Christopher W. Rainwater

Morphological variation in Homo erectus and the origins of developmental plasticity

Homo erectus was the first hominin to exhibit extensive range expansion. This extraordinary departure from Africa, especially into more temperate climates of Eurasia, has been variously related to technological, energetic and foraging shifts. The temporal and regional anatomical variation in H. erectus suggests that a high level of developmental plasticity, a key factor in the ability of H. sapiens to occupy a variety of habitats, may also have been present in H. erectus. Developmental plasticity, the ability to modify development in response to environmental conditions, results in differences in size, shape and dimorphism across populations that relate in part to levels of resource sufficiency and extrinsic mortality. These differences predict not only regional variations but also overall smaller adult sizes and lower levels of dimorphism in instances of resource scarcity and high predator load. We consider the metric variation in 35 human and non-human primate ‘populations’ from known environmental contexts and 14 time- and space-restricted paleodemes of H. erectus and other fossil Homo. Human and non-human primates exhibit more similar patterns of variation than expected, with plasticity evident, but in differing patterns by sex across populations. The fossil samples show less evidence of variation than expected, although H. erectus varies more than Neandertals. This article is part of the themed issue ‘Major transitions in human evolution’.

Chapter 2 – Patterned Thermal Destruction in a Forensic Setting

This chapter discusses the patterned thermal destruction of human remains in a forensic setting. In the rapidly changing world of forensic science, more specifically forensic anthropology, there is a necessity to understand and be able to interpret fire modification of human remains. With the enormous potential for fire and heat alterations to inhibit scientists’ abilities to interpret patterns to human remains, burn trauma analysis is inconsistent and has been slow to mature in many disciplines. The destructive forces of fire often significantly alter, damage or even destroy many recognisable patterns, characteristics and evidence that we normally depend on. This likely contributes to the existence and persistence of old and untested theories concerning burned bone where inaccurate interpretations, such as exploding skulls, persist for decades and terminology is inconsistent. In fatal fire cases, forensic anthropologists are primarily responsible for separating perimortem trauma from heat-induced fractures and for assigning temporal and sequential designations to trauma when possible. These findings may contribute to the determination of cause and manner of death, time of death and perpetrator behaviour.

The Optimized Summed Scored Attributes Method for the Classification of U.S. Blacks and Whites: A Validation Study†

Recently, Hefner and Ousley (2014) introduced the optimized summed scored attributes (OSSA) method that maximizes between‐group differences in U.S. black and white populations by dichotomizing six cranial morphoscopic trait scores. This study tests OSSA using an independent skeletal sample (Hamann‐Todd, n = 208) and positively identified forensic cases (Mercyhurst University, n = 28, and New York City Office of Chief Medical Examiner, n = 38). An evaluation of trait frequencies suggests shifting the heuristically selected sectioning point separating U.S. black and white populations from ≤ 3 to ≤ 4. We found a total correct classification of 73.0% (B = 50.9%, W = 89.2%) using the originally suggested sectioning point of ≤3, while the total correct classification increases to 79.2% (B = 80.2%, W = 78.5%) with a modified sectioning point of ≤4. With the increased total correct classification and reduced classification bias between ancestry groups, we suggest the modified sectioning point of ≤4 be used when assessing ancestry in forensic unknowns.