Quaternary mammal localities and heptaxodontid rodents of Jamaica. American Museum novitates ; no. 2803

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New York, N.Y. : American Museum of Natural History
"Harold E. Anthony (1920a, 1920b) identified five species of fossil rodents in material he collected from Jamaican caves during 1919-1920. Clidomys osborni, C. parvus, Speoxenus cundalli, and Spirodontomys jamaicensis were referred to the endemic Antillean caviomorph family Heptaxodontidae; Alterodon major was compared with members of Octodontidae sensu stricto but never actually placed as to family. No other West Indian island has a native octodontid or an equivalent abundance of heptaxodontids. These facts could be used to support hypotheses to the effect that Jamaica was the locus of a major adaptive radiation of caviomorphs, or that it was an important way-station for mammals penetrating farther into the Caribbean. Neither hypothesis is justified, however, because Anthony's species list is decidedly oversplit. Although cheek teeth of Jamaican heptaxodontids display some degree of variability, postcranial bones recovered from the same sites do not. Measurement of tali and calcanei, for example, demonstrates that there are only two size clusters in the available sample. These phena could represent two species of the same genus, or they could be the sexes of a single, highly dimorphic species. Investigation of variation in a few other caviomorphs, including the Puerto Rican heptaxodontid Elasmodontomys, indicates that the phena are best interpreted as different species. The larger species is Clidomys osborni (now including Speoxenus cundalli) and the smaller is C. parvus (now including Spirodontomys jamaicensis). The putative octodontid Alterodon major is based on a broken tooth; it is almost certainly heptaxodontid, and probably belongs in C. osborni. The genus Clidomys is defined and the distribution of Antillean Heptaxodontidae is briefly considered in light of dispersionist and vicariist concept of Caribbean biogeography. Although several expeditions have prospected in Jamaica for fossil mammals, for the most part the deposits yielding such remains have not been adequately described, and none has been radiometrically dated. Described here are locations, major features, and faunas of several localities, including Wallingford Roadside Cave, Wallingford Main Cave, Sheep Pen, and Long Mile Cave. A chelonian shell sample from Wallingford Roadside Cave has a minimum date of 33,250 BP; this is the oldest published date for a mammal-bearing fossil site in the Caribbean, and proves that the heptaxodontids from the same site are truly Pleistocene animals. At Long Mile Cave, bones drawn from unit 2, the layer believed to have yielded the jaw of the enigmatic primate Xenothrix, produced a date of 2145 BP. In view of the distinctiveness of this primate, so recent a date is astounding. Unfortunately, no additional bones referable to Xenothrix have been found at this or any other fossil locality"--P. [1]-2.
34 p. : ill., map ; 26 cm.
Includes bibliographical references (p. 32-34).