Ornitholestes (Bird robber)
Ornitholestes (Bird robber)
Named By : Henry Fairfield Osborn - 1903
Diet : Carnivore
Size : Estimated 2 meters long
Type of Dinosaur : Small Theropod
Type Species : O. hermanni (type)
Found in : USA - Morrison Formation
When it Lived : Late Jurassic, 150-144 million years ago
Ornitholestes, which means “bird robber”, is a small theropod dinosaur from the Jurassic (Brushy basin Member of Morrison Formation, middle Kimmeridgian era, approximately 154 million years ago) in Western Laurasia, the area that would become North America.
Ornitholestes has been identified only from one partial skeleton and a badly broken skull that was found in Wyoming’s Bone Cabin Quarry, Wyoming, 1900. Henry Fairfield Osborn described it in 1903. Later, an incomplete hand was attributed to Ornitholestes. However, it now seems to belong to Tanycolagreus. O. hermanni is the only species known to be the type. This name is in honor of Adam Hermann, a preparator at the American Museum of Natural History.
Ornitholestes is the first known theropod discovered in the 1900s. A joint expedition of Frederic Brewster Loomis, Paul Miller, and Peter C. Kaisen discovered the holotype skull (AMNH 619). It was found in Wyoming’s Bone Cabin Quarry in July 1900. It is a partial skull-skeleton, which includes many elements of the vertebral column and the forelimbs. Henry Fairfield Osborn scientifically described and named the specimen in 1903. Theodore Gill suggested the genus Ornitholestes. It means “bird robber”. The name is derived from the Greeks ornis/ornis and ornithos (“bird”), and lestes/lestes (robber). Adam Hermanni, the Museum’s head preparator, was the species name. He directed the restoration of the skeleton and its mounting.
Osborn’s 1903 description of the Genus gave Ornitholestes an incomplete hand (AMNH 587). Gregory S. Paul (1988), however, noted that the association was “tentative” because of the poor preservation in which the corresponding elements were found in the type specimen. In 2005, Kenneth Carpenter et al. Kenneth Carpenter et al. described a small theropod, Tanycolagreus. Its skeleton was discovered in Bone Cabin Quarry, just a few hundred meters from AMNH 587. AMNH 587 looked almost identical to the preserved Tanycolagreus hand specimen so it is now believed to be a Tanycolagreus dinosaur. Phil Senter (2006) stated that the only way to know Ornitholestes is from the holotype. John Foster (2007) suggested that fragments taken from Dry Mesa Quarry might be Ornitholestes. However, these fragments have yet to be described.
Charles Whitney Gilmore in 1920 concluded that Ornitholestes was the same as Coelurus. In 1934 Oliver Perry Hay recognized only a species difference and named a Coelurus hermanni. John Ostrom revived this genus in 1980.