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Poor Preservation (poor + preservation)
Selected AbstractsFossil fruits of Salsola L. s.l. and Halanthium K.Koch (Chenopodiaceae) from Lower Pleistocene lacustrine sediments in Armenia,FEDDES REPERTORIUM, Issue 3-4 2008Janna Akopian Dr. For the first time imprints of fossil fruits of Salsola L. s.l. and Halanthium K.Koch (Chenopodiaceae, Salsoloideae,) are reported from the territory of Armenia, the latter being the first fossil record of the Southwest Asian genus worldwide. They were collected from fluvio-lacustrine diatomite layers of the Lower Pleistocene (Sisian series) in the upper-middle Vorotan river valley recently dated at 1.4,0.935 my (Early Pleistocene). The fossils are described, figured and compared with recent relatives. Due to poor preservation, the identity of the Salsola fruit cannot be specified but the similar genus Kochia can be excluded. The Halanthium fruit seems to differ from those of extant species. Both are also discussed in the context of the very poor fossil Salsoloideae record and of the actual and lower Pleistocene vegetation and environment. The findings of truly semidesert species underline the presence of open landscapes and extremely semiarid to arid conditions. However, stratigraphically more refined analyses are needed to draw conclusions about the former vegetation and the duration of arid periods because most macrofossils reported from the same strata indicate semiarid and even humid environments. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Fossile Früchte von Salsola L. und Halanthium K.Koch (Chenopodiaceae) aus unterpleistozänen lakustrischen Sedimenten in Armenien Erstmals wird über Funde fossiler Früchte der Gattungen Salsola L. s.l. und Halanthium K.Koch (Chenopodiaceae, Salsoloideae) aus Armenien berichtet. Für die letztere Gattung handelt es sich weltweit um einen Erstfund. Die nur mäßig guten Abdrucke stammen aus fluvio-lakustrischen Diatomiten der Sisian Serie vom oberen Vorotan-Tal, die nach neuesten Datierungen 1,4,0,935 Millionen Jahre alt sind und damit in das Unterpleistozän gehören. Die Fossilien werden beschrieben, abgebildet und mit den nächsten rezenten Verwandten verglichen. Während bei der Salsola -Frucht wegen Beschädigungen vor der Einbettung keine Artbestimmung möglich ist, die Zugehörigkeit zu Kochia aber ausgeschlossen werden kann, stimmt die besser erhaltene Halanthium- Frucht mit keiner rezenten Art überein. Beide Arten werden im Zusammenhang mit dem bisher äußerst spärlichen Fossilbefund und im Hinblick auf ihren möglichen ökologischen und vegetationskundlichen Indikatorwert diskutiert. Die Nachweise dieser Halbwüstenpflanzen sprechen für eine waldfreie Umgebung und ein extremsemiarides oder arides Klima zur Zeit der Einbettung. Die gleichen Schichten enthalten aber vor allem Makrofossilien mesophytischer Gehölze, die an ein semiarides bis humides Klima gebunden sind. Weitergehende Rückschlüsse sind erst dann möglich, wenn eine feinstratigraphische Analyse vorliegt, durch die größere klimatische Fluktuationen nachgewiesen werden könnten. [source] An Ordovician age for the Muggort's Bay Lower Palaeozoic inlier, County Waterford, Ireland,the southernmost exposure of the Irish CaledonidesGEOLOGICAL JOURNAL, Issue 5 2005P. M. Brück Abstract The most southerly exposed Lower Palaeozoic strata in Ireland occur on the southwest coast of County Waterford along a 2.5,km long coastal section at Muggort's Bay where they are surrounded by Devonian rocks. Five formations can be distinguished which, in ascending order, are: the Ballycurreen, Carrickbrean, Rathnameenagh, Moanbrack and Killinoorin formations. The total thickness of the succession is over 1800,m. No macrofossils are present, but the lithologies are largely fine-grained turbidites and subordinate volcanic rocks which closely resemble the Ribband Group seen elsewhere in southeast Ireland and have previously therefore been classified with it. Palynological analysis was undertaken on 25 samples collected from Muggort's Bay, of which eight were productive. Diagnostic microfossils, comprising acritarchs, chitinozoans and scolecodonts, indicate an Early to Middle Ordovician age for both the Rathnameenagh and the Moanbrack formations. These ages confirm that the strata are part of the Ribband Group which elsewhere has been biostratigraphically dated as ranging from Mid-Cambrian to Mid-Ordovician. Reworked mid-Middle Cambrian acritarchs occur in the Moanbrack Formation and reworked late Middle to early Late Cambrian acritarchs in the Rathnameenagh Formation. Despite generally poor preservation of the organic matter, some 20 acritarch species have been distinguished. Among these, three species belong to the herein revised genus Retisphaeridium for which an emended diagnosis is proposed together with two new combinations, Retisphaeridium capsulatum (Jankauskas, 1976) Vanguestaine nov. comb. and Retisphaeridium pusillum (Moczydlowska, 1998) Vanguestaine nov. comb. Copyright © 2005 John Wiley & Sons, Ltd. [source] Roman Period fetal skeletons from the East Cemetery (Kellis 2) of Kellis, EgyptINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 5 2005M. W. Tocheri Abstract Much can be learned about the religious ideology and mortuary patterns as well as the demographic and health profiles of a population from archaeological human fetal skeletons. Fetal skeletons are rare, however, largely due to poor preservation and recovery, misidentification, or non-inclusion in general burial populations. We present an analysis of 82 fetal/perinatal skeletons recovered from Kellis 2, a Roman Period cemetery dated to the third and fourth centuries AD, located in the Dakhleh Oasis, Egypt. Most of the fetal remains were individually wrapped in linen and all were buried among the general cemetery population in a supine, east,west orientation with the head facing to the west. Gestational age estimates are calculated from diaphysis lengths using published regression and Bayesian methods. The overall similarity between the fetal age distributions calculated from the regression and Bayesian methods suggests that the correlation between diaphysis length and gestational age is typically strong enough to avoid the ,regression' problem of having the age structure of reference samples adversely affecting the age distribution of target samples. The inherent bias of the regression methods, however, is primarily reflected in the gestational