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Skeletal Elements (skeletal + element)
Selected AbstractsDNA Preservation in Skeletal Elements from the World Trade Center Disaster: Recommendations for Mass Fatality Management,JOURNAL OF FORENSIC SCIENCES, Issue 4 2009Amy Z. Mundorff M.A. Abstract:, The World Trade Center (WTC) victim identification effort highlights taphonomic influences on the degradation of DNA from victims of mass fatality incidents. This study uses a subset of the WTC-Human Remains Database to evaluate differential preservation of DNA by skeletal element. Recovery location, sex, and victim type (civilian, firefighter, or plane passenger) do not appear to influence DNA preservation. Results indicate that more intact elements, as well as elements encased in soft tissue, produced slightly higher identification rates than more fragmented remains. DNA identification rates by element type conform to previous findings, with higher rates generally found in denser, weight-bearing bones. However, smaller bones including patellae, metatarsals, and foot phalanges yielded rates comparable to both femora and tibiae. These elements can be easily sampled with a disposable scalpel, and thus reduce potential DNA contamination. These findings have implications for DNA sampling guidelines in future mass fatality incidents. [source] Skeletal elements in the vertebrate eye and adnexa: Morphological and developmental perspectivesDEVELOPMENTAL DYNAMICS, Issue 5 2006Tamara A. Franz-Odendaal Abstract Although poorly appreciated, the vertebrate eye and adnexa are relatively common sites for skeletogenesis. In many taxa, the skeleton contributes to internal reinforcement in addition to the external housing of the eye (e.g., the circumorbital bones and eyelids). Eyeball elements such as scleral cartilage and scleral ossicles are present within a broad diversity of vertebrates, albeit not therian mammals, and have been used as important models for the study of condensations and epithelial,mesenchymal interactions. In contrast, other elements invested within the eye or its close surroundings remain largely unexplored. The onset and mode of development of these skeletal elements are often variable (early versus late; involving chondrogenesis, osteogenesis, or both), and most (if not all) of these elements appear to share a common neural crest origin. This review discusses the development and distribution of the skeletal elements within and associated with the developing eye and comments on homology of the elements where these are questionable. Developmental Dynamics 235:1244,1255, 2006. © 2006 Wiley-Liss, Inc. [source] Development of the pharyngeal arch skeleton in Catostomus commersonii (Teleostei: Cypriniformes)JOURNAL OF MORPHOLOGY, Issue 3 2009Jeffrey M. Engeman Abstract Skeletal elements of the gill arches of adult cypriniform fishes vary widely in number, size, and shape and are important characters in morphologically based phylogenetic studies. Understanding the developmental basis for this variation is thus phylogenetically significant but also important in relation to the many developmental genetic and molecularly based studies of the early developing and hence experimentally tractable gill arches in the zebrafish, a cyprinid cypriniform. We describe the sequence of the chondrification and ossification of the pharyngeal arches and associated dermal bones from Catostomus commersonii (Catostomidae, Cypriniformes) and make selected comparisons to other similarly described pharyngeal arches. We noted shared spatial trends in arch development including the formation of ventral cartilages before dorsal and anterior cartilages before posterior. Qualitatively variable gill arch elements in Cypriniformes including pharyngobranchial 1, pharyngobranchial 4, and the sublingual are the last such elements to chondrify in C. commersonii. We show that the sublingual bone in C. commersonii has two cartilaginous precursors that fuse and ossify to form the single bone in adults. This indicates homology of the sublingual in catostomids to the two sublingual bones in the adults of cobitids and balitorids. Intriguing patterns of fusion and segmentation of the cartilages in the pharyngeal arches were discovered. These include the individuation of the basihyal and anterior copula through segmentation of a single cartilage rod, fusion of cartilaginous basibranchials 4 and 5, and fusion of hypobranchial 4 with ceratobranchial 4. Such "fluidity" in cartilage patterning may be widespread in fishes and requires further comparative developmental studies. J. Morphol., 2009. © 2008 Wiley-Liss, Inc. [source] Hindlimb adaptations in Ourayia and Chipetaia, relatively large-bodied omomyine primates from the Middle Eocene of UtahAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2006Rachel H. Dunn Abstract North American omomyids represent a tremendous Eocene radiation of primates exhibiting a wide range of body sizes and dietary patterns. Despite this adaptive diversity, relatively little is known of the postcranial specializations of the group. Here we describe hindlimb and foot bones of Ourayia uintensis and Chipetaia lamporea that were recovered from the Uinta B member (early Uintan Land Mammal Age), Uinta Formation, Utah. These specimens provide insights into the evolution of postcranial adaptations across different body sizes and dietary guilds within the Eocene primate radiation. Body mass estimates based on talar measurements indicate that Ourayia uintensis and Chipetaia lamporea weighed about 1,500,2,000 g and 500,700 g, respectively. Skeletal elements recovered for Ourayia include the talus, navicular, entocuneiform, first metatarsal, and proximal tibia; bones of Chipetaia include the talus, navicular, entocuneiform, and proximal femur. Both genera had opposable grasping big toes, as indicated by the saddle-shaped joint between the entocuneiform and first metatarsal. Both taxa were arboreal leapers, as indicated by a consistent assemblage