Endocranial anatomy of the Guercy 1 early Neanderthal from Baume Moula‐Guercy (Soyons, Ardèche, France)

Abstract

We provide the first comparative description of the endocranium of the Guercy 1 Early Neanderthal and examine its affinities to Preneanderthals, Neanderthals, and Homo sapiens. The Guercy 1 cranium derives from deposits chronostratigraphically and biostratigraphically dated to the Eemian Interglacial (MIS 5e). For comparative purposes, we compiled a sample of European and Southwest Asian subadult and adult Middle-to-Late Pleistocene hominins (≈MIS 12-MIS 1; N = 65). We sampled both a Preneanderthal-Neanderthal group and a Homo sapiens group. The Preneanderthal-Neanderthal group was further divided into three time-successive subgroups defined by associated MIS stages. Metric and morphological observations were made on original fossils and physical and virtual endocranial reconstructions. Guercy 1 and other Early Neanderthals, differ from Preneanderthals by increased development of the prefrontal cortex, precentral and postcentral gyri, inferior parietal lobule, and frontoparietal operculum. Early Neanderthal differ, in general, from Late Neanderthals by exhibiting less development in most of the latter brain structures. The late group additionally differentiates itself from the early group by a greater development of the rostral superior parietal lobule, angular gyrus, superior and middle temporal gyri, and caudal branches of the superior temporal gyrus. Endocranial morphology assessed along the Preneanderthal-Neanderthal sequence show that brain structures prominent in Preneanderthals are accentuated in Early-to-Late Neanderthals. However, both the Early and Late groups differentiate themselves by also showing regionally specific changes in brain development.This pattern of morphological change is consistent with a mosaic pattern of neural evolution in these Middle-to-Late Pleistocene hominins.

Neanderthal child's maxilla from Baume Moula‐Guercy (Soyons, Ardèche, France)

“…Skeletal remains of Early Neanderthals are rare (Richards et al, 2021, 2022a,b), and the maxillary sample accentuates this fact. Currently, there are 10 Early Neanderthals that retain, or solely comprise, maxillary remains (Table S1).…”

“…This subgroup of Neanderthals has variously been referred to as "Preneanderthals" (Elyaqtine, 1995(Elyaqtine, , 1996, "recent Preneanderthals" (Rougier, 2003), "Stage 3" European hominins (included specimens vary, Dean et al, 1998;Hublin, 1998), or as "Neanderthal 1" ). Here we follow Verna et al (2010), Richards et al (2021), and Richards et al (2022aRichards et al ( , 2022b in referring to these individuals as Early Neanderthals. Hominin remains associated with MIS 8 may also be included in the Early Neanderthal group (Dean et al, 1998;Hublin, 2002), but they are rare and incomplete, being known only from isolated teeth and a parietal fragment from Payre (Southeastern France: Moncel & Condemi, 2007;Moncel et al, 2008;Valladas et al, 2008, Condemi et al, 2010.…”