Precuneus proportions and cortical folding: A morphometric evaluation on a racially diverse human sample.

Recent analyses have suggested that the size and proportions of the precuneus are remarkably variable among adult humans, representing a major source of geometrical difference in midsagittal brain morphology. The same area also represents the main midsagittal brain difference between humans and chimpanzees, being more expanded in our species. Enlargement of the upper parietal surface is a specific feature of Homo sapiens, when compared with other fossil hominids, suggesting the involvement of these cortical areas in recent modern human evolution. Here, we provide a survey on midsagittal brain morphology by investigating whether precuneus size represents the largest component of variance within a larger and racially diverse sample of 265 adult humans. Additionally, we investigate the relationship between precuneus shape variation and folding patterns. Precuneus proportions are confirmed to be a major source of human brain variation even when racial variability is considered. Larger precuneus size is associated with additional precuneal gyri, generally in its anterior district. Spatial variation is most pronounced in the dorsal areas, with no apparent differences between hemispheres, between sexes, or among different racial groups. These dorsal areas integrate somatic and visual information together with the lateral elements of the parietal cortex, representing a crucial node for self-centered mental imagery. The histological basis and functional significance of this intra-specific variation in the upper precuneus remains to be evaluated.

Cranial sutures: a multidisciplinary review.

INTRODUCTION: Progress in cranial suture research is shaping our current understanding of the topic; however, emphasis has been placed on individual contributing components rather than the cranial sutural system as a whole. Improving our holistic view helps further guide clinicians who treat cranial sutural abnormalities as well as researchers who study them. MATERIALS AND METHODS: Information from anatomy, anthropology, surgery, and computed modeling was integrated to provide a perspective to interpret suture formation and variability within the cranial functional and structural system. RESULTS: Evidence from experimental settings, simulations, and evolution suggest a multifactorial morphogenetic process associated with functions and morphology of the sutures. Despite molecular influences, the biomechanical cranial environment has a main role in both the ontogenetic and phylogenetic suture dynamics. CONCLUSIONS: Furthering our holistic understanding of the intricate cranial sutural system promises to expand our knowledge and enhance our ability to treat associated anomalies.

The primates of the Western Palaearctic: a biogeographical, historical, and archaeozoological review.

The Western Palaearctic is traditionally regarded as a zoogeographical unit which is lacking in primatological fauna. The representatives of this taxonomic group which has been documented within its boundary can be referred to the genera Macaca, Papio, and Chlorocebus, and possibly also to Erythrocebus and Galago. The data for the present research were collected through a review of all previous knowledge of the primates of this biogeographical region, including their history, and through original sightings and direct observation of field signs. Surveys were carried out directly in North Africa, the peninsula of Gibraltar, and in the Sahara. Additional data on primate distribution were obtained through the examination and evaluation of the materials conserved in several museums. A historical and archaeological investigation was also carried out, appraising both archaeozoological fndings and prehistoric and ancient artistic production, in order to evaluate the importance of the monkeys of the Western Palaearctic in relation to local human activities and needs.

Paleoneurology of an "early" Neandertal: endocranial size, shape, and features of Saccopastore 1.

The Saccopastore 1 cranium was found near Rome in 1929, and its most probable age is about 120 ka (OIS 5e). The Neandertal morphology of the specimen was recognized just after the discovery by the Italian anthropologist S. Sergi, and subsequently confirmed by several authors. The present paper provides a complete description and analysis of the endocranial shape and features of this specimen, considering anatomical traits, metrics, and landmark data. The main endocranial diameters and the vascular traces resemble the morphology displayed by Middle Pleistocene humans, although lacking some traits described in the European samples referred to as ante-Neandertals. Nevertheless, proportions and endocranial shape support a definite Neandertal morphology, mostly taking into account the lateral development of the frontal lobes and the shape of the parietal areas. Therefore, it may be hypothesized that the Neandertal neurocranial architecture was present since at least OIS 5, as already suggested on the basis of ectocranial morphology.