Taxonomic reassignment of the Paleolithic human navicular from Cueva de los Torrejones (Guadalajara, Spain)

Abstract

Evidence of human activity and hominin remains are very scarce inland on the Iberian Peninsula. This fact raises the issue of the scarcity of evidence that Paleolithic Homo sapiens occupied this area outside of the littoral margins (Atlantic, Cantabrian, and Mediterranean coasts). Here, we comparatively describe a human right adult navicular bone recovered in the Cueva de los Torrejones site, located in the village of Tamajon (Guadalajara, Spain). This fossil was preliminarily established as belonging to Homo cf. neanderthalensis, due to the late Pleistocene faunal association, mainly because of the presence of Crocuta crocuta and Panthera pardus. The metrical and morphological study of the navicular T93-S3.27 from Cueva de los Torrejones clearly differentiates it from Neandertals and their ancestors, the hominins from Sima de los Huesos, allowing for this fossil to be taxonomically assigned with confidence as H. sapiens. The navicular from the Cueva de los Torrejones is absolutely and relatively medio-laterally narrow with a low wedging index as those of fossil and modern H. sapiens, and clearly different of Neandertals. The increased discoveries and publications of new naviculars belonging to genus Homo, together with the findings of P. pardus and C. crocuta in more recent chronologies in the Iberian Peninsula, are compatible with this reevaluation. We propose a probable chronology for this fossil between 12 and 15 ka and ca. 25 ka, based on the biostratigraphy and the oldest presence of H. sapiens in the Iberian Peninsula. This work confirms the human presence within the Iberian Peninsula during the Upper Paleolithic and reopens the question of the peopling of the inner Peninsula during this period.