Anolis roosevelti Grant, 1931
Culebra Giant Anoles
Anolis roosevelti is a possibly extinct species of large Anolis lizards originally described from a specimen collected on Isla Culebra but subsequently determined to have inhabited at least three other nearby islands in the eastern Caribbean.
Conservation and Management
The last known specimen of Anolis roosevelti (UMMZ 73644) was collected more than 75 years ago in 1932; however, almost 70 years elapsed between the collection of the specimens described by Reinhardt and Lutken (1863) and that of the specimens described by Grant (1931, 1932). Several independent searches for giant anoles have been made by herpetologists over the past 40 years on Culebra, Vieques, Saint John, and Tortola, all without success. Thus, Anolis roosevelti appears to be rare, and it may be extinct (Mayer, 1989). If extinct, the reasons are unknown, though deforestation is a likely cause. All of the islands on which the species was known to occur have been deforested (Mayer 1989), and lizards of this species typically inhabit trees. Anolis roosevelti is listed as Endangered by the United States Fish and Wildlife Service (USFWS, 2010) and as Critically Endangered by the International Union for the Conservation of Nature (IUCN, 2010).
Lizards of the species Anolis roosevelti are giant anoles, with a maximum recorded snout-vent length of 162 mm and a total length of approximately 485 mm. (In the Anolis clade, lizards exceeding 100 mm snout-vent length are commonly classified as giants—Lazell, 1972). Males are larger than females (150-162 mm versus 140-144 mm snout-vent length, based on the 6 known specimens). Adults have well-developed canthal and nasal ridges on the dorsal surface of the snout, with distinct groves between them. Males have a high tail fin with five scales between the neural spines of the tail vertebrae. Lizards of both sexes are brownish-gray in coloration and have 32-34 lamellar scales under the third and fourth phalanges of the fourth toe. (Description based on Mayer, 1989.)
Little is known about the ecology of Anolis roosevelti. The purported collector of the holotype reported seeing Culebra giant anoles on high branches in a forest of Bursera (gumbo limbo) and Ficus (fig) trees (Dodd and Campbell, 1982). The lizards were seen most commonly when the Ficus fruits were ripe, and the lizards were reported to have fed on the fruits. Culebra giant anoles appear to be members of the crown giant ecomorph (Mayer 1989), an ecologically and morphologically defined category for giant anoles that spend most of their time high in the crowns of trees (Williams, 1983; Losos, 2009).
Anolis roosevelti was originally known from two specimens collected on Isla Culebra (Grant, 1931, 1932), which is politically part of the Commonwealth of Puerto Rico and geographically part of the Virgin Islands chain in the eastern Caribbean. Mayer (1989) determined that additional specimens had been collected earlier from Isla Vieques, Saint John (U.S. Virgin Islands), and Tortola (British Virgin Islands). All of these islands are geographically part of the Virgin Islands chain, which, along with Puerto Rico, represents the currently exposed part of the Puerto Rican Bank, a submarine platform that was exposed during glacial periods during the Pleistocene thus uniting all of the islands from which Anolis roosevelti is known (as well as Puerto Rico) into a single landmass. Anolis roosevelti does not occur on Puerto Rico, which is inhabited by a closely related species of giant anoles, Anolis cuvieri.
Evolution and Systematics
Systematics and Taxonomy
Anolis roosevelti was described by U.S. Army Major Chapman Grant (1931), grandson of President Ulysses S. Grant and founder of the Herpetologists’ League, based on a single adult male from Isla Culebra, now in the Museum of Comparative Zoology (MCZ 36138). The species name is after Theodore Roosevelt, Jr., then governor of Puerto Rico (1929-1932) and son of President Theodore Roosevelt. Only a single specimen has been collected subsequently (Grant, 1932), which is now in the collection of the University of Michigan Museum of Zoology (UMMZ 73644). However, Mayer (1989) discovered that several specimens of Anolis roosevelti had been collected and discussed in the literature prior to Grant’s formal naming of the species. Thus, Cope (1861) listed the species Anolis velifer as inhabiting the Island of Vieques. As this name is now considered a synonym of Anolis cuvieri, the name of a closely related species of giant anoles, and as Anolis roosevelti is the only species of giant anoles definitely known from Vieques, it seems likely that Cope was referring to Anolis roosevelti, though the specimen or specimens upon which his statement was based are currently unknown. Shortly thereafter, Reinhardt and Lutken (1863) described four specimens under the name Anolis velifer, two from Vieques, one from Tortola, and one from Saint John. Their description indicates that the specimens (which are housed in the collection of the Zoological Museum, Natural History Museum of Denmark) are referable to Anolis roosevelti, and Mayer (1989) has confirmed that identification for three of them (the fourth is lost) as well an additional specimen in the Swedish Museum of Natural History.
Xiphosurus velifer Gray 1840 (Cope 1861)
Anolis velifer Cuvier 1829 (Rienhardt and Lutken 1863)
Anolis cuvieri Merrem 1820 (Boulenger 1885; in part)
Semiurus roosevelti Schwartz and Henderson 1988
The name Xiphosurus roosevelti is used for this species in the ITIS database, but this combination does not appear to have been used in any scientific publication. This name is presumably based on Guyer and Savage’s (1987) proposal to “split” Anolis into several taxa at the rank of genus, of which the one containing Anolis roosevelti is Semiurus, and the fact that Xiphosurus Fitzinger 1826 has priority over Semiurus Fitzinger 1843.