Anolis sagrei in Florida: Phenetics of a Colonizing Species I. Meristic Characters

Abstract

from 25 Florida localities reveals that 10 of the 12 scale characters analyzed are geographically variable. Although Florida lizards are known to be descended from Cuban and Bahamian stocks, a simple Cuba-Bahama dichotomy is not apparent in the Florida material. Discrete phena cannot be recognized on morphological grounds, perhaps due to random genetic processes operating in small founding populations. Secondary sexual dimorphism is characteristic of Florida lizards and is itself geographically variable. Sexual dimorphism is most strongly and consistently expressed in numbers of dorsals, ventrals, gulars and subdigital lamellae, for all of which males characteristically exceed females. Comparisons of samples collected early in the colonization of Florida at or near points of initial establishment, with samples collected at the same localities in 1981 reveal significant differences in numbers of subdigital lamellae and dorsal scales for certain samples. Intralocality variation in scale characters has not changed measurably over what it was 20 to 50 years ago. Recent samples are slightly less morphologically distinct from one another than are early samples, and covariation among scale characters appears to have increased slightly over time. The data are suggestive of microevolutionary adjustment of morphology in the Florida populations over the last 50 years, but a competing hypothesis that invokes multiple undetected introductions is not excluded.