Mosasauria

Polcyn, M. J., Jacobs L. L., Schulp A. S., & Mateus O. (2007).  Morphology and systematic position of Angolasaurus bocagei and the evolution of the braincase in Plioplatecarpine mosasaurs. Second Mosasaur Meeting. , May 3-6, 2007, Sternberg Museum, Hays, Kansaspolcyn_et_al_2007_angolosaurus_mosasaurmeetingabstracts.pdf
Strganac, C., Jacobs L., Polcyn M., Mateus O., Myers T., Araújo R., Fergunson K. M., Gonçalves A. O., Morais M. L., Schulp A. S., da Tavares T. S., & Salminen J. (2015).  Geological Setting and Paleoecology of the Upper Cretaceous Bench 19 Marine Vertebrate Bonebed at Bentiaba, Angola. Netherlands Journal of Geosciences. 94(1), 121-136. Abstractstrganac_et_al_2014_geological_setting_bentiaba_angola.pdfWebsite

The Bench 19 Bonebed at Bentiaba, Angola, is a unique concentration of marine vertebrates preserving six species of mosasaurs in sediments best correlated by magnetostratigraphy to chron C32n.1n between 71.4 and 71.64 Ma. The bonebed formed at a paleolatitude near 24°S, with an Atlantic width at that latitude approximating 2700 km, roughly half that of the current width. The locality lies on an uncharacteristically narrow continental shelf near transform faults that controlled the coastal outline of Africa in the formation of the South Atlantic Ocean. Biostratigraphic change through the Bentiaba section indicates that the accumulation occurred in an ecological time dimension within the 240 ky bin delimited by chron 32n.1n. The fauna occurs in a 10 m sand unit in the Mocuio Formation with bones and partial skeletons concentrated in, but not limited to, the basal 1–2 m. The sediment entombing the fossils is an immature feldspathic sand shown by detrital zircon ages to be derived from nearby granitic shield rocks. Specimens do not appear to have a strong preferred orientation and they are not concentrated in a strand line. Stable oxygen isotope analysis of associated bivalve shells indicates a water temperature of 18.5°C. The bonebed is clearly mixed with scattered dinosaur and pterosaur elements in a marine assemblage. Gut contents, scavenging marks and associated shed shark teeth in the Bench 19 Fauna indicate biological association and attrition due to feeding activities. The ecological diversity of mosasaur species is shown by tooth and body-size disparity and by δ13C analysis of tooth enamel, which indicate a variety of foraging areas and dietary niches. The Bench 19 Fauna was formed in arid latitudes along a coastal desert similar to that of modern Namibia on a narrow, tectonically controlled continental shelf, in shallow waters below wave base. The area was used as a foraging ground for diverse species, including molluscivorus Globidens phosphaticus, small species expected near the coast, abundant Prognathodon kianda, which fed on other mosasaurs at Bench 19, and species that may have been transient and opportunistic feeders in the area.

Jacobs, L. L., Mateus O., Polcyn M. J., Schulp A. S., Antunes M. T., Morais M. L., & da Silva Tavares T. (2006).  The occurrence and geological setting of Cretaceous dinosaurs, mosasaurs, plesiosaurs, and turtles from Angola. Paleont. Soc. Korea. 22(1), 91-110. Abstractjacobs_mateus-et_al_2006_angola.pdf

Vertebrate-bearing fossiliferous outcrops of Cretaceous age in sub-Saharan Africa are rare because of younger superficial deposits, vegetation cover, and the widespread occurrence of Precambrian metamorphic plateau basement comprising much of the continent. However, one area of extensive marine and nonmarine
Cretaceous exposures is found between the plateau and the coast in Angola. The Angolan margin was formed in conjunction with the breakup of Gondwana and subsequent growth of the South Atlantic. Cretaceous deposits are constrained in age by the emplacement of oceanic crust, which began no later than magnetozone M3
(approximately 128 Ma, Barremian). Shallow marine facies are exposed in sea cliffs but equivalent facies become increasingly terrestrial inland. Few vertebrate fossils have been described from Angola aside from sharks.
Notable exceptions are the late Turonian mosasaurs Angolasaurus bocagei and Tylosaurus iembeensis from northern Angola. Those taxa are significant because they are among the earliest derived mosasaurs. Recent field work led to the discovery of a new skull of Angolasaursus as well as sharks, fish, plesiosaurs, the skull of a new taxon of turtle, additional mosasaurs, and the articulated forelimb of a sauropod dinosaur, the first reported dinosaur from Angola. In southern Angola, marine sediments spanning the Cretaceous-Paleogene boundary are found.

