Rhinelepini
Encyclopedia
Rhinelepini is a tribe
of armored suckermouth catfish
family
within the Hypostominae
subfamily.
group currently containing three genera
: Pogonopoma
, Pseudorinelepis
, and Rhinelepis
. When the tribe was first described, Pogonopomoides was a valid genus, but it is now a synonym
of Pogonopoma. Pseudorinelepis is the most basal
, and Rhinelepis and Pogonopoma are more derived
sister groups
.
as opposed to the bilobed, omega iris. These species end to have relatively thick armor plates on their bodies. In Iquitos
, Peru
, Pseudorinelepis genibarbis is known as carachama sin costilla, which actually means "Loricariid without ribs"; this refers to the trait that it shares with other Rhinelepini catfish; members of this tribe do not have ribs past the sixth vertebra.
One of the characters that binds this group together is a large U-shaped diverticulum
of the digestive tract; this is always filled with air. The first part of the diverticulum is modified from the esophagus
and consists of thick musculature; this passes a short distance before reaching the second, main, U-shaped part of the diverticulum. In Rhinelepis and Pseudorinelepis, the diverticulum functions as an accessory respiratory organ. In Rhinelepis, the diverticulum is more attached to the abdominal wall and the interior of the diverticulum is more textured. In Pogonopoma, the diverticulum is similar to a swim bladder
and may be used as a hydrostatic organ; the first part of the diverticulum is greatly reduced and the second part is larger and has a smooth interior surface and less vascularized.
and reveal information about the aquatic systems of South America
. There is a split between the species that inhabit Amazon
and those that inhabit the eastern river systems. Pseudorinelepis, the most basal group, is found only in the Amazon basin. Pogonopoma, is found in the Mucuri
, Paraíba do Sul
, and Uruguay River
systems in southeastern Brazil
. Rhinelepis is found in São Francisco River
and Paraná River
. It is also thought to have spread through to the Paraíba by a sharing of its headwaters with the Paraná in the past, which eventually got separated into two basins.
It is interesting to note that the oldest group, Pseudorinelepis, inhabits the Amazon area, while the distribution of the newer, more derived groups occurs in Southern Brazil, which is comparatively older.
Tribe (biology)
In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...
of armored suckermouth catfish
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...
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...
within the Hypostominae
Hypostominae
Hypostominae is a subfamily of catfishes of the family Loricariidae.Studies conducted with representatives of some genera of Hypostominae showed that within thisgroup, the diploid number ranges from 2n = 52 to 2n = 80...
subfamily.
Taxonomy
This tribe is a well diagnosed monophyleticMonophyly
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...
group currently containing three genera
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...
: Pogonopoma
Pogonopoma
Pogonopoma is a genus of South American catfish of the family Loricariidae. It includes three species, P. obscurum, P. parahybae, and P. wertheimeri.-Taxonomy:...
, Pseudorinelepis
Pseudorinelepis
Pseudorinelepis genibarbis is a species of the Hypostominae subfamily of the Loricariidae catfish family. P. genibarbis is distributed throughout the Upper Amazon River basin.-Taxonomy:...
, and Rhinelepis
Rhinelepis
Rhinelepis is a genus of South American catfish of the family Loricariidae. It contains two species, R. aspera and R. strigosa. It is one of three genera in the tribe Rhinelepini.-Distribution:...
. When the tribe was first described, Pogonopomoides was a valid genus, but it is now a synonym
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
of Pogonopoma. Pseudorinelepis 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:...
, and Rhinelepis and Pogonopoma are more derived
Derived
In phylogenetics, a derived trait is a trait that is present in an organism, but was absent in the last common ancestor of the group being considered. This may also refer to structures that are not present in an organism, but were present in its ancestors, i.e. traits that have undergone secondary...
sister groups
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...
.
Appearance and anatomy
Rhinelepini species are generally medium to large-sized Loricariids. Rhinelepini species are unique among Loricariidae for having a normal, circular irisIris (anatomy)
The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...
as opposed to the bilobed, omega iris. These species end to have relatively thick armor plates on their bodies. In Iquitos
Iquitos
Iquitos is the largest city in the Peruvian rainforest, with a population of 370,962. It is the capital of Loreto Region and Maynas Province.Located on the Amazon River, it is only above sea level, although it is more than from the mouth of the Amazon at Belém on the Atlantic Ocean...
, Peru
Peru
Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....
, Pseudorinelepis genibarbis is known as carachama sin costilla, which actually means "Loricariid without ribs"; this refers to the trait that it shares with other Rhinelepini catfish; members of this tribe do not have ribs past the sixth vertebra.
One of the characters that binds this group together is a large U-shaped diverticulum
Diverticulum
A diverticulum is medical or biological term for an outpouching of a hollow structure in the body. Depending upon which layers of the structure are involved, they are described as being either true or false....
of the digestive tract; this is always filled with air. The first part of the diverticulum is modified from the esophagus
Esophagus
The esophagus is an organ in vertebrates which consists of a muscular tube through which food passes from the pharynx to the stomach. During swallowing, food passes from the mouth through the pharynx into the esophagus and travels via peristalsis to the stomach...
and consists of thick musculature; this passes a short distance before reaching the second, main, U-shaped part of the diverticulum. In Rhinelepis and Pseudorinelepis, the diverticulum functions as an accessory respiratory organ. In Rhinelepis, the diverticulum is more attached to the abdominal wall and the interior of the diverticulum is more textured. In Pogonopoma, the diverticulum is similar to a swim bladder
Gas bladder
The swim bladder, gas bladder, fish maw or air bladder is an internal gas-filled organ that contributes to the ability of a fish to control its buoyancy, and thus to stay at the current water depth without having to waste energy in swimming...
and may be used as a hydrostatic organ; the first part of the diverticulum is greatly reduced and the second part is larger and has a smooth interior surface and less vascularized.
Distribution
The tribe Rhinelepini has an interesting biogeographyBiogeography
Biogeography is the study of the distribution of species , organisms, and ecosystems in space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area...
and reveal information about the aquatic systems of South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
. There is a split between the species that inhabit Amazon
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...
and those that inhabit the eastern river systems. Pseudorinelepis, the most basal group, is found only in the Amazon basin. Pogonopoma, is found in the Mucuri
Mucuri River
-References:*...
, Paraíba do Sul
Paraíba do Sul
thumbThe Paraíba do Sul , or simply termed Paraíba, is a river in the south-east of Brazil. It flows 1,137 kilometres west to northeast from its farthest source at the source of the river Paraitinga to the sea near Campos...
, and Uruguay River
Uruguay River
The Uruguay River is a river in South America. It flows from north to south and makes boundary with Brazil, Argentina, and Uruguay, separating some of the Argentine provinces of the Mesopotamia from the other two countries...
systems in 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...
. Rhinelepis is found in 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...
and Paraná River
Paraná River
The Paraná River is a river in south Central South America, running through Brazil, Paraguay and Argentina for some . It is second in length only to the Amazon River among South American rivers. The name Paraná is an abbreviation of the phrase "para rehe onáva", which comes from the Tupi language...
. It is also thought to have spread through to the Paraíba by a sharing of its headwaters with the Paraná in the past, which eventually got separated into two basins.
It is interesting to note that the oldest group, Pseudorinelepis, inhabits the Amazon area, while the distribution of the newer, more derived groups occurs in Southern Brazil, which is comparatively older.