Sombrero ameiva

Sombrero ameiva
Conservation status
Critically Endangered  (IUCN 3.1)[1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Family:	Teiidae
Genus:	Pholidoscelis
Species:	P. corvinus
Binomial name
Pholidoscelis corvinus (Cope, 1861)
Synonyms
Ameiva corvina Cope, 1861

The Sombrero ameiva (Pholidoscelis corvinus), also known commonly as the Sombrero groundlizard,[2] is a species of lizard in the family Teiidae. The species is endemic to Sombrero, a small, uninhabited island in the Lesser Antilles under the jurisdiction of Anguilla. The species was originally described in the genus Ameiva.

Description

Adults of P. corvinus are melanistic, appearing plain brown to slate black, with a dark green to black ventral surface mottled with light blue.[3] The tail is sometimes spotted green. Males have brown flecks on the dorsal surface and browner heads. Males grow to 133 mm (5.2 in) snout-to-vent length (SVL), with females being considerably smaller.

It is superficially similar in coloration and scalation to P. atratus and P. corax, two other melanistic species also found on small, barren islands in the Caribbean. As the islands have similar habitats, this is likely the result of independent adaptation.[4]

Diet

The diet of P. corvinus includes the eggs of ground-nesting birds.

Conservation

The Sombrero ameiva is listed as critically endangered on the IUCN Red List due to its limited distribution, an area less than 0.37 km^2 (91 acres) in size.[1] A 1999 study estimated between 396 and 461 individuals, including adults and juveniles, based on mark-recapture data.[1] Although there are no permanent human settlements on Sombrero, increased rodent populations such as introduced mice may put pressure on the lizards.[1] Flooding and sea level rise may also threaten the species.[1] The population appeared to be thriving in the early 2000s, possibly due to its isolation from human activity[5], then crashed steeply to less than 100 individuals as of 2018 due to a combination of invasive species (primarily mice), severe hurricanes, and general environmental degradation. Mouse eradication and native plant restoration by conservation groups allowed the population to rebound to more than 1,600 individuals as of 2024.[6]

References

1. Powell, R.; Daltry, J.C. (2017). "Pholidoscelis corvinus". IUCN Red List of Threatened Species. 2017: e.T174139A121640244. doi:10.2305/IUCN.UK.2017-3.RLTS.T174139A121640244.en. Retrieved 12 November 2021.
2. Species Pholidoscelis corvinus at The Reptile Database www.reptile-database.org.
3. Description of the species is given in Malhotra & Thorpe 1999, p. 53.
4. The species are compared in Malhotra & Thorpe 1999, p. 54.
5. Powell & Henderson 2005, pp. 66–67
6. Baisas, Laura (2024-12-18). "Population of nearly extinct lizard grows 16X in only six years". Popular Science. Retrieved 2024-12-23.

Further reading

• Cope ED (1861). "On the Reptilia of Sombrero and Bermuda". Proceedings of the Academy of Natural Sciences of Philadelphia 13: 312–314. (Ameiva corvina, new species, pp. 312–313).
• Goicoechea N, Frost DR, De la Riva I, Pellegrino KCM, Sites J Jr, Rodrigues MT, Padial JM (2016). "Molecular systematics of Teioid lizards (Teioidea/Gymnophthalmoidea: Squamata) based on the analysis of 48 loci under tree-alignment and similarity-alignment". Cladistics 32 (6): 624–671. (Pholidoscelis corvinus, new combination, p. 659).
• Malhotra, Anita; Thorpe, Roger S. (1999). Reptiles and Amphibians of the Eastern Caribbean. London and Oxford: Macmillan Education Ltd. pp. 53–54. ISBN 0-333-69141-5.
• Powell, Robert; Henderson, Robert W. (2005). "Conservation Status of Lesser Antillean Reptiles". Iguana. 12 (2): 63–77.
• Kuta, Sarah (2024). "This Once-Rare Lizard Bounced Back From the Brink of Extinction After 'Painstaking' Restoration Efforts in the Caribbean". Smithsonian (December).