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MARIA E. MCNAMARA PATRICK J. ORR TOM MANZOCCHI LUIS ALCALÁ PERE ANADÓN ENRIQUE PEÑALVER 《Lethaia: An International Journal of Palaeontology and Stratigraphy》2012,45(2):210-226
McNamara, M.E., Orr, P.J., Manzocchi, T., Alcalá, L., Anadón, P. & Peñalver, E. 2011: Biological controls upon the physical taphonomy of exceptionally preserved salamanders from the Miocene of Rubielos de Mora, northeast Spain. Lethaia, Vol. 45, pp. 210–226. The middle Miocene Rubielos de Mora Konservat‐Lagerstätte of northeast Spain is hosted within profundal, finely laminated, lacustrine mudstones. The diverse biota includes abundant salamanders. Most individuals died during separate episodes and sank rapidly postmortem. Specimens are typically preserved in dorso‐ventral aspect, the most hydrodynamically stable orientation. The near‐cylindrical morphology of the body, however, allowed some carcasses to settle in or subsequently re‐orientate into, lateral orientations. Loss of skeletal elements (i.e. reduced completeness) reflects their location within the body and followed a distal to proximal trend. Two stages are identified: initial loss of a small number of phalanges, followed by loss of more proximal limb bones plus additional phalanges. Disarticulation is more complex: it occurred via several mechanisms (notably, abdominal rupture and re‐orientation of part of the body and limbs during decay) and shows no consistent pattern among specimens. The physical taphonomy of the salamanders is controlled predominantly by intrinsic biological factors, i.e. the geometry of the body and of individual skeletal elements, the orientation, inherent strength and location of specific joints and the extent to which soft tissues, particularly the skin, persist during decay. These biological factors probably control patterns of physical taphonomy of other fossil tetrapods with a similar skeletal configuration. □Articulation, completeness, Konservat‐Lagerstätten, orientation, quantitative taphonomy, salamanders. 相似文献
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WOUTER HOLLEMAN SOPHIE VON DER HEYDEN GUIDO ZSILAVECZ 《Zoological Journal of the Linnean Society》2012,166(4):827-853
The Clinus superciliosus complex comprises six closely related species. Three of the species were originally recognized by Gilchrist and Thompson as two distinct species, Clinus superciliosus (Linnaeus, 1758) and Clinus ornatus Gilchrist & Thompson, 1908, and a variety, Clinus superciliosus var. arborescens Gilchrist & Thompson, 1908. A number of other authors described various similar species, which subsequently were all synonymized with Clinus superciliosus. A further species, Clinus spatulatus Bennett, 1983, an obligate estuarine dweller, is known only from the Bot, Kleinmond, and Klein river estuaries in the Western Cape, South Africa. Two further species, Clinus musaicus sp. nov. (discovered while searching for C. ornatus specimens) and Clinus exasperatus sp. nov. , are herein described: the first is currently known from False Bay and the west coast of the Cape Peninsula, whereas the second species is known from only two specimens just east of False Bay. Clinus ornatus and Clinus arborescens Gilchrist & Thompson, 1908 are recognized as a valid species, and can be distinguished from C. superciliosus and C. spatulatus on the basis of meristic values, form of the orbital cirrus, position of the dorsal‐fin crest, taste bud number and pattern, diet, and coloration. All extant types of C. superciliosus are examined as specimens, or photographs and radiographs, and their validity and identification are assessed. Genetic analysis of mitochondrial and nuclear DNA supports species differentiation. A key is provided for the species complex. Furthermore, the variable coloration of four of the species, probably related to the substrate the larvae settle upon, and the increase in the number of vertebrae, and fin‐ray and spine number, with decreasing water temperature is discussed. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society 2012, 166 , 827–853. 相似文献
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Background: This article describes the types of community‐wide benefits provided by investigators conducting public health research in South Asia as well as their self‐reported reasons for providing such benefits. Methods: We conducted 52 in‐depth interviews to explore how public health investigators in low‐resource settings make decisions about the delivery of ancillary care to research subjects. In 39 of the interviews respondents described providing benefits to members of the community in which they conducted their study. We returned to our narrative dataset to find answers to two questions: What types of community‐wide benefits do researchers provide when conducting public health intervention studies in the community setting, and what reasons do researchers give when asked why they provided community‐wide benefits? Findings: The types of community‐wide benefits delivered were directed to the health and well‐being of the population. The most common types of benefits delivered were the facilitation of access to health care for individuals in acute medical need and emergency response to natural disasters. Respondents' self‐reported reasons when asked why they provided such benefits fell into 2 general categories: intrinsic importance and instrumental importance. 相似文献
