Taxonomic, palaeobiological and evolutionary implications of a phylogenetic hypothesis for Ornithischia (Archosauria: Dinosauria) Author Norman, David B Author Baron, Matthew G Author Garcia, Mauricio S Author Müller, Rodrigo Temp text Zoological Journal of the Linnean Society 2022 2022-12-01 196 4 1273 1309 https://academic.oup.com/zoolinnean/article/196/4/1273/6680019 journal article 10.1093/zoolinnean/zlac062 0024-4082 7381299 Saurischia ( Fig. 6 : stem/branch 2) Definitionadopted: The most inclusive clade containing Allosaurus fragilis (Marsh, 1877) and Camarasaurus supremus Cope, 1877 but not Stegosaurus stenops Marsh, 1887 (after Langer et al. , 2020 ). Characters in support: Subnarial foramen present (Char. 5: 0 → 1); premaxilla with a deep narial fossa at the rostroventral corner of the naris (Char. 19: 0 → 1); maxilla with significantly deeper rostrally than caudally surface ventral to the external antorbital fenestra (Char. 29: 1 → 0); caudal chonos of cranial cervical vertebrae as a shallow fossa (Char. 109: 0 → 1); epipophyses present in cervical vertebrae 6-9 (Char. 111: 0 → 1); neural arch of cervical vertebrae lower than caudal articular facet of the centrum (Char. 113: 0 → 1); articular surface of the rib of the first primordial sacral vertebra is C-shaped in lateral view (Char. 130: 0 → 1); transverse processes of sacral vertebrae roof the space between the ribs (Char. 131: 0 → 1); humerus + radius/femur + tibia length ratio less than 0.55 (Char. 141: 0 → 1); apex of deltopectoral crest between 30% and 43% down the length of the humerus (Char. 142: 0 → 1); expanded deltopectoral crest of the humerus (Char. 143: 0 → 1); humerus shorter than 0.6 of the length of the femur (Char. 145: 0 → 1); humerus sigmoid in lateral view (Char. 147: 0 → 1); average length of digits I–III of the manus more than 0.4 of the total length of humerus plus radius (Char. 153: 0 → 1); trenchant unguals on digits I–III of the manus (Char. 155: 0 → 1); deep extensor pits on distal/dorsal portion of metacarpals II-III (Char. 156: 0 → 1); width of the shaft of metacarpal IV significantly narrower than that of metacarpals I-III (Char. 167: 0 → 1); ventral margin of the acetabular wall of the ilium straight to concave (Char. 175: 0 → 1/2); distal end of the pubis slightly expanded (Char. 190: 0 → 1); kinked transition from the femoral shaft to the femoral head and expanded head (Char. 190: 1 → 2); deep groove between the lateral condyle and crista tibiofibularis on the distal end of the femur (Char. 231: 0 → 1); cnemial crest of the tibia arcs craniolaterally (Char. 234: 1 → 2); tibial articulation caudal to the ascending process of the astragalus with a markedly rimmed and elliptical fossa (Char. 249: 0 → 1); proximal articular facet for fibula of astragalus less than 0.3 of the transverse width of the bone (Char. 250: 0 → 1); cranial ascending process separated from the cranial surface of the astragalar body by a platform (Char. 256: 1 → 2); calcaneum with a concave articular surface for the fibula (Char. 261: 0 → 1); pointed caudal prong of the distal tarsal 4 (Char. 265: 0 → 1); distal tarsal 4 with a medial process (Char. 266: 0 → 1); and metatarsal IV with an expanded proximal portion (Char. 272: 0 → 1).