Dental eruption in Southern Placental Mammals

ASHER, ROBERT; CIANCIO, MARTÍN R.; CASTRO, MARIELA C.; GALLIARI, FERNANDO; CARLINI, ALFREDO A.; PATTINSON, DAVID; HAUTIER, LIONEL

Lyme Regis, Dorset

Simposio; 59th Annual Symposium of Vertebrate Palaeontology and Comparative Anatomy; 2011

Relative to most mammals, xenarthrans (sloths, anteaters, and armadillos) have a verydistinctive dentition. Anteaters lack teeth completely; armadillos and sloths show homogeneous,peg-like teeth, often characterized as lacking both enamel and diphyodonty. In fact, thearmadillo genus Dasypus exhibits both a narrow layer of enamel and a replacement generation,and appears to be the only xenarthran with two generations of teeth.It is not yet known if the pattern of deciduous tooth eruption in Dasypus, or replacement of itsdeciduous set by permanent teeth, resembles patterns exhibited by other clades of mammals.The possibility that "late eruption" of the permanent dentition, as observed among endemicAfrican mammals, also characterizes Dasypus has not yet been definitively tested. Here, wepresent data showing that Dasypus reaches adult size prior to the completion of dentalreplacement, consistent with the hypothesis that it exhibits an afrotherian-like pattern of dentalreplacement. In addition, we compare data on dental eruption of the deciduous teeth usingdevelopmental series of mammalian embryos and fetuses, including Dasypus, and ask to what extent armadillos and afrotherians exhibit more diversity within vs. among their constituentclades.