1,721,052 research outputs found
Posadia feroniensis n. gen., n. sp. (Lituolida, Hormosinidae) from the Bathonian of Sardinia, Italy
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Bathyal large lituolids from the Thanetian of northeastern Italy and their extinction at the Paleocene/Eocene boundary
No full textSeveral large agglutinated foraminifera resembling the genus Navarella Ciry & Rat (1951), were recently recovered in middle-lower bathyal Thanetian hemipelagites from the Belluno Basin, northeastern Italy. These navarellids first appear in the basal Thanetian and become quite common in the >500 μm washed residue from the uppermost Thanetian. They abruptly disappear at the Paleocene/Eocene boundary, in coincidence with the extinction of Paleocene cosmopolitan taxa (Benthic Foraminiferal Extinction Event).
Navarella is a large lituolid belonging to the family Ammobaculinidae Saidova 1981 and attaining a maximum length of 5 mm, with a first streptospirally enrolled test, later uncoiled, and with an aperture varying during ontogeny from slit-like to cribrate. The genus was originally described from the Maastrichtian flysch of the Spanish Pyrenees, and then reported elsewhere in Europe from Campanian to Maastrichtian rocks. The validity of this taxon and its range distribution is, however, controversial and strongly debated.
In order to document the internal chamber arrangement and the agglutinated wall microstructure of the Thanetian navarellids and to compare them with similar individuals recovered from the Upper Cretaceous and Danian strata of the same section, the collected specimens were sectioned and analysed using a Scanning Electron Microscope (SEM), equipped with an energy-dispersive X-ray spectrometer (EDX). Our results show a typical bi-layered wall microstructure in the Thanetian specimens, whereas the older Maastrichtian and Danian specimens display a single, thicker agglutinated wall. The taxonomy of the Italian navarellids is discussed and compared with other Navarella-like taxa known in the literature.
Based on available data, we infer that bi-layered navarellids, which are morphologically identical to Maastrichtian-Danian specimens but that differ in their internal microstructure, appeared and developed in the Thanetian but they were eventually driven to extinction during the environmental perturbations associated to the Paleocene-Eocene Thermal Maximum.
We also argue how the finding of new and well-preserved material from the Paleocene Scaglia Rossa beds of Italy may help shed light on both taxonomy and ecological preferences of the still poorly known deep-water lituolids
Remarks on the Early-Middle Eocene biomagnetochronology based on planktic foraminiferal evidences from the Tethyan successions of northeastern Italy
No full textAlveolina postalensis n. sp. (Foraminiferida, Alveolinidae) from the upper Ypresian of Monte Postale and Pesciara di Bolca (Northern Italy).
No full textA new species of the genus Alveolina, Alveolina postalensis n. sp., is herein described from the Monte Postale and Pesciara di Bolca sites (northern Italy). Our biometric data allow us to distinguish this species from the related Alveolina croatica Drobne, 1977, A. levantina Hottinger, 1960, and A. hottingeri Drobne, 1977. We hypothesise that Alveolina postalensis n. sp. could be the ancestor of A. croatica and that A. postalensis n. sp. and A. levantina could share a common ancestor. Based on the larger foraminiferal assemblage co-occurring with the new taxon, we can ascribe Alveolina postalensis n. sp. to the SB11 Zone (middle Cuisian, upper Ypresian, lower Eocene)
New insights on Anthracotherium monsvialense De Zigno, 1888 (Mammalia, Cetartiodactyla) from the lower Oligocene of Monteviale (Vicenza, northeastern Italy)
Full text linkIn Italy, anthracotheres are represented by a few fossils, most of them described during the XIX century and without a standardized scientific method. Anthracotherium monsvialense De Zigno, 1888 was originally
erected from a fossil discovered in the site of Monteviale (Vicenza, northeastern Italy), whose Rupelian (MP21) lignitic beds yielded the richest lower Oligocene evidence of the genus Anthracotherium in Europe. A. monsvialense ranges from MP21 to MP23 and its small size has been interpreted as a consequence of the insular environment, at least at Monteviale. In this study, we summarize the long history of Italian findings providing new descriptions of dental and postcranial morphological features of A. monsvialense, and comparing such small anthracothere with its Asian and European relatives. Morphometric analyses are also performed on teeth, in order to verify the presence of evolutionary trends of the genus Anthracotherium
Early-Middle Eocene Hyperthermals from the Tethyan Possagno section, Southern Alps, Italy
No full textA Tethyan planktonic foraminiferal and stable carbon isotope record of the Early Eocene Climatic optimum (Possagno section of northeastern Italy).
No full textA new cuspidate ptychodontid shark (Chondrichthyes; Elasmobranchii), from the Upper Cretaceous of Morocco with comments on tooth functionalities and replacement patterns
Full text linkThe first articulated dentition of †Ptychodus from Africa is described herein. The specimen, likely coming from the Turonian of the Asfla area (Goulmima region, southeastern Morocco), exhibits a well-preserved lower dental plate of a second-level predator. A new species, †P. maghrebianus sp. nov., is erected herein based on this durophagous dentition characterised by imbricated cuspidate teeth. We employed for the first time in †Ptychodus multiple quantitative analyses and statistical parametric and non-parametric tests to process biometrical data taken from articulated, associated and isolated teeth. The quantitative approach (morphospace analysis) is exploited herein to support the traditional taxonomic identification (qualitative examination) of †P. maghrebianus sp. nov. and to separate it from the similar cuspidate species, †P. mortoni. Morphospace reconstructions confirm a marked lower dental heterodonty (mesio-distal patterns) for both species. The analysis protocol employed here also allows assigning indeterminate teeth as belonging to †P. mortoni. The reconstruction of the entire lower dental plate of †P. maghrebianus sp. nov. shows a cuspidate dentition probably able to reduce tooth damages when crushing thin-shelled prey. Both dental morphologies and tooth wear patterns suggest a peculiar food processing and a diet mainly consisting of bivalves, decapods and small fish for this durophagous predator. Trophic reconstructions of the Turonian ichthyofauna inhabiting the middle to outer ramp environment of the Asfla area emphasize that †P. maghrebianus sp. nov. and the batoid †Tingitanius most likely represented second-level consumers, whereas the sclerorhynchiforms †Asflapristis and †Ptychotrygon represented third-level predators. Top positions within the food web were occupied by larger predaceous elasmobranchs (e.g., †Squalicorax)
Tethyan planktic foraminiferal record of the early Eocene hyperthermal events ETM2, H2 and I1 (Terche section, northeasternItaly)
No full textThe Terche section, located in the Venetian Prealps of northeastern Italy, is an expanded upper Paleocene-lower Eocene succession deposited in a bathyal setting of a continental margin of the central-western Tethys. This section contains three well-exposed and expanded marly-clay units (MUs) corresponding to intervals of negative carbon isotope excursions (CIEs). Calcareous plankton biostratigraphy allow us to correlate them to hyperthermal events ETM2 (or H1;~ 53.7 Ma), H2 (~ 53.6 Ma) and I1(~ 53.3 Ma). We present the response of planktic foraminfieral assemblages to these early Eocene events
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