Gomphos elkema was an early lagomorph – closely related to the ancestors of modern rabbits, hares, and pikas – that lived during the Early Eocene, about 56-47 million years ago, in what is now Mongolia and northern China.
Around 20cm long (~8″), it had some anatomical features surprisingly similar to modern rabbits and hares, such as long feet and hindlimbs capable of hopping. But unlike its modern relatives it also had a longer tail, and more “primitive” features in its jaw and teeth that link it to lagomorphs’ shared ancestry with rodents.
References:
- AMNH. “Earliest Rabbit Fossil Suggests Modern Mammals Emerged as Dinosaurs Faced Extinction.” American Museum of Natural History, 05 February 2006. https://www.amnh.org/explore/news-blogs/earliest-rabbit-fossil-discovery
- Asher, Robert J., et al. “Stem Lagomorpha and the antiquity of Glires.” Science 307.5712 (2005): 1091-1094. https://doi.org/10.1126/science.1107808
- Ge, Deyan, et al. “Evolutionary history of lagomorphs in response to global environmental change.” PLoS One 8.4 (2013): e59668. https://doi.org/10.1371/journal.pone.0059668
- Wikipedia contributors. “Gomphos” Wikipedia, 17 Jun. 2025, https://en.wikipedia.org/wiki/Gomphos