Japanese Skeletons Research Articles

The journey of hull-fouling mobile invaders: basibionts and boldness mediate dislodgement risk during transit

Vessel hull-fouling is responsible for most bioinvasion events in the marine environment, yet it lacks regulation in most countries. Although experts advocate a preventative approach, research efforts on pre-arrival processes are limited. The performance of mobile epifauna during vessel transport was evaluated via laboratory simulations, using the well-known invasive Japanese skeleton shrimp (Caprella mutica), and its native congener C. laeviuscula as case study. The invader did not possess any advantage in terms of inherent resistance to drag. Instead, its performance was conditioned by the complexity of secondary substrate. Dislodgement risk was significantly reduced when sessile fouling basibionts were added, which provided refugia and boosted the probability of C. mutica remaining attached from 7 to 65% in flow exposure trials. Interestingly, the invader exhibited significantly higher exploratory tendency and motility than its native congener at zero-flow conditions. Implications in terms of en-route survivorship, invasion success and macrofouling management are discussed.

Morphological divergence in the curvature of human femoral diaphyses: Tracing the central mass distributions of cross-sections.

The diaphysis of the human femoral bone has a physiological anterior curvature; additionally, there is a curvature to the medial side or lateral side. In addition to compression stress from gravity during standing, walking, and running, these bones are continuously exposed to complex stresses from the traction forces of the various strong muscles attached to them. The femoral diaphysis is subjected to these mechanical stresses, and the direction and size of its curvature are defined according to Wolff's law and the mechanostat theory of Frost. The purpose of this study was to quantitatively evaluate the curvature of the femoral diaphysis in Japanese skeletons by determining the curve connecting the central mass distributions (CMD) of cross-sectional images. A total of 90 right femora (46 males and 44 females) were randomly selected from modern Japanese skeletal specimens. Full-length images of these bones were acquired using a clinical computed tomography scanner. The range between the lower end of the lesser trochanter and the adductor tubercle of each femur was divided at regular intervals to obtain ten planes, and nine levels were analyzed. The CMD curve was determined by connecting the CMDs of each of the nine cross-sections. First, the CMD of a cross-section in each of the nine slices was calculated, and the nine trajectories were superimposed from above. Then, by converting the shape of the entire CMD curve to superimpose the coordinates of the endpoint on the starting point, a closed arc representing the curvature of the femur was determined. For both males and females, the patterns varied from mostly medial to largely lateral curvature. The size of the curvature also varied for individuals. By analyzing only the coordinates of the vertex of the CMD curve of each femoral bone, the outlines of the diaphyseal curvatures could be recognized. The femora were thereby divided into two groups: medial bending and lateral bending. Considering males and females together, the number in the lateral-curvature group (n=51) was larger than that in the medial-curvature group (n=39). Moreover, the average age of the lateral-curvature group was significantly higher than that of the medial-curvature group (p<0.05). In males, with an increase in the cortical bone proportion of the cross-sectional area, the anterior vertex of diaphyseal bending tended to be more prominent. This cortical proportion was significantly higher in the medial-curvature groups than in the lateral-curvature group (p<0.01). The phenomena observed in this study may be related to pathophysiologies such as atypical fractures of the femur and osteoarthritis of the knee joints.

Design and implementation of two surveys targeted at describing fouling communities and identifying non-native species within active ports

AbstractPorts have long been considered ‘high-risk’ areas for the introduction of non-native species (NNS) and should therefore be a focus of NNS monitoring. The industrial nature of active ports can, however, provide various problems when attempting to carry out monitoring programmes. Current methodologies designed to identify NNS and to describe fouling communities have not been developed specifically for use in active ports and can encounter a number of issues when used in these environments. Here, two surveys were developed and trialled within an active port in South Wales, UK, designed to describe fouling communities, identify NNS and overcome some of the major limitations to conducting surveys within ports. Over a 6-month period, fouling communities dominated by solitary ascidians developed in each survey. Seven NNS were identified, mostly species already recorded in the 1950s, including the Mediterranean crab Brachynotus sexdentatus, and the more recently introduced Japanese skeleton shrimp Caprella mutica. Each survey was evaluated independently with respect to key factors, including the ability to detect NNS and practical aspects of using these survey methods in an applied context. We conclude that whilst each survey can function independently, the use of both survey types in conjunction offers the most robust solution to identifying NNS and describing wider fouling communities within active ports. This research has implications for the future monitoring and management of NNS within UK ports.