of characters in all represented bones, most notably the somewhat elongated naviculars, the high and distinct trochlear crests of the talus, the posteriorly oriented tibial plateau (Ourayia), and the cylindrical head of the femur (Chipetaia). The closest resemblances to Ourayia and Chipetaia are found among the Bridger omomyines, Omomys and Hemiacodon. The results of our comparisons suggest that the later, larger, more herbivorous omomyines from Utah retained a skeletal structure characteristic of earlier, smaller North American omomyids. Am J Phys Anthropol, 2006. © 2006 Wiley-Liss, Inc. [source] Use of the first rib for adult age estimation: a test of one methodINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 5 2005H. Kurki Abstract The human first rib is relatively easy to identify and is often preserved, in comparison with elements such as the fourth rib and pubic symphysis. Therefore it is potentially a valuable skeletal element for estimating age in forensic and archaeological contexts. A method of adult age estimation using the first rib (Kunos et al., 1999) is tested on a sample of known age skeletons from the J.C.B. Grant Collection (n,=,29, mean age,=,55.7 years). The high correlation coefficient (r,=,0.69) and moderate coefficient of determination (r2,=,0.47) demonstrate agreement between the known and estimated ages, suggesting that the first rib demonstates morphological changes with age. The inaccuracy and bias are high (all ages inaccuracy,=,10.4 years, bias,=,4.7 years) but comparable to several other age estimation methods in common use. Although the results are not as good for younger age categories (<,50 years: inaccuracy and bias rank ninth of nine age estimation methods), the inaccuracy and bias for the older age categories are relatively low (60,+ years inaccuracy,=,8.9 years, ranks third out of nine; bias,=,,,5.8 years, ranks first out of nine) compared with other age estimation methods. The first rib method is reasonably precise (93% of individuals fall within the limits of agreement of the mean difference between two trials). The first rib method is therefore a useful addition to the methods available for biological profile reconstructions from skeletal remains, especially if it is suspected that the remains represent an older individual. Copyright © 2005 John Wiley & Sons, Ltd. [source] DNA Preservation in Skeletal Elements from the World Trade Center Disaster: Recommendations for Mass Fatality Management,JOURNAL OF FORENSIC SCIENCES, Issue 4 2009Amy Z. Mundorff M.A. Abstract:, The World Trade Center (WTC) victim identification effort highlights taphonomic influences on the degradation of DNA from victims of mass fatality incidents. This study uses a subset of the WTC-Human Remains Database to evaluate differential preservation of DNA by skeletal element. Recovery location, sex, and victim type (civilian, firefighter, or plane passenger) do not appear to influence DNA preservation. Results indicate that more intact elements, as well as elements encased in soft tissue, produced slightly higher identification rates than more fragmented remains. DNA identification rates by element type conform to previous findings, with higher rates generally found in denser, weight-bearing bones. However, smaller bones including patellae, metatarsals, and foot phalanges yielded rates comparable to both femora and tibiae. These elements can be easily sampled with a disposable scalpel, and thus reduce potential DNA contamination. These findings have implications for DNA sampling guidelines in future mass fatality incidents. [source] Frequencies of Morphological Characteristics in Two Contemporary Forensic Collections: Implications for Identification,JOURNAL OF FORENSIC SCIENCES, Issue 5 2006Debra Komar Ph.D. ABSTRACT: Positive identification relies on comparison of antemortem and postmortem data. Some identifications are based on morphological features such as fracture, pathological condition, and surgical hardware, despite little literature indicating the frequencies of such traits. This study examines whether such features are sufficiently rare as to be deemed individualizing. Data were collected on two modern North American skeletal collections (N=482 individuals). Presence/absence of features was scored by skeletal element and side. Results indicate that frequencies vary by geographic region (higher frequency of fractures and pathological conditions in New Mexico while individuals in Tennessee were more likely to have surgical interventions), many features such as fractures are remarkably common and that even suites of traits may not be individualizing. Caution is warranted when using written data rather than radiographic comparisons as the primary source of identification. The implications of these findings to missing person databases are also discussed. [source] Lines of arrested growth in bone and age estimation in a small primate: Microcebus murinusJOURNAL OF ZOOLOGY, Issue 1 2004J. Castanet Abstract In primates, age determination using lines of arrested growth (LAGs) from bones has rarely been attempted, and the reliability of these structures has never been experimentally validated. In order to test skeletochronology in primates, LAGs were studied mainly in the long bones of known age Microcebus murinus, a small primate, whose potential longevity may reach 12 years. LAGs were extensively studied in 43 males and 23 females ranging from juveniles to 11-year-old adults. All individuals were born and reared in captivity. Some young individuals were injected with fluorescent dyes to quantify bone growth rates. LAGs in the diaphysis of the tibia are well correlated with age and this skeletal element appears to be the best for assessing skeletochronology in Microcebus murinus. There is strong evidence that the seasonal cycle of photoperiodicity is more important than age alone in producing LAGs. [source] Violence and weapon-related trauma at Puruchuco-Huaquerones, PeruAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2010Melissa