La Gomera giant lizard
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|La Gomera giant lizard|
It is easily distinguishable from any other member of Gallotia by the intense white colour that covers its neck, chest and area around the mouth, in spectacular contrast to its dark brown back. This lizard is generally diurnal and mostly herbivorous, and grows up to half a metre long[verification needed]. The females lay a single clutch annually of three to seven eggs on average.
Status and conservation
Apparent La Gomera giant lizards are listed in reports on La Gomera up to the 19th century, but not thereafter. The species was originally described from subfossil remains in 1985 (Hutterer 1985), presumably having gone extinct by then. Spanish biologists led by Juan Carlos Rando rediscovered this species in 1999 (Nogales et al. 2001). The biologists found only six living individuals (BBC News 2000).
The current population of the La Gomera giant lizard consists of (2004) 90 individuals remaining in the wild, and a captive stock of about 44 animals. This species is now only known from two separate inaccessible cliffs 2 km apart, close to the Valle Gran Rey. The La Gomera giant lizard is thought to have once ranged throughout much of La Gomera and in many habitat types. Nowadays it is found in the Parque Rural de Valle Gran Rey, and the present range is less than one hectare and restricted to dry cliffs with sparse vegetation.
The La Gomera Giant Lizard is listed as Critically Endangered by the IUCN Red List. The species historically declined through overgrazing, hunting, and predation by feral cats and rats. Nowadays the main threats are predation by feral cats, and rock falls within its restricted range. The species is protected by international legislation, and a species recovery plan is in place. On La Gomera, a captive breeding programme has been established in order to increase the number of individuals. To ensure the survival of the remaining populations and facilitate eventual reintroductions, the feral cat population around the species' range needs to be controlled (Miras & Pérez-Mellado 2005).
Taxonomy and systematics
In his scientific description, the German zoologist R. Hutterer referred the subfossil remains from La Gomera to two subspecies of Gallotia simonyi with the differences being size related. He named these Gallotia simonyi bravoana and Gallotia simonyi gomerana. Bischoff (1998) synonymized them to a single taxon[verification needed].
Barbadillo et al. (1999) decided for bravoana when they elevated the taxon to species rank. Nogales et al. (2001) concurred as regards species status, but used Gallotia gomerana. Following the ruling of the International Commission on Zoological Nomenclature, gomerana is a junior synonym or bravoana (Miras & Pérez-Mellado 2005). It is not unequivocally accepted that it does constitute a distinct species, however (e.g. Bischoff 2000); in all likelihood, G. simonyi is its closest living relative (Maca-Meyer et al. 2003).
- Barbadillo, L.J., Lacomba, J.I.; Pérez-Mellado, V.; Sancho, V. & López-Jurado, L.F. (1999): Anfibios y Reptiles de la Península Ibérica, Baleares y Canarias. 419 pp. Editorial Planeta, Barcelona.
- BBC News (2000): Scientists find 'extinct' giant lizards. Version of 2000-MAR-21. Downloaded on 18 May 2006.
- Bischoff, Wolfgang (1998): Bemerkungen zu den "fossilen" Rieseneidechsen der Kanarischen Inseln. In: Bischoff, Wolfgang (ed.): Handbuch der Reptilien und Amphibien Europas 6 (Die Reptilien der Kanarischen Inseln, der Selvagens-Inseln und des Madeira-Archipels): 387-407. Aula-Verlag, Wiesbaden.
- Bischoff, Wolfgang (2000): DGHT-AG Lacertiden aktuell: Rieseneidechsen auf La Gomera. Version of 2000-MAY-23. Retrieved 2007-FEB-25.
- Hutterer, R. (1985): Neue Funde von Rieseneidechsen (Lacertidae) auf der Insel Gomera. Bonner zoologische Beiträge 36(3/4): 365-394.
- Maca-Meyer, N.; Carranza, S.; Rando, J.C.; Arnold, E.N. & Cabrera, V.M. (2003): Status and relationships of the extinct giant Canary Island lizard Gallotia goliath (Reptilia: Lacertidae), assessed using ancient mtDNA from its mummified remains. Biol. J. Linn. Soc. 80(4): 659–670. doi:10.1111/j.1095-8312.2003.00265.x (HTML abstract)
- Miras, J.A.M. & Pérez-Mellado, V. (2005). Gallotia bravoana. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 11 May 2006. Database entry includes a range map and justification for why this species is critically endangered
- Nogales, M.; Rando, J.C.; Valido, A. & Martín, A. (2001): Discovery of a living giant lizard, Genus Gallotia (Reptilia: Lacertidae), from La Gomera, Canary Islands. Herpetologica 57: 169-179. HTML abstract
|Wikispecies has information related to: Gallotia bravoana|
- lacerta.de: Gallotia bravoana image gallery. Retrieved 2007-FEB-25.