[D] Tawa hallae [sG] [T]
Nesbitt, Smith, Irmis, Turner, Downs & Norell 2009
Triassic Late Norian Rhaetian
Saurischia Theropoda [Neotheropoda]
Chinle Formation, Petrified Forest Member, Ghost Ranch, Rio Arriba County, New Mexico, US
GR 241. A nearly complete associated but disarticulated skull and postcranial skeleton.
A nearly complete skeleton of a larger individual (GR 242) and at least six other individuals found in the same area of the quarry [see supporting online material including femora, pelvis, and tail (GR 155) and cervical vertebrae (GR 243). A complete right femur (GR 244) is from Hayden Quarry (HQ) site 3.
Tawa, Hopi name for the Puebloan sun god; hallae, after Ruth Hall, who collected many of the specimens that formed the genesis of the Ghost Ranch Ruth Hall Museum of Paleontology (GR) collections.Locality and horizon. Site 2, HQ, Ghost Ranch, Rio Arriba County, New Mexico, USA. The HQ has been dated to ~215 to 213 million years ago and is in the lower portion of the Petrified Forest Member of the Upper Triassic Chinle Formation .
A theropod diagnosed by the following combination of characters: Prootics meet on the ventral midline of the endocranial cavity; anterior tympanic recess greatly enlarged on the anterior surface of the basioccipital and extending onto prootic and parabasisphenoid; deep recess on the posterodorsal base of paroccipital process; sharp ridge extending dorsoventrally on the middle of the posterior face of the basal tuber; incomplete ligamental sulcus on the posterior side of the femoral head and semicircular muscle scar/ excavation on the posterior face of the femoral head; small semicircular excavation on the posterior margin of the medial posterior condyle of the proximal end of the tibia*; “step” on ventral surface of the astragalus*; and metatarsal I similar in length to other metatarsals.