age categories between 36 and 42 weeks corresponding with the expected increase in growth variation during the late third trimester. The results suggest that the fetal age distribution at Kellis 2 does not differ from the natural expected mortality distribution. Therefore, practices such as infanticide can be ruled out as having a significant effect on the observed mortality distribution. Moreover, the Kellis 2 sample is well represented in each gestational age category, suggesting that all premature stillbirths and neonatal deaths received similar burial rites. The age distribution of the Kellis 2 fetal remains suggests that emerging Christian concepts, such as the ,soul' and the ,afterlife', were being applied to everyone including fetuses of all gestational ages. Copyright © 2005 John Wiley & Sons, Ltd. [source] A simple and economical method for the manual construction of frozen tissue arraysAPMIS, Issue 10 2010SHU-CHUAN TSAO Tsao S-C, Wu C-C, Wen C-H, Huang Y-C, Chai C-Y. A simple and economical method for the manual construction of frozen tissue arrays. APMIS 2010; 118: 739,43. Tissue microarray has been developed to enable multiple cores of tissue in one or more new paraffin blocks. Currently, almost all tissue microarrays are made by coring cylindrical tissues from formalin-fixed and paraffin-embedded tissues. The disadvantages of formalin-fixed and paraffin-embedded tissues include the poor preservation of antigenicity of certain proteins and mRNA degradation induced by the fixation and embedding process. However, frozen tissue array construction presents technical difficulties, and tissue array devices are expensive, particularly for small- and medium-sized laboratories. We describe a simple manual method for producing well-aligned tissue arrays by a capsule freeze method that allows us to successfully perform hematoxylin,eosin and immunohistochemical stain. All 120 tissue samples were collected and constructed into blocks by this capsule freeze method. The capsules were not affected during the sectioning process, and the capsule material always disappeared during the aqueous steps of the stain processing. The frozen tissue arrays were smoothly sectioned without the use of a tape transfer system and immunohistochemical study was performed with satisfactory results. This alternative method can be applied in any laboratory, and is both simple and economical. [source] A critical reappraisal of the fossil record of the bilaterian phylaBIOLOGICAL REVIEWS, Issue 2 2000GRAHAM E. BUDD ABSTRACT It has long been assumed that the extant bilaterian phyla generally have their origin in the Cambrian explosion, when they appear in an essentially modern form. Both these assumptions are questionable. A strict application of stem- and crown-group concepts to phyla shows that although the branching points of many clades may have occurred in the Early Cambrian or before, the appearance of the modern body plans was in most cases later: very few bilaterian phyla sensu stricto have demonstrable representatives in the earliest Cambrian. Given that the early branching points of major clades is an inevitable result of the geometry of clade diversification, the alleged phenomenon of phyla appearing early and remaining morphologically static is seen not to require particular explanation. Confusion in the definition of a phylum has thus led to attempts to explain (especially from a developmental perspective) a feature that is partly inevitable, partly illusory. We critically discuss models for Proterozoic diversification based on small body size, limited developmental capacity and poor preservation and cryptic habits, and show that the prospect of lineage diversification occurring early in the Proterozoic can be seen to be unlikely on grounds of both parsimony and functional morphology. Indeed, the combination of the body and trace fossil record demonstrates a progressive diversification through the end of the Proterozoic well into the Cambrian and beyond, a picture consistent with body plans being assembled during this time. Body-plan characters are likely to have been acquired monophyletically in the history of the bilaterians, and a model explaining the diversity in just one of them, the coelom, is presented. This analysis points to the requirement for a careful application of systematic methodology before explanations are sought for alleged patterns of constraint and flexibility. [source] Early Jurassic Coleopterans from the Mintaja Insect Locality, Western AustraliaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 4 2010Sarah K. MARTIN Abstract: Beetles (Coleoptera) are the most common insects recovered from the Lower Jurassic Mintaja insect locality of Western Australia, with over half of the fossils recorded from this site being isolated coleopteran elytra. A range of partial beetle bodies and other isolated beetle sclerites have also been recovered from the locality; much of this material is taxonomically unidentifiable due to its disarticulation and poor preservation. A number of the Mintaja coleopterans are assigned to the archostematan family Ommatidae, including Zygadenia westraliensis (Riek, 1968) comb. nov, previously placed in the morphogenus Mesothoris, and an unnamed species of Tetraphalerus. Also recorded is a new species of elaterid, Lithomerus wunda sp. nov., along with other fragments likely attributable to the same family. The remaining material is assigned into morphospecies, separated primarily on preserved body parts , specifically, there are three morphospecies based on partially articulated coleopteran bodies, two morphospecies based on isolated head capsules, three morphospecies based on isolated thoracic sclerites, three morphospecies based on isolated abdominal sclerites, and 13 morphospecies based on isolated elytra. Overall, the ecology of these fossils is difficult to interpret due to poor preservation, although some of the beetles were likely aquatic, and the Ommatidae and Elateridae were both likely xylophilous. There is a strong similarity between the Mintaja coleopterans and those from the Late Triassic Denmark Hill locality of Queensland, though many of these similarities are based on morphotaxa and may be superficial in nature. Of the species that have been assigned to named taxa, all are generally typical of the Late Mesozoic worldwide, with Zygadenia, Tetraphalerus and Lithomerus all long-ranging, cosmopolitan genera. [source] | |||||||||||||