JC virus (JCV) is a useful marker for tracing human dispersal. Four genotypes of JCV (CY, SC, B1-b, and MY) are mainly distributed in Asia. The population history of humans carrying CY, SC, or MY has been studied in some detail, but that of humans carrying B1-b remains poorly understood. The objective of this study was to gain insights into the population history of Asians carrying B1-b. A neighbor-joining phylogenetic tree was reconstructed from 26 complete B1-b DNA sequences from various regions of Asia. On the tree, the B1-b DNA sequences diverged into two clades, designated B1-b1 and B1-b2, each clustered with a high bootstrap probability. The split into B1-b1 and B1-b2 was estimated to have occurred about 20000 years ago, based on Ks values (synonymous substitutions per synonymous site) and the suggested rate of synonymous nucleotide substitutions. Comparison of the complete B1-b1 and B1-b2 sequences revealed that two single nucleotide polymorphisms (SNPs) between B1-b1 and B1-b2 occurred in a 610 bp region (the IG region) of the viral genome. Based on these SNPs, 145 B1-b isolates previously identified in the Old World were classified into B1-b1 or B1-b2. B1-b1 was widespread on the Asian continent, spreading from Northeast Siberia to West Asia. In contrast, B1-b2 was localized to part of South Asia, including South India and Sri Lanka. On the basis of the present findings, we inferred the dispersals of Asians carrying B1-b.

抄録全体を表示

The application of modern methodological taphonomic approaches to Pleistocene faunal assemblages that were excavated and interpreted before taphonomic analyses became common are critical to verifying whether the original interpretations are valid. Even though taphonomic research is common in North America, Africa, and Europe, few such studies of faunal collections have been carried out in East Asia. In this regard, taphonomic analysis of the faunal assemblage from Hanaizumi, Japan serves as an excellent case study because few taphonomic re-analyses of previously excavated Pleistocene assemblages have been performed in Japan. Hanaizumi was excavated in the 1950s and the original behavioral interpretation was that hunter-gatherers were responsible for the accumulation of the faunal assemblage, which is dominated by bison (Bison priscus). The taphonomic analysis presented here indicates that evidence of human modification is present on the bones. However, results suggest that even though hunter-gatherers may have had primary access to many of the bison in the assemblage, Hanaizumi was probably not a kill site or a hunter-gatherer home base as was originally proposed. Rather, the acquisition of bison may have taken place further up river and Hanaizumi is the locality to which the already processed carcasses were transported via fluvial movement. Accordingly, it is difficult to use the Hanaizumi faunal dataset to address current paleoanthropological debates. Future fieldwork at the site may indicate that hunter-gatherers played a more significant role in the formation of the bison bone assemblage. For now, Hanaizumi is best considered an allochthonous paleontological collection that has assisted in paleoenvironmental reconstructions of Late Pleistocene Japan.

抄録全体を表示

Parapresbytis eohanuman is a colobine known from two middle Pliocene localities southeast of Lake Baikal, northern East Asia. This study examined the morphology of postcranial specimens, a distal humerus and an ulna, of Parapresbytis. A total of 18 and 13 linear measurements were taken from the humerus and the ulna, respectively, and compared with those of extant and European fossil colobines using principal components analysis. The distal humeral specimen of Parapresbytis is slightly larger than those of male Semnopithecus and Nasalis, while the ulnar specimen is much larger than those of extant colobines and is nearly as large as that of a male Papio ursinus. Morphologically, the distal humeri and ulnae of terrestrial colobines such as Semnopithecus, Dolichopithecus, and Mesopithecus can be distinguished from those of arboreal colobines. The morphology of the Parapresbytis elbow is within the range of the arboreal colobines, contradicting previous suggestions that this genus is terrestrially adapted and is phylogenetically close to Dolichopithecus. Because the arboreally adapted elbow is shared by most extant colobines, the morphology of the elbow does not provide evidence for phylogenetic proximity between Parapresbytis and a particular taxon of arboreal colobine such as Rhinopithecus. The elbow morphology suggests that Parapresbytis was adapted to arboreal locomotion as much as the extant arboreal colobines are. This is congruent with the paleoenvironmental evidence, which indicates the presence of forests in the Lake Baikal area during the middle Pliocene.

