• Equus
• Evolution
• Quaternary
• Horses

The evolution of the genus Equus has been a matter of long debate with a multitude of hypotheses. Currently, there is no consensus on either the taxonomic content nor phylogeny of Equus.
In this contribution, the validity of different fossil and extant the genera is assessed by a new cladistic analysis combined with cranial anatomy. This cladistic analysis, supports the monophyly of Equus, denies the recognition of Plesippus and Allohippus and supports the derivation of Equus grevyi and members of the zebra-ass clade from European stenonine horses.
The Early Pleistocene Equus species have been reviewed, in order to clarify their taxonomy, biochronology and evolution. This revision is based on multiple comparisons of the European E. stenonis record, allowing to identify the of European E. stenonis as a monotypic but polymorphic species. Moreover, the distribution of the European Early Pleistocene species Equus livenzovensis, Equus senezensis, Equus major, Equus altidens and Equus suessenbornensis have been reviewed, with new remarks on their taxonomy, biochronology, paleoecology and evolution.