Influence of Late Triassic climate on the dinosaur evolution and biogeography

Dinosaurs primarily appeared in the mid-latitude regions of hostile Pangaea around the early Late Triassic as a diverging subgroup of Archosaurs. They may have lived in restricted, moderate areas until climatic amelioration caused early low-latitudinal distributions in the Norian age (~۲۲۰-۲۱۵ Ma). Nevertheless, this biography is not without any challenge given the recent study that suggests an earlier low-latitude existence for dinosaurs. Climate acted also as a ruler in further geographic dispersals during the Late Triassic, especially for sauropodomorphs, as they were in more constrains by climatic impact than contemporary theropods. During the Norian-Rhaetian ages, climatic patterns and environmental fluctuations gradually made new evolutionary innovations through the group. Sauropodomorph began to obtain larger body sizes and quadrupedal locomotions, while theropods remained bipedal and maintained their agility as predatory dinosaurs. Some taxa developed as gregarious components of Late Triassic to take advantage of team work. Such evolutionary process made Triassic dinosaurs the survivors of an unfavorable climatic crisis around the Triassic-Jurassic boundary. Here, I give a brief review of current studies exploring the climatic influences on biogeographic niche of dinosaurs primarily during the Late Triassic interval, as well as their early evolution towards the next geological period. The paper also reveals the paleontological gaps through the early successions of dinosaurs, as potential cases for additional research in the future.

کلیدواژه ها:

Climate ، Dinosaur ، Evolution ، Biogeography ، Late Triassic