Early Cretaceous Dinosaurs from the Sahara

Abstract

A major question in Mesozoic biogeography is how the land-based dinosaurian radiation responded to fragmentation of Pangaea. A rich fossil record has been uncovered on northern continents that spans the Cretaceous, when continental isolation reached its peak. In contrast, dinosaur remains on southern continents are scarce. The discovery of dinosaurian skeletons from Lower Cretaceous beds in the southern Sahara shows that several lineages of tetanuran theropods and broad-toothed sauropods had a cosmopolitan distribution across Pangaea before the onset of continental fragmentation. The distinct dinosaurian faunas of Africa, South America, and Asiamerica arose during the Cretaceous by differential survival of once widespread lineages on land masses that were becoming increasingly isolated from one another.

Theropod teeth from the Middle-Upper Jurassic Shishugou Formation of northwest Xinjiang, China

“…The maxilla of Megalosauridae shows ten to 14 maxillary alveoli (SOM 2: Table 1), and an exact tooth count is known in Dubreuillosaurus and Megalosaurus which both have 13 maxillary teeth (Allain 2002;Benson 2010a), and Afrovenator which bears 14 teeth (Sereno et al 1994). In megalosaurid dentaries, the typical condition is 13 to 15 teeth (SOM 2: Table 1), and a complete dentary with 13 teeth is only known in Dubreuillosaurus (Allain 2002).…”

“…Material.-We examined and collected morphometric data on the dentition of all representatives of each megalosaurid genus sensu Carrano et al (2012) preserving teeth, i.e., Eustreptospondylus oxoniensis (Walker 1964), Magnosaurus nethercombensis (Huene 1923), Afrovenator abakensis (Sereno et al 1994), Dubreuillosaurus valesdunensis (Allain 2002), Duriavenator hesperis (Waldman 1974), Megalosaurus bucklandii (Mantell 1827), Torvosaurus tanneri (Galton and Jensen 1979), and the newly named Torvosaurus gurneyi (Hendrickx and Mateus 2014b; see SOM 6 in Supplementary Online Material available at http://app.pan.pl/SOM/app60-Hendrickx_etal_SOM.pdf).…”

An Early Cretaceous vertebrate assemblage from the Cabao Formation of NW Libya

“…Earlier sites of the 'Continental Intercalaire' (a name suggested by Kilian in 1931 to designate the Palaeozoic and Mesozoic continental levels located between the latest marine Palaeozoic rocks and the Cenomanian transgression across the Sahara desert) in Niger (Taquet, 1976;Sereno et al 1994), Mali (O' Leary et al 2004), Algeria and several other places (see Rauhut & Lopez-Arbello, 2009 for a recent review) are still extremely poorly dated because of the absence of marine incursions during the early Cretaceous in these areas. Other Early Cretaceous sites have been recognized in Tunisia (Bouaziz et al 1988;Benton et al 2000;D.…”

A new sauropod dinosaur from the Early Cretaceous of Tunisia with extreme avian-like pneumatization

“…C retaceous dinosaurs of the peri-Mediterranean regions are the subject of an increasing number of studies focusing on some of the most important and debated topics in vertebrate palaeontology, inter alia Cretaceous biogeography and insular faunas, biodiversity, timing of radiation of groups and phylogenetic relationships among Gondwanan dinosaur clades with respect to their European counterparts [1][2][3][4][5][6][7][8][9][10][11] . In addition, Mediterranean dinosaur remains, particularly northern African specimens, are important for understanding some of the most extreme Cretaceous ecosystems.…”