S. Murphy Abstract Conquest of indigenous peoples in North America is understood primarily through ethnohistorical documents, archaeological evidence, and osteological analyses. However, in the Central Andes, the colonial enterprise and its effects are understood only from postcontact historical and ethnohistorical sources. Few archaeological and bioarchaeological studies have investigated Spanish Conquest and colonialism in the Andean region [for exceptions see Klaus and Tam: Am J Phys Anthropol 138 (2009) 356,368; Wernke, in press; and Quilter, in press]. Here we describe bioarchaeological evidence of violence from the cemeteries of Huaquerones and 57AS03 within the archaeological zone of Puruchuco-Huaquerones, Peru (circa A.D. 1470,1540). A total of 258 individuals greater than 15 years of age were analyzed for evidence of traumatic injuries. Individuals were examined macroscopically and evidence of traumatic injuries was analyzed according to the skeletal element involved, the location of the injury on the skeletal element, and any additional complications of the injury. This study examines and compares the evidence of perimortem injuries on skeletonized individuals from the two cemeteries and focuses specifically on the interpretation of weapon-related perimortem injuries. Evidence of perimortem trauma is present in both cemeteries (18.6%, 48/258); however, the frequency of injuries in 57AS03 is greater than that in Huaquerones (25.0% vs. 13.0%). Several injuries from 57AS03 are consistent with documented cases of injuries from firearms and 16th Century European weapons. We believe that the nature and high frequency of perimortem trauma at 57AS03 provide evidence of the violence that occurred with Spanish Conquest of the Inca Empire. Am J Phys Anthropol 142:636,649, 2010. © 2010 Wiley-Liss, Inc. [source] Growth and differentiation of the developing limb bud from the perspective of chondrogenesisDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 6 2007Hirohito Shimizu Limb skeletal elements develop from a cartilage template, which is formed by the process termed chondrogenesis. This process is crucial in determining the shape and size of definitive bones in vertebrates. During chondrogenesis, aggregated mesenchymal cells undergo a highly organized process of proliferation and maturation along with secretion of extracellular matrix followed by programmed cell death and replacement by bone. The molecular mechanisms underlying this sophisticated process have been extensively studied. It has been demonstrated that several transcription factors such as Sox genes and Runx genes are indispensable for the major steps in chondrogenesis. Additionally, a number of signaling molecules including Bmps, Fgfs and Ihh/PTHrP are known to regulate chondrogenesis through highly coordinated interactions. This review is meant to provide an overview of the current knowledge of chondrogenesis with particular emphasis on the cellular and molecular aspects. [source] Skeletal elements in the vertebrate eye and adnexa: Morphological and developmental perspectivesDEVELOPMENTAL DYNAMICS, Issue 5 2006Tamara A. Franz-Odendaal Abstract Although poorly appreciated, the vertebrate eye and adnexa are relatively common sites for skeletogenesis. In many taxa, the skeleton contributes to internal reinforcement in addition to the external housing of the eye (e.g., the circumorbital bones and eyelids). Eyeball elements such as scleral cartilage and scleral ossicles are present within a broad diversity of vertebrates, albeit not therian mammals, and have been used as important models for the study of condensations and epithelial,mesenchymal interactions. In contrast, other elements invested within the eye or its close surroundings remain largely unexplored. The onset and mode of development of these skeletal elements are often variable (early versus late; involving chondrogenesis, osteogenesis, or both), and most (if not all) of these elements appear to share a common neural crest origin. This review discusses the development and distribution of the skeletal elements within and associated with the developing eye and comments on homology of the elements where these are questionable. Developmental Dynamics 235:1244,1255, 2006. © 2006 Wiley-Liss, Inc. [source] Occurrence and distribution of sesamoid bones in squamates: a comparative approachACTA ZOOLOGICA, Issue 3 2010Adriana Jerez Abstract Jerez, A., Mangione, S. and Abdala, V. 2010. Occurrence and distribution of sesamoid bones in squamates: a comparative approach.,Acta Zoologica (Stockholm) 91: 295,305 Sesamoids are defined as skeletal elements that develop within a continuous band of regular dense connective tissue (tendon or ligament) adjacent to an articulation or joint. In this work, we discuss developmental data on two squamate species, provide data on the onset of the squamate sesamoids and the muscles they are associated to. Our results show that Mabuya mabouya and Liolaemus albiceps exhibited rather similar ontogenetic patterns and that the first sesamoids appear in embryos. The ossifying sesamoid timing is different between M. mabouya and L. albiceps, being faster in the former. In adults, we found 41 sesamoids, considering both fore and hindlimbs. We did not find any intrataxonomic differences, or any differences between the right and left side of the specimens in relation to the sesamoid presence. We recognize four types of sesamoids: (1) embedded sesamoids; (2) interosseus sesamoids; (3) glide sesamoids; and (4) supporting sesamoids. A table is included with a preliminary survey of the sesamoid distribution pattern in 10 Squamate clades. [source] The earliest evidence of host,parasite interactions in vertebratesACTA ZOOLOGICA, Issue 2009evics, ns Luk Abstract Traces of parasite action have been discovered in the Middle,Upper Devonian fish from Estonia, Latvia and European Russia. Such traces are known in heterostracan Psammolepis venyukovi, antiarchs