Histograms of relative enamel content for upper and lower molars of each species.

<p>Histograms of relative enamel content for upper and lower molars of each species.</p

Boxplots of overall relative enamel content per tooth position.

<p>*: <i>p</i> = 0.05, ***: <i>p</i> = 0.001, n.s. = not significant (all p-values from post-hoc Tukey test).</p

Test statistics for the phylogenetic MANOVA.

<p>Species was used as the independent variable and relative enamel content per tooth position as the dependent variables. No significant influence of phylogeny was detected. <i>df</i> = degree of freedom, <i>F</i> = test value, <i>p</i> = significance level.</p

Boxplots of pooled relative enamel content of all upper versus all lower molars. *: p = 0.05, ***: p = 0.001, n.s. = not significant (all p-values from post-hoc Tukey test).

<p>Boxplots of pooled relative enamel content of all upper versus all lower molars. *: p = 0.05, ***: p = 0.001, n.s. = not significant (all p-values from post-hoc Tukey test).</p

Enamel proportion for each tooth position.

<p>* = The lower m3 of <i>Antidorcas marsupialis</i> was not fully mineralised and has hence very low enamel content.</p><p>Enamel proportion for each tooth position.</p

Results of one-way ANOVA with tooth position or jaw as factor and relative enamel content as the numeric variable.

<p>Values in bold indicate a significant interaction (<i>p</i> ≤ 0.05). Statistics abbreviations: <i>df</i> = degree of freedom, <i>SumSq</i> = sum of squares, <i>MeanSq</i> = mean of squares, <i>F</i> = test value, <i>p</i> = significance level.</p

Results of Post-hoc Tukey test for multiple comparisons of means with 95% family-wise confidence level.

<p>Values in bold indicate a significant difference (<i>p</i> ≤ 0.05) for relative enamel content between tooth positions. Statistics abbreviations: <i>diff</i> = difference between group means, <i>lower</i> = lower end point of the interval, <i>upper</i> = upper end point of the interval, <i>p</i> = significance level.</p

Geographic location of the investigated Late Miocene sampling sites.

<p>Geographic location of the investigated Late Miocene sampling sites.</p

Frequency of hipparionine specimens in the different mesowear categories (in percentage) and mesowear scores.

*<p>HS = Combination of high relief H and sharp cusp S (score = 0), HR = combination of high relief H and round cusp R (score = 1), LS = combination of low relief L and sharp cusp S (score = 2), LR = combination of low relief L and round cusp R (score = 3), LB = combination of low relief L and blunt cusp B (score = 4). Average score per population is computed by the mean of the average score per individual in case that several teeth represent an individual.</p

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

<div><p>Background</p><p>The equid <i>Hippotherium primigenium</i>, 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 <i>H. primigenium</i> 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.</p><p>Methodology/Principal Findings</p><p>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 <i>H. primigenium</i> 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‰) seasonal variations for all four <i>H. primigenium</i> populations. Dental wear and carbon isotope compositions are compatible with dietary differences. Except for the Höwenegg hipparionines, dental microwear data indicate a browse-dominated diet. By contrast, the tooth mesowear patterns of all populations range from low to high abrasion suggesting a wide spectrum of food resources.</p><p>Conclusions/Significance</p><p>Combined dental wear and stable isotope analysis enables refined palaeodietary reconstructions in C₃ ecosystems. Different <i>H. primigenium</i> 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 <i>Anchitherium</i> by the hypsodont <i>H. primigenium</i> in Europe.</p></div