The origins of dinosaurs remain largely enigmatic, with the oldest known fossils dating back approximately 230 million years, discovered in southern Brazil, Argentina, and Zimbabwe. However, significant gaps in the fossil record suggest that dinosaurs may have evolved in a region now difficult to access, according to a study led by Joel Heath, a PhD student at University College London.
Heath emphasized that while dinosaurs are extensively studied, their true origins are still unclear. The fossil evidence indicates that dinosaurs likely originated in western, low-latitude Gondwana, characterized by hotter and drier environments, rather than in Antarctica, which, despite being part of Gondwana, was not conducive to their initial evolution.
The research team conducted climate modeling for the mid-Triassic period, identifying equatorial regions of Gondwana as potential hotspots for early dinosaur evolution. This area lies between known dinosaur relatives in Laurasia and the first known habitats of their descendants in southern Gondwana.
In their analysis, the authors utilized various family trees for early dinosaurs and alternative planetary topologies to enhance the reliability of their findings. The results consistently pointed to equatorial Gondwana as a likely origin site, especially if ornithischian dinosaurs descended from silesaurids, a hypothesis supported by some paleontologists.
Professor Philip Mannion, the senior author of the study, noted that early dinosaurs appeared well adapted to hot and arid conditions. Among the three main dinosaur groups, sauropods, which include species like Brontosaurus and Diplodocus, maintained a preference for warmer climates, while theropods and ornithischians later expanded into polar regions.