But, fossil records show that Theropoda dinosaur groups like Dromaeosauridae, Compsognathidae, Oviraptorosauria, Therizinosauridae and even Tyrannosauroidea which were likely to had feathers made the evidence that these were theropds and even prehistoric basal birds.
32.
Recent researchers have concluded that its position is hard to determine with any certainty beyond a general Theropoda " incertae sedis ", and that it should be considered a " nomen dubium ".
33.
By far the earliest fossils of Theropoda ( not counting the basal saurischians ) are of the Coelophysoidea, including " Coelophysis " and others, from late Triassic and early Jurassic 227-180 Ma.
34.
This is interesting because according to a recent cladistic analysis, " Utahraptor " is about as far from the ancestral Theropoda as it is possible to get, further than " Archaeopteryx ".
35.
This includes imbricated rows of scales on top of its tail and also a covering of scales branching into feather-like structures, which until its discovery were thought to be exclusive to the Theropoda, of the saurischian line.
36.
Langer ( 2004 ) mentioned that this hypothesis was widely accepted, but that more later authors instead preferred to place " Herrerasaurus " as well as " Eoraptor " basal to Theropoda and Sauropodomorpha, a clade called Eusaurischia.
37.
Various possible evolutionary trees place it as the sister taxon of Dinosauria, the most basal member of Ornithischia ( the group that includes most herbivorous Mesozoic dinosaurs ), or a member of Theropoda ( the group that includes most carnivorous dinosaurs as well as birds ).
38.
The great radiation of Theropoda into many different clades of Coelurosauria must have happened in the mid to late Jurassic, because " Archaeopteryx " was around in about 152-154 Ma, and cladistic analysis has shown that many other groups of Coelurosauria branched off before that.
39.
*Smith, Nathan D .; Makovicky, Peter J .; Hammer, William R .; and Currie, Philip J . ( 2007 ) . " Osteology of Cryolophosaurus ellioti ( Dinosauria : Theropoda ) from the Early Jurassic of Antarctica and implications for early theropod evolution ".
40.
The evolutionary paths taken by the Theropoda are very complicated . " The Dinosauria " ( 2004 ), a major reference work on dinosaurs, splits the Theropoda into groups Ceratosauria, Basal Tetanurae, Tyrannosauroidea, Ornithomimosauria, Therizinosauroidea, Oviraptorosauria, Troodontidae, Dromaeosauridae and Basal Avialae in turn.
