During the Middle and Late Woodland periods in the American Midwest some small-scale societies transitioned from grit to limestone as the primary clay temper. Limestone offers experimentally demonstrated benefits to vessel manufacture, including decreased wall thickness, but given the society-wide changes in mobility and exchange that also occurred, we investigated whether the use of limestone temper resulted in a different vessel weight relative to an analogous grit-tempered vessel. Our analyses demonstrated a significant difference: post-firing, limestone-tempered vessels were 4.5% lighter than grit-tempered ones. The combination of reduced weight and other benefits could help explain why limestone became the predominant temper type throughout much of the Midwest. These issues have direct analogs in the biological realm, and we use three concepts from evolutionary biology - modularity, mosaic evolution, and constraint - to investigate the role limestone temper played not only in vessel weight but also in other aspects of vessel production and use.

Background Dehydroepiandrosterone-sulfate is the most abundant circulating androgen in humans and other catarrhines. It is involved in several biological functions, such as testosterone production, glucocorticoid antagonist actions, neurogenesis and neuroplasticty. Although the role of dehydroepiandrosterone-sulfate (DHEAS) in cognition remains elusive, the DHEAS/cortisol ratio has been positively associated with a slower cognitive age-decline and improved mood in humans. Whether this relationship is found in nonhuman primates remains unknown. Methods We measured DHEAS and cortisol levels in serum of 107 adult chimpanzees to investigate the relationship between DHEAS levels and age. A subset of 21 chimpanzees was used to test the potential associations between DHEAS, cortisol, and DHEAS/cortisol ratio in cognitive function, taking into account age, sex, and their interactions. We tested for cognitive function using the primate cognitive test battery (PCTB) and principal component analyses to categorize cognition into three components: spatial relationship tasks, tool use and social communication tasks, and auditory-visual sensory perception tasks. Results DHEAS levels, but not the DHEAS/cortisol ratio, declined with age in chimpanzees. Our analyses for spatial relationships tasks revealed a significant, positive correlation with the DHEAS/cortisol ratio. Tool use and social communication had a negative relationship with age. Our data show that the DHEAS/cortisol ratio, but not DHEAS individually, is a promising predictor of spatial cognition in chimpanzees.

ABSTRACT During the North American Late Archaic Period, people produced ceramic vessels from clay and stone vessels from soapstone. While both ceramic and soapstone vessels proliferated across eastern North America, the former evolved and endured into the subsequent periods, while the latter declined. Here, we conducted an experiment to assess heating effectiveness between soapstone and ceramic vessels. We examined heating rate, ability to boil, heat retention, and thermal shock resistance. We predicted that if cooking performance contributed to the decline of soapstone vessels, then they would perform poorly relative to ceramic vessels. Our results did not support that hypothesis and revealed soapstone vessels were significantly more likely to reach a boil. We consider three other related factors: (1) sourcing and production costs; (2) subsistence change; and (3) exchange and mobility, which may have contributed to the decline of the soapstone cooking vessel and the continued investment in ceramic technology.

Seeman, Morris, and Summers misrepresent or misunderstand the arguments we have made, as well as their own previous work. Here, we correct these inaccuracies. We also reiterate our support for hypothesis-driven and evidence-based research.

Background A novel physis in hominins modulates broadening and shortening of the ilium. We report analysis of a vascular canal system whose origin may be associated with this physis and which appears to be also unique to hominins. Its presence is potentially identifiable in the fossil record by its association with a highly enlarged foramen that is consistently present in modern humans and hominin fossils. Methods We measured the diameter of this foramen in humans, fossil hominins, and African great apes and corrected for body size. Results The mean relative human foramen diameter is significantly greater than those of either Pan or Gorilla . Moreover, eight of the nine values of the Cohen’s d for these differences in ratios are highly significant and support the ordering of magnitudes: Pan < Gorilla < Homo . The relative foramen diameter of A.L. 288-1 is above the 75th percentile of all other hominoids and at the high end of humans. The foramen is also present in ARA-VP-6/500. Conclusions We posit that the presence and significant enlargement of this foramen in fossils can reasonably serve as an indicator that its anterior inferior iliac spine emerged via the unique hominin physis. The foramen can therefore serve as an indicator of hominin iliac ontogenetic specialization for bipedality in fossil taxa.

