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11 2 MEET THE ANOLES! The goal of this chapter is twofold. First, to introduce anoles: what they are, what makes them unique, and where they occur. Second, to focus on what it is to be an anole species. How do species differ from one another? How do we tell one from another? How do they tell one from another? Of course, understanding what constitutes a species is a prerequisite for studying how new species arise from old ones, so this discussion will set the stage for understanding anole evolutionary diversification. WHAT MAKES AN ANOLE AN ANOLE? Anoles are typical lizards in many ways. Consider the following: Species range in adult length from 33–191 mm snout-vent length (SVL),13 with a tail—capable of detachment and regeneration in most species14 —that is 1–4 times the 13. Snout-vent length is the distance from the tip of the snout to the anterior end of the vent, or cloaca, which is the orifice through which excretion and reproduction occur. According to Schwartz and Henderson (1991), from whom I took body size measurements listed here and elsewhere in the book, the largest West Indian anole is the Cuban crown-giant A. luteogularis and the smallest is a Cuban grass-bush anole, A. cupeyalensis. Estimates of the maximum size for species are imprecise: as a result, determining which species are truly the smallest and largest is difficult, but the extreme species almost surely belong to species in the two Cuban clades that contain A. luteogularis and A. cupeyalensis. Mainland anoles do not achieve the extremes exhibited by island species, although some species are close. 14. Many lizards drop their tails when they are grabbed by a predator. Such “autotomy” is facilitated by specializations in the vertebrae and attendant muscles and blood vessels that facilitate detachment with minimal trauma (Etheridge, 1967; Arnold, 1984; see figure 8.10). losos_ch02.qxd 4/11/09 8:46 AM Page 11 length of the body. Young hatch out of eggs after 25–130 days at a length of 15–40 mm SVL (Andrews and Rand, 1974; Schlaepfer, 2003; Köhler, 2005; Sanger et al., 2008a). Body color is usually gray, brown, or green; color can lighten and darken, and green species can turn dark brown. Anoles are visually-oriented lizards with excellent eyesight and color vision which extends into the ultraviolet (Fleishman and Persons, 2001). Their sense of smell is poor and their tongues are used primarily for prey capture rather than for chemoreception (Schwenk, 2000). Anoles can hear (e.g., Werner, 1972) and some species vocalize, most often upon being captured (Milton and Jenssen, 1979), but the extent to which anoles respond to sound in nature is unknown (Rothblum et al., 1979). Very few anoles are dietary specialists and most species eat a wide range of insects. The incidence of myrmecophagy varies greatly among species; many mainland species seem to avoid ants entirely. Carnivory, frugivory, and molluscivory all occur, primarily in larger species and larger individuals of medium-sized species. Moving up the food chain, in many respects anoles are the lunchbox of the neotropics . They are eaten by all manner of birds, mammals, snakes, other lizards (including conspecifics, as well as other anoles), frogs, even spiders and other invertebrates. Predation differs among regions, and even among habitats within regions.15 Overall, anoles are little different from many other types of lizards. However, some of the most interesting features that have evolved repeatedly in lizards16 —e.g., extreme limb reduction and loss, exclusively herbivorous diet, viviparity, and parthenogenesis— do not occur among anoles. In what ways, then, do anoles differ from other lizards? Anolis is characterized most obviously by two characteristics: the possession of a dewlap and of subdigital toepads. In addition, a number of other features are notable, especially aspects of the anole visual system and reproductive cycle. THE DEWLAP The dewlap is an extensible structure located on the throat and extending far down the belly in some species. Most of the time retracted and barely visible, it can be deployed by movements of the hyoid apparatus. The hyoid, evolutionarily derived from the gill arches of fish, is composed of a series of thin, rod-like elements, mostly cartilaginous, that are located in the floor of the mouth and throat of tetrapod vertebrates.17 Anoles have extremely long second ceratobranchial elements (as much as 67% of snout-vent length and reaching the pelvic girdle [Font and Rome, 1990]) which lie within the ventral margin...

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