Listrura
Encyclopedia
Listrura is a genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of catfish
Catfish
Catfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...

es (order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Siluriformes) of the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Trichomycteridae
Trichomycteridae
Trichomycteridae is a family of catfishes commonly known as the pencil or parasitic catfishes. This family includes the infamous candiru fish, feared by some people for its alleged habit of entering into the urethra of humans....

. It includes five species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

, L. boticario, L. camposi, L. nematopteryx, L. picinguabae, and L. tetraradiata.

Taxonomy

Listrura was first described in 1988 for two species from southeastern Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

, the first record of the subfamily Glanapteryginae
Glanapteryginae
Glanapteryginae is a subfamily of catfishes of the family Trichomycteridae. It includes four genera, Glanapteryx, Listrura, Pygidianops, and Typhlobelus.-Phylogeny:...

 outside of the Amazon River
Amazon River
The Amazon of South America is the second longest river in the world and by far the largest by waterflow with an average discharge greater than the next seven largest rivers combined...

 basin. It was described for the species L. nematopteryx and L. camposi; L. camposi had been assigned to the genus Eremophilus, while L. nematopteryx had been misidentified as another species of Eremophilus. L. tetraradiata was described in 2002 from the Rio de Janeiro State
Rio de Janeiro (state)
Rio de Janeiro is one of the 27 states of Brazil.Rio de Janeiro has the second largest economy of Brazil behind only São Paulo state.The state of Rio de Janeiro is located within the Brazilian geopolitical region classified as the Southeast...

 in Brazil. L. boticario was described later in 2002 from southern Brazil. L. picinguabae was described in 2006. This genus is currently monophyletic
Monophyly
In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group. The term is synonymous with the uncommon term holophyly...

.

With the description of L. tetraradiata in 2003, it was hypothesized that L. tetraradiata possibly constitutes the sister group
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...

 to a clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

 comprising the only other two previously described species of Listrura, L. camposi and L. nematopteryx. As of 2006, two species of Listrura, L. camposi and L. boticario, were known only from their holotypes
Biological type
In biology, a type is one particular specimen of an organism to which the scientific name of that organism is formally attached...

. The lack of osteological information for these species impedes a complete analysis of phylogenetic
Phylogenetics
In biology, phylogenetics is the study of evolutionary relatedness among groups of organisms , which is discovered through molecular sequencing data and morphological data matrices...

 relationships within the genus. It was hypothesized that L. nematopteryx and L. picinguabae comprise a monophyletic assemblage, given the fact that the pectoral fin of these species consists of a single ray and the ray is in the form of a long filament, a condition not present in any other trichomycterids thus far described.

Listura is the most basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...

 member of the subfamily Glanapteryginae; it is sister to a clade formed by the other three genera, Glanapteryx
Glanapteryx
Glanapteryx is a genus of catfishes of the family Trichomycteridae. It includes two species, G. anguilla and G. niobium....

, Pygidianops
Pygidianops
Pygidianops is a genus of catfishes of the family Trichomycteridae. It includes three species, P. cuao, P. eigenmanni, and P. magoi.-Distribution:...

, and Typhlobelus
Typhlobelus
Typhlobelus is a genus of catfishes of the family Trichomycteridae. It includes four species, T. guacamaya, T. lundbergi, T. macromycterus, and T. ternetzi.-Distribution:...

.

Distribution

Listrura is endemic to small coastal river basins of southeastern Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

. L. boticario originates from Da Figueira and Guaraqueçaba River basins, Paraná State
Paraná (state)
Paraná is one of the states of Brazil, located in the South of the country, bordered on the north by São Paulo state, on the east by the Atlantic Ocean, on the south by Santa Catarina state and the Misiones Province of Argentina, and on the west by Mato Grosso do Sul and the republic of Paraguay,...

. L. camposi inhabits the Poço Grande River, a tributary of the Juquiá River
Juquiá River
The Juquiá River is a river of São Paulo state in southeastern Brazil.-References:*...

 in the São Paulo State
São Paulo (state)
São Paulo is a state in Brazil. It is the major industrial and economic powerhouse of the Brazilian economy. Named after Saint Paul, São Paulo has the largest population, industrial complex, and economic production in the country. It is the richest state in Brazil...

, and Ribeirão da Ilha of Florianópolis
Florianópolis
-Climate:Florianópolis experiences a warm humid subtropical climate, falling just short of a true tropical climate. The seasons of the year are distinct, with a well-defined summer and winter, and characteristic weather for autumn and spring. Frost is infrequent, but occurs occasionally in the winter...

 in Santa Catarina State
Santa Catarina (state)
Santa Catarina is a state in southern Brazil with one of the highest standards of living in Latin America. Its capital is Florianópolis, which mostly lies on the Santa Catarina Island. Neighbouring states are Rio Grande do Sul to the south and Paraná to the north. It is bounded on the east by...

. L. nematopteryx is distributed in the Imbariê Creek and basin of the Estrela River system of Piabetá in the Rio de Janeiro State
Rio de Janeiro (state)
Rio de Janeiro is one of the 27 states of Brazil.Rio de Janeiro has the second largest economy of Brazil behind only São Paulo state.The state of Rio de Janeiro is located within the Brazilian geopolitical region classified as the Southeast...

, and Picinguaba
Picinguaba
Picinguabas were people indigenous to the Campo Grande, Rio de Janeiro neighborhood of Rio de Janeiro until 1565, when the first Portuguese colonists arrived there....

 in the São Paulo State. L. picinguabae is only known from small tributaries to the da Fazenda River in the São Paulo State. L. tetraradiata is from the Ibicuíba River of the Araruama Lagoon system.

Description

The body is elongate and may be cylindrical. These fish have three pairs of barbels
Barbel (anatomy)
A barbel on a fish is a slender, whiskerlike tactile organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, sturgeon, the zebrafish and some species of shark...

. The mouth is subterminal. These fish are lacking in pelvic fins. The caudal fin is rounded. The caudal skeleton is compact and fused. Listura species grow to about 3.7–4.9 centimetre
Centimetre
A centimetre is a unit of length in the metric system, equal to one hundredth of a metre, which is the SI base unit of length. Centi is the SI prefix for a factor of . Hence a centimetre can be written as or — meaning or respectively...

s (1.5–1.9 in
Inch
An inch is the name of a unit of length in a number of different systems, including Imperial units, and United States customary units. There are 36 inches in a yard and 12 inches in a foot...

) SL
Fish measurement
Fish measurement refers to the measuring of the length of individual fish and of various parts of their anatomy. These data are used in many areas of ichthyology, including taxonomy and fisheries biology.-Overall length:...

.

Ecology

Listrura occur in shallow-water leaf-litter deposits underlain by mud or deeper layers of leaf litter. Listrura inhabits extremely small, shallow, and temporary water bodies, marginal to main water courses covered with vegetation; no species of Listrura is known to occur in creeks or rivers, except apparently as stray or colonizing specimens. L. picinguabae inhabits narrow and shallow (about 20 cm or 12 in deep) streams in dense tropical forest; it is encountered buried in the litter bottom. L. tetraradiata has been found in small, clear water forest streams; these habitats are shallow (about 40 cm or 16 in deep), with large rocks on the banks and gravel and sand on the bottom. L. tetraradiata has been found to have copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...

s, insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

 larva
Larva
A larva 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...

e, and mite
Mite
Mites, along with ticks, are small arthropods belonging to the subclass Acari and the class Arachnida. The scientific discipline devoted to the study of ticks and mites is called acarology.-Diversity and systematics:...

s in their stomach contents.
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