The marine vertebrate faunas from the Late Cretaceous phosphates of Syria

Abstract

Marine vertebrate faunas from the latest Cretaceous phosphates of the Palmyrides Chain of Syria are described for the first time. Recent fieldwork in the phosphatic deposits of the Palmyra area (mines of Charquieh and Khneifiss, outcrops of Bardeh, Soukkari and Soukhneh) have yielded a rich and diversified assemblage of marine vertebrates, including more than 50 species of chondrichthyes, osteichthyes, squamates, chelonians, plesiosaurians and crocodilians. Selachians are the most abundant and diverse component of the faunas and are represented by at least 34 species of both sharks and rays. Actinopterygians include representatives of six families, the most common being the enchodontids. Squamates are known by six mosasaurid species and an indeterminate varanoid. Chelonians are represented by at least two bothremydids and two chelonioids. Finally, elasmosaurid plesiosaurs and indeterminate crocodilians are also present in the fossil assemblages. The difference in faunal composition observed between the sites is interpreted as being due to palaeoecological preferences related to the Hamad Uplift palaeostructure. The marine vertebrate faunas of Syria show close affinities with those of the latest Cretaceous phosphatic deposits of North Africa and the Middle East and are typical of the southern Tethyan realm. From a biostratigraphical point of view, the selachians are the only suitable material to provide elements of an answer to the long debated question of the age of the Syrian Senonian phosphates. They suggest an Early Maastrichtian age for most of the phosphates of the Palmyrides Chain.