Asterolepis radiata and Bothriolepis ciecere, sarcopterygians Holoptychius sp., Ventalepis ketleriensis and Eusthenodon sp. nov. The traces include evidence of parasitic fixation and penetration as well as dwelling traces. Pathologies are developed as (1) round fossulae on the external surface of bones and scales; (2) oval fossulae with a slight elevation in the centre of the pit; (3) hollow swellings (possible galls); (4) openings (perforations) that have been repaired to various degrees; (5) variously shaped buttresses on the visceral surface of sarcopterygian scales; and (6) porous spongy formations on the non-overlapped surface of sarcopterygian scales. The round fossulae in sarcopterygian, placoderm and psammosteid skeletal elements could be produced by parasites that are similar to copepod crustaceans. Gall formation in Asterolepis is most likely to be caused by a larva, possibly of a trematode. The perforations of scales (and dermal bones) might arise from the attacks of ectoparasites (copepods?) or different worms. The spongy formations on the Holoptychius scales could be the result of invasion of a unicellular parasite. [source] Bite marks as evidence of predation in early vertebratesACTA ZOOLOGICA, Issue 2009Oleg 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] Appendicular skeleton in Bachia bicolor (Squamata: Gymnophthalmidae): osteology, limb reduction and postnatal skeletal ontogenyACTA ZOOLOGICA, Issue 1 2009Adriana Jerez Abstract The osteology of the appendicular skeleton and its postnatal development are described in Bachia bicolor, a serpentiform lizard with reduced limbs. The pectoral girdle is well developed and the forelimb consists of a humerus, ulna, radius, five carpal elements (ulnare, radiale, distal carpals 4,3, centrale), four metacarpals (II, III, IV, V) and phalanges (phalangeal formula X-2-2-2-2). In the hindlimb, the femur is small and slender, and articulates distally with a series of ossified amorphous and extremely reduced elements that correspond to a fibula, tibia and proximal and distal tarsals 4 and 3. The pelvic girdle consists of ischium, pubis and ilium, but its two halves are widely separated; the ilium is the least reduced element. We describe the ossification and development during postnatal skeletal ontogeny, especially of epiphyseal secondary centres, ossifications of carpal elements, apophyseal ossifications and sesamoids. Compared to other squamates, B. bicolor shows an overall reduction in limb size, an absence of skeletal elements, a fusion of carpal elements, an early differentiation of apophyseal centres, and a low number of sesamoids and apophyseal centres. These observations suggest that the reductions are produced by heterochronic changes during postnatal development and probably during embryonic development; therefore the appendicular skeleton exhibits a pattern of paedomorphic features. [source] The late Pleistocene horned crocodile Voay robustus (Grandidier & Vaillant, 1872) from Madagascar in the Museum für Naturkunde BerlinFOSSIL RECORD-MITTEILUNGEN AUS DEM MUSEUM FUER NATURKUNDE, Issue 1 2009Constanze Bickelmann Abstract Crocodylian material from late Pleistocene localities around Antsirabe, Madagascar, stored in the collection of the Museum für Naturkunde, Berlin, was surveyed. Several skeletal elements, including skull bones, vertebrae, ribs, osteoderms, and limb bones from at least three large individuals could be unambiguously assigned to the genus Voay Brochu, 2007. Furthermore, the simultaneous occurrence of Voay robustus Grandidier & Vaillant, 1872 and Crocodylus niloticus Laurenti, 1768 in Madagascar is discussed. Voay robustus and Crocodylus niloticus are systematically separate but similar in stature and size, which would make them direct rivals for ecological resources. Our hypothesis on the extinction of the species Voay, which was endemic to Madagascar, suggests that C. niloticus invaded Madagascar only after V. robustus became extinct. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Diagnostic osteology and analysis of the Mid- to Late Holocene dynamics of shags and cormorants in Tierra del FuegoINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 2 2007D. Causey Abstract We present here illustrated characteristics and anatomical descriptions of features that can be used to discriminate between four common skeletal elements (i.e. humerus, coracoid, femur, tarsometatarsus) of the five species of shags and cormorants known to occur in southern South America. We also present a detailed study of their distribution and abundance from about 6000 years before present to historical times as revealed by identification of faunal material excavated earlier and by re-analysis of material published previously. Our results present a high-resolution examination of the avian resource base used by early human hunters, and provide a foundation for future studies on the palaeoavifauna of Tierra del Fuego during the Mid- to Late Holocene. On the broadest scales, species diversity of the Phalacrocoracidae is qualitatively stable over space and time, a pattern that is also reflected in the larger marine bird community. On a finer scale, however, our results indicate that the abundance and distribution of cormorants and shags in Mid- and Late Holocene zooarchaeological deposits varied in a complex manner through time. These patterns do not appear to be related to proximity effects of hunters to colonies, but to other factors possibly associated with environmental change. Copyright © 2006 John Wiley & Sons, Ltd. [source] Analysis and interpretation of flint toolmarks found on bones from West Tump long barrow, GloucestershireINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 1 2004M. J. Smith Abstract West Tump is a Neolithic chambered tomb originally excavated in 1880. The mound was found to contain a mixed skeletal assemblage, the majority of which was disarticulated. Between 2000 and 2001 material from the site including human bone was re-examined