Parotocinclus 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...

 Loricariidae

Loricariidae

Loricariidae is the largest family of catfish , with almost 700 species and new species being described each year. Loricariids originate from fresh water habitats of Costa Rica, Panama, and tropical and subtropical South America. These fish are noted for the bony plates covering their bodies and...

.

Taxonomy

By an analysis published in 2005, Parotocinclus is not a 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...

 genus. P. jumbo is not closely related to P. maculicauda, but is positioned, instead, as a 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:...

 lineage of the Hypoptopomatinae

Hypoptopomatinae

Hypoptopomatinae is a subfamily of catfishes of the family Loricariidae.Hypoptopomatinae is a monophyletic assemblage within the family Loricariidae. It is composed by 17 genera and approximately 80 species. This subfamily represents about one-tenth of all loricariid species.It is divided into two...

. Additionally, P. collinsae is not closely related to P. maculicauda, and may be more closely related to Hypoptopoma

Hypoptopoma

Hypoptopoma is a genus of catfishes of the family Loricariidae.-Taxonomy:The genus was established by Albert C. L. G. Günther in 1868 for his new species H. thoracatum, on the basis of the peculiar, depressed, spatulate formation of the head with the eyes on the lateral edges of the head...

and four other genera. P. jumbo and P. collinsae may eventually be transferred to new genera. P. bidentatus and P. muriaensis form a monophyletic pair of sister taxa

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...

 that is more closely related to a subset of species of Parotocinclus (which includes P. maculicauda) than to any other genus of the subfamily Hypoptopomatinae.

Distribution

Parotocinclus species are distributed in the Atlantic coastal drainages of Guyana

Guyana

Guyana , officially the Co-operative Republic of Guyana, previously the colony of British Guiana, is a sovereign state on the northern coast of South America that is culturally part of the Anglophone Caribbean. Guyana was a former colony of the Dutch and of the British...

 and Surinam, eastern and 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...

. Seven species of Parotocinclus are known from Brazilian rivers south of the São Francisco River

São Francisco River

The São Francisco is a river in Brazil. With a length of , it is the longest river that runs entirely in Brazilian territory, and the fourth longest in South America and overall in Brazil...

 basin: P. maculicauda (southeastern coastal rivers from Espírito Santo

Espírito Santo

Espírito Santo is one of the states of southeastern Brazil, often referred to by the abbreviation "ES". Its capital is Vitória and the largest city is Vila Velha. The name of the state means literally "holy spirit" after the Holy Ghost of Christianity...

 to Santa Catarina

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...

 States); P. bahiensis (Senhor do Bonfim

Senhor do Bonfim

Senhor do Bonfim is a town and municipality in the state of Bahia in the North-East region of Brazil.-See also:**List of municipalities in Bahia-References:...

, Bahia

Bahia

Bahia is one of the 26 states of Brazil, and is located in the northeastern part of the country on the Atlantic coast. It is the fourth most populous Brazilian state after São Paulo, Minas Gerais and Rio de Janeiro, and the fifth-largest in size...

 State); P. doceanus (Doce River

Doce River

The Doce River is a river in southeast Brazil, which has an extension of 853 km.It is formed by the junction of the Piranga and the Carmo near the historical city of Ouro Preto, whose sources are located in the foothills of the Mantiqueira and Espinhaço mountain chains at altitudes of about 1,200...

, Espírito Santo State); P. minutus (Canudos

Canudos

Canudos was a town founded in the racially diverse Bahia state of northeastern Brazil in 1893 by Antônio Vicente Mendes Maciel. Antonio was an itinerant preacher from Ceara who had been wandering through the backroads and lesser-inhabited areas of the country from the 1870s onwards, followed by a...

, Bahia State); P. cristatus (Ilhéus

Ilhéus

Ilhéus is a major city located in the southern coastal region of Bahia, Brazil, 430 km south of Salvador, the state's capital. The city was originally founded in 1534 as Vila de São Jorge dos Ilhéus and is known as one of the most important tourism centers of the northeast of Brazil.The...

, Bahia State); P. jimi (Itagibá

Itagibá

Itagibá is a town and municipality in the state of Bahia in the North-East region of Brazil.-References:...

, Bahia State); and P. planicauda (Suaçui Pequeno River

Suaçuí Pequeno River

-See also:* ] map]* Rand McNally, The New International Atlas, 1993....

, a tributary of the Doce River, flowing near the city of Coroaci, Minas Gerais State).

Description

Most species of Parotocinclus have the caudal peduncle oval in cross section

Cross section (geometry)

In geometry, a cross-section is the intersection of a figure in 2-dimensional space with a line, or of a body in 3-dimensional space with a plane, etc...

; however, in P. planicauda and P. cristatus, it is quadrangular.

Ecology

It has been found that Characidium species may interact with Parotocinclus maculicauda. The small Characidium will follow grazing P. maculicauda, which release particulate matter dislodged from the catfish's foraging.