Jurassic belemnites represent promising proxies especially for palaeoecological and also palaeobiogeographical reconstructions. However, basic knowledge on taxonomic composition, biostratigraphy and diversity of Early Jurassic belemnites is still dramatically low, especially for France. The present study provides new data on belemnites from the southern part of the Northwest European Province. More than 700 specimens have been collected along the Tournadous section in the Causses Basin (Southern France); they represent ten genera and 30 species belonging to Hastitidae, Megateuthididae, Passaloteuthididae, and Salpingoteuthididae. Furthermore, numerous ammonites have been collected, allowing to establish a standard chronostratigraphical scheme of the studied section and thus to assign, for the first time, a precise chronostratigraphical distribution to the Early Jurassic belemnites of Southern France. The analysis of belemnite diversity and its variations along the section compared to the well-known fauna of the northern part of the Northwest European province (Germany and England) open interesting prospective for belemnites palaeobiogeography.
14 October 2020 in Carnets de géologie (Notebooks on geology)
Nowadays, the living species of the terrapin genus Mauremys (Testudinoidea: Geoemydidae) are mostly found in eastern Asia, but three of them inhabit the Western Palearctic ecozone. In Italy, occurrences of living individuals of Mauremys are interpreted as records of alien species; however, a growing fossil record demonstrates that this genus has inhabited Italy as recently as the Late Pleistocene. We report on a new fossil specimen of Mauremys from the Upper Pliocene (Piacenzian) marginal-marine deposits of Tuscany (central Italy). This find, consisting of a partial plastron and a loose neural, represents the second authentic report of Mauremys from the Italian Pliocene, as well as the first one from the Piacenzian of Italy. Therefore, it is a significant fossil that fills a gap in the chronostratigraphic distribution of Italian fossil Mauremys, helping – together with the Lower Pliocene holotype of Mauremys portisi – to bridge the rich Miocene and Pleistocene segments of this record. Moreover, two unusual scars observed on the external surface of the studied plastron are here referred to the ichnospecies Thatchtelithichnus holmani. These traces represent one of the few records worldwide of this rarely identified ichnospecies, as well as its geologically youngest published occurrence. Hypotheses regarding the origin of the Thatchtelithichnus traces are reevaluated, and an origin as attachment scars of aquatic ectoparasites (possibly ticks, leeches, or flukes) is reaffirmed as probable in cases of traces occurring on the exterior of the plastral bones of turtles.
31 March 2022 in Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen
The present paper deals with the systematic description of the belemnite assemblages from the Lower Jurassic, collected at the Roche Blain quarry, Fresney-le-Puceux. In spite of the reduced thickness of the succession at Fresney-le-Puceux, 13 successive ammonite chronozones could be documented in this rather unique outcrop situation in mainland Europe. Twelve genera and 26 species of belemnites belonging to the Passaloteuthididae, Hastitidae, Megateuthididae, Salpingoteuthididae, and family incertae sedis are described and illustrated herein. The stratigraphical range of the belemnites is correlated with the standard ammonite zonation, using the chronozone concept: the described specimens range from the lower Pliensbachian (Davoei Chronozone) to the uppermost Toarcian (Aalensis Chronozone) while ammonites indicate the Aalenian (Murchisonae Chronozone) to be present too, but these beds delivered no identifiable belemnites so far. The belemnite diversity from Normandy is compared to data from coeval outcrops in Western and Central Europe.
6 August 2020 in International Journal of Ethics Education