New teeth of allotherian mammals from the English Bathonian, including the earliest multituberculates

摘要

Twenty one isolated multituberculate-like teeth are described from the Forest Marble (late Bathoman) of Oxfordshire and Dorset, England. Eighteen are additional to the teeth described as Eleutherodon oxfordensis by Kermack et al. (1998), and three of those are placed in new taxa. Six new molars of Eleutherodon provide further information on variation in size, proportion and root pattern. Millsodon superstes gen. et sp. nov. (family indeterminate), based on first and last lower molars and a referred upper molar, has resemblances to Haramiyidae and Therotemidae. Kirtlingtonia catenata gen. et sp. nov. (family indeterminate), based on last upper molars and a probable upper premolar, has a slight resemblance to Eleutherodon, and also to M2 of some paulchoffatiid multituberculates. Kermackodon multicuspis gen. et sp. nov. (family Kermackodontidae nov.) and Hahnotheriton antiquton gen. et sp. nov. (family Hahnotheriidae nov.) are based on second upper molars, recognised as multituberculate by their horizontal wear and inferred occlusal displacement with respect to m2. A lower molar referred to H. antiquum confirms this. A blade-like lower premolar and an upper premolar with conical cusps, referred to Kermackodon, are multituberculate-like, but distinctive. Divergence between the two Bathonian multituberculates indicates that the order originated much earlier, more probably from a haramiyid than from a morganucodontid source. Mojo is regarded as probably a haramiyid. The Hahnodontidae, which have basined wear, are removed from the Multituberculata to the "Haramiyida".