Anolis sagrei (Duméril and Bibron, 1837) Introduced - Reptilenesia
Anolis sagrei - Reptilenesia
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| A Brown Anole, Anolis sagrei, photographed in southern Florida. JCM |
Description of Anolus Sagrei
Size. Males to 70 mm, females 48 mm; hatchlings 16 mm SVL. Smallest sexually mature male 35 mm, female 34 mm.
Identification. Brown to gray, with white or yellow patterning on the back. Dewlap orange or red with a white or yellow edge. Scales between the supraorbitals are variable ranging from none to several; scales separate the interparietal and supraorbital from the semicircles scales. Head scales keeled; five postrostrals; two postmentals. Mid dorsum has six rows of slightly enlarged scales; tail laterally compressed and may have a slight crest; keeled ventral scales that are pointed posteriorly.
Similar species. All Trinidad and Tobago anoles have cycloid (rounded) ventral scales with the exception of Anolis planiceps. Anolis sagrei has the subocular scales in contact with the upper labials. Anolis planiceps has the subocular scales and the upper labials separated by a row of scales. Anolis tigrinus has no enlarged mid-dorsal scales. Polychrus has femoral pores but all anoles lack them.
Distribution. This species has five currently recognized subspecies. Which one was introduced on Trinidad is unknown. The species is widespread in the Lesser Antilles and has been introduced into the USA (California, Florida, Texas, and Hawaii), Mexico, Belize, Aruba, and Taiwan. In Trinidad it is known only from the heart of Port of Spain, suggesting it may have arrived with ornamental plants.
Habitat. A ground dweller but will climb into low vegetation; this species thrives in almost all man-made habitats and they are abundant in suburban and urban environments.
Biology. Diurnal. Basks and forages on the ground and in vegetation. The diet includes insects, spiders, and other invertebrates (mites, isopods, gastropods). Females lay a single egg in moist soil or rotten wood at about 14-day intervals.
Identification. Brown to gray, with white or yellow patterning on the back. Dewlap orange or red with a white or yellow edge. Scales between the supraorbitals are variable ranging from none to several; scales separate the interparietal and supraorbital from the semicircles scales. Head scales keeled; five postrostrals; two postmentals. Mid dorsum has six rows of slightly enlarged scales; tail laterally compressed and may have a slight crest; keeled ventral scales that are pointed posteriorly.
Similar species. All Trinidad and Tobago anoles have cycloid (rounded) ventral scales with the exception of Anolis planiceps. Anolis sagrei has the subocular scales in contact with the upper labials. Anolis planiceps has the subocular scales and the upper labials separated by a row of scales. Anolis tigrinus has no enlarged mid-dorsal scales. Polychrus has femoral pores but all anoles lack them.
Distribution. This species has five currently recognized subspecies. Which one was introduced on Trinidad is unknown. The species is widespread in the Lesser Antilles and has been introduced into the USA (California, Florida, Texas, and Hawaii), Mexico, Belize, Aruba, and Taiwan. In Trinidad it is known only from the heart of Port of Spain, suggesting it may have arrived with ornamental plants.
Habitat. A ground dweller but will climb into low vegetation; this species thrives in almost all man-made habitats and they are abundant in suburban and urban environments.
Biology. Diurnal. Basks and forages on the ground and in vegetation. The diet includes insects, spiders, and other invertebrates (mites, isopods, gastropods). Females lay a single egg in moist soil or rotten wood at about 14-day intervals.
Synonymy: partly after SCHWARTZ & HENDERSON 1988. Norops sagrei sagrei and Norops sagrei ordinatus were originally introduced to southern Florida, but they can no longer be distinguished (CONANT & COLLINS 1991). Poe et al. 2017 consider ordinatus and greyi synonyms of sagrei. NICHOLSON et al. 2018 do not recognize mayensis but they do list N. s. greyi and N. ordinatus as valid.
Ecology: Schoener et al. (2001) studied how A. sagrei recovered on 88% of the 66 Bahamas islands that were hit by hurricane Floyd in 1999. Later, Schoener et al. (2005) showed that survival of N. sagrei correlated with vegetation height: the island with the shortest vegetation had nearly the highest survival recorded for any lizard. However, when Leiocephalus carinatus, a predator of N. sagrei (which forages mostly on the ground), was introduced, N. sagrei shifted to taller vegetation.
Evolution: On small islands in Florida, Stuart et al. 2014 found that the lizard Anolis carolinensis moved to higher perches following invasion by Anolis sagrei and, in response, adaptively evolved larger toepads after only 20 generations.
Variation: A. sagrei is a widespread and variable species. Among other varieties, red- and orange-headed varieties have been described (see, e.g. various Anole Annals posts for photos).
Subspecies: Norops sagrei sagrei and Norops sagrei ordinatus were originally introduced to southern Florida, but they can no longer be distinguished (CONANT & COLLINS 1991). Anolis sagrei nelsoni, and A. s. luteosignifer, and ordinatus are treated here as full species.
Distribution: Has been erroneously recorded from “Porto Rico” (= Puerto Rico). Reports from Venezuela are doubtful (DONOSO-BARROS 1968). May have been introduced to Jamaica.
Species group: Norops sagrei species group (fide NICHOLSON et al. 2012).
Karyotype: 2n=28, XY (males) or XX (females) (Giovannotti et al. 2016)
