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Cave 1B, in the Klasies River Main site complex (KRM), is best known for the recovery of the KRM 41815/SAM-AP 6222 human mandible. After initial skepticism over the modernity of this specimen, it is accepted that the mix of archaic and modern traits it displays is characteristic of early Homo sapiens individuals. Different authors have associated this specimen with the Middle Stone Age (MSA) I and II/Mossel Bay cultural phases, but the published data do not allow an unambiguous attribution. KRM 41815's frequent use in studies of the evolution of the human mandible, and its well-developed chin, makes clarifying its age and context important objectives. The field and micromorphology observations presented here provide greater insight into the stratigraphy and formation of the sequence exposed in the PP38 excavation. There are three major divisions: the basal Light Brown Sand (LBS) Member (not excavated), the Rubble Sand (RS) Member (MSA I), and the Shell and Sand Dark Carbonized (SASDC) Submember (MSA II). Cultural stratigraphy based on lithic artifacts remains the only way to make secure (but broad) temporal correlations with the rest of the site complex. This investigation shows that a range of anthropogenic, geogenic, and biogenic processes contributed to the deposition and post-depositional alteration of the identified microfacies. Short depositional hiatuses are reasonably common, and a significant hiatus was identified between the RS and SASDC. The impact of post-depositional processes on the RS is significant, with anthropogenic deposits poorly preserved. In comparison, the SASDC is dominated by hearths contained within deposits rich in reworked anthropogenic materials known as carbonized partings. Small shell disposal features are also present. The distribution of these anthropogenic features suggests continuity in the management of space throughout the MSA II occupations, from before 110 ka. New stratigraphic correlations indicate that KRM 41815 is unambiguously associated with the MSA I. Therefore, it predates 110 ka, with a lower age limit potentially in Marine Isotope Stage 6.

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The Early Pleistocene site of Dmanisi is now well known for its large number of fossils of early Homo erectus as well as associated artifacts and faunal remains, recovered mainly in pipe-related geologic features. Testing in the M5 unit 100 m to the west of the main excavations revealed a thick stratigraphy with no evidence of pipes or gullies, indicating that the geologic record at Dmanisi included spatially distinct sedimentary environments that needed further investigation. Here we report the results of a geoarchaeological program to collect data bearing on contexts and formation processes over a large area of the promontory. That work has defined over 40,000 m2 of in situ deposits with artifacts and faunas. Stratum A ashes bury the uppermost Mashavera Basalt, which we have dated to 1.8 Ma in the M5 block. The Stratum A deposits contain stratified occupations that accumulated quickly and offer good potential for recovery of in situ materials. Stratum B1 deposits above the A/B unconformity include all of the pipe and gully facies at Dmanisi, reflecting a brief but very intense phase of geomorphic change. Those deposits contain the majority of faunas and all of the hominin fossils. B1 slope facies offer excellent formation contexts away from the piped area, and all B1 deposits are sealed by Stratum B2 over the whole promontory. Strata B2 to B5 register a return to slope facies, with no further evidence of pipes or gullies. Those deposits also present excellent contexts for recovery of in situ occupations. Overall, Dmanisi's geologic history preserves an exceptional record of the activities and environmental context of occupations during the first colonization of Eurasia.

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North Vietnam is situated on a major route of Pleistocene hominin dispersal in East Asia, and the area's karstic caves preserve many prehistoric shell middens. Fossil and genomic evidence suggest a complex human history in this region and more widely across Southeast Asia and southern China, but related archaeological investigations are hampered by challenging site stratigraphies. Recent investigations of shell middens in other geographical settings have revealed the microstratigraphic complexity of these anthropogenic deposits. But caves promote distinctive site formation processes, while tropical climates may catalyse geomorphic and diagenetic changes. These environmental factors complicate the interpretation of North Vietnam's shell middens and constraining their effects upon the formation, preservation and destruction of these sites is critical to understanding the archaeology of this region. We examine two archaeological cave sites, dated to the Late Pleistocene and located in the limestone uplands surrounding the Hanoi Basin. Each contains multiple shell midden layers associated with prehistoric occupation and burials. Using thin-section micromorphology (microstratigraphy), we reconstruct the depositional and post-depositional histories of these sites, presenting a geoarchaeological framework of interpretation that is applicable to shell middens in mainland Southeast Asia and tropical zones more widely. This work represents a further step towards improving our understanding of prehistoric human dispersals and adaptations in this region. This article is part of the theme issue 'Tropical forests in the deep human past'.