Validity of body mass estimation based on the femoral osteometry in Japanese skeletons

Validity of body mass estimation based on the femoral osteometry in Japanese skeletons

Distribution of the invasive Caprella mutica Schurin, 1935 and native Caprella linearis (Linnaeus, 1767) on artificial hard substrates in the North Sea: separation by habitat

Studying offshore natural and artificial hard substrates in the southern North Sea (51oN–57oN/1oW–9oE), the invasive introduced Japanese skeleton shrimp Caprella mutica Schurin, 1935 was found to co-exist with the native Caprella linearis (Linnaeus, 1767) only on near-shore locations that had an intertidal zone (e.g., wind farm foundations). In contrast, on far offshore and strictly subtidal locations, such as shipwrecks and rocky reefs, only C. linearis was found. Based on these exploratory observations, we hypothesised that artificial structures that are only subtidal are inhabited exclusively by C. linearis, and never by C. mutica. To test this hypothesis and understand factors driving each species’ habitat preferences, habitat suitability models were constructed using generalised additive models, based on samples collected in 2013–2015 from offshore gas platforms, buoys, shipwrecks, and rocky reefs and combined with data from other published and unpublished surveys (2001–2014). The models showed that the presence of C. mutica is explained by the availability of intertidal and floating hard substrates, suspended particulate matter density (SPM), mean annual sea surface temperature, salinity, and current velocity. The C. linearis model included subtidal hard substrates, SPM, salinity, temperature, and current velocity. The modelled distributions showed a significant difference, demonstrating that C. linearis’ habitat preference does not fully overlap with that of C. mutica. Thus, the native and alien Caprella species are likely to be able to co-exist in the North Sea.

Periarticular Osteophytes as an Appendicular Joint Stress Marker (JSM): Analysis in a Contemporary Japanese Skeletal Collection

ObjectiveThe aim of this study was to investigate the possibility that periarticular osteophytes plays a role as a appendicular joint stress marker (JSM) which reflects the biomechanical stresses on individuals and populations.MethodsA total of 366 contemporary Japanese skeletons (231 males, 135 females) were examined closely to evaluate the periarticular osteophytes of six major joints, the shoulder, elbow, wrist, hip, knee, and ankle and osteophyte scores (OS) were determined using an original grading system. These scores were aggregated and analyzed statistically from some viewpoints.ResultsAll of the OS for the respective joints were correlated logarithmically with the age-at-death of the individuals. For 70 individuals, in whom both sides of all six joints were evaluated without missing values, the age-standardized OS were calculated. A right side dominancy was recognized in the joints of the upper extremities, shoulder and wrist joints, and the bilateral correlations were large in the three joints on the lower extremity. For the shoulder joint and the hip joint, it was inferred by some distinctions that systemic factors were relatively large. All of these six joints could be assorted by the extent of systemic and local factors on osteophytes formation. Moreover, when the age-standardized OS of all the joints was summed up, some individuals had significantly high total scores, and others had significantly low total scores; namely, all of the individuals varied greatly in their systemic predisposition for osteophytes formation.ConclusionsThis study demonstrated the significance of periarticular osteophytes; the evaluating system for OS could be used to detect differences among joints and individuals. Periarticular osteophytes could be applied as an appendicular joint stress marker (JSM); by applying OS evaluating system for skeletal populations, intra-skeletal and inter-skeletal variations in biomechanical stresses throughout the lives could be clarified.

