''Xiphophorus milleri'', the Catemaco platyfish, is a poeciliid fish endemic to Mexico's Lake Catemaco and its tributaries. As it has traits of both

swordtails ''Xiphophorus'' is a genus of euryhaline and freshwater fishes in the family Poeciliidae of order Cyprinodontiformes, native to Mexico and northern Central America. The many ''Xiphophorus'' species are all known as platyfish (or platies) and ...

and platies, its discovery confirmed that these two groups should be consolidated into a single genus, ''

Xiphophorus ''Xiphophorus'' is a genus of euryhaline and freshwater fishes in the family Poeciliidae of order Cyprinodontiformes, native to Mexico and northern Central America. The many ''Xiphophorus'' species are all known as platyfish (or platies) and s ...

''.

Taxonomy

The species was named after American ichthyologist Robert Rush Miller, who collected it along with other ''

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

should be classified in the same genus, 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 Polymorphism, polymorphic, polymorph, polymorphous, or polymorphy may refer to: Computing * Polymorphism (computer science), the ability in programming to present the same programming interface for differing underlying forms * Ad hoc polymorphis ...

, 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 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 The variable platyfish (''Xiphophorus variatus''), also known as variatus platy or variegated platy, is a species of freshwater fish in family Poecilidae of order Cyprinodontiformes. A live-bearer, it is native to southern Tamaulipas and norther ...

'' 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 ''Xiphophorus montezumae'', the Montezuma swordtail, is a livebearing freshwater fish of the order Cyprinodontiformes, family Poeciliidae, and genus Xiphophorus. It is in the same genus as the common platy and the swordtail. ''Xiphophorus'' mea ...

'' and '' X. pygmaeus''). Adult males have deep yellow-orange bellies. Females grow to total length, 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 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 aquarium fish that retain the eggs inside the body and give birth to live, free-swimming young. Among aquarium fish, livebearers are nearly all members of the family Poeciliidae and include guppies, mollies, platies and swordtails ...

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