The Evolutionary History of Sauropod Dinosaurs

摘要: Most recent studies of dinosaur phylogeny have concentrated on theropods and ornithischians. As a result, the evolutionary relationships sauropod dinosaurs are poorly understood. In this paper previous reviewed contrasted with results cladistic analysis. This analysis forms basis for reconstruction phylogeny. Sauropods diverged from other at some time in Upper Triassic, but large part their early history is totally unknown. Vulcanodon currently most primitive sauropod. Many, perhaps not all, Jurassic Chinese sauropods form monophyletic radiation (the Euhelopodidae) which may reflect geographic isolation China during Lower Jurassic. Members Euhelopodidae, such as Mamenchisaurus, considered to be closely related Diplodocidae. \`Forked' chevrons, played an important role phylogeny, here evolved twice within Sauropoda. convergence correlation between chevron shape use tail weapon these two families. The \`Neosauropoda' (sister group contains Brachiosauridae, Camara-sauridae new superfamilies Titanosauroidea Diplodocoidea. Cetiosauridae (here defined rather restricted sense) also provisionally included Neosauropoda, removed future studies. enigmatic Cretaceous sauropod, Opisthocoelicaudia, thought sister taxon Titanosauridae camarasaurid previously suggested. Diplodocoidea well established families, Dicraeosauridae Diplodocidae, family Nemegtosauridae. Finally, overview compared recently published palaeogeographic reconstructions. There many difficulties associated biogeographic distribution. Nevertheless, aspects linked break-up Laurasia Gondwanaland Cretaceous.