The Japanese skeleton shrimp Caprella mutica (Amphipoda: Caprellidae) in Sweden (Eastern Skagerrak)

The Japanese skeleton shrimp Caprella mutica, originally from the north-west Pacific, artificially introduced to many parts of the world, is recorded in Sweden for the first time. The new record is from Eastern Skagerrak, slightly north of the border between the North Sea and the Baltic Sea. A detailed morphological description of the specimens from Swedish waters with notes on habitat is presented. In comparison with the specimens from the native range, the large males of C. mutica from Sweden, and material earlier reported from elsewhere in Europe, are characterized by rather long pereonites 1 and 2, which are longer than the combined length of pereonites 3 and 4; and long segments of antenna 1 peduncle; among them segment 3 is longer than flagellum. (Less)

Reliability of metric determination of sex based on long-bone circumferences: perspectives from Yuigahama-minami, Japan

The purpose of this study is to develop new standards to determine the sex of fragmentary human skeletal remains from archaeological sites in Japan. In order to accomplish this, we measured the long-bone circumferences of Japanese skeletons from the medieval period and provided metric diagnosis of sex using discriminant function analysis. We discuss whether the osteometric approach provides the criterion for sex assessment of human skeletal remains. The materials comprised human skeletal remains from the Yuigahama-minami site, Kamakura, Japan. The sample size used in this study was 68 males and 62 females excavated from individual burial graves. The accuracy of sex classification is more than 80% for discriminant functions with only one variable and reaches 90% for those with a combination of multiple variables. The multivariate functions provide better results than the univariate functions. Another improvement in sex diagnosis which this study contributes to is that new standards enabling reliable diagnosis with small numbers of variables are developed from well-preserved parts of the skeletons. This paper provides new standards, focusing on the diaphysial circumferences of limb bones from a medieval population, and will contribute to the advancement of medieval studies of skeletal remains from archaeological sites in Japan.

Sex determination using mastoid process measurements: standards for Japanese human skeletons of the medieval and early modern periods

The purpose of this study was to develop new standards for determining the sex of fragmentary human skeletal remains. We measured height, width, and length of the mastoid process in medieval to early modern Japanese skeletons, from the Yuigahama-minami and Hitotsubashi sites, in order to provide a metric standard for the diagnosis of sex using the mastoid process. We calculated discriminant functions based on these measurements; the accuracy of sex classification was over 80% using a single variable, and reached 82–92% with two variables, mastoid height and width. This accuracy is equal to or better than that reported by some previous studies of sex determination using the cranium. However, when we examined intra- and interobserver errors in the mastoid process measurements, we found a high level of errors, and this highlights the difficulty involved in intraobserver repeatability and interobserver reproducibility. Our results imply that, in order to achieve reliable results of sex determination using the mastoid process, the measurement methods need to be carefully determined and executed.

Is the Japanese skeleton shrimp Caprella mutica a filter feeder? I. Head morphology and kinematics

Is the Japanese skeleton shrimp Caprella mutica a filter feeder? I. Head morphology and kinematics

A possible case of spondyloarthropathy in a prehistoric Japanese skeleton

Palaeopathology helps to define the migration of past diseases. Genetic and environmental factors play a role in the development of spondyloarthropathy (SpA). We report skeletal remains with SpA from the Jomon period in Japan. The skeleton is of a female who died at a young adult age. The skeleton had characteristic features seen in SpA as follows: (1) polyarticular arthritis; (2) erosions accompanying some bone formation; (3) enthesial ossification; and (4) periostitis in lower long bones. The findings suggest that SpA was present in prehistoric Japan before contact with European civilisation, and the present example of SpA is the oldest in Asia and the Old World. Copyright © 2004 John Wiley & Sons, Ltd.

