Fig. 3. Alterodon major AMNHP 17638 in A Possible Heptaxodontine and Other Caviidan Rodents from the Quaternary of Jamaica

Fig. 3. Alterodon major AMNHP 17638 (holotype), stereopairs: (A)?distal and (B)?mesial aspects. We argue (see text) that this tooth is broken; in the intact state it would have closely resembled cheekteeth of Clidomys in being composed of separate or conjoined lamellae connected by interlamellar plaques of cementum (indicated by dense stippling in fig. 4). Spencer (1987) argued instead that the plaque identified as feature 1 in A is all that is left of a thick layer of cementum that originally enwrapped the entire tooth (thus making the specimen, in his view, much more octodontid­like). Feature 2 is a plaque that does not continue to the lateral surface because it fills a space formed by conjoined lamellae, but this is not unusual in Clidomys cheekteeth (cf. fig. 4C, E, I, J). Feature 3 is a developmental interruption in enamel formation, also occasionally encountered in Clidomys (fig. 4B) and thus adding to the sense of similarity. For tooth pattern see figure 4E.