Serpenteko Cave: An anatomical study of Early Holocene Lynx remains in the Northern Iberian Peninsula

The presence of Eurasian lynx in the Iberian Peninsula has been demonstrated through mitochondrial DNA (mtDNA) analyses. Here, we examine the morphology of three Lynx specimens from the Serpenteko Leze de Mezkiritz pit (Navarre, Spain) that were assigned to Lynx lynx based on mtDNA. We conducted metrical and geometric morphometric analyses of the crania and mandibles and compared diagnostic traits of all cranial and post-cranial elements recovered from the site. We concur with the classification of two specimens (SPT-2 and SPT-3) as L. lynx and suggest that boreal lynxes in the Iberian Peninsula were larger than extant European populations. In contrast, several traits in one specimen (SPT-1) support its attribution to Lynx pardinus. This finding raises the possibility that L. lynx and L. pardinus populations overlapped in northern Iberia around the Pleistocene-Holocene transition, without species replacement. If they coexisted, this phenomenon could have permitted hybridization between L. lynx and L. pardinus, potentially explaining the discrepancy between our morphological results and previous genetic assignments for SPT-1. However, we cannot assert the coexistence of both species without a clearer understanding of the site's stratigraphy. It is a challenging task, given the admixture of the remains due to the cave's function as a natural trap.