Primary visual cortex in neandertals as revealed from the occipital remains from the El Sidrón site, with emphasis on the newSD‐2300 specimen

Abstract

The comparative analysis of the endocranial surface of the El Sidrón new occipital fragment SD-2300 shows meaningful differences in the configuration of the occipital pole region between neandertals and anatomically modern humans (AMH). The particular asymmetries found in neandertals in the venous sinus drainage and the petalial patterns are recognizable in this new specimen as well. In addition, the supra- and infracalcarine fossae of the occipital pole region appear to deviate obliquely from the mid-line when compared with sapiens. Due to the excellent preservation conditions of SD-2300, the main sulci and gyri of the occipital pole area have been identified, this degree of detail being uncommon in a fossil specimen; in general, the gyrification pattern is similar to AMH, but with some notable differences. Particularly interesting is the description of the lunate and the calcarine sulci. The lunate sulcus is located close to the occipital pole, in a similar posterior position to in other Homo species. Regarding the calcarine sulcus, there are significant differences in the primary visual cortex, with the V1 area, or Brodmann area 17, being larger in Homo neanderthalensis than in Homo sapiens. This may lead to greater visual acuity in neandertals than in sapiens.

Sulcal pattern variation in extant human endocasts

“…The lateral calcarine sulcus may also be asymmetrical (LHs = 55%; RHs = 20%), due to distortion occasionally created by overlay of the right dominant dural venous sinus groove (García‐Tabernero et al. ).…”

“…The size of the calcarine sulcus and its association with the primary visual cortex has recently been discussed in Neanderthal brain endocasts, which revealed potential differences in visual capacity when compared with Homo sapiens (García‐Tabernero et al. ).…”

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

“…He noted that this feature is typically observed on modern human occipitals, and we have confirmed its presence in many, but not all, subadult modern human endocrania. Recently, García‐Tabernero et al (2018) identified two raised lines in the cerebellar fossa of the El Sidrón SD 2300 occipital that appear to be associated with cerebellar fissures. However, we believe their prepyramidal fissure is more likely to be the horizontal fissure of the cerebellum, as seen in M‐S‐41 and identified by Heim (1976) in La Ferrassie 1.…”

“…The evolution of occipital shape and related changes in associated superstructures has been a focus of studies of Pleistocene Homo (Huxley, 1863; Fraipont & Lohest, 1887; Gorjanovíc‐Kramberger, 1902, Gorjanović‐Kramberger, 1906; Klaatsch, 1902; Weidenreich, 1940; Thoma, 1966, 1975; Krufoff, 1970; Piveteau, 1970; Wolpoff, 1977; Hublin, 1978a, 1978b, 1978c, 1980, 1984; Trinkaus & LeMay, 1982; Spitery, 1985; Caspari, 1991, 2005, 2006; Bastir et al, 2010; Verna et al, 2010; Balzeau & Rougier, 2010, 2013; Balzeau et al, 2011; Mussini, 2011; Mussini et al, 2011; Peña‐Melián et al, 2011; García‐Tabernero et al, 2018; Nowaczewska et al, 2019). These works are based on a relatively large sample of occipitals ( N ≈ 131); however, many are quite fragmentary.…”

Aproximación y comparativa en el estudio dental de diversas poblaciones prehistóricas

“…Precisamente esta curiosa morfología facial es la que, según algunos estudios, habría permitido una gran adaptación al frío y una alta demanda energética (Azevedo et al, 2017;Wroe et al, 2018;García-Martínez et al, 2020). Según algunos estudios, se ha podido comprobar que los individuos neandertales poseerían una mayor agudeza visual con respecto a Homo sapiens (García-Tabernero et al, 2018), todo ello a partir del análisis de la superficie endocraneal del occipital de los primeros, que muestra diferencias significativas con estos últimos.…”