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Skeletal Parts (skeletal + part)

Distribution by Scientific Domains

Life Sciences	50%

Selected Abstracts

Bite marks as evidence of predation in early vertebrates

ACTA ZOOLOGICA, Issue 2009
Oleg A. Lebedev
Abstract Study of lifetime bite traces on agnathans and fish (or gnathostomes) from Ukraine, Estonia, Latvia and north-western and central European Russia reveals evidence of predator,prey relationships in communities of Devonian age. Numerous bite traces on skeletal parts of agnathan pteraspidiforms and psammosteiforms, placoderm arthrodires and antiarchs and sarcopterygian porolepiforms and osteolepiforms are described. Evidence of healing shows that prey organisms responded to predation by reconstruction of damaged skeletal elements. Ichthyofaunistic analysis is used to establish possible predators. The most probable predators in the Middle and Late Devonian communities are sarcopterygian porolepiforms and osteolepiforms. Predatory tetrapods become evident during the Famennian. Global analysis of aquatic predators during the Silurian,Devonian interval shows a gradual increase in species numbers with time. During the Late Silurian, only ischnacantid acanthodians, early osteichthyans and sarcopterygians are known to belong to this trophic group. By the end of the Devonian this list is complemented by chondrichthyans, arthrodires, porolepiform, osteolepiform, struniiform and rhizodontiform sarcopterygians and tetrapods. Only Devonian agnathans show no predatory groups. In sarcopterygians, predatory dentitions, which developed according to more or less the same pattern, show little change during the Devonian. [source]

Aragonite Formation in the Chiton (Mollusca) Girdle

HELVETICA CHIMICA ACTA, Issue 4 2003
Keren Treves
In the chitons (Polyplacophora, Mollusca), the body is not entirely protected by the shell. Mineralized spicules or scales often, but not always, decorate the exposed part of the girdle. Here, we report a study on the composition and ultrastructural organization of these mineralized skeletal parts in four different chiton species. In all specimens, the mineral component (97,98,wt-%) is aragonite, and the organic matrix (2,3,wt-%) consists of highly glycosylated proteins. X-Ray diffraction and scanning electron microscopy show that the organic matrix fibers are aligned, morphologically and crystallographically, with the prismatic aragonite crystals. Matrix and mineral are thus clearly related. The matrix,mineral composite bundles are, however, assembled in the various skeletal parts examined with widely different degrees of alignment and order. In the same organism, the crystals are aligned within a range of ±15° in one type of spicule, while they are randomly oriented in another type. The wide heterogeneity in shape, density, and ultrastructure suggests that the girdle mineralized tissues do not fulfill a fundamental role necessary for the survival of the organism. This, together with the lack of chitin in the organic matrix, supports the hypothesis that they evolved separately from the other chiton mineralized tissues, namely the shell plates and teeth. [source]

Bone weight: new reference values based on a modern Portuguese identified skeletal collection

INTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 5 2009
A. M. Silva
Abstract Skeletal weight and/or weight of the different bones of the human skeleton are currently used in a wide range of applications such as archaeological cremations and forensics. Still, few reference values are available that compare the mean weights for the different skeletal parts. In this paper we present new reference values for total skeletal weight, including the weight of the different skeletal bones based on a modern Portuguese Identified Skeletal Collection (CEI) curated in the Museum of Anthropology of the University of Coimbra (Portugal). The mean weight of the entire skeleton for the CEI pooled sample is 3323.8,±,779.6,g. Sex and age differences were investigated. As expected, males display heavier bones, at a statistically significant level. The mean weight of the male skeletons is 3850,g, and 2797.6,g for the female sample. Age differences were found, especially for the female samples in the 29,39 versus 50,59,and/or >60 age groups, probably as a consequence of age-related bone loss in post-menopausal women. For the male sample, no clear age-related trend was observed but for the unexpected result that the second highest bone weight recorded is in the oldest age group (>60 years). This could result from high mechanical loadings and thus greater bone robusticy and amount of cortical bone. The percentage of weight of the different parts of the skeleton was also calculated. These new values can be quite useful in the study of very fragmentary and/or commingled human remains, recovered from historic or forensic contexts, since the complete identification, by side, of the remains is not necessary. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Double child burial from sunghir (Russia): Pathology and inferences for upper paleolithic funerary practices

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2004
Vincenzo Formicola
Abstract The double child burial from Sunghir (Russia) is a spectacular Mid Upper Palaeolithic funerary example dated to about 24,000 BP. A boy (Sunghir 2) and a girl (Sunghir 3), about 12,13 and 9,10 years old, respectively, were buried at the same time, head to head, covered by red ocher and ornamented with extraordinarily rich grave goods. Examination of the two skeletons reveals that the Sunghir 3 femora are short and exhibit marked antero-posterior bowing. The two femora do not show any asymmetry in the degree of shortening and bowing. Bowing affects the whole diaphysis and shows a regularly incurved profile, with the highest point at midshaft. Pathology is confined to the femora, and no other part of this well-preserved specimen shows abnormality. The isolated nature of the Sunghir 3 anomalies points to cases reported in the medical literature under the label of "congenital bowing of long bones" (CBLB). These are a group of rare conditions exhibiting localized, sometimes bilateral, bowing and shortening which are nonspecific and may result from different causes, including abnormalities of the primary cartilaginous anlage (i.e., the aggregation of cells representing the first trace of an organ). Localized ossification disturbances, possibly linked to a diabetic maternal condition, might explain the shortening and the coincidence of maximum midshaft curvature with the position of the primary ossification center, as well as the lack of involvement of other skeletal parts. This scenario, rather than other possibilities (early bilateral midshaft fracture, acute plastic bowing deformities, or faulty fetal posture), provides the most likely explanation for the Sunghir 3 femoral deformities. The intriguing combination of a pathological condition apparent since birth with a spectacular burial of unusually positioned young individuals of different sexes recalls significant aspects of the triple burial from the contemporary site of Dolní V,stonice (Moravia), evoking a patterned relationship between physical abnormality and extraordinary Upper Paleolithic funerary behavior. Am J Phys Anthropol, 2003. © 2003 Wiley-Liss, Inc. [source]