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- The biogeography of Paravian dinosaurs is the study of the global distribution of Paraves through geological history. Paraves is a clade that includes all of the Theropoda that are more closely related to birds than to oviraptorosaurs. These include Dromaeosauridae and Troodontidae (historically grouped under Deinonychosauria) and Avialae (including crown group birds, i.e. modern birds). The distribution of paraves is closely related to the evolution of the clade. Understanding the changes in their distributions may shed light on problems like how and why paraves evolve, eventually gaining the ability to fly. Paraves first appeared in the fossil record in early Late Jurassic (163–145 million years ago), then rapidly diversified and dispersed during Cretaceous (145–66 million years ago). They emerged during the breakup of Pangea (since Early-Middle Jurassic), which influenced the biogeographic processes such as speciation, geodispersal and extinction. By the Late Cretaceous, Paraves reached global distribution with fossils found in modern Asia, Europe, Australia, Antarctica etc. Almost all Paravian dinosaurs died out before or during the end-Cretaceous mass extinction (~66 million years ago), also called the Cretaceous-Paleogene (K-Pg) mass extinction. As a result of this extinction event, only a small group of avialans – neornithines – were able to survive. This group of Avialae continued to flourish in Cenozoic and later evolved into all modern birds. There are limitations to be considered when studying the paleobiogeography of Paraves. Firstly, the fossil record may not represent the actual distribution of the three clades mainly due to taphonomic bias. Also, the fossil record may be incomplete, which may lead to misinterpretations. (en)
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