POLAR PALEOBIOGEOGRAPHIC PATHWAYS; BERINGIA AND BARENTSIA AS DINOSAUR BIOGEOGRAPHIC HIGHWAYS

As Pangea broke apart in the Late Jurassic, widening ocean basins separated terrestrial regions in tropical and temperate latitudes, isolating dinosaur faunas. However, at the North and South Poles, land areas remained connected throughout most of the Jurassic and Cretaceous. In the northern hemisphere, terrestrial migration routes can be traced eastwards from Greenland to Europe and northern Asia throughout the Triassic, Jurassic and Cretaceous. This land connection is referred to as Barentsia and is here considered a primary northern hemisphere dispersal route for dinosaurs until the Mid-Cretaceous. Connections between western North America and northeastern Eurasia were more sporadic, but a good case can be made that Arctic Canada and Siberia were connected continuously from the Albian (~110 Ma) - Cenomanian (~95 Ma) and on through the end of the Cretaceous. As Beringia became tectonically assembled and available for dinosaur dispersal in the west, Barentsia became increasingly isolated in the east.

In the southern hemisphere, dinosaur migration pathways were more complex. South America, Africa, Madagascar, India, Antarctic and Australia were interconnected from the Triassic, throughout the Jurassic and into the mid-late Cretaceous (~95 Ma). In the late Aptian – early Albian, India and Madagascar became isolated from the other Gondwanan continents. India became an island continent shortly thereafter (~90 Ma). Migration of dinosaurs and reptiles from South America down the West Antarctic peninsula, across Antarctica and into Australia was possible until the establishment of the Drake Passage and Tasman-Antarctic strait. In this paper we present 18 paleogeographic maps centered on the North and South Poles that illustrate the polar paleobiogeographic pathways that connected the continents during the Jurassic and Cretaceous. Dinosaur distributions and available dispersal routes are discussed in relation to changing Mesozoic tectonics and eustatic cycles.