The Cenomanian Bahariya Formation of the Bahariya Oasis in the Egyptian Western Desert preserves one of the richest Afro-Arabian early Late Cretaceous (~98 Ma) vertebrate faunas yet discovered. This fauna includes a diversity of cartilaginous and bony fishes, plesiosaurs, squamates, turtles, crocodyliforms, and non-avian dinosaurs. The Bahariya Formation has yielded the type specimens of the non-avian theropods Spinosaurus, Carcharodontosaurus, Bahariasaurus, the titanosaurian sauropods Paralititan and Aegyptosaurus, and the crocodyliforms Libycosuchus, Stomatosuchus, and Aegyptosuchus. Regrettably, most of the Egyptian archosaur collection was destroyed during World War II in the Allied bombing of Munich in April 1944. Since then, additional paleontological efforts have endeavored to rediscover the Bahariya vertebrate fauna. Over the course of the last decade, paleontological fieldwork carried out by researchers from the Mansoura University Vertebrate Paleontology Center (MUVP) resulted in the re-identification of previously known localities and several new vertebrate fossil localities within the Bahariya Formation. New fossils recovered from this unit include those of cartilaginous and bony fishes, plesiosaurs, squamates, turtles, crocodyliforms, pterosaurs, and non-avian dinosaurs. Here we focus on the description of recently recovered fossils referable to Pterosauria and Crocodyliformes. MUVP 507, an isolated, three-dimensionally preserved left first wing phalanx (= left manual phalanx IV-1), belongs to a medium-sized pterosaur and compares favorably with the equivalent element in ornithocheirid pterosaurs in general and exhibits anhanguerid affinities specifically. The fused and ossified proximal extensor tendon process (ETP) indicates that the individual in question was osteologically mature. The ETP of the specimen is comparable in overall morphology with that in anhanguerids, including the presence of a subrectangular extensor tubercle, the position of the prominent pneumatic foramen and the small nutrient foramina, the expanded curvature of the dorsal cotyle, the thin bony wall, and the posterior flare of the proximal articulation. Moreover, the specimen differs morphologically from the first wing phalanx of penecontemporaneous azhdarchoids, in which the extensor tubercle is subtriangular and the dorsal cotyle is only weakly curved. The presence of Ornithocheiridae in the lower Cenomanian Bahariya Formation represents the first record of this family from Egypt and adds to mounting evidence of high taxonomic diversity of the group in the Upper Cretaceous of northern Africa. MUVP 523, an isolated, well-preserved partial right dentary, shows affinities with those of other Upper Cretaceous Peirosauridae from Madagascar and South America, such as Miadanasuchus and Barrosasuchus. Phylogenetic analysis recovers the Bahariya form within Peirosauridae, in a clade including Miadanasuchus and Barrosasuchus. Characters in support of this affiliation include: (1) shape of dentary symphysis in ventral view is U-shaped and smoothly curving anteriorly, (2) distinct anteroposteriorly elongate shallow concavity situated lateral to the 5th–10th teeth on the lateral surface of the dentary to receive an enlarged maxillary tooth, (3) lack of posterior peg at the posterior edge of the mandibular symphysis. MUVP 523 therefore represents the first peirosaurid fossil from Egypt and northeastern Africa more generally. The new peirosaurid specimen from Egypt demonstrates the wide geographic distribution of Peirosauridae across North Africa during the middle Cretaceous and augments the already extraordinarily diverse crocodyliform assemblage of the Bahariya Formation, a record that also includes representatives of Ziphosuchia, Stomatosuchidae, and Aegyptosuchidae. These new discoveries add to the already rich and diverse fossil record of the Bahariya Formation. The presence of a medium-sized peirosaurid crocodyliform and an ornithocheirid pterosaur in the lower Cenomanian Bahariya Formation represents the first record of these families from Egypt, highlighting the high taxonomic diversity of these groups in northern Africa during the Upper Cretaceous. These findings provide valuable insights into the evolution and biogeography of these archosaurs during the Upper Cretaceous. |
