''Xiphophorus milleri'', the Catemaco platyfish, is a

poeciliid Poeciliidae are a family of freshwater ray-finned fishes of the order Cyprinodontiformes, the tooth-carps, and include well-known live-bearing aquarium fish, such as the guppy, molly, platy, and swordtail. The original distribution of the fam ...

fish endemic to Mexico's Lake Catemaco and its tributaries. As it has traits of both swordtails and

platies Platy is a common name of freshwater fish in the genus ''Xiphophorus'' that lack a "sword" at the bottom of their tails. This species is a livebearer, similar to other fish of the family Poeciliidae, such as the guppy and molly. Platies are nati ...

, its discovery confirmed that these two groups should be consolidated into a single

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

, ''

Xiphophorus ''Xiphophorus'' is a genus of euryhaline and freshwater fishes in the family Poeciliidae of order (biology), order Cyprinodontiformes, native to Mexico and northern Central America. ''Xiphophorus'' species can be divided into three groups based ...

''.

Taxonomy

The species was named after American ichthyologist

Robert Rush Miller Robert Rush Miller (April 23, 1916 – February 10, 2003) was an important figure in American ichthyology and Conservation movement, conservation from 1940 to the 1990s. He was born in Colorado Springs, earned his bachelor's degree at Universit ...

, who collected it along with other ''

'' species. Its discovery enabled scientists to definitely conclude that

and swordtails should be classified in the same

, for it combines traits that were thought to separate platies from swordtails into different genera. Namely, ''X. milleri'' resembles the swordtails in body shape, pigmentation, and ecology, but shares the platies' secondary sexual characteristics, pigmentary polymorphism, and the absence of a sword.

Description

''Xiphophorus milleri'' is a small to medium ''Xiphophorus'' species. Its body is slender. Nearly a half of specimens have

melanophore Chromatophores are cells that produce color, of which many types are pigment-containing cells, or groups of cells, found in a wide range of animals including amphibians, fish, reptiles, crustaceans and cephalopods. Mammals and birds, in contrast ...

markings of varying sizes. These are arranged in one of two types of patterns: irregular dark spots on the body; and definite rows of spots on the side. Three tail patterns exist: one with a single small spot (similar to those of '' X. variatus'' and '' X. maculatus''), one with a single large spot (similar to that of some ''X. variatus'' specimens), and a bar-like pattern (similar to those of '' X. montezumae'' and '' X. pygmaeus''). Adult males have deep yellow-orange bellies. Females grow to

total length Fish measurement is the measuring of individual fish and various parts of their anatomies, for data used in many areas of ichthyology, including taxonomy and fishery biology. Overall length Standard length (SL) is the length of a fish measured f ...

, while males attain . The males are elongated, while the females appear humpbacked and compact.

Distribution and habitat

''Xiphophorus milleri'' was discovered in a steep-banked stream flowing into Lake Catemaco in Mexico. It prefers clear or

white water Whitewater forms in the context of rapids, in particular, when a river's gradient changes enough to generate so much turbulence that air is trapped within the water. This forms an unstable current that froths, making the water appear opaque ...

habitats with sparse green algae growth on a substrate of mostly sand and silt with occasional rocks. '' X. helleri'' is found in the same habitat. It appears to be restricted to Lake Catemaco and its tributaries.

Reproduction

''Xiphophorus milleri'' is a

livebearer Livebearers are fish that retain their eggs inside the body and give birth to live, free-swimming young. They are especially prized by aquarium owners. Among aquarium fish, livebearers are nearly all members of the family Poeciliidae and include: ...

; the female gives birth every 24 to 28 days. The size of each brood normally ranges from 15 to 50 fry.

Filial cannibalism Filial cannibalism occurs when an adult individual of a species consumes all or part of the young of its own species or immediate offspring. Filial cannibalism occurs in many species ranging from mammals to insects, and is especially prevalent in ...

is rare.

References

Bibliography

* * {{taxonbar, from=Q972225 milleri Freshwater fish of Mexico Endemic fish of Mexico Taxa named by Donn Eric Rosen Fish described in 1960