CT-Informed Skull Osteology of Palaeolagus haydeni (Mammalia: Lagomorpha) and Its Bearing on the Reconstruction of the Early Lagomorph Body Plan

Lagomorpha is a clade of herbivorous mammals nested within Euarchontoglires, one the major placental groups represented today. It comprises two extant families with markedly different body plans: long-eared and long-limbed Leporidae (hares rabbits) short-eared short-limbed Ochotonidae (pikas). These lagomorph lineages diverged probably during latest Eocene/early Oligocene, but it unclear whether last common ancestor crown lagomorphs was more leporid- or ochotonid-like in morphology. Palaeolagus , an early dominant western North America from late Eocene to Oligocene particular importance for addressing this controversy. Here, we present new comprehensive data on cranial anatomy haydeni type species genus, based micro-computed tomography (μCT). Our μCT allow us confirm, revise score very first time states several leporid-like characters skull . This mixed architecture differentiates supports its phylogenetic status as stem taxon.