Dinosauria Owen, 1842

Nesbitt, Sterling J., 2011, The Early Evolution Of Archosaurs: Relationships And The Origin Of Major Clades, Bulletin of the American Museum of Natural History 2011 (352), pp. 1-292 : 210

Dinosauria Owen, 1842

ORIGINAL DEFINITION: All descendants of the most recent common ancestor of birds and Triceratops ( Padian and May, 1993).

REVISED DEFINITION: Node: The least inclusive clade containing Triceratops horridus ( Marsh, 1889) and Passer domesticus Linnaeus, 1758 (sensu Sereno, 2005).

TEMPORAL RANGE: Late Triassic (?Carnian–early Norian Pisanosaurus mertii Casamiquela 1967 ) to Recent ( Passer domesticus Linnaeus, 1758 ).

SUPPORT: (1) Exoccipitals do not meet along the midline on the floor of the endocranial cavity (115-1)*. Also in Crocodylomorpha and Effigia + Shuvosaurus . (2) Supratemporal fossa present anterior to the supratemporal fenestra (144-1). (3) Epipophyses present in postaxial anterior cervical vertebrae (186-0)*. (4) Apex of deltopectoral crest situated at a point corresponding to more than 30% down the length of the humerus (230-1)*. (5) Radius shorter than 80% of humerus length (241-1). (6) Proximal articular surfaces of the ischium with the ilium and the pubis separated by a large concave surface (297-2)*. (7) Fourth trochanter a sharp flange (316-1)*. (8) Fourth trochanter asymmetrical, with distal margin forming a steeper angle to the shaft (317-1). (9) Cnemial crest arcs anterolaterally (328- 2)*. (10) Distinct proximodistally oriented ridge present on the posterior face of the distal end of the tibia (336-1)*. (11) Proximal articular facet for fibula of the astragalus occupies less than 0.3 of the transverse width of the element (362-1). (12) Concave articular surface for the fibula of the calcaneum (378- 2).

Other possible synapomorphies: AC- CTRAN: Three premaxillary teeth (6-0); premaxillary narial fossa expanded in the anteroventral corner of the naris (9-1); posterior process of the jugal is split by the anterior process of the quadratojugal (71-3); forelimb–hind limb length ratio less than 0.55 (212-1); concave ventral margin of the acetabulum of the ilium (273-2); concave emargination ventral to the proximal head of the femur (304-2); posterior groove of the astragalus absent (363-1); calcaneal tuber absent (373-1). DELTRAN: Postfrontal absent (44-1); posttemporal opening absent or less than half the diameter of the foramen magnum (141-1); interclavicle absent (214-1); proximal articular surface of the humerus separated by a gap from the deltopectoral crest (233-1); three or two phalanges on manual digit IV (258-2); calcaneal tuber absent (373-1).