Such a pelvic arrangement is typical for the Ornithischia, to which group part of the fossils of " Chilesaurus " were at first incorrectly referred.
22.
Furthermore, the bird-hipped dinosaurs, Ornithischia, have all been designated dinosaurs with a more recent common ancestor to " Triceratops " than modern birds.
23.
Dinosaurs can be defined as the last common ancestor of birds ( Saurischia ) and " Triceratops " ( Ornithischia ) and all the descendants of that ancestor.
24.
Although " Lesothosaurus " comes from 195-206 Ma, skeletal features suggest that it branched from the main Ornithischia line at least as early as " Pisanosaurus ".
25.
For example, the earliest branching point in dinosaur evolution was between the Ornithischia, whose defining characteristics include a backward-rotated pelvis, and Saurischia, whose defining characteristics include an asymmetrical hand.
26.
Molnar in 1980 acknowledged that these were ossified tendons, but denied that they were homologous to the ossified tendons of other Ornithischia and claimed that they resembled the pathological tendon aponeurosis of modern crocodiles.
27.
The first exact clade definition of Stegosauria was given by Peter Malcolm Galton in 1997 : all thyreophoran Ornithischia more closely related to " Stegosaurus " than to " Ankylosaurus ".
28.
"Pisanosaurus " is very basal within Ornithischia; the postcrania seem to lack any good ornithischian synapomorphy and it was even suggested by Paul Sereno in 1991 that the fossil is a chimera.
29.
In 1870, Huxley expanded this into a full article, in which he became the first researcher to notice that the Ornithischia ( not yet known as such at the time ) had a pubic bone pointing backwards like birds.
30.
Though at first it was considered by Thulborn a member of the Fabrosauridae and by Peter Galton a hypsilophodontid, Paul Sereno ( 1991 ) classified " A . kuehnei " as Ornithischia " incertae sedis ".