with a portion of this project focused on taphonomic evidence observed on the human skeletal material. Amongst the factors selected for investigation were deliberate toolmarks. Three specimens were identified as exhibiting toolmarks. Analysis demonstrated that the observed features were cutmarks, consistent with the use of flint tools. However those on two of the specimens were found to be both post-mortem and recent. The cutmarks observed on the remaining specimen, a right clavicle, were identified as having been inflicted during the peri-mortem period and consistent with decapitation. British Neolithic mortuary practice has been the subject of ongoing debate since the earliest excavations of relevant sites, but until very recently few assemblages from such contexts have been re-examined and much of the data in use has derived from sources of considerable age and questionable reliability. The selective removal of specific skeletal elements (particularly skulls) has repeatedly been described in the literature regarding the collective funerary monuments of this period. It has often been assumed that such practices took place after the soft tissues had decayed. One of the examples discussed, suggests this may not always have been the case and the potential significance of this finding is discussed in addition to a possible interpretation of the cutmarks seen on the remaining specimens. Copyright © 2004 John Wiley & Sons, Ltd. [source] Molecular systematics of the speciose Indo-Pacific soft coral genus, Sinularia (Anthozoa: Octocorallia)INVERTEBRATE BIOLOGY, Issue 4 2009Catherine S. McFadden Abstract. The speciose tropical soft coral genus Sinularia traditionally has been divided into five intrageneric taxonomic groups based on variation in a single morphological character: the shape of the club sclerites (calcite skeletal elements) embedded in the surface tissues of the colony. To test the phylogenetic utility of this system of classification, we used a 735-bp fragment of the octocoral-specific mitochondrial msh1 gene to construct a molecular phylogeny that included 80 of the ,150 recognized morphospecies of Sinularia. The msh1 phylogeny recovered five well-supported clades, but they were not congruent with the traditional intrageneric taxonomic groups. Mapping of characters onto the tree suggested that the five major clades plus several additional sub-clades of Sinularia can be distinguished based on a suite of four morphological characters; these include the presence of sclerites in the tentacle, collaret, and point regions of the polyps, in addition to the shape of the club sclerites in the surface tissues. The overall growth form of the colony also distinguishes some clades. Polyp sclerites have for the most part been overlooked taxonomically in Sinularia, and as a result information on these characters is lacking or is incorrect in many species descriptions. As has been the case in other recent studies of lower metazoan groups, construction of a molecular phylogeny has led us to recognize the phylogenetic and taxonomic importance of previously overlooked morphological characters. A revised taxonomic key that includes these characters is already improving our ability to discriminate species boundaries, and facilitating description of new Sinularia species. [source] Comments on the mechanism of attachment in species of the monogenean genus GyrodactylusINVERTEBRATE BIOLOGY, Issue 1 2003Andrew P. Shinn Abstract. In species of the monogenean helminth Gyrodactylus, the opisthaptor is the main organ of attachment to the host. The opisthaptor comprises two large centrally positioned hooks or hamuli and sixteen peripherally distributed marginal hooks. This paper describes the functional morphology and the mechanism and sequence of attachment in this species. Information on the attachment process was gathered from observations of live gyrodactylids, from transmission electron microscopy, from scanning electron microscopy of skeletal elements, and by histochemical and X-ray elemental analysis of hook chemical composition. The marginal hooks provide the principal force of attachment whilst the hamuli are not actively employed in the process of attachment. Instead, the hamuli provide a system preventing accidental dislodgement and assist the action of the marginal hooks. Attachment is achieved by the alternating action of two systems of muscles attached respectively to the hamuli and to the marginal hooks. Relaxation or contraction of the muscles connected to the hamuli manoeuvres the hamuli over the extremities of the accessory ventral bar and allows them to pivot around their longitudinal axis, effectively raising or lowering the opisthaptoral dome. Under reduced opisthaptoral tension, the independent gaffing activity of the marginal hooks ensures a secure attachment to the host's epidermis. Repositioning of the hamuli then raises the opisthaptoral dome to tension the peripheral marginal hooks. The sequence of attachment is complete when all the muscles associated with the hooks are in a state of relaxation but are held securely and under tension by the surrounding, stretched, opisthaptoral dome. [source] Habitual use of the primate forelimb is reflected in the material properties of subchondral bone in the distal radiusJOURNAL OF ANATOMY, Issue 6 2006Kristian J. Carlson Abstract Bone mineral density is directly proportional to compressive strength, which affords an opportunity to estimate in vivo joint load history from the subchondral cortical plate of articular surfaces in isolated skeletal elements. Subchondral bone experiencing greater compressive loads should be of relatively greater density than subchondral bone experiencing less compressive loading. Distribution of the densest areas, either concentrated or diffuse, also may be influenced by the extent of habitual compressive loading. We evaluated subchondral bone in the distal radius of several primates whose locomotion could be characterized in one of three