SIZE PATTERNS IN WEST INDIAN ANOLIS LIZARDS .I. SIZE AND SPECIES DIVERSITY

Anolis lizard species have solitary populations on certain West Indian islands. These populations have a narrow range in mean body size, very different for the two sexes, though they inhabit islands varying greatly in area and environmental diversity. Smallsized exceptions to this uniformity are northerly. Sizes of males for solitary forms are collectively significantly larger than sizes of males on the richest islands. With increasing species diversity from island to island, species size distributions for males irregularly decrease in median but increase in range and skewness. On the three richest islands, smaller species are significantly more often restricted in geographic range. From simple assumptions about competition for resources, a relation is derived which holds that snout-vent length or some power thereof for a given species is equal to some multiple of the reciprocal of the number of closely related species on its island plus some constant. This relation is shown to better describe data than two alternatives. The ratio of the length of the principal trophic structure (the head) to the entire body length of a given species is sometimes but not always predictable from the number of congeneric species on its island. © 1969, Oxford University Press. All rights reserved.