[D] Shuvuuia deserti ~/~
Chiappe, Norell & Clark, 1998
Cretaceous Late Campanian
Saurischia Theropoda Tetanurae Coelurosauria Maniraptora Avialae Alvarezsauridae
Ukhaa Tolgod [MGI 100/975, MGI 100/977, MGI 100/1001] and Tugrugeen Shireh [MGI 100/99; MPD100/120, partial skeleton], South Gobi Aimak, Mongolia. Tentatively Djadochta Formation.
Genus - Typespecies
The taxon represented by two exquisitely preserved skulls the first known for Alvarezsauridae- details of which support the theory that the group is related to birds. Other earlier evidence that suggested that the alvarezsaurids were birds included the presence of a movable joint between the quadratojugal and quadrate, speparate squamosal and braincase articulations of the quadrate, confluance between the caudal tympanic recess and columelaar recess, a triadiate palatine, an unusually large foramen magnam, and the loss of a coronoid bone.
Shuvuuia deserti differs from all alvarezsaurids because it has a sharp ridge on the medial margin of the distal tibiotarsus a character that we have interpreted to be an autapomorphy [a novel character of a terminal taxon that evolved from an existing character].
The skull of Shuvuuia deserti shows several characteristics that we have interpreted as autamorphies, including the articulation between quadrate and postorbital, the elongated basispterygoid processes, the numerous teeth and the hypertrophied prefrontal/ectethmoid