general ways (quadrupedal, suspensory or bipedal), each exemplifying a different manner of habitual forelimb loading (i.e. compression, tension or non-weight-bearing, respectively). We employed computed tomography osteoabsorptiometry (CT-OAM) to acquire optical densities from which false-colour maps were constructed. The false-colour maps were used to evaluate patterns in subchondral density (i.e. apparent density). Suspensory apes and bipedal humans had both smaller percentage areas and less well-defined concentrations of regions of high apparent density relative to quadrupedal primates. Quadrupedal primates exhibited a positive allometric effect of articular surface size on high-density area, whereas suspensory primates exhibited an isometric effect and bipedal humans exhibited no significant relationship between the two. A significant difference between groups characterized by predominantly compressive forelimb loading regimes vs. tensile or non-weight-bearing regimes indicates that subchondral apparent density in the distal radial articular surface distinguishes modes of habitually supporting of body mass. [source] The development and evolution of the pharyngeal archesJOURNAL OF ANATOMY, Issue 1-2 2001ANTHONY GRAHAM abstract A muscularised pharynx, with skeletal support, serving the dual functions of feeding and respiration, is a fundamental vertebrate characteristic. Embryologically, the pharyngeal apparatus has its origin in a series of bulges that form on the lateral surface of the embryonic head, the pharyngeal arches, whose development is complex. These structures are composed of a number of disparate embryonic cell types: ectoderm, endoderm, neural crest and mesoderm, whose development must be coordinated to generate the functional adult apparatus. In the past, most studies have emphasised the role played by the neural crest, which generates the skeletal elements of the arches, in directing pharyngeal arch development, but it has also become apparent that the endoderm plays a prominent role in directing arch development. Neural crest cells are not required for arch formation, their regionalisation nor to some extent their sense of identity. Furthermore, the endoderm is the major site of expression of a number of important signalling molecules, and this tissue has been shown to be responsible for promoting the formation of particular components of the arches. Thus vertebrate pharyngeal morphogenesis can now be seen to be a more complex process than was previously believed, and must result from an integration of both neural crest and endodermal patterning mechanisms. Interestingly, this also mirrors the fact that the evolutionary origin of pharyngeal segmentation predates that of the neural crest, which is an exclusively vertebrate characteristic. As such, the evolution of the vertebrate pharynx is also likely to have resulted from an integration between these 2 patterning systems. Alterations in the interplay between neural crest and endodermal patterning are also likely to be responsible for the evolutionary that occurred to the pharyngeal region during subsequent vertebrate evolution. [source] Effect of rearing techniques on skeletal deformities and osteological development in red porgy Pagrus pagrus (Linnaeus, 1758) larvaeJOURNAL OF APPLIED ICHTHYOLOGY, Issue 2 2010J. Roo Summary Red porgy is a candidate species for marine aquaculture diversification. The objective of the present study was to describe the osteological development in this species and the occurrence of skeletal deformities in relation to the intensification of the rearing system. Fish samples were periodically collected along the development from hatching to juveniles (95 days after hatching). Osteological development and the presence of skeleton abnormalities were evaluated. Larvae reared under S-IS showed a better growth in terms of total length in comparison with IS reared ones. Regarding to osteological development for red porgy, this was similar between fish from both culture systems, but differing in timing of apparition and ossification of skeletal elements. X-ray studies revealed a high number of fish with skeletal deformities (Semi-intensive: 38.8%; Intensive: 46.5%), but no significant effect of the rearing technique on the incidence of deformities such as lordosis or fused vertebrae was found. However, cranial abnormalities and kyphosis incidences were significantly higher in intensive system cultured red porgy. These results, suggest a relationship among rearing technique, osteological development and the apparition of certain deformities. [source] Targeted Expression of SHH Affects Chondrocyte Differentiation, Growth Plate Organization, and Sox9 Expression,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2004Sara Tavella Abstract The role of Hedgehogs (Hh) in murine skeletal development was studied by overexpressing human Sonic Hedgehog (SHH) in chondrocytes of transgenic mice using the collagen II promoter/enhancer. Overexpression caused a lethal craniorachischisis with major alterations in long bones because of defects in chondrocyte differentiation. Introduction: Hedgehogs (Hhs) are a family of secreted polypeptides that play important roles in vertebrate development, controlling many critical steps of cell differentiation and patterning. Skeletal development is affected in many different ways by Hhs. Genetic defects and anomalies of Hhs signaling pathways cause severe abnormalities in the appendicular, axial, and cranial skeleton in man and other vertebrates. Materials and Methods: Genetic manipulation of mouse embryos was used to study in vivo the function of SHH in skeletal development. By DNA microinjection into pronuclei of fertilized oocytes, we have generated transgenic mice that express SHH specifically in chondrocytes using the cartilage-specific collagen II promoter/enhancer. Transgenic skeletal development was studied at different embryonic stages by histology. The expression pattern of specific chondrocyte