Various methods exist for measuring and analyzing dental wear patterns in mam-mals, and these patterns have been extensively studied in ungulates. Mesowear has proven useful as a method to compare large numbers of individuals, particularly fossil individuals, observe trends through time or between groups, and estimate paleoenvi-ronmental conditions. Levels of attrition (tooth-on-tooth wear) and abrasion (tooth-on-food wear) can be readily compared by observing the shape of the cusp and relative crown height of the tooth. This study uses a modified method of mesowear analysis, examining actual cusp angles of the population of Tapirus polkensis from the Gray Fossil Site, a densely canopied, hickory and oak dominated forest located in Gray, Tennes-see. Crown height and cusp angle were measured for 38 specimens arranged into eruption series from young juveniles to old adults. Results found a strong correlation between eruption series and cusp angle with a steady increase in mean angle as the individuals increase in age. A strong correlation between cusp angle and crown height was also found. Overall, the population showed relatively low wear rates, as would be expected of a forest-dwelling browser. As a mesowear analysis across all age groups for a population has not been conducted before, this study could be useful for measuring relative wear rates at different life stages and could be applied across other com-munities.

O material aqui estudado provém da Formação Rio Madeira, da localidade de Araras, Município de Nova Mamoré. O espécime UNIR-PLV-M009, um crânio quase completo, apresenta as sinapomorfias do gênero Tapirus, mas difere de todas as espécies conhecidas pelos frontais largos, cuja pneumatização se estende até a sutura fronto-parietal, pela crista sagital alta e pelo P2 pouco molarizado, constituindose numa nova espécie, não nominada, de Tapirus. O espécime UMVT-4075, um palato incompleto com todos os dentes, difere de UNIR-PLV-M009 pelo P2 molarizado, e compartilha com Tapirus terrestris este e os demais caracteres dentários. / The material here studied comes from Rio Madeira Formation, locality of Araras, Nova Mamoré city. The UNIR-PLV-M009 specimen, an almost complete skull, presents the synapomorphies of the genus Tapirus but differs all known species for broad frontals, whose pneumatization extends until the frontoparietal suture, for high sagital crest, and for little molarized P2, so characterizing new unominated Tapirus species. The UMVT-4075 specimen, an incomplete palate with all teeth, differs from UNIR-PLV-M009 in the molarized P2, and it shares with Tapirus terrestris this and the other tooth characteristics.

O material aqui estudado provém da Formação Rio Madeira, da localidade de Araras, Município de Nova Mamoré. O espécime UNIR-PLV-M009, um crânio quase completo, apresenta as sinapomorfias do gênero Tapirus, mas difere de todas as espécies conhecidas pelos frontais largos, cuja pneumatização se estende até a sutura fronto-parietal, pela crista sagital alta e pelo P2 pouco molarizado, constituindose numa nova espécie, não nominada, de Tapirus. O espécime UMVT-4075, um palato incompleto com todos os dentes, difere de UNIR-PLV-M009 pelo P2 molarizado, e compartilha com Tapirus terrestris este e os demais caracteres dentários. / The material here studied comes from Rio Madeira Formation, locality of Araras, Nova Mamoré city. The UNIR-PLV-M009 specimen, an almost complete skull, presents the synapomorphies of the genus Tapirus but differs all known species for broad frontals, whose pneumatization extends until the frontoparietal suture, for high sagital crest, and for little molarized P2, so characterizing new unominated Tapirus species. The UMVT-4075 specimen, an incomplete palate with all teeth, differs from UNIR-PLV-M009 in the molarized P2, and it shares with Tapirus terrestris this and the other tooth characteristics.

O material aqui estudado provém da Formação Rio Madeira, da localidade de Araras, Município de Nova Mamoré. O espécime UNIR-PLV-M009, um crânio quase completo, apresenta as sinapomorfias do gênero Tapirus, mas difere de todas as espécies conhecidas pelos frontais largos, cuja pneumatização se estende até a sutura fronto-parietal, pela crista sagital alta e pelo P2 pouco molarizado, constituindose numa nova espécie, não nominada, de Tapirus. O espécime UMVT-4075, um palato incompleto com todos os dentes, difere de UNIR-PLV-M009 pelo P2 molarizado, e compartilha com Tapirus terrestris este e os demais caracteres dentários. / The material here studied comes from Rio Madeira Formation, locality of Araras, Nova Mamoré city. The UNIR-PLV-M009 specimen, an almost complete skull, presents the synapomorphies of the genus Tapirus but differs all known species for broad frontals, whose pneumatization extends until the frontoparietal suture, for high sagital crest, and for little molarized P2, so characterizing new unominated Tapirus species. The UMVT-4075 specimen, an incomplete palate with all teeth, differs from UNIR-PLV-M009 in the molarized P2, and it shares with Tapirus terrestris this and the other tooth characteristics.