Evolution of Dinosaurs - Biogeography

Biogeography

Dinosaurian faunas, which were relatively uniform in character when Pangaea began to break up, became markedly differentiated by the close of the Cretaceous. Biogeography is based on the splitting of an ancestral species by the emplacement of a geographic barrier. Interpretation is limited by a lack of fossil evidence for eastern North America, Madagascar, India, Antarctica and Australia. No unequivocal proof of the biogeographical action on Dinosaur species has been obtained, but some authors have outlined centres of origin for many dinosaur groups, multiple dispersal routes, and intervals of geographic isolation.

Dinosaurs that have been given as evidence of biogeography include abelisaurid theropods from South America and possibly else where on Gondwana.

Relationships between dinosaurs show abundant evidence of dispersal from one region of the globe to another. Tetanuran theropods travelled widely through western North America, Asia, South America, Africa and Antarctica. Pachycephalosaurs and ceratopsians show clear evidence of multiple bidirectional dispersion events across Beringa.