Paleoecology and population dynamics of the early Miocene (Hemingfordian) horseParahippus leonensisfrom the Thomas Farm site, Florida

Abstract

ABSTRACT The horse Parahippus leonensis is the most numerous large mammal known from the important early Miocene Thomas Farm fossil locality. A large sample of mandibles (n = 89) of P. leonensis was analyzed. Despite having a variable dental morphology, morphometric studies indicate that only one species is represented. Sexual dimorphism in body size is suggested by bimodality of several measured characters, although there is some overlap between the sexes. The sample of P. leonensis seems to be attritional, although the youngest wear-class (estimated age at death 0–2 weeks) is underrepresented, probably due to taphonomic factors. The population does not exhibit discrete dental wear-classes, indicating a lack of breeding synchrony in the population, or that mortality was not seasonal. Individuals of P. leonensis are estimated to have lived an average of three to four years, with a maximum potential lifespan of about nine years. The rate of cheektooth wear in P. leonensis indicates that it had not shifted ...