Dental eruption in Southern Placental Mammals. 59th Annual Symposium of Vertebrate Palaeontology and Comparative Anatomy

ASHER, RJ; CIANCIO MR; CASTRO, MC; GALLIARI, FC; CARLINI AA.; PATTISON, D.; HAUTIER, L.

LYME REGIS

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

Relative to most mammals, xenarthrans (sloths, anteaters, and armadillos) have a very distinctive dentition. Anteaters lack teeth completely; armadillos and sloths show homogeneous, peg-like teeth, often characterized as lacking both enamel and diphyodonty. In fact, the armadillo 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 its deciduous set by permanent teeth, resembles patterns exhibited by other clades of mammals. The possibility that "late eruption" of the permanent dentition, as observed among endemic African mammals, also characterizes Dasypus has not yet been definitively tested. Here, we present data showing that Dasypus reaches adult size prior to the completion of dental replacement, consistent with the hypothesis that it exhibits an afrotherian-like pattern of dental replacement. In addition, we compare data on dental eruption of the deciduous teeth using developmental series of mammalian embryos and fetuses, including Dasypus, and ask to what extent armadillos and afrotherians exhibit more diversity within vs. among their constituent clades.