Steindachneridion
Encyclopedia
Steindachneridion is a genus
of South America
n Pimelodid
catfish
(order
Siluriformes).
under the name Platystoma parahybae. Later, Carl H. Eigenmann
and Rosa Smith Eigenmann
described Steindachneridia, named for Steindachner, for this species and for S. amblyurum (designated as the type species
) in 1888. The next year, Eigenmann and Eigenmann described S. doceanum. In 1918, Miranda Ribeiro described S. scriptum and S. scriptum punctatum; later, S. punctatum was studied and considered to be a species of its own. However, because Steindachneria was already being used, these fish were transferred to Steindachneridion in 1919. The most recent species, S. melanodermatum, was described by Garavello in 2005. This genus currently includes six extant species.
There are two fossil
species of Steindachneridion. The first fossil species to be described, S. iherengi, was first described to Arius
, but subsequently moved to Steindachneridion; though originally considered to be of Pleistocene
age, it has later been argued that it is actually of Oligocene
age. The second fossil species to be described was S. silvasantosi in 1999.
The phylogenetic placement of Steindachneridion and its relationship to other Pimelodid genera is unresolved. These fish have been classified with Sorubim
-like fish such as Brachyplatystoma
and Pseudoplatystoma
. They have also been classified as being more closely related to Phractocephalus and Leiarius
.
and are restricted to eastern Brazil
ian coastal drainages, plus the upper Paraná
and Uruguay River
basin. S. amblyurus originates from the Jequitinhonha River
basin. S. doceanum originates from the Doce River
basin. S. melanodermatum originates from Iguaçu River
in Brazil
. S. parahybae originates from Paraíba do Sul
and Jequitinhonha River basins. S. punctatum originates from the upper Paraná River and the Uruguay River basins. S. scriptum originates from the Uruguay River.
The large species of Steindachneridion always occur in swift-flowing, clear water rivers running over large stony beds. These fish are naturally scarce in their habitats.
s (40 in
) TL
or more. S. doceanum reaches 42 cm (17 in) SL
. S. melanodermatum reaches a length of about 53.2 cm (21 in) SL. S. punctatum reaches about 70 cm (28 in) SL.
These fish have relatively small eyes and head. They have long maxillary barbels
that extend to the base of the dorsal fin
or the adipose fin. The adipose fin is relatively long and straight, and its base is longer than the base of the anal fin. Pectoral and dorsal fin spines are short. Most of these species have light grayish or brownish ground color pattern combined with dark brown, vermiculated dark stripes or spots; however, S. doceanum has reticulations over its body instead of spots, and S. melanodermatum is unique in the genus for its dark brown ground color. S. amblyurum differs from other members of this species by having a rounded caudal fin instead of a caudal fin that is notched.
; consequently, some of them are highly endangered and practically extinct in various parts of their original areas of distribution. Due to their economic importance as a food source, some aquaculture
stations are currently developing programs for captive propagation of Steindachneridion species. Fish produced by these programs would be used in fish farms as well to restore natural stocks in degraded habitats.
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 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...
n Pimelodid
Pimelodidae
Pimelodidae, commonly known as the long-whiskered catfishes, is a family of catfishes .-Taxonomy:Pimelodidae has undergone much revision. Currently, the family contains about 30 genera and about 90 recognized and known but unnamed species...
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...
(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).
Taxonomy
The first species of the genus, S. parahybae, was described in 1877 by Franz SteindachnerFranz Steindachner
Franz Steindachner was an Austrian zoologist.- Work and career :Being interested in natural history, Steindachner took up the study of fossil fishes on the recommendation of his friend Eduard Suess...
under the name Platystoma parahybae. Later, Carl H. Eigenmann
Carl H. Eigenmann
Carl H. Eigenmann was an ichthyologist who, along with his wife Rosa Smith Eigenmann, described many of the fishes of North America and South America for the first time....
and Rosa Smith Eigenmann
Rosa Smith Eigenmann
Rosa Smith Eigenmann was the first notable female ichthyologist; first publishing in her own right, she later collaborated with her husband Carl H. Eigenmann, and some 150 species of fish are today credited "Eigenmann & Eigenmann" as a result.She was born in Monmouth, Illinois, the last of nine...
described Steindachneridia, named for Steindachner, for this species and for S. amblyurum (designated as the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
) in 1888. The next year, Eigenmann and Eigenmann described S. doceanum. In 1918, Miranda Ribeiro described S. scriptum and S. scriptum punctatum; later, S. punctatum was studied and considered to be a species of its own. However, because Steindachneria was already being used, these fish were transferred to Steindachneridion in 1919. The most recent species, S. melanodermatum, was described by Garavello in 2005. This genus currently includes six extant species.
