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The Earliest Known Dino?
sciencehabit writes "A team of paleontologists thinks it may have identified the earliest known dinosaur — a creature no bigger than a Labrador retriever that lived about 243 million years ago. That's at least 10 million years earlier than the oldest known dinos and could change researchers' views of how they evolved. But some scientists, including the study's authors, caution that the fossils could instead represent a close dino relative."
"Reptiles" is a paraphyletic group, and is no longer used. The classification "reptile" has some serious problems, as for instance turtles branched early from the other reptiles, later the mammal-like reptiles, and then the other branches of reptiles radiated. So reptiles would cover a very incomplete tree where one early branch is missing (mammals) and one very late one (birds). Instead we are talking "amniotes", meaning animals whose early development involves the growing of an amnios, a pouch in which the embryo develops. The amniotes then branch into Anapsides (including turtles), Synapsides (mammals and their predecessors) and Diapsides (all other reptile-like animals including the birds).