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Anolis roosevelti

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA REPTILIA SQUAMATA DACTYLOIDAE

Scientific Name: Anolis roosevelti
Species Authority: Grant, 1931
Common Name/s:
English Culebra Giant Anole, Culebra Island Giant Anole, Roosevelt's Giant Anole

Assessment Information [top]

Red List Category & Criteria: Critically Endangered D ver 3.1
Year Published: 2011
Date Assessed: 2009-06-30
Assessor/s: de Queiroz, K. & Mayer, G.C.
Reviewer/s: Böhm, M., Collen, B. & Ram, M.
Contributor/s: De Silva, R., Wearn, O.R., Milligan, H.T., Wren, S., Zamin, T., Sears, J., Wilson, P., Lewis, S., Lintott, P. & Powney, G.
Justification:
Anolis roosevelti has been assessed as Critically Endangered because it is unlikely that there are more than 50 mature individuals remaining, if any at all. It was known to occur at four sites but is only known from eight specimens. It is tagged as 'Possibly Extinct' because it has not been seen since 1932 despite extensive surveys across its historical range. Further surveys are needed to determine if this species should be listed as Extinct, particularly on smaller offshore islands. If it is relocated, the establishment and management of new protected areas should be a high priority along with other conservation measures to ensure the continued survival of this species.
History:
1996 Critically Endangered
1994 Endangered (Groombridge 1994)
1990 Endangered (IUCN 1990)
1988 Endangered (IUCN Conservation Monitoring Centre 1988)
1986 Endangered (IUCN Conservation Monitoring Centre 1986)

Geographic Range [top]

Range Description: This species is endemic to the smaller islands of the eastern portion of the Puerto Rican Bank, and is known historically from Vieques and Culebra (part of Puerto Rico), St. John (part of the US Virgin Islands), and Tortola (part of the British Virgin Islands) (Mayer 1989). Eight specimens are known to have been collected, six of them around the early 1860s, one in 1931, and the last in 1932. Both of the 1930s specimens came from Culebra (Mayer 1989). The area of the four inhabited islands totals approximately 290 km2; the portion of this area historically inhabited by the species is unknown.
Countries:
Possibly extinct:
Puerto Rico; Virgin Islands, British; Virgin Islands, U.S.
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: No specimens have been collected since 1932. Dumas, who is supposed to have collected the holotype, reported seeing this species as recently as 1978 (Dodd and Campbell 1982). Several searches on Culebra have been unsuccessful, and some verbal reports of giant anoles have turned out to refer to green iguanas (Dodd and Campbell 1982, Campbell and Dodd 1982, USFWS 1986, Gaa Ojeda Kessler 2010, R. Thomas, K. de Queiroz). Unsuccessful searches have also been made on Vieques (R. Crombie, J.B. Losos, K. de Queiroz) and Tortola (G.C. Mayer, J.D. Lazell, K. de Queiroz). Some (e.g., Williams 1983) consider the species probably extinct, although further investigation is warranted on some smaller islands (Gaa Ojeda Kessler 2010).
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: This species is reported on branches high in trees in Bursera and Ficus forest, most commonly when they were feeding on the ripe fig fruits (Dodd and Campbell 1982). These reports are consistent with the species being an ecological analogue of Puerto Rican A. cuvieri, i.e. a "crown-giant" ecomorph, but occurring in a dryer area with a more xeric-adapted vegetation (Mayer 1989).
Systems: Terrestrial

Threats [top]

Major Threat(s): The reasons for the species' decline and possible extinction are unknown. Deforestation, suggested as a reason by Campbell and Dodd (1982), has occurred on all four islands, and no primary forests remain (Gaa Ojeda Kessler 2010). Livestock grazing was widespread on Culebra before the island was turned into a military zone; after the departure of the military, housing and tourism development took over, often infringing on potential habitat for the species (Gaa Ojeda Kessler 2010). However, on some of the islands the amount of land under cultivation peaked prior to the second half of the 19th Century (Mayer 1989).

Conservation Actions [top]

Conservation Actions: The species has been listed as Endangered by the USFWS since 1977. The Culebra National Wildlife Refuge and the recently established (2001; greatly expanded 2003) Vieques National Wildlife Refuge include potential past or current areas of occupancy for the species. The Vieques refuge is an especially promising place to search for the species, due to its size, and because of its low level of development consequent upon it having formerly been a U.S. Navy base. The transfer of most of the Navy land to USFWS has protected this area from potential development. That there was a gap of some 70 years in collections of the species between the 1860s and 1930s gives some hope that the current long gap since the last collection might not indicate the species is extinct. Further research is needed into the populations of this species to determine whether this species is extinct in the wild.
Citation: de Queiroz, K. & Mayer, G.C. 2011. Anolis roosevelti. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 17 April 2014.
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