Modern view of Equid evolution
(according to Campbell et al. 1999)

    Note that speciation is depicted as a series of rectangular transitions, consistent with the "punctuationalist" model. Note also that, although evolution is generally depicted as moving from the lower left to the upper right, the lineage leading from Hyracotherium to Equus, the only extant genus, is not shown as a straight line.

Text material © 2005 by Steven M. Carr