Snout proportions in some Eurasian hipparions (Mammalia, Equidae): taxonomic and functional implications

In the hipparions, length and breadth of the snout and depth of the nasal opening are not well correlated with one another, nor with the shape and placement of the preorbital fossa, recently considered taxonomically important in these equids. These characters are distributed in a mosaic-like fashion among species, making species differentiation and phylogenetic reconstruction difficult.