Abbott, David R., Douglas B. Craig, Hannah Zanotto, Veronica X. Judd, and Brent Kober:MeasuringHohokam Household Inequality with Construction Costs of Domestic Architecture at Pueblo Grande, 368 Adams, Karen R., see Turner, Michelle I. Aiuvalasit, Michael, see Souses, B. Jacob Alt, Susan M., see Gamble, Lynn H. Ames, Kenneth M., see Lyons, Natasha Baller, Kendall, see Hegmon, Michelle Bamforth, Douglas, see Gamble, Lynn H. Banning, Edward B.: Sampled to Death? The Rise and Fall of Probability Sampling in Archaeology, 43 Barkwill Love, Lori: Rethinking “Village” at Mogollon Village (LA 11568): Formal Chronological Modeling of a Persistent Place, 153 Basnett, Lauren, see Thornton, Erin Kennedy Bebber, Michelle R., see Eren, Metin I. Beck, Jess, Erik Gjesfjeld, and Stephen Chrisomalis: Prestige or Perish: Publishing Decisions in Academic Archaeology, 669 Berkebile, Jean N., see Turner, Michelle I. Birch, Jennifer, and John P. Hart: Conflict, Population Movement, and Microscale Social Networks in Northern Iroquoian Archaeology, 350 Birch, Jennifer, Sturt W. Manning, Samantha Sanft, and MeganAnne Conger: Refined Radiocarbon Chronologies for Northern Iroquoian Site Sequences: Implications for Coalescence, Conflict, and the Reception of European Goods, 61 Bishop, Katelyn J., see Lesure, Richard G. Blair, Elliot H.: Reconsidering the Precolumbian Presence of Venetian Glass Beads in Alaska, 638 Blake, Michael, see Lyons, Natasha Bossio, Laura M., see Chenoweth, John M. Boudreaux, Edmond A., III, see Cobb, Charles R. Boulanger, Matthew T., see Eren, Metin I. Braje, Todd J., see Gill, Kristina M. Brenner-Coltrain, Joan, see Taylor, William Timothy Treal Britt, Brooks B., see Taylor, William Timothy Treal Brock, Fiona, see Metcalfe, Jessica Z. Brownstein, Korey J., see Damitio, William J. Buchanan, Briggs, see Diez-Martin, Fernando Buchanan, Briggs, see Eren, Metin I. Bush, Jennifer, see Eren, Metin I. Casana, Jesse, see McLeester, Madeleine Cerezo-Román, Jessica I.: A Comparison of Mortuary Practices among the Tucson Basin Hohokam and Trincheras Traditions, 327 Chase, Kelly Ledford, see Thornton, Erin Kennedy Chenoweth, John M., Laura M. Bossio, and Mark Salvatore: Modeling Colonial Paternalism: GIS and Multispectral Satellite Imagery at Kingstown, British Virgin Islands, 734 Chrisomalis, Stephen, see Beck, Jess Claassen, Cheryl, see Gamble, Lynn H. Clark, Bonnie J., see Metcalfe, Jessica Z. Cobb, Charles R., James B. Legg, Steven D. Smith, Chester B. Depratter, Brad R. Lieb, and Edmond A. Boudreaux III: The Remains of the Fray: Nascent Colonialism and Heterogeneous Hybridity, 569 Conger, Megan Anne, see Birch, Jennifer Craig, Douglas B., see Abbott, David R. Crossland, Zoë, see Flewellen, Ayana Omilade Dadiego, Danielle L., Alyssa Gelinas, and Tsim D. Schneider: Unpacking the Bead: Exploring a Glass Bead Assemblage from Mission Santa Cruz, California, Using LA–ICP–MS, 413 Damitio, William J., Shannon Tushingham, Korey J. Brownstein, R. G. Matson, and David R. Gang: The Evolution of Smoking and Intoxicant Plant Use in Ancient Northwestern North America, 715 Dean, Jeffrey S., see Nash, Stephen E. Depratter, Chester B., see Cobb, Charles R. De Vore, Steven L., see Green, William Diez-Martin, Fernando, Briggs Buchanan, James D. Norris, andMetin I. Eren:WasWelling, Ohio (33-Co-2), a Clovis Basecamp or LithicWorkshop? Employing Experimental Models to Interpret Old Collections, 183 Diez-Martin, Fernando see Eren, Metin I. Dockter, Abigail R., see Turner, Michelle I. Dolan, Sean G., and M. Steven Shackley: Pachuca Obsidian Blades from the U.S. Southwest: Implications for Mesoamerican Connections and Coronado’s Mexican Indian Allies, 773 Duke, Daron G., see Jazwa, Christopher S. Dunnavant, Justin P., see Flewellen, Ayana Omilade Eckert, Suzanne L., see Habicht-Mauche, Judith A. Eerkens, Jelmer W., see Gamble, Lynn H. Emerson, Thomas E., see Farnsworth, Kenneth B. Emerson, Thomas E., see Simon, Mary L.

Why, despite over 30,000 years of ceramic technology and tool diversity documented in the archaeological record - including examples of knapped ceramic scraping tools - was the ceramic arrowhead never invented? Here, we first review the use of ceramic projectile technology and tool use in the archaeological record. Then, via controlled ballistics tests, we investigate whether functional constraints played a role in this global non-invention. By creating "best case" and "worst case" models of ceramic arrowhead, and pitting them both against replica chipped stone counterparts, we show that the former perform significantly worse than the latter in terms of target penetrability and overall durability. By investigating "theoretical" artifacts, we can better understand the evolution of prehistoric technology and why the archaeological record appears the way it does.

