Earliest Old World Hypsodont Equids Were Opportunistic Feeders

Opportunistic Feeding Strategy for the Earliest Old World Hypsodont Equids: Evidence from Stable Isotope and Dental Wear Proxies

Authors:

1. Thomas Tütken (a)

2. Thomas M. Kaiser,

3. Torsten Vennemann,

4. Gildas Merceron

Affiliations:

a. Steinmann-Institut für Geologie, Mineralogie und Paläontologie, University of Bonn, Bonn, Germany

b. University Hamburg, Biozentrum Grindel, Hamburg, Germany

c. Institut de Géochimie, Université de Lausanne, Lausanne, Switzerland

d. iPHEP UMR 7262 CNRS, Université de Poitiers, Poitiers, France

Abstract:

Background

The equid Hippotherium primigenium, with moderately hypsodont cheek teeth, rapidly dispersed through Eurasia in the early late Miocene. This dispersal of hipparions into the Old World represents a major faunal event during the Neogene. The reasons for this fast dispersal of H. primigenium within Europe are still unclear. Based on its hypsodonty, a high specialization in grazing is assumed although the feeding ecology of the earliest European hipparionines within a pure C3 plant ecosystem remains to be investigated.

Methodology/Principal Findings

A multi-proxy approach, combining carbon and oxygen isotopes from enamel as well as dental meso- and microwear analyses of cheek teeth, was used to characterize the diet of the earliest European H. primigenium populations from four early Late Miocene localities in Germany (Eppelsheim, Höwenegg), Switzerland (Charmoille), and France (Soblay). Enamel δ13C values indicate a pure C3 plant diet with small (<1 .4="" a="" abrasion="" all="" and="" are="" br="" browse-dominated="" by="" carbon="" compatible="" compositions="" contrast="" data="" dental="" diet.="" dietary="" differences.="" except="" food="" for="" four="" from="" h.="" h="" high="" hipparionines="" indicate="" isotope="" low="" mesowear="" microwear="" of="" patterns="" populations.="" populations="" primigenium="" range="" resources.="" seasonal="" spectrum="" suggesting="" the="" to="" tooth="" variations="" wear="" wenegg="" wide="" with=""> Conclusions/Significance

Combined dental wear and stable isotope analysis enables refined palaeodietary reconstructions in C3 ecosystems. Different H. primigenium populations in Europe had a large spectrum of feeding habits with a high browsing component. The combination of specialized phenotypes such as hypsodont cheek teeth with a wide spectrum of diet illustrates a new example of the Liem’s paradox. This dietary flexibility associated with the capability to exploit abrasive food such as grasses probably contributed to the rapid dispersal of hipparionines from North America into Eurasia and the fast replacement of the brachydont equid Anchitherium by the hypsodont H. primigenium in Europe.