The find "pulls the origin of feathers down into the Triassic, when the saurischian
and ornithischian lineages of dinosaurs split", said Philip Currie at the University of Alberta in Canada.
in the squid and the crab, and the larger saurischian
dinosaurs with a "second brain" at the base of the tail), these exceptions act to fulfill the same fundamental plan.
Because the various groups had such dissimilar anatomies, early dinosaur investigators presumed that the bird-hipped ornithischians had evolved from a different stock of reptiles than had the sauropods and theropods, which together form a group called saurischian
dinosaurs, characterized by their lizard-like pelvises.
1992): A re-evaluation of the taxonomy of Newark Supergroup saurischian
dinosaur tracks, using extensive statistical data from a recently exposed tracksite near Culpeper, Virginia.
2002): Tails of saurischian
dinosaurs in the Early Jurassic of the Newark Supergroup (eastern North America).
Throughout the phylogenetic evolution of saurischian
dinosaurs, the eggshell structure evolved from a monolayered in primitive sauropods to a tri-laminated structure in avians (Grellet-Tinner and Chiappe, 2004; Grellet-Tinner et al.