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The term Pterosaur refers to two distinct sub-families: the primitive Rhamphorhynchoids and the advanced Pterodactyloids. The Rhamphorhynchoids appeared suddenly during the Late Triassic and remained the sole flying vertebrates until the Late Jurassic. It was during the Late Jurassic that Pterodactyloids first appeared. The two subfamilies competed amongst one another and by the Early Cretaceous only the Pterodactyloids remained. |
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© Patrick Lyons 1998. |