A rich decapod fauna from the Early Pleistocene (late Gelasian-early Calabrian) of Poggio i Sodi quarries (Siena, Tuscany, central Italy) is here reported. Integrated biostratigraphical, sedimentological and paleoecological analyses have been carried out, and some paleoenvironmental inferences are also proposed. The studied decapod community is herein assigned to the upper bathyal; several paleoenvironmental factors (cool water conditions at the sea floor, clay soft bottom, nutrients, very low environmental energy and sedimentation rate) influenced and promoted the crustacean settlement.
Razanandrongobe sakalavae
Maganuco, Dal Sasso & Pasini, 2006 is a large predatory archosaur from the Middle Jurassic (Bathonian) of the Mahajanga Basin, NW Madagascar. It was diagnosed on the basis of teeth and a fragmentary maxilla, but its affinities were uncertain. Here we describe new cranial remains (above all, an almost complete right premaxilla and a caudally incomplete left dentary) that greatly improve our knowledge on this enigmatic species and reveal its anatomy to be crocodylomorph. The right premaxilla indicates that the rostrum was deep, wide, and not pointed; it bears five teeth that are sub-vertical and just slightly curved lingually; the mesial teeth are U-shaped in cross-section and have serrated carinae on the lingual side; the aperturae nasi osseae (external bony nares) are confluent and face rostrally; and there is no lateral groove at the premaxillomaxillary suture for reception of a hypertrophied lower caniniform tooth. The preserved portion of the left dentary has an edentulous tip and bears eight large mandibular teeth of which the mesial (1–3) are the largest, but none is a hypertrophied caniniform tooth; the mandibular (dentary) symphysis extends caudally to the level of the third tooth; the splenial is not preserved, but its sutural marks on the dentary indicate that it contributed to the mandibular symphysis for at least 20% of the symphyseal length in dorsal aspect. On the basis of this new data, some previously uncertain features of the holotype maxilla—such as the margin of the suborbital fenestra, the contact surfaces for the palatine, the ectopterygoid, and the jugal—are now apparent. Testing of the phylogenetic position of the species within Crocodylomorpha indicates that R. sakalavae is a mesoeucrocodylian. It also represents one of the earliest events of exacerbated increase in body size along the evolutionary history of the group. In addition, it is by far the oldest notosuchian. A cranial reconstruction of this gigantic predator is also attempted here. The very robust jaw bones of R. sakalavae, coupled with its peculiar dentition, strongly suggest a diet that included hard tissue such as bone and tendon.
We investigate a new decapod macruran discovered in deposits identified at the top of Gara Sbaa slope, located in SE Morocco, along the “Hamada des Kem Kem”, close to the Algerian border. These fossiliferous levels are known in the literature as part of the Late Cretaceous Kem Kem beds. We report the new family Amazighopsidae, created to accommodate Amazighopsis cretacica n. gen., n. sp. Indeed, some morphological characters, such as a short rostrum with the serrate upper margin, cervical and antennal grooves not forming the characteristic W-shaped pattern, the telson without diaeresis, lateral margins of the telson with one movable median spine and two movable distal spines, and the uropodal exopod without diaeresis, are so peculiar and unique to justify the erection of the new family tentatively ascribed to the infraorder Astacidea.
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