抄録全体を表示

Mesiodistal and buccolingual crown diameters were examined to describe and compare patterns of metric dental variation in five modern samples from the Ryukyu Island chain (Miyako, Ishigaki, Tokunoshima, and two samples from Okinawa Island). Principal component analysis applied to two separate datasets, raw measurement and standardized (C-score) data, for 32 Asian and Pacific samples, including the five Ryukyu Islander series, produced an overall size factor and three shape factors (relative size of mesiodistal diameters versus buccolingual diameters and two kinds of front-back polarity). Ryukyu Islanders have similar crown dimensions as those of the predominant eastern Asian groups, characterized by mesodont dentition. In terms of shape factors, Ryukyu Islanders are distinctive among eastern Asian population groups on the one hand, and show diversity among themselves on the other hand. The inter-regional variation of Ryukyu Island groups estimated by F_st falls within the range of 4–6% of the total variance, which is greater than those of Arctic population samples (Aleuts and Eskimos). The average within-group variance of the Ryukyu Island series measured by the R-matrix method (intra-regional variation) is compatible with those of East and Northeast Asians, Micronesians, and Polynesians. These findings suggest that differential patterns of long-term gene flow from an outside source, geographical isolation, and genetic drift in each island of the Ryukyu Island chain has produced the morphological diversification of modern Ryukyu Islanders.

抄録全体を表示

Homo erectus has been broadly defined to include fossils from Africa, Asia, and possibly Europe, or restricted to a supposedly confined Asian clade. Recently discovered fossils of H. erectus are allowing new insights into aspects of its evolution, such as the timing and mode of the species’ emergence in Africa and its relationship to Asian populations. However, the currently available African record predating 1.0 Ma is poor, consisting of the Turkana basin, Olduvai and the more limited South African materials. Here, we describe and compare eight craniodental fossils of ~1.4 Ma recovered from Konso, Ethiopia, that we attribute to H. erectus. These include KGA10-1, one of the better-preserved H. erectus mandibular specimens known from eastern Africa, and other fragmentary dental and cranial remains. The Konso H. erectus fossils show a mosaic of primitive and derived features. These include a large and thick mandibular corpus, a moderately developed lateral prominence, a reduced premolar morphology, and a tendency for smaller relative sizes of the posterior molars compared with earlier Homo. In some dentognathic details, such as the lack of a buccolingually narrow M1 and the presence of double mental foramina, the Konso fossils differ from eastern African H. erectus of ≥1.5 Ma. The fragmentary cranial remains exhibit weak angular and occipital tori, and an apparently weak occipital flexion, as with the eastern African H. erectus examples known from ~1.65 to 1.2 Ma. The available evidence is consistent with the interpretation that African early H. erectus shows morphological continuity within the ~1.65 to 1.0 Ma time period, with relatively little morphological evolution prior to 1.4 Ma and advanced dentognathic gracility occurring sometime thereafter. The Konso evidence corroborates the hypothesis that the African H. erectus populations represent a variable but continuous evolutionary succession that was a likely source of multiple events of gene flow to the Eurasian continent.

抄録全体を表示

An adult maxilla and partial mandibles of a hominoid primate recovered from the late Miocene locality of Çorakyerler (central Anatolia) are recognized as a new species of Ouranopithecus, one of the rare western Eurasian hominoids to have survived well into the late Miocene. This species is distinguished from its sister taxon, and likely ancestor Ouranopithecus macedoniensis, by a constellation of dentognathic features. The new species, in which the male postcanine dentition is larger than that of any other Miocene ape besides Gigantopithecus, is associated with evidence indicating an open, dry environment. Dental features of Ouranopithecus apparently evolved in parallel with later Australopithecus, and suggest that Ouranopithecus was adapted to a diet of tough/abrasive foods.

抄録全体を表示

Minatogawa 1 is one of the rare well-preserved remains of Late Paleolithic Homo sapiens from East Asia, and is central to the investigation on the earlier phase of peopling in this region. In order to test the recent claim that the cranium and mandible of this specimen belong to different individuals, I re-examined its occlusion allowing for minor but significant distortion present in the original fossil specimen. It was confirmed that, when a correction is made for such a distortion, the maxillary and mandibular dentitions occlude perfectly in a normal Class I relation. Thus, the cranium and mandible of Minatogawa 1 no doubt belong to the same individual. A revised description on the state of tooth wear in Minatogawa 1 is also presented. No clear evidence of habitual non-masticatory oral activities is recognized, and the severe occlusal wear in this individual seems to result primarily from the nature of their foods and/or the food preparation techniques they used.

抄録全体を表示

The purpose of this study is to report on the results of the observations of newly excavated human skeletons from the Osaka castle site and to explore the metric features and weapon injuries of the skeletons. Our study allows some tentative observations. First, based on analyses of the Q-mode correlation coefficient and Penrose’s shape distance, the Osaka castle skeletons are similar to medieval populations in terms of both cranial and dental crown measurements. Second, we found five sword cuts on the skull and on the axis of a male individual. It seems very likely that this individual was decapitated, since the skull with its upper cervical vertebrae was unaccompanied by any other postcranial skeletal elements. This is the first study that addresses the morphological features and weapon injuries of human skeletons at the transition from the medieval to early modern periods in the Kinki District.

抄録全体を表示