Origin, evolution and biogeographic dynamics of the European rabbit (Oryctolagus cuniculus) in Southwestern Europe

The Pleistocene is a key period for understanding the evolutionary history and palaeobiogeography of the European rabbit (Oryctolagus cuniculus). The species was first documented in southeastern Iberia at the beginning of the Middle Pleistocene and appears to have rapidly spread throughout Southwestern Europe, where it was found in numerous palaeontological and archeological sites. However, this long period (~700 ka) saw significant climatic and environmental changes, and the extent to which these events influenced the species' biogeography and impacted the morphological variability is still unclear. This study examines the evolutionary history of European rabbits in southwestern Europe based on 55 fossil populations (55 stratigraphic units from 42 localities) in Southwestern Europe, spanning from the Middle to Late Pleistocene, using osteometric analyses on postcranial bones and 2D geometric morphometrics on the third lower premolar (p3). Results highlight substantial variation in bone size over time, suggesting a temporal association with climatic shifts. The p3 analysis reveals major morphological changes, with the oldest populations (MIS16-12) distinct from those of MIS11-6. From MIS6 onward, morphological evolution appears more gradual until MIS2, with distinct differences from modern populations. These findings identify various phases of biological rupture and continuity, suggesting local persistence, extinction, and recolonization phases. The palaeobiogeography of European rabbits was shaped by climatic oscillations and ecogeographical barriers, notably between the east and west of the Iberian Peninsula and southern France. The post-glacial recolonization of France at the end of MIS 2 likely originated from Iberia, facilitated by climate improvement and the return of the Atlantic forest.