La Gomera Giant Lizard
Encyclopedia
The La Gomera Giant Lizard (Gallotia bravoana; ) is a lacertid (wall lizard
) species
that can be found on the island of La Gomera
, one of the Canary Islands
.
It is easily distinguishable from any other 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. The females lay a single clutch annually of three to seven eggs on average.
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).
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
.
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).
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
) species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
that can be found on the island of La Gomera
La Gomera
La Gomera is one of Spain's Canary Islands, located in the Atlantic Ocean off the coast of Africa. In area, it is the second-smallest of the seven main islands of this group.- Political organization :...
, one of the Canary Islands
Canary Islands
The Canary Islands , also known as the Canaries , is a Spanish archipelago located just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. The Canaries are a Spanish autonomous community and an outermost region of the European Union...
.
It is easily distinguishable from any other 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
Diurnal animal
Diurnality is a plant or animal behavior characterized by activity during the day and sleeping at night.-In animals:Animals that are not diurnal might be nocturnal or crepuscular . Many animal species are diurnal, including many mammals, insects, reptiles and birds...
and mostly herbivorous, and grows up to half a metre long. The females lay a single clutch annually of three to seven eggs on average.
Status and conservation
Apparent La Gomera Giant Lizards are reported in reports on La Gomera up to the 19th century, but not thereafter. The species was originally described from subfossilSubfossil
Subfossil refers to remains whose fossilization process is not complete, either for lack of time or because the conditions in which they were buried were not optimal for fossilization....
remains in 1985 (Hutterer 1985), presumably having gone extinct by then. Spanish biologists led by Juan Carlos Rando rediscovered
Lazarus taxon
In paleontology, a Lazarus taxon is a taxon that disappears from one or more periods of the fossil record, only to appear again later. The term refers to the account in the Gospel of John, in which Jesus raised Lazarus from the dead...
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
Valle Gran Rey
Valle Gran Rey is located on the southwestern coast of La Gomera in the province of Santa Cruz de Tenerife of the Canary Islands, Spain. The Guanche name of the area was Orone. The seat of the municipality is La Calera since 1930, before it used to serve at Arure which was also a municipal name...
. 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
Hectare
The hectare is a metric unit of area defined as 10,000 square metres , and primarily used in the measurement of land. In 1795, when the metric system was introduced, the are was defined as being 100 square metres and the hectare was thus 100 ares or 1/100 km2...
and restricted to dry cliffs with sparse vegetation.
The La Gomera Giant Lizard is listed as Critically Endangered
Critically Endangered
Critically Endangered is the highest risk category assigned by the IUCN Red List for wild species. Critically Endangered means that a species' numbers have decreased, or will decrease, by 80% within three generations....
by the IUCN Red List
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
. The species historically declined through overgrazing, hunting, and predation by feral cats and rats
RATS
RATS may refer to:* RATS , Regression Analysis of Time Series, a statistical package* Rough Auditing Tool for Security, a computer program...
. 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 subspeciesSubspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
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
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
.
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
International Commission on Zoological Nomenclature
The International Commission on Zoological Nomenclature is an organization dedicated to "achieving stability and sense in the scientific naming of animals". Founded in 1895, it currently comprises 28 members from 20 countries, mainly practicing zoological taxonomists...
, 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).
External links
- lacerta.de: Gallotia bravoana image gallery. Retrieved 2007-FEB-25.