Iguanodectidae is a family of freshwater fish in the order

Characiformes Characiformes is an order of ray-finned fish, comprising the characins and their allies. Grouped in 18 recognized families, more than 2000 different species are described, including the well-known piranha and tetras.; Buckup P.A.: "Relationshi ...

that lives in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

. It is home to the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

Iguanodectinae Iguanodectinae is a subfamily of small freshwater fish in the family Iguanodectidae. They are most prominently found in the Amazon river basin and its major tributaries, but they are also known from the Tocantins, Orinoco, and Paraguay rivers. I ...

(Eigenmann, 1909) and the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

Bryconops ''Bryconops'' is a genus of freshwater fish in the family Iguanodectidae from South America. It consists of small fish, all under half-a-foot long, with slender bodies and silvery scales, though there is some mild color variation. Several species ...

'' clade. Several species in the family, such as the green line lizard tetra (''Iguanodectes spilurus''), the tailspot tetra (''Bryconops caudomaculatus''), and the orangefin tetra (''Bryconops affinis''), are sometimes taken as aquarium fish.

Description

Iguanodectids are generally small, and are brightly colored or reflective, making them moderately-popular ornamental fish. They range from 3.1 cm to 15 cm SL (standard length). They are rather narrow in shape, somewhat resembling

minnow Minnow is the common name for a number of species of small freshwater fish, belonging to several genera of the families Cyprinidae and Leuciscidae. They are also known in Ireland as pinkeens. Smaller fish in the subfamily Leusciscidae are co ...

s; ichthyologist Carl H. Eigenmann compared them to

smelt Smelt may refer to: * Smelting, chemical process * The common name of various fish: ** Smelt (fish), a family of small fish, Osmeridae ** Australian smelt in the family Retropinnidae and species ''Retropinna semoni'' ** Big-scale sand smelt ''At ...

Habitat

Iguanodectids are found in

, spread all across the northern half of the continent. Though they primarily inhabit freshwater, Iguanodectid fishes are known to tolerate brackish water as well. Habitat destruction, by way of land development and aquaculture, is the biggest threat to members of Iguanodectidae, though evaluated species are mostly considered least concern by the International Union for the Conservation of Nature (IUCN).

Classification

Iguanodectidae is in the order

, with three extant genera - ''

'', ''

Iguanodectes ''Iguanodectes'' is a genus of freshwater fish found in tropical South America, with eight currently described species. They are all small tetras, none longer than 5 inches, and often have attractive silvery or striped scales, which makes them a t ...

'', and ''

Piabucus ''Piabucus'' is a genus of freshwater tetras in the family Iguanodectidae. All three species are found in South America, largely the Amazon and its major tributaries. None of them are longer than half a foot long, with the largest reaching a maxi ...

''. Said genera used to be classified in the family

Characidae Characidae, the characids or characins is a family of freshwater subtropical and tropical fish, belonging to the order Characiformes. The name "characins" is the historical one, but scientists today tend to prefer "characids" to reflect their st ...

, but have since been reclassified in order to keep Characidae

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

. Species include: ''Bryconops'' is the most speciose genus, with 21 valid species. ''Iguanodectes'' is next-largest with 8, and ''Piabucus'' has the fewest at 3. ''Iguanodectes'' and ''Piabucus'' are largely considered to make up the subfamily

, with ''Bryconops'' becoming its own separate clade, but this is a matter of debate. Several sources accept the subfamily Iguanodectinae as its own entity, but others consider it synonymous with Iguanodectidae or simply don't acknowledge it, uniting the genera therein.

ITIS The Integrated Taxonomic Information System (ITIS) is an American partnership of federal agencies designed to provide consistent and reliable information on the taxonomy of biological species. ITIS was originally formed in 1996 as an interagenc ...

considers it synonymous with Characidae, which is a reflection of its older classification. Iguanodectinae, when first officially classified by Carl H. Eigenmann in 1909, was placed in the family Characidae, and only contained the genus ''Iguanodectes''; by 1929, it had grown to include the genus Piabucus. Through the year 1977, this remained the case. In 2011, Iguanodectinae was found to be closely related to ''Bryconops'', and the two clades were combined in Iguanodectidae.Oliveira, C., Avelino, G.S., Abe, K.T., Mariguela, T.C., Benine, R.C., Orti, G., Vari, R.P., & Correa e Castro, R.M. (2011)
Phylogenetic relationships within the speciose family Characidae (Teleostei: Ostariophysi: Characiformes) based on multilocus analysis and extensive ingroup sampling.
''BMC Evolutionary Biology, 11: 275. doi: 10.1186/1471-2148-11-275''

History

The family Iguanodectidae was resurrected from Eigenmann's work in the year 2011 by Oliveira et al. to contain Iguanodectinae and ''Bryconops''. Iguanodectinae itself was classified in 1909, and therefore Iguanodectidae is often considered to originate in the same year, despite the recent nature of the study.

Etymology

The family name "Iguanodectidae" originates in the genus name "''Iguanodectes''", which used to be its sole representative. The origin of such was not made clear upon its nomination, but is assumed to be from "

iguana ''Iguana'' (, ) is a genus of herbivorous lizards that are native to tropical areas of Mexico, Central America, South America, and the Caribbean. The genus was first described in 1768 by Austrian naturalist Josephus Nicolaus Laurenti in his bo ...

", the lizard, and "dectes", meaning "bite", in reference to the general dentition's almost lizard-like formation. The common name "lizard bite tetra" has been proposed in reference to this, though this has not been widely accepted as of 2022.

In Aquaria

Though data is limited, it is known that ''Bryconops colanegra'', ''Bryconops colaroja'', and ''Piabucus dentatus'' are seen in the ornamental fish trade. ''Iguanodectes geisleri'' is rare, but is sold under the name "red line lizard tetra". One of its congeners, ''Iguanodectes spilurus'', is called the "green line lizard tetra", and is sensitive to poor water conditions.

References

{{Taxonbar, from=Q18182928 Characiformes Ray-finned fish families