Polcyn, M. J., Jacobs L. L., Ara´ujo R., Schulp A. S., & Mateus O. (2014).  Physical drivers of mosasaur evolution. Palaeogeography, Palaeoclimatology, Palaeoecology. 400, 17-27. Abstractpolcyn_et_al_2014_physical_drivers_mosasaurs.pdf

Mosasaurs are marine squamates with a 32.5 million-year history from their appearance at 98 Ma to their extinction at the K-Pg boundary (65.5 Ma). Using a database of 43 generic and 94 species-level taxa, we compare the taxonomic diversity and patterns of morphological disparity in mosasaurs with sea level, sea surface temperature, and stable carbon isotope curves for the Upper Cretaceous to explore factors that may have influenced their evolution. No single factor unambiguously accounts for all radiations, diversification, and extinctions; however, the broader patterns of taxonomic diversification and
morphological disparity point to niche differentiation in a “fishing up” scenario under the influence of “bottom-up” selective pressures. The most likely driving force in mosasaur evolution was high productivity in the Late Cretaceous, driven by tectonically controlled sea levels and climatically controlled ocean stratification and nutrient delivery. When productivity collapsed at the end of the Cretaceous, coincident with bolide impact, mosasaurs became extinct.

Schulp, A. S., Polcyn M. J., Mateus O., & Jacobs L. L. (2013).  Two rare mosasaurs from the Maastrichtian of Angola and the Netherlands. Netherlands Journal of Geosciences — Geologie en Mijnbouw. 92(1), 3-10. Abstractschulp_et_al_2013_two_rare_mosasaurs_from_the_maastrichtian_of_angola__njg-92-1-schulp.pdf

We report here the addition of two rare mosasaur taxa to the Maastrichtian marine amniote fauna of Angola. The new specimens include a dentary fragment referable to the large carnivore Prognathodon saturator and an isolated tooth of the small durophage Carinodens belgicus. Both were recovered from Maastrichtian outcrops in southern Angola in 2011. Additionally, a complete posterior mandibular unit of a large mosasaur from the type Maastrichtian of The Netherlands, collected some time prior to 1879 and previously identified as ‘Mosasaurus giganteus’, is described and reassigned here to Prognathodon saturator; historical issues surrounding the taxonomic attribution of this specimen are clarified. The new material extends the known geographic distribution of Prognathodon saturator and Carinodens belgicus.

Mateus, O., Polcyn M. J., Jacobs L. L., Araújo R., Schulp A. S., Marinheiro J., Pereira B., & Vineyard D. (2012).  Cretaceous amniotes from Angola: dinosaurs, pterosaurs, mosasaurs, plesiosaurs, and turtles. V Jornadas Internacionales sobre Paleontología de Dinosaurios y su Entorno. 71-105., Salas de los Infantes, Burgos Abstractmateus_et_al_2012_amniotes_from_angola_cretaceous_amniotes_from_angola_dinosaurs_pterosaurs_mosasaurs.pdf

Although rich in Cretaceous vertebrate fossils, prior to 2005 the amniote fossil record of Angola was poorly known. Two horizons and localities have yielded the majority of the vertebrate fossils collected thus far; the Turonian Itombe Formation of Iembe in Bengo Province and the Maastrichtian Mocuio Formation of Bentiaba in Namibe Province. Amniotes of the Mesozoic of Angola are currently restricted to the Cretaceous and include eucryptodire turtles, plesiosaurs, mosasaurs, pterosaurs, and dinosaurs. Recent collecting efforts have greatly expanded our knowledge of the amniote fauna of Angola and most of the taxa reported here were unknown prior to 2005.

Strganac, C., Ferguson, K.M, Jacobs J. L., Polcyn M. J., & Mateus O. (2012).  Age and paleoecology of mosasaurs and plesiosaurs from the Late Cretaceous South Atlantic margin at Bentiaba, Angola. Journal of Vertebrate Paleontology, Program and Abstracts, 2012. 180.strganac_et_al_mateus_2012_age_bentiaba_angola_2012_svp_abstract.pdf
Schulp, A. S., Polcyn M. J., Mateus O., Jacobs L. L., & Morais M. L. (2008).  A new species of Prognathodon (Squamata, Mosasauridae) from the Maastrichtian of Angola, and the affinities of the mosasaur genus Liodon. Proceedings of the Second Mosasaur Meeting, Fort Hays Studies Special Issue 3, Fort Hays State University, Hays, Kansas. 1-12. Abstractschulp_et_al_2008_prognathodon_kianda.pdf

Here we describe a new species of the mosasaurine genus Prognathodon from the Maastrichtian of Namibe, Angola, on the basis of five specimens which represent most of the cranial skeleton including the diagnostic quadrate. Phylogenetic analysis shows this new taxon, P. kianda nov. sp., to be the sister taxon to all other species of Prognathodon. It is unique amongst Prognathodon in possessing a high marginal tooth count and relatively small pterygoid teeth. The tooth morphology in the new taxon is reminiscent of some species of the genus Liodon, allowing association of Liodon-like dentition with otherwise Prognathodon-like crania, and thus resolves the long-standing question of the phylogenetic affinities of Liodon.