Spondylosoma (meaning "vertebra body") is a genus of aphanosaur from the late Ladinian-age Middle Triassic Lower Santa Maria Formation in Geopark of Paleorrota, Brazil. Studies have gone back & forth on its identity, suggesting rauisuchian or basal saurischian dinosaur, with current consensus being that it was an aphanosaurian avemetatarsalian. The genus contains the type & only species S. absconditum.
History[]
Friedrich von Huene based the genus on a fragmentary post-cranial skeleton held at the University of Tübingen. This skeleton includes two teeth, two cervical vertebrae, four dorsal vertebrae, three sacral vertebrae, scapulae, part of a humerus, part of a femur, & part of a pubis. At the time, he thought it was a prosauropod.[1] With the discovery of basal dinosaur Staurikosaurus, Spondylosoma drew attention as a possible relative. Authors have gone back & forth on the question, considering it either as a basal dinosaur, or as a "thecodont" or other basal archosaur. The two most recent papers to address it illustrate this clearly: in 2000, Peter Galton claimed that it lacks dinosaurian characteristics & was probably a rauisuchian,[2] whereas in 2004 Max Langer disputed this & included Spondylosoma as a possible basal dinosaur similar to the herrerasaurs (but did not firmly rule out rauisuchian affinities).[3] It is now believed that their closest relatives are Dongusuchus, Teleocrater, & Yarasuchus, being firmly within Aphanosauria, with the sister clade being Ornithodira.
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