Bovid paleoecology and paleoenvironments from the Late Miocene of Bulgaria: evidence from dental microwear and stable isotopes

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V6R-4K8SC9K-3&_user=10&_coverDate=11%2F14%2F2006&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=941fa6219b71220a7d0fde44d04bc2f9International audienceA multi proxy approach was performed to characterize vegetation in southwestern Bulgaria during the end of the Early and the Middle Turolian (8.7–7.0 Ma). This period was marked by eustatic fluctuations in the Mediterranean Sea that are well documented. In order to estimate the impact of these marine events on continental landscapes, dental microwear and stable isotope profiles in enamel were used to characterize feeding habits of extinct bovids, and in turn vegetation. Analyses were made on permanent molars of fossil bovids from two Late Miocene localities: Hadjidimovo-1 (Early/Middle Turolian) and Kalimantsi (Middle Turolian). Carbon isotopes profiles of Tragoportax rugosifrons and Miotragocerus gaudryi from the Hadjidimovo-1 indicate a pure C3-based diet for the two boselaphini. Large inter-individual differences in absolute δ18O values were found for M. gaudryi suggesting little reliance on drinking water due to a browsing diet. Dental microwear shows that none of the bovid species exclusively grazed. In Hadjidimovo-1, microwear evidence suggests mixed feeding habits for Tragoportax rugosifrons, Gazella sp., and Palaeoreas lindermayeri and a leaf browsing diet for Miotragocerus gaudryi. Palaeoreas lindermayeri from Hadjidimovo-1 has a bimodal pattern indicating that its feeding preferences were tied to seasonal food availabilities. At Kalimantsi, Miotragocerus gaudryi show variations between individuals whereas Tragoportax cf. amalthea was an exclusive browser. Palaeoreas lindermayeri and Gazella sp. were also mixed feeders in Kalimantsi. Our combined approach shows no evidence for dense forested environments during the Early and Middle Turolian, and then supports previous hypotheses based on faunal analyses. Our results rather suggest that southwestern Bulgaria was dominated by open wooded landscapes where C3 graminoids grew in abundance among the herbaceous layer. Finally, microwear data suggest that the proportion of dicotyledons such as forbs, bushes or shrubs was probably higher in the plant communities of Kalimantsi than in those of Hadjidimovo-1