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Archaeological deposits build up inside standing buildings both under and between floors and these have the potential to provide considerable information about human behavior in the past. Under and between floor spaces provide a unique depositional environment that allow the survival of rare and fragile organic materials that typically do not survive in other archaeological contexts, including paper, cardboard, fabric and other fibres, seeds, leather, and human hair and skin cells. However, they require a clear understanding of depositional processes to allow their interpretation. Experimental archaeology was conducted to understand the process of artifact deposition and the interpretation of underfloor deposits in twelve standing buildings in Western Australia. Floors were built and a range of artifacts swept across them to determine how artifacts travelled across floorboards or fell through gaps between boards. Size, shape, and angularity of artifacts were key determinants of the likelihood of deposition. Sweeping activity makes it more likely that material will be deposited around the margins of rooms, and particularly, to either side of doorways. Underfloor deposits excavated from two specific Western Australian buildings, Ellensbrook Homestead, and the York Residency Museum, are interpreted based on the results of these experiments.

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This essay delves into some of the challenges of studying the coevolution of humans and domestic spaces. These constructed arenas center on food preparation, and as part of the heritable niche they can shift the opportunities for, and constraints on, social interaction and cooperation in evolutionary time. Domestic spaces are widely evidenced in the archeological record, but investigators have made little progress in demonstrating causal links between proposed feedback spirals and constructed spaces of any sort. Bridging fine-scale and large-scale processes in coevolutionary systems is a complex problem that must engage higher levels of generative evolutionary theory. Archaeology nonetheless stands to offer a great deal to larger research programs by documenting and analyzing the pathways of change based on site formation processes along with evidence from subsistence refuse and technology. Choice models remain valuable tools for investigating aspects of the fine-scale feedback processes involved.

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This study addresses the roles of biotic agents in site formation in the B1 strata of Block 2 at Dmanisi, Georgia, using theoretical and analogous frameworks for the interpretation of spatial behaviors of carnivores and hominins. For this study, stone material, faunal remains, and coprolites are analyzed to determine if any spatially distinct behaviors can be identified, located, and attributed to either hominins or carnivores. Faunal, stone, and coprolite assemblages are compared with each other, and lithic, taxonomic, and taphonomic subassemblages are compared with the overall distribution of their parent material. The spatial and taphonomic signatures suggest that hominin activity was only a small part of the contributing factors to site formation, whereas carnivores played a major role in the accumulation of bone.

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Cytochrome c oxidase (COX) was initially purified more than 70 years ago. A tremendous amount of insight into its structure and function has since been gleaned from biochemical, biophysical, genetic, and molecular studies. As a result, we now appreciate that COX relies on its redox-active metal centers (heme a and a3, CuA and CuB) to reduce oxygen and pump protons in a reaction essential for most eukaryotic life. Questions persist, however, about how individual structural subunits are assembled into a functional holoenzyme. Here, we focus on what is known and what remains to be learned about the accessory proteins that facilitate CuA site maturation.

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Geoarchaeological research at the Middle Pleistocene site of Schöningen 13 II-4, often referred to as the Speerhorizont, has focused on describing and evaluating the depositional contexts of the well-known wooden spears, butchered horses, and stone tools. These finds were recovered from the transitional contact between a lacustrine marl and an overlying organic mud, originally thought to be a peat that accumulated in place under variable moisture conditions. The original excavators proposed that hominin activity, including hunting and butchery, occurred on a dry lake shore and was followed by a rapid sedimentation of organic deposits that embedded and preserved the artifacts. Our geoarchaeological analysis challenges this model. Here, we present evidence that the sediments of Schöningen 13 II-4 were deposited in a constantly submerged area of a paleolake. Although we cannot exclude the possibility that the artifacts were deposited during a short, extreme drying event, there are no sedimentary features indicative of surface exposure in the sediments. Accordingly, this paper explores three main alternative models of site formation: anthropogenic disposal of materials into the lake, a geological relocation of the artifacts, and hunting or caching on lake-ice. These models have different behavioral ramifications concerning hominin knowledge and exploitation of the landscape and their subsistence strategies.

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In hydrozoans the sperm will fuse with the egg only at the site of polar body formation. The primary oocyte and maturing oocytes which have produced the first polar body cannot be fertilized even though maturing oocytes which have produced the first polar body attract sperm. These eggs do not acquire the ability to be fertilized until after second polar body formation. If either first or second polar body formation is inhibited or if first and second polar body formation do not take place in close proximity to each other, the fertilization site is not set up. Under normal circumstances the site of polar body formation takes place at the region on the maturing oocyte surface nearest the site where the germinal vesicle resided in the primary oocyte. When maturing oocytes are centrifuged prior to polar body formation, the site of polar body formation is frequently shifted so that it does not correspond to the site where it would be given off under normal circumstances. Under these conditions the shifted site of polar body formation is the only site where the egg can be fertilized, indicating that the fertilization site is selected during oocyte maturation.Oocyte maturation in these hydrozoans is mediated by a hormone released by the somatic cells of gonophores as a consequence of bringing dark adapted gonophores into the light. The hormone acts directly on the oocyte to induce maturation. The oocyte only has to be exposed to the hormone for the first few minutes of the maturation process in order to complete the process of maturation.