There are two fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
species of Steindachneridion. The first fossil species to be described, S. iherengi, was first described to Arius
Arius (genus)
Arius is a genus of catfishes of the family Ariidae. The genus Arius is distributed in brackish and fresh waters of Eastern Africa and south to southeast Asia....
, but subsequently moved to Steindachneridion; though originally considered to be of Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
age, it has later been argued that it is actually of Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
age. The second fossil species to be described was S. silvasantosi in 1999.
The phylogenetic placement of Steindachneridion and its relationship to other Pimelodid genera is unresolved. These fish have been classified with Sorubim
Sorubim
Sorubim is a small genus of Pimelodid catfish originating from tropical South America. A number of characteristics allows the differentiation of each species in the genus...
-like fish such as Brachyplatystoma
Brachyplatystoma
Brachyplatystoma is a genus of catfish from the family Pimelodidae. As the occasionally used common name goliath catfishes indicates, this genus includes some of the largest species of catfish, including the Piraíba, B. filamentosum, which reaches about in length...
and Pseudoplatystoma
Pseudoplatystoma
Pseudoplatystoma is a genus of several South American catfish species of family Pimelodidae. The three species are known by a number of different common names. They inhabit the major rivers of north-eastern Argentina, Paraguay, Peru, Bolivia, Uruguay and Brazil. They prefer the main channels and...
. They have also been classified as being more closely related to Phractocephalus and Leiarius
Leiarius
Leiarius is a genus of catfishes of the family Pimelodidae. It includes four species. Most of the genus' species are ornamental species kept as pets in the aquarium hobby.-Taxonomy:...
.
Distribution and habitat
Steindachneridion species originate from South AmericaSouth 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...
and are restricted to eastern 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...
ian coastal drainages, plus the upper Paraná
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...
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...
basin. S. amblyurus originates from the Jequitinhonha River
Jequitinhonha River
thumb|Source of the river in [[Serro]]|rightThe Jequitinhonha River is a river that flows mainly through the Brazilian state of Minas Gerais. Its source lies near Diamantina in the Serra do Espinhaço at an elevation of 1,200 m, after which it flows northward and then east-northeastward across the...
basin. S. doceanum originates from the 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...
basin. S. melanodermatum originates from Iguaçu River
Iguazu River
The Iguazu River is a river in Brazil and Argentina. It is an important tributary of the Paraná River. The Iguazu River is long, with a drainage basin of .-Course:...
in 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...
. S. parahybae originates from 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 Jequitinhonha River basins. S. punctatum originates from the upper Paraná River and the Uruguay River basins. S. scriptum originates from the Uruguay River.
The large species of Steindachneridion always occur in swift-flowing, clear water rivers running over large stony beds. These fish are naturally scarce in their habitats.
Appearance and anatomy
Steindachneridion species are large sized fishes, reaching 100 centimetreCentimetre
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 (40 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...
) TL
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:...
or more. S. doceanum reaches 42 cm (17 in) 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:...
. S. melanodermatum reaches a length of about 53.2 cm (21 in) SL. S. punctatum reaches about 70 cm (28 in) SL.
These fish have relatively small eyes and head. They have long maxillary 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...
that extend to the base of the dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
or the adipose fin. The adipose fin is relatively long and straight, and its base is longer than the base of the anal fin. Pectoral and dorsal fin spines are short. Most of these species have light grayish or brownish ground color pattern combined with dark brown, vermiculated dark stripes or spots; however, S. doceanum has reticulations over its body instead of spots, and S. melanodermatum is unique in the genus for its dark brown ground color. S. amblyurum differs from other members of this species by having a rounded caudal fin instead of a caudal fin that is notched.
Relationship to humans
Steindachneridion species suffer intense anthropogenic pressure, through modification to their habitat and due to overfishingOverfishing
Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....
; consequently, some of them are highly endangered and practically extinct in various parts of their original areas of distribution. Due to their economic importance as a food source, some aquaculture
Aquaculture
Aquaculture, also known as aquafarming, is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, which is the...
stations are currently developing programs for captive propagation of Steindachneridion species. Fish produced by these programs would be used in fish farms as well to restore natural stocks in degraded habitats.