The Late Cretaceous is an important interval in African biogeographical history, during which time the continent became isolated from the rest of Gondwana1 . Africa has played a critical role in discussions of the timing and order of Gondwanan break-up1 , and an understanding of intra- and intercontinental relationships of African taxa is central to elucidating patterns of continental fragmentation and palaeobiogeography, and recognizing possible dispersal routes or barriers2. However, the Late Cretaceous terrestrial vertebrate fossil of Africa is very sparse and poorly sampled3, hampering our understanding of large scale patterns.
The only way to rectify this situation is to find, describe and interpret the affinities and relationships of new fossil specimens. New sauropod dinosaur cervical vertebrae representing a single individual were recently acquired by the Natural History Museum, London (NHMUK PV R36834), from a previously unexplored Late Cretaceous locality in the Midelt Province of Morocco. Nearly all previous Cretaceous sauropod remains from Morocco come from the mid-Cretaceous Kem Kem beds3 , and thus stratigraphically younger specimens from a different area will provide crucial new information. Sauropod dinosaurs were a major Mesozoic radiation of gigantic herbivorous dinosaurs and included the largest known terrestrial animals. Their evolutionary history is reasonably well understood, with the main remaining gap in our knowledge pertaining to their mid–Late Cretaceous radiation, which is especially compounded by poor sampling of southern continents. Sauropods are also an ideal group to explore palaeobiogeographic patterns in that they were globally distributed, but also entirely restricted to terrestrial life, meaning that dispersal routes would need to be distinct land bridges. As such, these new vertebrae add an important data point for understanding sauropod evolution, but will also augment our knowledge in the wider context of Gondwanan palaeobiogeography.
This project will produce a detailed description of these vertebrae that will ultimately lead to a publication. Sauropod vertebrae have numerous external laminae (bony ridges) and fossae. Although this means that the anatomy of such elements can be complex (hence the student will need time to familiarize themselves with sauropod vertebral anatomy), importantly it means that it also provide a wealth of phylogenetic information, aiding the taxonomic identification of the Moroccan remains. In addition to being described and figured in detail, NHMUK PV R36834 will be compared with cervical vertebrae from other Cretaceous sauropods. These comparisons will include the few taxa with overlapping remains from Africa (i.e. Malawisaurus and Rukwatitan) and Madagascar (Rapetosaurus), but also taxa from elsewhere around the world, including making use of unpublished data compiled by PDM from specimens in southern continents, i.e. from Argentina and Australia.
As well as producing a description, this work will also place the new vertebrae in a phylogenetic context, incorporating them into a data matrix developed by PDM, which will be analyzed using the freely available program TNT v. 1.1. Even though the incorporation of highly incomplete specimens into a phylogenetic analysis is likely to produce a poorly resolved tree, taxon pruning methods will enable the position of NHMUK PV R36834 to be refined.
These approaches will enable the taxonomic affinities of NHMUK PV R36834 to be determined, and for it to be placed within both a regional and global context, adding an important new data point to our understanding of sauropod dinosaur evolution and Gondwanan palaeobiogeography in the Late Cretaceous.
Although all supervision of the student will be handled by PDM, Paul Barrett at the Natural History Museum London will facilitate collections access to the specimens under study. No specialist equipment at the museum is required.
1Upchurch P. 2008. Gondwanan break-up: legacies of a lost world? Trends in Ecology and Evolution 23: 229–236.
2Gheerbrant E, Rage J.-C. 2006. Paleobiogeography of Africa: How distinct from Gondwana and Laurasia? Palaeogeography, Palaeoclimatology, Palaeoecology 241: 224–246.
3Mannion PD, Barrett PM. 2013. Additions to the sauropod dinosaur fauna of the Cenomanian (early Late Cretaceous) Kem Kem beds of Morocco: palaeobiogeographical implications of the mid-Cretaceous African sauropod fossil record. Cretaceous Research 45: 49–59.