Craniodental anatomy of Late Ruscinian Trischizolagus (Leporidae: Lagomorpha) from Megalo Emvolon (Thessaloniki, Greece)

Abstract

During the Early Ruscinian, the leporid genus Trischizolagus (Leporidae: Mammalia) underwent a significant dispersion and increase in diversity, expanding from the peri-Paratethyan region to China, Spain, and Morocco. Its fossil record remains, however, poor, primarily comprising of isolated teeth, toothrows, and mandibles, while cranial material is extremely rare and often too fragmentary. The present paper presents a well-preserved and rich sample of Trischizolagus from the Megalo Emvolon-4 (MVL) fossil site near Thessaloniki (Greece) and provides for the first time the full cranial anatomy of T. dumitrescuae, the most common species known from the Late Ruscinian of SE Europe. The results allow an assessment of its intraspecific variation, while comprehensive craniodental comparisons fix some previous morphological misconceptions and provide additional distinctive cranial features with both extinct and extant Old World leporid taxa. Although a phylogenetic analysis failed to resolve the relationships of the genus, a review of its chronospatial distribution based on earlier hypotheses and new data confirms its debatable north Mediterranean Mio-Pliocene record and favors an origin closer to a dentally advanced Hypolagus population.