A REVISION OF THE LARGE LAGOMERYCID ARTIODACTYLS OF EUROPE

Large lagomerycids are only known in Europe from the Orleanian of the Loire Basin (France). At least three forms are recognized: Ligeromeryx gen. nov. praestans, Heterocemas? sp. and Lagomerycidae gen. et sp. i ndet. The genus Lagomeryx is restricted to small European species. If it is hypothesized that apophyseal appendages originated only once amo ng cervoids, then a hypothetical brachyodont ruminant with divergent, supraorbital appendages bearing a small, distal fork which was cast fr om time to time, could be considered to be not only the common ancesto r of lagomerycids and cervids, but also of merycodontines. Nevertheles s, there is substantial evidence that appendages were acquired several times, and the possibility that lagomercyids are an entirely independ ent clade among cervoids is postulated. Heterocemas was the most primi tive lagomerycid, having forked protoantlers with a prevalence of rami fication by sprouting. The move evolved forms acquired multibranched c onstruction (Ligeromeryx) and later, palmation at the protoantler basi s (Stephanocemas and Lagomeryx). Small size, accompanied by a subseque nt reduction of the protoantler size, could have been acquired seconda rily by Lagomeryx, probably when the lagomerycids filled forest-browsi ng niches.