A new postdoctoral researcher at JURASSICA (Dr. Jérémy Tissier) has just published a study in the scientific journal Proceedings of the National Academy of Sciences of the United States of America (PNAS) showing that the first horses appeared much later than previously thought. This study, funded by the Belgian Federal Public Service for Science Policy (BELSPO) through the PerissOrigin project, investigated the origin of the earliest perissodactyls, the group that includes horses. A new JURASSICA project funded by the Swiss National Science Foundation will now take over and make it possible to push this research even further.
Prof. Dr. Thierry Smith (left) and Dr. Jérémy Tissier (right) searching for fossils of the presumed earliest horses in Wyoming (USA) © Annelise Folie
Référence :
J. Tissier, & T. Smith, Earliest perissodactyls reveal large-scale dispersals during the PETM, Proc. Natl. Acad. Sci. U.S.A. 123 (4) e2519690122, https://doi.org/10.1073/pnas.2519690122 (2026).
This new article by Dr. Jérémy Tissier and Prof. Dr. Thierry Smith (Royal Belgian Institute of Natural Sciences and University of Namur) challenges the origin of horses as it has been considered for nearly 150 years. Hyracotherium, also known as Eohippus, the “dawn horse,” had long been considered the earliest horse, having appeared around 56 million years ago in North America. However, this new study shows that Hyracotherium were in fact not horses. The earliest relatives of horses would have appeared 5 to 10 million years later than previously thought, notably with the species Propaleotherium helveticum, discovered in Switzerland, or Orohippus in the United States.
“Horses have often been used as a textbook example of an evolutionary lineage, gradually evolving from very small, four-toed horses the size of a small dog into the large, single-toed, hoofed horses we know today,” says Dr. Jérémy Tissier. While several studies have re-evaluated some of these claims, the origin of horses 56 million years ago had never been questioned. “These discoveries somewhat overturn what we thought we knew about the origin of horses, but also of other perissodactyls.”
These results come at just the right time for JURASSICA, as the Swiss National Science Foundation has just awarded Dr. Olivier Maridet four years of funding to study the evolution of perissodactyls. This project will be carried out within the Jura-based institution by Dr. Jérémy Tissier, who will thus continue his research on the subject, along with a new PhD student, Tifanie Duprat. This new project will enable international collaborations with research laboratories in China, Belgium, and Romania, as well as within JURASSICA itself. In addition, another Swiss National Science Foundation project obtained by Dr. Damien Becker and led by Dr. Manon Hullot also focuses on early perissodactyls, with a particular emphasis on their diet in order to study major crises and environmental changes.