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GARY M. KOEHLER BENJAMIN T. MALETZKE JEFF A. VON KIENAST KEITH B. AUBRY ROBERT B. WIELGUS ROBERT H. NANEY 《The Journal of wildlife management》2008,72(7):1518-1524
Abstract Lynx (Lynx canadensis) occur in the northern counties of Washington state, USA; however, current distribution and status of lynx in Washington is poorly understood. During winters 2002–2004 we snow-tracked lynx for 155 km within a 211-km2 area in northern Washington, to develop a model of lynx-habitat relationships that we could use to assess their potential distribution and status in the state. We recorded movements and behaviors of lynx with a Global Positioning System and overlaid digitized lynx trails on various habitat layers using a Geographic Information System. Based on univariate analyses, lynx preferred Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) forests, with moderate canopy and understory cover, and elevations ranging from 1,525 m to 1,829 m but avoided Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa) forests, openings, recent burns, open canopy and understory cover, and steep slopes. A map of suitable lynx habitat based on a logistic regression model built using these candidate variables revealed that habitats at elevations >1,400 m where lynx historically occurred in Washington are intersected and fragmented by landscape features and forest conditions that are generally avoided by lynx. Our habitat suitability map predicts 3,800 km2 of lynx habitat in Washington that could support 87 lynx, far fewer than previous estimates. Since 1985, natural fires have burned >1,000 km2 of forested habitat in Okanogan County, the only region in Washington where lynx occurrence has been documented during that period. Loss of suitable habitat from natural and human-caused disturbances, and the lack of verifiable evidence of lynx occurrence in historic lynx range, suggests that fragmented landscape conditions may have impeded recolonization of these areas by lynx. Consequently, translocations may be necessary to ensure lynx persistence in Washington. We suggest that managers assess the potential for translocation by first identifying the scale and distribution of potential foraging habitats for lynx based on our or similar habitat models, survey various habitat conditions to obtain reliable estimates of snowshoe hare densities, and identify a genetically compatible source population of lynx. If habitat and source populations are adequate, reintroducing lynx to areas of their historic range may be an appropriate conservation strategy. 相似文献
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FERNANDO MENDONÇA D'HORTA JOSÉ MARIA CARDOSO DA SILVA CAMILA CHEREM RIBAS 《Biological journal of the Linnean Society. Linnean Society of London》2008,95(3):583-597
One of the best examples of differentiation and hybridization among South American passerine birds is exhibited by Icterus cayanensis (Epaulet Oriole) and Icterus chrysocephalus (Moriche Oriole). Icterus chrysocephalus is a monotypic species restricted to northern South America. Icterus cayanensis is a polytypc species that ranges from Suriname and French Guyana to northern Argentina. Five subspecies are recognized to I. cayanensis. Hybrid zones are known between I. cayanensis and I. chrysocephalus as well as between subspecies of I. cayanenis, even though character variation has never been adequately assessed and mapped. Although molecular data support the hypothesis that I. cayanensis and I. chrysocephalus form a monophyletic group, they do not support the species limits currently recognized within this group. We analysed the geographic variation of plumage characters along the range of this group to map the geographic variation of individual plumage characters and identify the populations that have uniform phenotypic character expression and therefore represent genuine phylogenetic species. We also used molecular data to investigate the phylogenetic relationships among these species. Geographic variation of plumage characters, habitat preferences and molecular data identified four species within I. cayanensis–chrysocephalus clade: an Amazonian species group, formed by I. cayanensis and I. chrysocephalus and a Southern species group composed of I. pyrrhopterus and I. tibialis. The Amazonian species are separated by a relatively narrow hybrid zone along the Amazon valley, whereas the Southern species are separated by a hybrid zone that is larger than the ranges of the two species individually. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 583–597. 相似文献