Anolis sagrei in Florida: Phenetics of a Colonizing Species III. West Indian and Middle American Comparisons

Abstract

Univariate and multivariate analyses were performed on a suite of meristic and morphometric variables recorded for 2373 specimens of Anolis sagrei representing 25 Floridian and 44 West Indian and Middle American localities. Cluster analyses, using the unweighted pair-group method with arithmetic averages (UPGMA), established the existence of two major morphological units in the West Indies (Cuban and Bahamian) and one in southeastern Mexico and northern Central America. The reality of these phenetic and geographic units was confirmed by discriminant function analysis. On average, Florida populations exhibit levels of intrapopulational variation in meristic characters that are comparable to that of West Indian and Middle American samples. The possibility that in the colonization of Florida lizards underwent a genetic bottleneck is, thus, unsupported by the meristic data. Moreover, Florida lizards exhibit about the same level of interlocality variation in meristic characters as do lizards from Cuba, the Bahamas, and Middle America. However, for morphometric characters, interlocality variation is significantly less for Florida lizards. Thus, in their morphometric characters, Florida populations exhibit less divergence than those long established elsewhere. For meristic characters, covariation is generally less in Florida samples than in the West Indian and Middle American ones, whereas covariation among the morphometric characters of Florida lizards is comparable to that found elsewhere. Samples of lizards collected early in the colonization of Florida are morphologically most similar to Cuban lizards; contemporary (1981) Florida samples also show strong Cuban affinities, but constitute a phenetic unit now distinguishable from all others, possibly the result of microevolutionary adjustment to the novel Florida environment. Although Bahamian lizards are known to have been introduced into southern Florida, the colonization has been largely a Cuban phenomenon, because in neither the early nor the contemporary Florida lizards is there evidence of the Bahamian.