In the absence of disease, ageing in the human brain is accompanied by mild cognitive dysfunction, gradual volumetric atrophy, a lack of significant cell loss, moderate neuroinflammation, and an increase in the amyloid beta (A β ) and tau proteins. Conversely, pathologic age-related conditions, particularly Alzheimer's disease (AD), result in extensive neocortical and hippocampal atrophy, neuron death, substantial A β plaque and tau-associated neurofibrillary tangle pathologies, glial activation and severe cognitive decline. Humans are considered uniquely susceptible to neurodegenerative disorders, although recent studies have revealed A β and tau pathology in non-human primate brains. Here, we investigate the effect of age and AD-like pathology on cell density in a large sample of postmortem chimpanzee brains ( n = 28, ages 12–62 years). Using a stereologic, unbiased design, we quantified neuron density, glia density and glia:neuron ratio in the dorsolateral prefrontal cortex, middle temporal gyrus, and CA1 and CA3 hippocampal subfields. Ageing was associated with decreased CA1 and CA3 neuron densities, while AD pathologies were not correlated with changes in neuron or glia densities. Differing from cerebral ageing and AD in humans, these data indicate that chimpanzees exhibit regional neuron loss with ageing but appear protected from the severe cell death found in AD. This article is part of the theme issue ‘Evolution of the primate ageing process’.

Archaeologists have attributed the decline of North American utilitarian copper tools to changes in demography and social complexity during the Archaic to Woodland transition, ca. 3000 B.P. However, not all utilitarian copper tools disappeared: the copper awl persisted. Given that the copper tool types that disappeared, such as projectile points and knives, have been experimentally shown to be functionally inferior to their non-copper counterparts, we tested whether the copper awl persisted because it was functionally superior to those made of bone. Using replicated copper and bone awls in a controlled punching experiment that utilized an Instron Universal Materials Tester, we demonstrate that copper awls require significantly less force to punch through leather relative to bone awls. These results strongly support the hypothesis that tool function played an important role in the evolution of the North American copper tool repertoire 3000 B.P.

Cardiac disease is a major cause of morbidity and mortality for adult gorillas. Previous research indicates a sex-based difference with predominantly males demonstrating evidence of left ventricular hypertrophy. To evaluate these findings, we analyzed serum markers with cardiac measures in a large sample of gorillas. The study sample included 44 male and 25 female gorillas housed at American Association of Zoo and Aquariums (AZA)-accredited zoos. Serum samples were collected from fasted gorillas during routine veterinary health exams and analyzed to measure leptin, adiponectin, IGF-1, insulin, ferritin, glucose, triglycerides, and cholesterol. Cardiac ultrasonography via transthoracic echocardiogram was performed simultaneously. Three echocardiographic parameters were chosen to assess cardiac disease according to parameters established for captive lowland gorillas: left ventricular internal diameter, inter-ventricular septum thickness, and left ventricular posterior wall thickness. Our data revealed that high leptin, low adiponectin, and lowered cholesterol were significantly and positively correlated with measures of heart thickness and age in males but not in females. Lowered cholesterol in this population would be categorized as elevated in humans. High leptin and low adiponectin are indicative of increased adiposity and suggests a potential parallel with human obesity and cardiovascular disease in males. Interestingly, while females exhibited increased adiposity with age, they did not progress to cardiac disease.

Most prehistoric societies that experimented with copper as a tool raw material eventually abandoned stone as their primary medium for tool making. However, after thousands of years of experimentation with this metal, North American hunter-gatherers abandoned it and returned to the exclusive use of stone. Why? We experimentally confirmed that replica copper tools are inferior to stone ones when each is sourced in the same manner as their archaeological counterparts and subjected to identical tasks. Why, then, did copper consistently lead to more advanced metallurgy in most other areas of the world? We suggest that it was the unusual level of purity in the North American copper sourced by North American groups, and that naturally occurring alloys yielded sufficiently superior tools to encourage entry into the copper-bronze-iron continuum of tool manufacture in other parts of the world.

In Alzheimer's disease (AD), the brain's primary immune cells, microglia, become activated and are found in close apposition to amyloid beta (Aβ) protein plaques and neurofibrillary tangles (NFT). The present study evaluated microglia density and morphology in a large group of aged chimpanzees (n = 20, ages 37-62 years) with varying degrees of AD-like pathology. Using immunohistochemical and stereological techniques, we quantified the density of activated microglia and morphological variants (ramified, intermediate, and amoeboid) in postmortem chimpanzee brain samples from prefrontal cortex, middle temporal gyrus, and hippocampus, areas that show a high degree of AD pathology in humans. Microglia measurements were compared to pathological markers of AD in these cases. Activated microglia were consistently present across brain areas. In the hippocampus, CA3 displayed a higher density than CA1. Aβ42 plaque volume was positively correlated with higher microglial activation and with an intermediate morphology in the hippocampus. Aβ42-positive vessel volume was associated with increased hippocampal microglial activation. Activated microglia density and morphology were not associated with age, sex, pretangle density, NFT density, or tau neuritic cluster density. Aged chimpanzees displayed comparable patterns of activated microglia phenotypes as well as an association of increased microglial activation and morphological changes with Aβ deposition similar to AD patients. In contrast to human AD brains, activated microglia density was not significantly correlated with tau lesions. This evidence suggests that the chimpanzee brain may be relatively preserved during normal aging processes but not entirely protected from neurodegeneration as previously assumed.