Social connections predict brain structure in a multidimensional free-ranging primate society

Reproduction and survival in most primate species reflects management of both competitive and cooperative relationships. Here, we investigated the links between neuroanatomy and sociality in free-ranging rhesus macaques. In adults, the number of social partners predicted the volume of the mid–superior temporal sulcus and ventral-dysgranular insula, implicated in social decision-making and empathy, respectively. We found no link between brain structure and other key social variables such as social status or indirect connectedness in adults, nor between maternal social networks or status and dependent infant brain structure. Our findings demonstrate that the size of specific brain structures varies with the number of direct affiliative social connections and suggest that this relationship may arise during development. These results reinforce proposed links between social network size, biological success, and the expansion of specific brain circuits

Utility of Osteoarthritis as an Indicator of Age in Human Skeletal Remains: Validating the Winburn and Stock (2019) Method

In forensic anthropology, and biological anthropology more broadly, age estimation is a crucial element of the biological profile. The development of osteoarthritis (OA) is correlated with age and, in 2019, Winburn and Stock published a method of estimating age in a sample of 408 white American individuals using OA presence/absence. The current study expanded the original study by testing its accuracy on a more diverse sample, including black, indigenous, and people of color (BIPOC). This served to test whether embodied inequity from lived experiences may preclude the ability of the OA presence/absence method to estimate age at death. This study’s results demonstrated both that the original methodology was validated, and that the approach was accurate at estimating the age of death of BIPOC individuals. Furthermore, this study revealed that the hip and shoulder were highly consistent and reliable and are recommended for use as the strongest indicators of age at death, while the TMJ and ankle performed poorly and should not be used for age estimation

Skeletal indicators of shark feeding on human remains: Evidence from Florida forensic anthropology cases

This research examines a series of six Florida forensic anthropology cases that exhibit taphonomic evidence of marine deposition and shark-feeding activities. In each case, we analyzed patterns of trauma/damage on the skeletal remains (e.g., sharp-force bone gouges and punctures) and possible mechanisms by which they were inflicted during shark predation/scavenging. In some cases, shark teeth were embedded in the remains; in the absence of this evidence, we measured interdental distance from defects in the bone to estimate shark body length, as well as to draw inferences about the potential species responsible. We discuss similarities and differences among the cases and make comparisons to literature documenting diagnostic shark-inflicted damage to human remains from nearby regions. We find that the majority of cases potentially involve bull or tiger sharks scavenging the remains of previously deceased, adult male individuals. This scavenging results in a distinctive taphonomic signature including incised gouges in cortical bone.Journal ArticleFinal article publishe

The importance of processing procedures and threshold values in CT scan segmentation of skeletal elements: An example using the immature os coxa

As the accessibility and utility of virtual databases of skeletal collections continues to grow, the impact that scan processing procedures has on the accuracy of data obtained from virtual databases remains relatively unknown. This study quantifies the intra- and inter-observer error generated from varying computed tomography (CT) scan processing protocols, including re-segmentation, incrementally varying thresholding value, and data collectors’ selection of the threshold value on a set of virtual subadult pelves. Four observers segmented the subadult ossa coxarum from postmortem CT scans of the fully-fleshed bodies of eleven individuals of varying ages. Segmentation protocol was set, with the exception of each observer selecting their own thresholding value for each scan. The resulting smoothed pelvic surfaces were then compared using deviation analyses. Root mean square error (RMSE), average distance deviation, and maximum deviation distances demonstrated that thresholding values of ∼50 HU (Hounsfield units) are easily tolerated, the surfaces generated are robust to error, and threshold value selection does not systematically vary with user experience. The importance of consistent methodology during segmentation protocol is highlighted here, especially with regards to consistency in both selected thresholding value as well as smoothing protocol, as these variables can affect subsequent measurements of the resultant surfaces