We present a stratigraphic log supporting a preliminary magnetostratigraphy of a Tithonian–Berriasian section in Porto da Calada (Portugal). Based on biostratigraphy and reversed and normal magnetostratigraphy, the location of the Tithonian–Berriasian boundary is tentatively located at ca. 52 m, not in disagreement
with former proposals. Due to the occurrence of later remagnetization (diagenesis), the magnetostratigraphic definition of the Tithonian–Berriasian section at the Cabo Espichel (Portugal) location was not able to be established.

A single, geographically and temporally restricted horizon at Bentiaba, Angola (14.3° S), preserves a concentration of skeletons and isolated elements representing sharks, rays, bony fish, at least three species of turtles, two species of plesiosaurs, at least five species of mosasaurs, and rare volant and terrestrial forms. The concentration, referred to as the Bench 19 Fauna, formed on a narrow continental shelf at paleolatitude 24°S as predicted by paleomagnetic data and confirmed by plate motion models. The shelf evolved as a transform passive margin along faults associated with the opening of the South Atlantic. Latitude 24°S falls today along the coast of northern Namibia, an area of intense upwelling and hyperarid coastal desert. The Namibe Basin in southern Angola is separated from the Walvis Basin of Namibia by the Walvis Ridge, and the continental shelf in northern Namibia is eight times the width of that at Bentiaba. However, the sediment entombing the fossils at Bentiaba is an immature feldspathic sand, shown by detrital zircon ages to be derived from nearby exposed granitic shield rocks, suggesting similar climatic and drainage conditions between the two regions. Temporal control of the Bentiaba section is provided by magnetostratigraphy and stable carbon isotope chemostratigraphy anchored by an Ar40/Ar39radiometric date on basalt. The age of Bench 19 is constrained to chron C32n.1n and thus falls between 71.4 and 71.64 Ma. Massive bedding without hummocky cross-bedding or other sedimentary structures indicates deposition in shallow water below wave base. δ18O analysis of bivalve shells indicates a water temperature of 18° C immediately below Bench 19. Nearest neighbor distance peaks at 5 m (n=19

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.