Equus stenonis is one of the most iconic fossil species of the Early Pleistocene. Although it is known from the 19th century, its taxonomic and evolutionary position has been extensively debated among equid specialists, including multiple interpretations. The current work aims to review the European E. stenonis record, by morphological, morphometrical and statistical analyses combined with body mass and net primary production estimates. Furthermore, we investigate the evolution of E. stenonis cranial anatomy in comparison with the Plio-Pleistocene species from North America, Eurasia and Africa, and extant zebras and asses. Our review of European E. stenonis samples has closely considered the E. stenonis subspecies Equus stenonis vireti, Equus stenonis guthi, Equus stenonis pueblensis, Equus stenonis olivolanus and Equus stenonis stenonis which we recognize as being ecomorphotypes of Equus stenonis, with the exception of Equus stenonis senezensis and Equus stenonis mygdoniensis. These two last subspecies warrant the species ranks of Equus senezensis and Equus altidens, respectively. This has led us to propose a new revised biochronology of European Early Pleistocene Equus. Our evolutionary interpretations based on cranial morphology reveals that the evolutionary lineage of extant zebras can be recognized in deep time from the North American species Equus simplicidens, through the European E. stenonis and the African Equus koobiforensis. European stenonine horses likewise represent the original source for the African Pleistocene fossil species and extant Equus grevyi.

Equus steonis是早更新世最具标志性的化石物种之一。尽管它在 19 世纪就已为人所知，但它的分类学和进化地位在马科动物专家中引起了广泛的争论，包括多种解释。目前的工作旨在通过形态学、形态计量学和统计分析，结合体重和净初级生产估计，审查欧洲棘球蚴记录。此外，我们研究了与来自北美、欧亚大陆和非洲的 Plio-Pleistocene 物种以及现存的斑马和驴相比，E. stenonis颅骨解剖结构的进化。我们对欧洲细齿细杆虫样本的审查仔细考虑了细细杆线虫亚种雅科仕stenonis vireti，雅科仕stenonis guthi，雅科仕stenonis pueblensis，雅科仕stenonis olivolanus和雅科仕stenonis stenonis我们承认作为是ecomorphotypes雅科仕stenonis，与外雅科仕stenonis senezensis和雅科仕stenonis mygdoniensis。这最后两个亚种分别保证了Equus senezensis和Equus altidens的物种等级。这使我们建议欧洲早更新世的新修订biochronology雅科仕. 我们基于颅骨形态的进化解释表明，现存斑马的进化谱系可以从北美物种Equus simplicidens到欧洲E. stenonis和非洲Equus koobiforensis 的很长一段时间内被识别出来。欧洲 stenonine 马同样代表了非洲更新世化石物种和现存Equus grevyi的原始来源。