Recent paleoanthropological surveys conducted in the Lower Awash basin (Afar Rift) have led to the discovery of new localities. Here we announce and describe the latest addition to the roster of hominid-bearing research areas in this basin. Located east of the modern Awash River and west of the Megenta mountain ridge, localities in the new research area contain extensive clay and silty-sand deposits variably capped by a widespread sandstone layer rich in archaeology and vertebrate fossils. Some of the localities are associated with volcanic tuffs suitable for radioisotopic age determination. A Middle Pleistocene antiquity is strongly inferred from the sampled fauna and archaeology; precise age estimates await results from ongoing tephra geochronological and geochemical analyses. Much of the archaeology falls under the conventional category of late Acheulean; assemblages identifiable as ‘Middle’ and ‘Later Stone Age’ are documented in a few localities. The vertebrate fauna from the closely probed Acheulean and hominid-bearing localities indicates a relatively wooded, near-water habitat. The cranial and post-cranial fossil hominid (and faunal) remains from the new localities promise insights into the patterns of human evolution across the Middle Pleistocene, a period currently poorly understood. Similarly, the archaeological occurrences provide unique opportunities for testing outstanding hypotheses about the origin of nuanced technologies and behaviors across the later Middle Pleistocene.

The excavation of the Shomyoji shell midden in 2017 recovered more than 26 human skeletal remains belonging to the Jomon, Kofun, and Heian periods. In this paper, we describe one Heianperiod (AD 794–1185) individual (SK1), who was dated to 957–900 calBP by radiocarbon dating. SK1 is well preserved, presumably a male, and aged approximately 20–35 years. The morphology of the cranium and teeth are not similar to that seen in the Kanto Jomon and Kamakura populations; it is closer to that of Yayoi immigrants from northern Kyusyu. SK1 has a severe lesion around the hip joint, and the left innominate bone and femur are atrophied. From this lesion, we can presume that SK1 had suffered from a hip joint disease such as tuberculous arthritis of the hip.

Sesamoids of the metacarpophalangeal joint are tiny bones located in the volar plate and articulated with the metacarpal head. Almost all living humans have radial and ulnar sesamoids in their pollical metacarpophalangeal joints. These bones protect and guide the tendon of the long (= extrinsic) pollical flexor. Whereas this condition is considered to be primitive for primates, living great apes have a tendency to lose these pollical sesamoids. Susman (Science 1994; 265: 1570–1573) correlated the loss of the pollical sesamoids in living great apes with the remarkable reduction/loss of the tendon of the long pollical flexor. However, the prevalence of these pollical sesamoids in chimpanzees drastically differs among previous studies. Thus, we CT-scanned cadavers of 12 chimpanzees, four gorillas, and two orangutans, and investigated the frequency of pollical metacarpophalangeal joint sesamoids in these apes. Combining our findings with previously reported data gave updated frequencies of 21% in chimpanzees (n = 24) and 0% in gorillas (n = 7) and orangutans (n = 6). This result is in accordance with the purported independent reduction (or loss) of the tendon of extrinsic flexor of the pollex in great apes (Diogo et al., Journal of Human Evolution 2012; 63: 64–78) and underscores the view that living great apes independently lost this tendon–sesamoid complex. Given that a reduction (or loss) of the tendon of extrinsic pollical flexor in great apes is a trade-off between emphasis on hook grips and pollical reduction, human hands have not experienced specialization for hook grips and retain the primitive condition in this regard. Orangutans and chimpanzees independently specialized for hook grips. The case for gorillas, whose hand proportion is similar to that of humans, is equivocal. Gorilla hands may have attained their current state secondarily or they may have lost the powerful extrinsic flexor of the pollex for reasons other than specialized hook grips.