| Surtsicna/sandbox | |
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| A male | |
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| A female | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Cyprinodontiformes |
| Family: | Poeciliidae |
| Genus: | Xiphophorus |
| Species: | X. nezahualcoyotl
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| Binomial name | |
| Xiphophorus nezahualcoyotl | |
Xiphophorus nezahualcoyotl, the northern mountain swordtail, is a live bearing fish in the family Poeciliidae.[2][3]
The species most closely related to X. nezahualcoyotl according to a nuclear DNA analysis is the long-sworded X. montezumae,[4] of which it was originally thought to be a subspecies.[5] Mitochondrial DNA tests indicate a closer relationship with the short-sworded X. continens, however, which point to X. nezahualcoyotl being a species of hybrid origin. Because of its close relationship with X. montezumae, the specific epithet of which refers to the Aztec ruler Moctezuma II, X. nezahualcoyotl was named after the Aztec ruler and philosopher Nezahualcoyotl.[5]
X. nezahualcoyotl males have a long sword (elongation of the caudal fin), though not as long as that of X. montezumae males. The species also has a prominent gravid spot. Like X. montezumae, X. nezahualcoyotl has multiple zigzag lateral stripes. X. nezahualcoyotl stays smaller, however, with the maximum recorded standard length in wild populations measuring 48 mm.[5]
X. nezahualcoyotl inhabits the extreme headwaters of the tributaries of the Tamesí and Tampaón rivers, including the Frío and Sabinas rivers. Most of these localities are above 1000 m above sea level.[5]
References
edit- ^ Daniels, A.; Maiz-Tome, L. (2019). "Xiphophorus nezahualcoyotl". IUCN Red List of Threatened Species. 2019: e.T191789A127376221. doi:10.2305/IUCN.UK.2019-2.RLTS.T191789A127376221.en. Retrieved 20 November 2021.
- ^ "Xiphophorus nezahualcoyotl". Integrated Taxonomic Information System. Retrieved 12 Sep 2012.
- ^ Froese, Rainer; Pauly, Daniel (eds.). "Xiphophorus nezahualcoyotl". FishBase. August 2019 version.
- ^ Kang, J.H.; M. Schartl; R.B. Walter; A. Meyer (2013). "Comprehensive phylogenetic analysis of all species of swordtails and platies (Pisces: Genus Xiphophorus) uncovers a hybrid origin of a swordtail fish, Xiphophorus monticolus, and demonstrates that the sexually selected sword originated in the ancestral lineage of the genus, but was lost again secondarily". BMC Evolutionary Biology. 13 (25): 25. Bibcode:2013BMCEE..13...25K. doi:10.1186/1471-2148-13-25. PMC 3585855. PMID 23360326.
- ^ a b c d Kallman, Klaus D.; Morizot, Donald C.; Rauchenberger, Mary. "Monophyly and geography of the Río Pánuco Basin swordtails (genus Xiphophorus) with descriptions of four new species". American Museum Novitates. New York: American Museum of Natural History. Retrieved 1 September 2024.