pressure differential between areas. Removing air from a space results in a pressure differential. Suction pressure is therefore limited by external air pressure. Even a perfect vacuum cannot ...

-feeding of shallowly buried

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s. Stomach contents typically include

chironomid The Chironomidae (informally known as chironomids, nonbiting midges, or lake flies) comprise a family of nematoceran flies with a global distribution. They are closely related to the Ceratopogonidae, Simuliidae, and Thaumaleidae. Many species ...

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. Th ...

e, sand, and detritus.

References

{{Taxonbar, from=Q6528103 Doradidae Fish of South America Catfish genera Taxa named by George Albert Boulenger Freshwater fish genera