[D] Guaibasaurus candelariai [sG] [T]
Bonaparte & Ferigolo, Ribeiro, 1999
Triassic Late Carnian
Santa Maria Formation [= Caturrita Formation] southern Brazil
Genus - Typespecies
A primitive saurischian Material includes a pelvis and virtually complete hind limb, perhaps other stuff. Resembles Staurikosaurus and Herrerasaurus in some features, but nothing else in other features. Metatarsals I-IV long, V splintlike with no digit. Formation is dated as approximately \\\"Ischigualastian.\\\" : \\\"Two incomplete specimens of a new genus and species of Saurischia, Guaibasaurus candelariensis, from the Caturrita Formation of Rio Grande do Sul, southern Brazil, offers new data on the basal dinosaurs and a new interpretation of the early evolution of the Saurischia.
The new taxon is more primitive than the Herrerasauridae, in the structure of the dorsal vertebrae, ilium, pubis, femur, tarsus and foot. The mesotarsal condition and the outline of the distal section of tibia indicate the saurischian nature of this new form, but the almost unreduced medial wall of the acetabular portion of ilium shows an unrecorded primitive condition within the cited group.
These particular characters lead us to propose a new family: the [Guaibasauridae]. Several features suggesting affinities with both the Prosauropoda and Theropoda, imply that Guaibasaurus candelariensis may belong to the ancestral group for both of them.\\\"
(MCN-PV 2355) five incomplete dorsal centra (22 mm), three incomplete dorsal neural arches, five incomplete dorsal ribs, two incomplete sacral centra (29, 19 mm), ten caudal vertebrae (51 mm), chevrons, incomplete scapula, incomplete coracoid, incomplete ilium (~87 mm), pubes (136 mm), incomplete ischia (131 mm), incomplete femora (~214 mm), tibiae (~212 mm), fibulae (~207 mm), astragalus (40x22 mm), calcaneum, metatarsal I (57 mm), phalanx I-1, ungual I, metatarsal II (85 mm), phalanx II-1, phalanx II-2, ungual II, metatarsal III (95 mm), phalanx III-1, phalanx III-2, phalanx III-3, ungual III, metatarsal IV (83 mm), phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, ungual IV, metatarsal V (41 mm)