Increasing and decreasing functional area of the dentition (FAD) of Mammuthus primigenius
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RESEARCH PAPER
Increasing and decreasing functional area of the dentition (FAD) of Mammuthus primigenius Ulrike Anders • Wighart von Koenigswald
Received: 18 September 2012 / Accepted: 15 January 2013 Ó Springer-Verlag Berlin Heidelberg 2013
Abstract The occlusal morphology and continuous molar replacement in elephants provide a very effective functional area for grinding the biomass that is more or less abrasive. Parts of two subsequent molars contribute to the ‘‘functional area of the dentition’’ (FAD). The FAD size, measured in cm2, is associated with age and body size. The FAD stage is indicated by the specific teeth contributing to the FAD and represents the individual age. This study concentrates on Mammuthus primigenius and compares the FAD stages, as derived from growth series, with the fossil Elephas antiquus, as well as the extant Elephas maximus and Loxodonta africana. During the life history of the taxa studied, the functional area increases simultaneously with an increase in body size, but decreases severely in senile age stages. In some senile individuals, the FAD is only about 20–50 % of the mean area of an adult animal. The reduction of the FAD beyond a specific size does not mean an immediate starvation of the animal. The general constitution of the individual and the resources of fat accumulation earlier may support the animal for some time but certainly not over a longer period. Nevertheless, the highly reduced functional area was sufficient to keep the animal alive despite its full adult body mass. A much larger FAD
Electronic supplementary material The online version of this article (doi:10.1007/s12542-013-0168-2) contains supplementary material, which is available to authorized users. U. Anders (&) W. von Koenigswald Steinmann-Institut fu¨r Geologie, Mineralogie und Pala¨ontologie, Rheinische Friedrich-Wilhelms-Universita¨t Bonn, Nussallee 8, 53115 Bonn, Germany e-mail: [email protected] W. von Koenigswald e-mail: [email protected]
in all adult stages provides the energy requirements needed for all additional life functions including competition and reproduction. Keywords Elephantidae Dentition Growth trajectory Tooth wear Life history Kurzfassung Bei den Elefanten bilden die Kaufla¨chen der Molaren bei einem horizontalen Zahnwechsel eine ho¨chst effektive Reibfla¨che zur Zerteilung der Nahrung. An dieser Reibfla¨che, die hier als funktionales Areal der Dentition (FAD) bezeichnet wird, sind meist zwei aufeinander folgende Backenza¨hne beteiligt. Die Zahnpositionen, die zur FAD beitragen, bestimmen das FAD-Stadium. Die FAD-Gro¨ße (in cm2 gemessen) kann mit dem Alter und der Ko¨rpergro¨ße korreliert werden. Die Studie konzentriert sich auf Mammuthus primigenius und vergleicht die Ergebnisse mit dem fossilen Waldelefanten (Elephas antiquus) sowie den rezenten Elefanten Asiens und Afrikas (Elephas maximus und Loxodonta africana). Wa¨hrend des Lebens wa¨chst die FAD zuna¨chst entsprechend der zunehmenden Ko¨rpergro¨ße an, schrumpft aber im senilen Alterstadium wieder. Bei einigen
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