Homodiaetus
Encyclopedia
Homodiaetus is a genus
of catfish
es (order
Siluriformes) of the family
Trichomycteridae
. It includes four species
, H. anisitsi, H. banguela, H. graciosa, and H. passarellii.
, from Urugay
to Paraguay River
s in the west to the coastal drainages of the Rio de Janeiro State
, Brazil
. H. anisitsi originates from the Paraná
-Paraguay River basin. H. banguela inhabits the São João River
and H. passarellii is known from coastal basins in the State of Rio de Janeiro. H. graciosa is distributed in coastal basins of southeastern Brazil in states of Paraná
and São Paulo
.
by the combination of the origin of the pelvic fin midlength between the tip of the snout and the caudal-fin origin, the opercle
with three or more odontode
s, and the gill
membranes confluent with the isthmus
. Homodiaetus species are small and grow up to 42 millimetres (1.7 in) SL
. They are transparent with the except of the head and abdomen. Homodiaetus species have a thin body and depressed head that is almost as wide as the head is long. The dorsal and ventral profiles are straight except for a convex head. The mouth is inferior.
H. anisitsi has three dark bands on its caudal fin, while dark lines are irregular or absent in the other three species. Among the other three species, H. graciosa has 5–6 rows of teeth in the dentary (vs. 6–7 in the other two species). H. graciosa has 7–9 (usually 8) opercular odontode
s, H. passarellii has 6–7, and H. banguella has 9.
s and arenaceous rivers of little depth. These fish are known to be lepidophagous
, meaning they feed upon scales.
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 four 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...
, H. anisitsi, H. banguela, H. graciosa, and H. passarellii.
Distribution
The distribution of Homodiaetus is restricted you southeastern 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...
, from Urugay
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...
to Paraguay River
Paraguay River
The Paraguay River is a major river in south central South America, running through Brazil, Bolivia, Paraguay, and Argentina...
s in the west to the coastal drainages of 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...
, 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...
. H. anisitsi originates from the 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...
-Paraguay River basin. H. banguela inhabits the São João River
São João River
-Brazil:* São João River * São João River * São João River * São João River * São João River * São João River * São João River...
and H. passarellii is known from coastal basins in the State of Rio de Janeiro. H. graciosa is distributed in coastal basins of southeastern Brazil in states of Paraná
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,...
and São Paulo
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...
.
Description
Homodiaetus is currently distinguished from other genera of StegophilinaeStegophilinae
Stegophilinae is a subfamily of catfishes of the family Trichomycteridae.It includes twelve genera, Acanthopoma, Apomatoceros, Haemomaster, Henonemus, Homodiaetus, Megalocentor, Ochmacanthus, Parastegophilus, Pareiodon, Pseudostegophilus, Schultzichthys, and Stegophilus...
by the combination of the origin of the pelvic fin midlength between the tip of the snout and the caudal-fin origin, the opercle
Ichthyology terms
Ichthyology uses several terms that are unique to the science.Contents: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z- A :* Abdomen: belly* Abdominal: pertaining to the belly* Actinosts: a series of bones at the base of the pectoral rays....
with three or more odontode
Odontode
Odontodes, or dermal teeth, are hard structures found on the external surfaces of animals or near internal openings. They comprise a soft pulp surrounded by dentine and covered by a mineralized substance such as enamel, a structure similar to that of teeth. They generally do not have the same...
s, and the gill
Gill
A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...
membranes confluent with the isthmus
Ichthyology terms
Ichthyology uses several terms that are unique to the science.Contents: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z- A :* Abdomen: belly* Abdominal: pertaining to the belly* Actinosts: a series of bones at the base of the pectoral rays....
. Homodiaetus species are small and grow up to 42 millimetres (1.7 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:...
. They are transparent with the except of the head and abdomen. Homodiaetus species have a thin body and depressed head that is almost as wide as the head is long. The dorsal and ventral profiles are straight except for a convex head. The mouth is inferior.
H. anisitsi has three dark bands on its caudal fin, while dark lines are irregular or absent in the other three species. Among the other three species, H. graciosa has 5–6 rows of teeth in the dentary (vs. 6–7 in the other two species). H. graciosa has 7–9 (usually 8) opercular odontode
Odontode
Odontodes, or dermal teeth, are hard structures found on the external surfaces of animals or near internal openings. They comprise a soft pulp surrounded by dentine and covered by a mineralized substance such as enamel, a structure similar to that of teeth. They generally do not have the same...
s, H. passarellii has 6–7, and H. banguella has 9.
Ecology
Homodiaetus species are found in lagoonLagoon
A lagoon is a body of shallow sea water or brackish water separated from the sea by some form of barrier. The EU's habitat directive defines lagoons as "expanses of shallow coastal salt water, of varying salinity or water volume, wholly or partially separated from the sea by sand banks or shingle,...
s and arenaceous rivers of little depth. These fish are known to be lepidophagous
Lepidophagy
Lepidophagy is a specialised feeding behaviour in fish that involves eating of scales of other fish. Lepidophagy is widespread, having been independently evolved in at least five freshwater families and seven marine families...
, meaning they feed upon scales.