A hypothesis on the homology of proboscidean tusks based on paleontological data. American Museum novitates ; no. 2895

Abstract

"The nature and development of proboscidean tusks has long been discussed. New observations, mainly on the Upper Miocene elephantoid species Amebelodon floridanus (Leidy), and comparisons with other fossil proboscideans (Moeritherium and different elephantoid taxa) lead to the conclusion that the tusks of Moeritherium and Elephantoidea are not homologous. Factors considered were the precocity of incisor development and succession in elephantoids, the observed associations of the two pairs of lower incisors protruding out of the symphasis for a short period of time, the position of the loci in the premaxilla and the mandibular rostrum, and the hypothesis of homology of the loci in Moeritherium and elephantoids. It is proposed that the two pairs of incisors of elephantoids are incisors of the first dentition with no dental replacement and the permananet incisors (tusks) are dI2/di1"--P. [1].