Saurornithoides (Bird like lizard)

Short Info

Saurornithoides (Bird like lizard)

Phonetic : Sore-orn-ih-thoy-deez

Named By : Henry Fairfield Osborn – 1924

Diet : Carnivore

Size : Estimated 2 – 3 meters long

Type of Dinosaur : Small Theropod

Type Species : S. mongoliensis (type)

Found in : Mongolia – Djadochta Formation

When it Lived : Late Cretaceous, 85-80 million years ago

Saurornithoides (/so:,ro:rnI’thoIdi:z/ saw-ROR-ni-THOY-deez) is a genus of troodontid maniraptoran dinosaur, which lived during the Late Cretaceous period. They were predators who could speed up on their hind limbs and were extremely sighted and heard. The name derives of an ancient Greek stems saur (lizard) ornith (bird) and the word eides (form) which refers to the skull of a bird.


Saurornithoides mongoliensisRyan Somma, CC BY-SA 2.0, via Wikimedia Commons


Saurornithoides is one of the troodontids. They are a collection of small bird-like maniraptorans. The troodontids are all distinct characteristics of the skull like narrowly spaced dental teeth on the jaw’s lower side and a large number of teeth. Troodontids possess raptorial and sickle-claw hands. They also have they have some of the most impressive non-avian encephalization rates, which means they were extremely intelligent and had sharp senses. Saurornithoides was a tiny troodontid. Although it is possible to be an adult, the specimen had the midline size of just 189 millimetres which is compared to 272 millimetres of Zanabazar junior, which is believed to be 2.3 meters long. The eye sockets were large as well as stereoscopic eyes, which allowed for excellent depth perception. It was likely to have good vision in bright light conditions and excellent night vision. It was a tall and small head and a low muzzlewith sharp teeth, and an extremely big brain. Quick and intelligent, similar to it’s North American cousin Troodon, Saurornithoides likely scoured the Gobi Desert looking for reptiles or mammals that were small enough to consume. Like all troodontids it had a larger claw that could be retracted at one foot’s second and third toe that was moderately sized, but quite curvaceous.

The juvenile form that belonged to S. mongoliensis was first described in 1993, and provided insights into the evolution of the species, as well as its close relatives. The high-ossified hindlimb suggests that Saurornithoides and troodontids in general were fully developed from birth and had minimal or none parental care.

An update of Saurornithoides’ genus, published in 2009 revealed the possibility of a differential diagnosis and an inventory of the traits that Saurornithoides distinguished itself from other related relatives, focusing mainly on its position within the tree of evolution. It is believed that Saurornithoides mongoliensis could be more derivative, and superior in tree in comparison to Sinornithoides and Sinusonasus is demonstrated by the absence of a fenestra prosmaxillaris and a tiny gap on the front of the snout. It also indicates the presence of huge denticles along the rear edges of the teeth and also the large number of sacral vertebrae. The possibility that S. mongoliensis may be more basal and lower in the tree than Zanabazar and Troodon can be seen in the appearance of the recessus dorsalis, which is the highest of three tiny openings on the sides of the braincase. They are located within the inner ear region.

At first, just two or maybe one person of Saurornithoides were identified as closely related with that same stratum of Djadochta Formation of Mongolia. The fossils were discovered on the 9th of July, 1923, by Chih, a Chinese worker from an American Museum of Natural History expedition called Chih. The specimen included a single skull and jaw, together with vertebrae, pelvis fragments as well as hindlimbs and a foot with. The bones were later added but later proved to belong to Protoceratops. Henry Fairfield Osborn at first planned to call the creature “Ornithoides”, the “bird-like one” and in 1924, he referred to this name in a well-known publication but with no description, to make it untrue as a nomen nudum. Then, he formally described the remains later in the same year, and found them to be a new genus as well as a species that he called Saurornithoides mongoliensis. The name was picked because of the bird-like bone of the taxon, which were believed to be a symbol of the megalosaurian, meaning “saurian with bird-like rostrum”. Saurornithoides was observed to look like Velociraptor but is slower in the opinion of Osborn. The Holotype sample is AMNH 6516. The specimen was the very first troodontid skeleton discovered however at the time , the connection to Troodon that was at the time only known by it’s teeth, had not been fully realized.

In 1964, a different specimen was reported in 1964. It was from in the Late Cretaceous of Mongolia. The first specimen to be collected by an expert Mongolian Palaeontologist It was assigned the number of the specimen IGM 100/1. The specimen was classified in the work of Rinchen Barsbold as a brand new specie, Saurornithoides junior. This species was designated to the Genus on the basis of an examination of cranial features in addition to the similarity of provincialism. But, since the descriptionwas made, more troodontids were described using skull material. As an example, a study from 2009 on Saurornithoides assigned this species in its own species genus Zanabazar.

In 1993 the year 1993, a juvenile sample of S. mongoliensis was identified. The hindlimb was extremely ossified, suggesting that Saurornithoides and the troodontids that were similar to them were fully developed from birth and needed little or none parental care.

Many different Saurornithoides species were identified but none is considered to be valid today. In 1928 the Baron Franz Nopcsa coined Saurornithoides sauvagei. But, it was due to an error in printing He had intended to name the species Teinurosaurus sauvagei. It was in 1982 that Kenneth Carpenter renamed Stenonychosaurus inequalis Sternberg 1932 as Saurornithoides inequalis. In the present, it is generally viewed as a junior synonym for Troodon formosus. It was in 1991 that George Olshevsky renamed Pectinodon asiamericanus Nesov into Saurornithoides asiamericanus. In 1995, he renamed it an Troodon Asiaamericanus. Because of its origins of its ancestry to Cenomanian of Uzbekistan the species is generally considered to be a distinct taxon to Saurornithoides. The year 2000 saw Olshevsky changed the name of Troodon isfarensis Nessov 1995 to Saurornithoides isfarensis. In 2007, the species was proven to be an hadrosaurid fossil.

Source: Wikipedia