H. crassum Age and Occurrences
According to Depéret (1890), H. crassum is found mostly in the Middle Piocene of Roussillon (MN 15), probably also in the Pliocene of Montpellier (MN 14), and possibly in the Red Crags of Suffolk, England, and in the Messinian of Toscany at Casino, Italy. Pirlot (1956) gave figures of some hipparion teeth from Casino and Suffolk.
Indeed, most of the available material does come from Zone MN 15 : lower MN 15 : Perpignan (route de Lassus ; Serrat d’en Vacquer) ; upper MN 15 : two from Puymoisson (or Grenouillet). One upper M3 is from Montpellier ; seven upper cheek teeth and one lower are from La Pompignanne, also from Zone MN 14. Finally, there is one lower from Riottier (MN 16).
Impressed by the variability of the fossils referred to H. crassum, Sondaar (1974) wondered if three different species were not mixed under the same name : the true H. crassum of Perpignan, Hipparion sp. form A with very large teeth and a robust tibia at Montpellier, and Hipparion sp. form B with a very plicated enamel and a slender tibia, also at Montpellier. Hipparion sp. form B could be the one found at Casino and in the Red Crags.
Crusafont (1958) and Alberdi (1974) referred to H. crassum a few specimens from Alcoy, Spain, but the evidence is not conclusive (Forsten, 1968 ; Eisenmann and Sondaar, 1989). The occurrence of H. crassum at Ptolemais, Greece (Koufos, 1982) is also problematic. Fossils more or less similar to H. crassum have been described under the names of H. moriturum at Kislang, Hungary (Kretzoi, 1954), H. malustenense at Malusteni, Beresti, Iaras-Carriera, Romania (Samson, 1975), and H. tchicoicum in Mongolia and Transbaikalia (Zhegallo, 1978 ; Forsten, 1992). Pictures of some of them are included in Plates of H. crassum. See also Shamar Shamar data and photos and Franzfeld Franzfeld data and photos.