| Yellow swordtail | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Cyprinodontiformes |
| Family: | Poeciliidae |
| Genus: | Xiphophorus |
| Species: | X. clemenciae |
| Binomial name | |
| Xiphophorus clemenciae Álvarez, 1959 | |
The yellow swordtail (Xiphophorus clemenciae) is a species of freshwater fish in the family Poeciliidae. [2] It is endemic to the upper Coatzacoalcos River basin in southern Mexico. [3] It is typically found in brooks and streams with slow current; it is less frequent in areas with strong current. [2] The yellow swordtail is considered a threatened species by Mexican authorities. [4] It reaches up to 5.1 cm (2.0 in) in standard length. [2]
Unusually, the yellow swordtail appears to be the result of hybrid speciation, and its ancestors a platy species and a swordtail species. [3] [5] The southern mountain swordtail (X. monticolus), which is found further south in the Coatzacoalcos River basin than the yellow swordtail, is the result of a similar event. [3]
The fish is named in honor of Álvarez' wife Clemencia, whose help and advice made it possible for him to devote himself to the pursuit of his scientific research. [6]