[D] Saurornithoides mongoliensis [Su] [sG] [T]
Cretaceous Late ?Santonian Campanian
Saurischia Theropoda Tetanurae Coelurosauria Maniraptora Troodontidae
Djadochta Formation, Bayan Dzak, Omnogov, Mongolia
Genus - Typespecies
Saurornithoides mongoliensis (Osborn, 1924)
Skull with fragmentary postcrania skeleton. S. mongoliensis was the first troodontid discovered in Asia.
AMNH 6516 skull poorly preserved, with remains of the postcranial skeleton. Small saurornithoidid with 17-18 teeth in the upper and 27-28 in the lower jaw. 12 serrations along 5 mm of posterior edge of teeth.
A bird-like theropod dinosaur. Material include the major part of a skull found in one sandstone nodule and, a little way away from this, parts of the backbone, pelvis, legs and feet. All these remains were collected in 1923 by a Chinese assistant on the Central Asiatic Expedition of the American Museum of Natural History.
At first supposed to be an early toothed bird, because its skull had a long rather bird-like, narrow muzzle. In general shape and proportions the skull is rather similar to that of Velociraptor which was incidentally described at the same time and came from the same area of Mongolia. However, the teeth (in particular) are rather different; those of Saurornithoides are smaller and more numerous with 38 teeth in the upper jaw, while Velociraptor had no more than 30 teeth.
The teeth were also unusual in that only their back edges were serrated whereas both front and back edges of Velociraptor were serrated. In 1932 some more bones were described by Charles Sternberg; these came from the Late Creaceous near Steveville on the Red Deer river, Alberta. The remains included a complete foot, several hand bones and a few vertebrae.
The hand bones were rather similar to those of Ornitholestes and Chirostenotes with uneven finger lengths. The foot, however was rather unusual because, although it showed the typical bird-like arrangement of toes. At first, both of these dinosaurs were included with other dromaeosaurids .
However in 1974 Rinchen Barsbold (Ulan Bator, Mongolia) described more material of Saurornithoides which had been discovered at Bugeen Tsav in Mongolia. This material, ascribed the name Saurornithoides junior (younger bird-like reptile) was found in slightly earlier rocks and was 30 percent larger than Osborn\\\\\\\'s species while the number of teeth in the jaws was also greater and was redescribed in 2009 as Zanabazar junior by Norell et al.