Anoline lizards

TitleAnoline lizards
Publication TypeBook Chapter
Year of Publication1996
AuthorsReagan, PD
EditorReagan, PD, Waide, RB
Book TitleThe food web of a tropical rain forest
PublisherUniversity of Chicago Press
CityChicago, Illinois
Accession NumberLUQ.517
KeywordsAnolis, Anolis ecology, herpetology, LTER, phylogenetic

Anoline lizards (family Polychridae, genus Anolis) are the most conspicuous and abundant vertebrates inhabiting terrestrial ecosystems on Caribbean islands (William 1969, 1976; Moermond 1979a). As a group, anoles are diurnal, predominantly insectivorous, and occur throughout all vertical strata of the ecosystems they inhabit. Anole abundance and high visibility have made them a subject of numerous studies that have contributed to our understanding of island biogeography (Williams 1969, 1972, 1983), resource partitioning (Schoener 1968, 1974), limiting factors (Licht 1974, Andrews 1976), habitat selection (Keister et al. 1975), competition (Schoener 1969a,b,c; Stamps 1977; Wright 1981; Pacala and Roughgarden 1983; Rummel and Roughgarden 1985), niche relationships (Ruibal and Philibosian 1970; Lister 1976), and foraging behavior (Moermond 1973) 1979a,b; Reagan 1986). Anoles are among the most studied of any vertebrate genus in the tropics.

Williams (1976) conducted a test analysis of the evolutionary radiation of anoline lizard on Puerto Rico because the anole fauna was relatively well-known and moderately complex. He introduced the ecomorph concept to describe the convergent evolutionary pattern of a set of animals showing similar correlations of morphology, ecology and behavior, but not lineage. While the concept has been reasonably applied to widely divergent taxa on continents (Karr and James 1975), Williams convincingly demonstrated this concept in the radiation of a single genus (Anolis) within the archipelago. He described six ecomorphs: crown giant, twig dwarf, trunk-crown, trunk, trunk-ground, and grass-bush. Williams (1983) added additional categories by recognizing obvious subdivisions of the original categories and started that for the Greater Antilles, body size and perch characteristics separate the ecomorphs. Roughgarden and Pacala (1989) summarize the current understanding of Anolis systematics for the eastern Caribbean, including Puerto Rico.

Five anoline species inhabit the tabonuco forests of Puerto Rico (Rand 1964; Turner and Gist 1970; Schoener and Schoener 1971). The Puerto Rican giant anole, Anolis cuvieri, a crown giant ecomorph, is the largest species. Three smaller anole species A. gundlachi (trunk-ground ecomorph), A. evermanni (trunk-ground ecomoprh and generalist), and A. stratulus (twig dwarf), are relatively common within the forest. A fifth species, A. occultus, occurs near the forest edge or in the openings along the streams, but it is generally rare in the tabonuco forest.

Examining various lines of evidence Williams (1972) discussed phylogenetic relationships an presented a phylogeny of Puerto Rican anoles based on ostelogical (Etheridge 1960, 1965), karyotypic (Gorman and Atkins 1969) and electrophoretic (Maldonado and Ortiz 1966) studies. These phylogenies show A. cuvieri and A. occultus as the most primitive and distinct species. A. gudlachi diverged from two closely related species, A. evermanni and A. stratulus in more recent times. Current evidence indicates that the primary route of anoline invasions of Puerto Rico was from the Hispaniola.

On the Caribbean islands where there were no large animals such as those found in mainland ecosystems (e.g., tapirs, jaguars), anoles constitute a substantial portion of the total of animal biomass. Their abundance, widespread ecological distribution, and functional role as higher order consumers make them important components of insular animal communities throughout the food webs in Caribbean islands (Schoener and Toft 1983; Schoener and Spiller 1987), and Reagan (1986) described the role of anoles as important consumers in the food web of tabonuco forest at El Verde. This chapter summarizes aspects of anole biology relevant to food web structure and organization in tabonuco forest.

Short TitleAnoline Lizards