The First Record of a Pleuromya Species from Lower Cenomanian of Bouarif (Batna, Northeast, Algeria): Systematics and Palaeoenvironmental Significance

This research reports the first record of a pleuromyid from Cenomanian of the Aures domain in Northeastern Algeria. Consequently, a new order, Pholadomyoida Newell, is added to the nine others previously described in the Batna region. This order is represented by the species Pleuromya servesensis Choffat, recorded in the upper part of lower Cenomanian of Smail Marls Formation at Bouarif, in the Batna range. Its occurrence corresponds to the Mantelliceras dixoni Zone. Distinct morphological characters, such as a rather elongated and inflated shell, slightly prosogyrate, and large umbones, in addition to well-developed large and widely spaced concentric ribs, facilitate its identification. This species exhibits a close affinity to the same species found in South America and India. Palaeoenvironmental factors influencing its occurrence can be summarized as moderately deep, cold waters with low energy and soft substrate. Additionally, the direction of water currents appears to have played an important role in the distribution of pleuromyids across different regions of the world.