Pedal symphalangism in modern American and Japanese skeletons

Pedal symphalangism is a surprisingly common heritable trait of the human foot. In individuals exhibiting the trait, the joint between the intermediate and distal phalanges of one or more lateral toes never develops, resulting in toes with two phalanges rather than three. This study was undertaken to explore variation in the frequency of pedal symphalangism among groups with widely different geographic ancestry, and to consider the applicability of this trait to skeletal biological distance studies. A total of 460 Euro-American, 191 African-American and 99 Japanese skeletons were examined for presence of pedal symphalangism. The American individuals date to the first half of the 20th c, while the Japanese individuals date to the late 19th and early 20th c. Although the country of ancestry is unknown for most of the American individuals, the Euro-Americans appear to be largely northern European, with roots in Germany, Ireland and Scandinavia, while the African-Americans are primarily descendants of slaves with roots in west African countries such as Nigeria, Benin, Togo, Ghana and Sierra Leone. Frequencies of fifth toe pedal symphalangism were calculated and compared among all three samples and found to be significantly higher in modern Japanese (83.7%) than in either Euro-Americans (46.4%) or African-Americans (44.0%). The Euro- and African-American frequencies were statistically indistinguishable for symphalangism of the fifth toe. In the fourth toe, however, the opposite result was found. The African-American frequency (7.9%) was significantly higher than the Euro-American frequency (2.6%), while no difference was found between the African-Americans and Japanese (11.7%). Since fourth toe pedal symphalangism has never been observed in the absence of fifth toe involvement, some of the same genes are clearly involved in producing the trait in both toes. However, differences in the pattern of fourth and fifth toe expression among the three groups identified in this study suggest that additional genetic or developmental factors may play a role in expression of pedal symphalangism in each of the toes.

Analysis of Injuries by Swords in Medieval Japanese Skeletons from Yuigahama, Kamakura

Analysis of Injuries by Swords in Medieval Japanese Skeletons from Yuigahama, Kamakura

Erosive peripheral polyarthritis in ancient Japanese skeletons: A possible case of rheumatoid arthritis

The antiquity of rheumatoid arthritis (RA) is still in dispute, due to the difficulty of conclusively differentiating peripheral polyarthritis, especially from spondyloarthropathy, in archaeological populations. In view of the importance of genetic factors in developing spondyloarthropathy and of the far lower prevalence of the disease in modern Japanese, a rarity of peripheral polyarthritis would be anticipated in the ancient Japanese population, given that RA had not been present there. One hundred and sixty adult Japanese skeletons of the late and final Jomon period (3400–2400 years bp) were examined to find peripheral polyarthritis. There was one male skeleton with peripheral polyarthritis, showing marginal and surface erosions in the joints of the hands, feet, ankle and zygoapopheseal joints of the thoracic vertebrae. RA is suggested as the most probable cause of this pathology. This report raises the significance of further studies to consider whether more cases than anticipated exist in skeletal populations that would have been resistant to developing spondyloarthropathy. Copyright © 1999 John Wiley & Sons, Ltd.

Erosive peripheral polyarthritis in ancient Japanese skeletons: A possible case of rheumatoid arthritis

The antiquity of rheumatoid arthritis (RA) is still in dispute, due to the difficulty of conclusively differentiating peripheral polyarthritis, especially from spondyloarthropathy, in archaeological populations. In view of the importance of genetic factors in developing spondyloarthropathy and of the far lower prevalence of the disease in modern Japanese, a rarity of peripheral polyarthritis would be anticipated in the ancient Japanese population, given that RA had not been present there. One hundred and sixty adult Japanese skeletons of the late and final Jomon period (3400–2400 years bp) were examined to find peripheral polyarthritis. There was one male skeleton with peripheral polyarthritis, showing marginal and surface erosions in the joints of the hands, feet, ankle and zygoapopheseal joints of the thoracic vertebrae. RA is suggested as the most probable cause of this pathology. This report raises the significance of further studies to consider whether more cases than anticipated exist in skeletal populations that would have been resistant to developing spondyloarthropathy. Copyright © 1999 John Wiley & Sons, Ltd.

Nonmetric Cranial Variants in a Medieval Japanese Sample from Ichikishima-jinja Site.

