94 research outputs found

    Woodland in a fluvio-lacustrine environment on the dry Mongolian Plateau during the late Paleocene: Evidence from the mammal bearing Subeng section (Inner Mongolia, PR China)

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    In the understanding of the global faunal turnover during the Paleocene-Eocene transition, an important role has been attributed to the Asian continent, although the Asian fossil record for this period is still incomplete. Here we present a multidisciplinary study of the Subeng section (Inner Mongolia, P.R. China), integrating sedimentological, stratigraphical and diverse palaeontological data, in order to reconstruct the palaeoenvironment and to enhance the understanding of the late Paleocene communities that once thrived on the Mongolian Plateau. The Subeng section starts with the Maastrichtian Iren Dabasu Formation directly covered by the late Paleocene Nomogen Formation. This Nomogen Formation is composed of typical lacustrine deposits at the base, covered by fluvio-lacustrine deposits at the top. Both types of deposits provided rich ostracod and charophyte assemblages, closest to those of the Naran Member, Naran Bulak Formation of Mongolia. Palynomorphs from the lake sediments suggest a local flora at Subeng more wooded and closed than reported from elsewhere in this region. The fluvio-lacustrine deposits of the Nomogen Formation have yielded a vertebrate fauna especially rich in mammals. The mammal fauna from Subeng is close to that from Bayan Ulan and typical for the Gashatan Asian Land Mammal Age. The presence of reworked pedogenic carbonate nodules and mud aggregates suggests an at least seasonally dry regional climate. Combined sedimentological and palaeontological data suggest the late Paleocene Nomogen Formation at Subeng was an isolated woodland in a fluvio-lacustrine environment, representing a locally humid environment on the semi-arid Mongolian Plateau. The mammal fauna reflects these differences and shows a number of relatives to mammals from the more humid northeastern Chinese biotic province as well as some North American immigrants. © 2006 Elsevier B.V. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

    First Evidence of Reproductive Adaptation to “Island Effect” of a Dwarf Cretaceous Romanian Titanosaur, with Embryonic Integument In Ovo

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    <div><h3>Background</h3><p>The Cretaceous vertebrate assemblages of Romania are famous for geographically endemic dwarfed dinosaur taxa. We report the first complete egg clutches of a dwarf lithostrotian titanosaur, from Toteşti, Romania, and its reproductive adaptation to the “island effect”.</p> <h3>Methodology/Findings</h3><p>The egg clutches were discovered in sequential sedimentary layers of the Maastrichtian Sânpetru Formation, Toteşti. The occurrence of 11 homogenous clutches in successive strata suggests philopatry by the same dinosaur species, which laid clutches averaging four ∼12 cm diameters eggs. The eggs and eggshells display numerous characters shared with the positively identified material from egg-bearing level 4 of the Auca Mahuevo (Patagonia, Argentina) nemegtosaurid lithostrotian nesting site. Microscopic embryonic integument with bacterial evidences was recovered in one egg. The millimeter-size embryonic integument displays micron size dermal papillae implying an early embryological stage at the time of death, likely corresponding to early organogenesis before the skeleton formation.</p> <h3>Conclusions/Significance</h3><p>The shared oological characters between the Haţeg specimens and their mainland relatives suggest a highly conservative reproductive template, while the nest decrease in egg numbers per clutch may reflect an adaptive trait to a smaller body size due to the “island effect”. The combined presence of the lithostrotian egg and its embryo in the Early Cretaceous Gobi coupled with the oological similarities between the Haţeg and Auca Mahuevo oological material evidence that several titanosaur species migrated from Gondwana through the Haţeg Island before or during the Aptian/Albian. It also suggests that this island might have had episodic land bridges with the rest of the European archipelago and Asia deep into the Cretaceous.</p> </div

    Plan of the Cities and Suburbs of Philadelphia

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    New lissamphibians and squamates from the Maastrichtian of Hateg Basin, Romania

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    Numerous remains of amphibians and squamates were discovered in the continental sediments of the Maastrichtian Sânpetru Formation, south of Pui Village (Haţeg Basin, western Romania). The lissamphibians are represented by a salamander−like allocaudatan (Albanerpeton sp.) and at least two discoglossid frogs (cf. Eodiscoglossussp. and cf. Paradiscoglossussp.). The numerous lizards are represented by, e.g., the teiid Bicuspidon hatzegiensissp. nov., and for the first time in a Late Cretaceous site, by two species of the paramacellodid Becklesius (Becklesius nopcsai sp. nov. and Becklesius cf. B. hoffstetteri). Snakes are also present in this site by an indeterminante madtsoiid, which represents the first occurrence of this family in eastern Europe. The presence of Albanerpeton in this site confirms that this genus appeared in Europe by at least the Late Cretaceous instead of Miocene as previously thought. The presence of both Albanerpeton and Bicuspidon in Haţeg Basin suggests a North American influence on eastern European amphibian and lacertilian faunas by Maastrichtian times
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