molecules was studied by immunohistochemistry and in situ hybridization. Results: Transgenic mice died at birth with severe craniorachischisis and other skeletal defects in ribs, sternum, and long bones. Detailed analysis of long bones showed that chondrocyte differentiation was blocked at prehypertrophic stages, hindering endochondral ossification and trabecular bone formation, with specific defects in different limb segments. The growth plate was highly disorganized in the tibia and was completely absent in the femur and humerus, leading to skeletal elements entirely made of cartilage surrounded by a thin layer of bone. In this cartilage, chondrocytes maintained a columnar organization that was perpendicular to the bone longitudinal axis and directed toward its outer surface. The expression of SHH receptor, Patched-1 (Ptc1), was greatly increased in all cartilage, as well as the expression of parathyroid hormone-related protein (PTHrP) at the articular surface; while the expression of Indian Hedgehog (Ihh), another member of Hh family that controls the rate of chondrocyte maturation, was greatly reduced and restricted to the displaced chondrocyte columns. Transgenic mice also revealed the ability of SHH to upregulate the expression of Sox9, a major transcription factor implicated in chondrocyte-specific gene expression, in vivo and in vitro, acting through the proximal 6.8-kb-long Sox9 promoter. Conclusion: Transgenic mice show that continuous expression of SHH in chondrocytes interferes with cell differentiation and growth plate organization and induces high levels and diffuse expression of Sox9 in cartilaginous bones. [source] Estimation of Age-at-Death for Adult Males Using the Acetabulum, Applied to Four Western European Populations,JOURNAL OF FORENSIC SCIENCES, Issue 4 2007Carme Rissech Ph.D. Abstract:, Methods to estimate adult age from observations of skeletal elements are not very accurate and motivate the development of better methods. In this article, we test recently published method based on the acetabulum and Bayesian inference, developed using Coimbra collection (Portugal). In this study, to evaluate its utility in other populations, this methodology was applied to 394 specimens from four different documented Western European collections. Four strategies of analysis to estimate age were outlined: (a) each series separately; (b) on Lisbon collection, taken as a reference Coimbra collection; (c) on Barcelona collection, taken as a reference both Portuguese collections; and (d) on London collection taken as reference the three Iberian collections combined. Results indicate that estimates are accurate (83,100%). As might be expected, the least accurate estimates were obtained when the most distant collection was used as a reference. Observations of the fused acetabulum can be used to make accurate estimates of age for adults of any age, with less accurate estimates when a more distant reference collection is used. [source] LYSTROSAURUS MURRAYI (THERAPSIDA, DICYNODONTIA): BONE HISTOLOGY, GROWTH AND LIFESTYLE ADAPTATIONSPALAEONTOLOGY, Issue 6 2005SANGHAMITRA RAY Abstract:, Examination of the bone microstructure of Lystrosaurus murrayi from India and South Africa reveals a predominance of fibrolamellar bone tissue, which suggests rapid periosteal osteogenesis and an overall fast growth. Four distinct ontogenetic stages have been identified based on tissue type, organization of the primary osteons, incidence of growth rings, secondary reconstruction and endosteal bone deposition. An indeterminate growth strategy is proposed for Lystrosaurus. Inter-elemental histovariability suggests differential growth rate of the skeletal elements within the same individual, and among different individuals. The high cortical thickness of the dorsal ribs, an extensive secondary reconstruction in the cortical region of different skeletal elements that resulted in erosionally enlarged channels from the perimedullary to the midcortical region, and trabecular infilling of the medullary region even in the diaphyseal sections of the limb bones suggest at least a semi-aquatic lifestyle for L. murrayi. [source] Lumbar ontogenetic growth and sexual dimorphism in modern humansAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 5 2010Elías Valverde To detect and differentiate between possible heterochronic processes in the ontogenetic growth pattern of the human lumbar region, in relationship with sexual dimorphism. We measured the growth trajectories of average length and width, length/width ratio, posterior projected surface area, and bone mineral density using dual energy X-ray absorptiometry, in a sample group of 1718 modern humans. These growth patterns were analyzed using the Gompertz model. In adult lumbar region, only surface area and width were significantly higher in men. Regarding the ontogenetic growth pattern leading to the dimorphic states, all values obtained for women were significantly higher than those obtained for men. Maximum initial growth rates occurred for surface area and density in women. Width scaled faster than length in both sexes. The lumbar region followed patterns similar to those of other skeletal elements when compared with a previous classification of growth patterns in the human skeleton; however, in this study, the growth rate was slower. With regard to the effect of dimorphism, sexual differences in growth rate accounted for only a small proportion of the variation in lumbar length, mineral density, and surface area. Nevertheless, these sexual differences played an important role in the increase of the length/width ratio, which was reflected in the ages at which sexual dimorphism developed. The sexual dimorphism found in the lumbar region of human adults is not caused by any heterochronic process. The lower values of bone mineral density in adult women could explain the origin of some pathologies related. Am. J. Hum. Biol. 22:596,603, 2010. © 2010 Wiley-Liss, Inc. [source] Stature estimation in an