The incidences of 20 nonmetric cranial traits of medieval Japanese skeletons excavated at the Ichikishima-jinja site in southern central Japan are reported, and compared with those of other population samples from Japan by means of Smith's Mean Measure of Divergence (MMD). The Ichikishima sample is proved to be biologically far from both the prehistoric Jomon and recent Hokkaido Ainu samples, and close to the samples from the protohistoric Kofun to the recent period, especially to the Kanto samples of the Muromachi and Kamakura periods. For both the recent and Kofun periods, the Ichikishima sample is closer to the eastern then to the western Japan samples. A secular trend, which is perhaps independent of the extent of admixture between the Jomon and immigrant elements, is suggested for the Japanese samples after the Yayoi period.

Sexual dimorphism in modern Japanese crania.

The Japanese population has gone through significant micro-evolutionary changes during the last half century. One approach to quantify these changes is an osteometric analysis of sexual variation in the skeleton. The present study evaluates sexual dimorphism in modern Japanese cranial dimensions. Comprehensive osteometric data were obtained from 84 modern Japanese skeletons of known sex and age at death from the dissecting room collection at Jikei Medical University, Tokyo. The remains were macerated between 1960 and 1970 and thus are from individuals who lived through World War II. A total of 16 cranial dimensions were subjected to SPSS-X discriminant function analysis. Using 11 measurements of the cranium, five dimensions were selected by the stepwise discriminant methods, including bigonial breadth. In a second stepwise function using 11 cranial measurements, seven contributed to the function. In both functions, mastoid height was selected first and prediction accuracy averaged 84%. Because of its significant contribution, a function was calculated from mastoid height alone. This produced an average of 74% prediction accuracy. In general, width dimensions better reflected differences between the sexes. The accuracy of correct classification from the Jikei sample was slightly lower than those of earlier Japanese populations. The results of this study also suggested that sexual dimorphism in Japanese crania may have decreased as a result of an increase in size of females. © 1995 Wiley-Liss, Inc.

Sex Determination from the Tibia: Standards for Contemporary Japan

It is vital that skeletal biologists and forensic anthropologists observe populations over time so that changes can be detected and monitored. The purpose of this study is to determine if temporal changes are manifest in the skeleton and, if so, develop appropriate standards to determine sex from the tibia in the contemporary inhabitants of Japan. Osteometric data were obtained from 84 recent Japanese skeletons located at Jikei Medical University, Tokyo. The collection was assembled from the anatomy dissecting room between 1960-1970. With a mean age of about 56 years for males and 51 for females, this sample represents individuals who lived through WWII. Seven tibial measurements were taken and subjected to SPSS-X discriminant function analysis. Results indicated that proximal and distal breadth measurements were selected by the stepwise procedure as the most discriminating. In addition, a number of combinations of measurements were used to develop formulae that would be suitable for fragmentary bones. Average prediction accuracy ranged from 80% from minimum shaft circumference to 89% with proximal epiphyseal breadth. Classification accuracy was higher in males (96%) than in females (79%). Compared with earlier studies of the Japanese, Jikei tibiae are longer, especially in females and thus exhibit less sexual dimorphism. The present research provides new standards that better reflect the Japanese people of today. Furthermore, unlike earlier length based formulae, these results allow sexing from fragmentary bones.

Reply to Hockings and Brace

Gatherers and Agriculturalists. American Journal of Physical Anthropology 63:39-56. Suzuki, Hisashi 1956 Medieval Japanese Skeletons From the Burial Site at Zaimokuza, Kamakura City. (In Japanese, English Abstract, pp. 171-190.) Anthropological Society of Nippon. Tokyo: Shoten. Waugh, L. M. 1937 Influence of Diet on Jaws and Face of the American Eskimo. Journal of the American Dental Association 24:16401647.

Sexing of Japanese Skeleton and Teeth by Discriminant Function Method

Sexing of Japanese Skeleton and Teeth by Discriminant Function Method