10 research outputs found
First Evidence of Reproductive Adaptation to âIsland Effectâ of a Dwarf Cretaceous Romanian Titanosaur, with Embryonic Integument In Ovo
<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 ToteĹti, Romania, and its reproductive adaptation to the âisland effectâ.</p> <h3>Methodology/Findings</h3><p>The egg clutches were discovered in sequential sedimentary layers of the Maastrichtian Sânpetru Formation, ToteĹti. The occurrence of 11 homogenous clutches in successive strata suggests philopatry by the same dinosaur species, which laid clutches averaging four âź12 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 HaĹŁeg 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 âisland effectâ. The combined presence of the lithostrotian egg and its embryo in the Early Cretaceous Gobi coupled with the oological similarities between the HaĹŁeg and Auca Mahuevo oological material evidence that several titanosaur species migrated from Gondwana through the HaĹŁeg 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
Lower Cretaceous Provenance and Sedimentary Deposition in the Eastern Carpathians: Inferences for the Evolution of the Subducted Oceanic Domain and its European Passive Continental Margin
Reconstructing orogenic systems made up dominantly by sediments accreted in trenches is challenging because of the incomplete lithological record of the subducted oceanic domain and its attached passive continental margin thrusted by collisional processes. In this respect, the remarkable similar to 600 km long continuity of sediments exposed in the Eastern Carpathian thin-skinned thrust and fold belt and the availability of quantitative reconstructions for adjacent continental units provide excellent conditions for a paleogeographical study by provenance and sedimentological techniques constraining sediment routing and depositional systems. These sediments were deposited in the Ceahlau-Severin branch of the Alpine Tethys Ocean and over its European passive continental margin. We report sedimentological, paleomagnetic, petrographic, and detrital zircon U-Pb data of Lower Cretaceous sediments from several thin-skinned tectonic units presumably deposited in the Moldavides domain of the Eastern Carpathians. Sedimentological observations in the innermost studied unit demonstrate that deposition took place in a deepwater basin floor sheets to sandy turbidite system. Detrital zircon age data demonstrate sourcing from internal Carpathian basement units. The sediment routing changes in more external units, where black shales basin floor sheets to sandy mud turbidites were sourced from an external, European continental area. Although some degree of mixing between sources located on both margins of the ocean occurred, constraining a relatively narrow width of the deep oceanic basin, these results demonstrate that the internal-most studied unit was deposited near an Early Cretaceous accretionary wedge, located on the opposite internal side relative to the passive continental margin domain of other Moldavides units.6 month embargo; first published: 20 April 2020This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Nature and significance of a Cambro-Ordovician high-K, calc-alkaline sub-volcanic suite: The late- to post-orogenic Motru Dyke Swarm (Southern Carpathians, Romania)
SCOPUS: ar.jinfo:eu-repo/semantics/publishe