early medieval (XI-XII c.) Polish population: Testing the accuracy of regression equations in a bioarcheological sampleAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2009Giuseppe Vercellotti Abstract Accurate stature estimation from skeletal remains can foster useful information on health and microevolutionary trends in past human populations. Stature can be estimated through the anatomical method and regression equations. The anatomical method (Fully: Ann Med Leg 36 [1956] 266,273; Raxter et al.: Am J Phys Anthropol 130 [2006] 374,384) is preferable because it takes into account total skeletal height and thus provides more accurate estimates, but it cannot be applied to incomplete remains. In such circumstances, regression equations allow estimates of living stature from the length of one or few skeletal elements. However, the accuracy of stature estimates from regression equations depends on similarity in body proportions between the population under examination and those used to calibrate the equations. Since genetic affinity and body proportions similarity are not always clearly known in bioarcheological populations, the criteria for selection of appropriate formulae are not always straightforward. This may lead to inaccurate stature estimates and imprecise accounts of past life conditions. Prompted by such practical and theoretical concerns this study aimed at (1) estimating living stature in an early medieval (XI-XII c.) Polish sample (40 male; 20 female) through the anatomical method and developing population-specific regression formulae; and (2) evaluating the accuracy of estimates obtained with regression methods commonly employed in European populations. Results indicate that when applied to the skeletal remains from Giecz, our formulae provide accurate estimates, with non-age-corrected formulae performing better than age-corrected ones. Our formulae provide better estimates than those calibrated on recent populations and their use in medieval Polish populations is preferable. Am J Phys Anthropol, 2009. © 2009 Wiley-Liss, Inc. [source] The petrous bone,A new sampling site for identifying early dietary patterns in stable isotopic studiesAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2009Marie Louise S. Jørkov Abstract Intraskeletal variation in the composition of carbon (,13C) and nitrogen (,15N) stable isotopes measured in collagen is tested from various human bones and dentine. Samples were taken from the femur, rib, and petrous part of the temporal bone from well-preserved skeletons of both adults (n = 34) and subadults (n = 24). Additional samples of dentine from the root of 1st molars were taken from 16 individuals. The skeletal material is from a medieval cemetery (AD 1200,1573) in Holbæk, Denmark. Our results indicate that the petrous bone has an isotopic signal that differs significantly from that of femur and rib within the single skeleton (P < 0.001 and P < 0.001, respectively), with only minor variation seen between femur and rib. On the other hand, there was no significant difference between the petrous bone and the 1st molar. The intraskeletal variation may reflect differences in turnover rate among skeletal elements. The inner periosteal layer of the petrous bone is formed in uterus and does not undergo any further remodelling after the age of 2 years, whereas the rib and femur have a continuous turnover rate of ,5 and 10,20 years, respectively. From the results of this study it is believed the petrous bone may be a new useful bone element and a supplement or a proxy for teeth in the analysis of early dietary patterns as it may reflect diet in fetal stages and early years of life. Am J Phys Anthropol 2009. © 2008 Wiley-Liss, Inc. [source] Robusticity and sexual dimorphism in the postcranium of modern hunter-gatherers from AustraliaAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2007Kristian J. Carlson Abstract Throughout much of prehistory, humans practiced a hunting and gathering subsistence strategy. Elevated postcranial robusticity and sexually dimorphic mobility patterns are presumed consequences of this strategy, in which males are attributed greater robusticity and mobility than females. Much of the basis for these trends originates from populations where skeletal correlates of activity patterns are known (e.g., cross-sectional geometric properties of long bones), but in which activity patterns are inferred using evidence such as archaeological records (e.g., Pleistocene Europe). Australian hunter-gatherers provide an opportunity to critically assess these ideas since ethnographic documentation of their activity patterns is available. We address the following questions: do skeletal indicators of Australian hunter-gatherers express elevated postcranial robusticity and sexually dimorphic mobility relative to populations from similar latitudes, and do ethnographic accounts support these findings. Using computed tomography, cross-sectional images were obtained from 149 skeletal elements including humeri, radii, ulnae, femora, and tibiae. Cross-sectional geometric properties were calculated from image data and standardized for body size. Australian hunter-gatherers often have reduced robusticity at femoral and humeral midshafts relative to forager (Khoi-San), agricultural/industrialized (Zulu), and industrialized (African American) groups. Australian hunter-gatherers display more sexual dimorphism in upper limb robusticity than lower limb robusticity. Attributing specific behavioral causes to upper limb sexual dimorphism is premature, although ethnographic accounts support sex-specific differences in tool use. Virtually absent sexual dimorphism in lower limb robusticity is consistent with ethnographic accounts of equivalently high mobility among females and males. Thus, elevated postcranial robusticity and sexually dimorphic mobility do not always characterize hunter-gatherers. Am J Phys Anthropol, 2007. © 2007 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||||||||