The Pannonian C hipparions from the Vienna Basin

Abstract

The “Hipparion” Datum has been recognized as being a key geochronologic marker for early late Miocene Eurasian and African horizons. The Vienna Basin Pannonian C hipparions are the stratigraphically oldest (basal MN9, ca. 11.4–11.0Ma), and we contend herein, the most primitive of all Old World hipparions. We evaluate the stratigraphic context, cheek tooth morphological characters, paleodietary and paleoenvironmental context of the three Pannonian C hipparion assemblages from Gaiselberg, Atzelsdorf and Mariathal, Austria. We find that the Gaiselberg and Atzelsdorf are slightly more primitive than the Mariathal hipparion assemblage and refer the first two assemblages to Hippotherium sp., while the Mariathal assemblage is referred to Hippotherium aff. primigenium exhibiting some advanced characters that presage Austrian and German later Vallesian age. We review the chronology and biogeography of the Old World “Hipparion” Datum and evolutionary relationships of first occurring European, West and South Asian and North African “Hipparion” to North American Cormohipparion. We evaluate, and expand upon earlier paleodietary studies of Pannonian C hipparions and determine that they were browser dominant, mixed “opportunistic” feeders.