Thursday, October 6, 2011

Oriental garden lizard, Bloodsucer Lizard and CALOTES VERSICOLOR

Calotes versicolor, Agamidae, Bloodsucker, Oriental Garden Lizard

MANY non-native lizard species of tropical origin have become established in southern Florida, and Florida now has more nonindigenous amphibian and reptile species than any other state (Butterfield et al., 1997). In this paper, we report the first established population of Calotes versicolor (Daudin 1802), an Asian agamid lizard, in Florida. Butterfield and co-workers (1997) included Calotes versicolor in their list of established exotic herpetofaunal species in Florida based upon a personal communication from R. D. Bartlett. However, the purported C. versicolor population was misidentified and was actually C. mystaceus (Bartlett, 2003), which occurs in two small areas in the vicinity of pet dealerships in Glades and Okeechobee counties (Bartlett and Bartlett, 1999).

Of the 21 recognized species of Calotes (Vindum et al., 2003), C. versicolor is the most widespread, ranging from southeastern Iran and Afghanistan east to Indo-China and as far south as Sri Lanka, Sumatra, and northern Peninsular Malaysia (Boulenger, 1912; Smith, 1935; Zhao and Adler, 1993; Cox et al., 1998).
Calotes versicolor is distinguished from its congeners by having lateral body scales pointing backwards and upwards, no oblique fold or pit anterior to the shoulder, two separated spines above the tympanum, and 35–52 scales around the body (Smith, 1935). Calotes versicolor exhibits obvious geographic variation in coloration, scalation, and size across its wide range, but only two subspecies have been  described (Auffenberg and Rehman, 1993, 1995); our specimens were of the nominate subspecies.

Males may measure 140 mm snout-vent length (SVL) and have a slender tail 295 mm long (Radder et al., 2001). Adults have large heads, massive shoulders, expandable dewlaps, and laterally flattened bodies with a crest extending from the neck almost to the tail. The ground color is typically dull brown, gray, or olive with
irregular dark brown spots or bars, but breeding males have pale yellow bodies with a large black patch on each side of the throat. Breeding males also develop bright orange or crimson areas around the head and shoulders, but this brilliant coloration can change rapidly depending upon mood or environmental conditions (Bhatti and Bhatti, 1986; Cox et al., 1998). This red coloration accounts for these lizards commonly being called bloodsuckers. Other names for this arboreal species are the oriental or tropical garden lizard, Indian tree lizard, crested tree lizard, and changeable lizard.

In its native range, Calotes versicolor is commonly observed in parks, gardens, agricultural areas, waste land, and open forests (Cox et al., 1998). They typically live among leafy undergrowth and grass in open habitats, but males often display from fences and other conspicuous perches (Cox et al., 1998). Juveniles forage and bask mostly at ground level, whereas subadults and adults spend much of their time on tree trunks, often in a head-down posture surveying for prey (Diong et al., 1994).

Calotes versicolor is a very adaptable, prolific species that is commonly found in human-altered environments and can survive even in urban areas in Asia (Erdelen, 1988). In its native range, C. versicolor preys primarily on arthropods, but adults prey occasionally on their own young as well as small birds and nestlings, frogs, geckos, and small snakes (Rao, 1975; Dhindsa and Toor, 1983; Sharma, 1991a, 1991b, 1999; Diong, 1994). Calotes versicolor was introduced into Singapore in the 1980s, where it rapidly established populations (Chou, 1994) and partially displaced populations of a native agamid, the green crested lizard (Bronchocela cristatella) (Diong et al., 1994). We do not know what effect C. versicolor will have on populations of sympatric native lizard species in Florida, such as the green anole (Anolis carolinensis), ground
skink (Scincella lateralis), and southeastern five-lined skink (Eumeces inexpectatus).

Populations of the non-native brown anole (Anolis sagrei) and knight anole (A. equestris) are already common in the area, and non-native brown basilisks (Basiliscus vittatus) and green iguanas (Iguana iguana) are occasionally observed in adjacent areas (Flowers, 2003; Ward, 2003). Calotes versicolor is yet another exotic species that may compete with or prey upon Florida’s native species.


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