
Ornithodesmus (meaning "bird link") is a genus of small dromaeosaurid dinosaur from the Isle of Wight in England, dating to about 125 million years ago. It is known from a sacrum a series of vertebrae fused to the hip bones.
Description[]

Ornithodesmus is a small dromaeosaurid. It was about 1.8 meters (5.9 feet) long in life, similar to Velociraptor.
It would have been a predator. hunting small mammals such as yaverlestes and dinosaurs like Hypsilophodon. Stabbing them in the neck with a sickle like claw on its toe.
It may have been arboreal climbing trees to escape predators or to use as a vantage point to ambush prey.
History and classification[]

Ornithodesmus cluniculus was first described by Harry Govier Seeley in 1887, based on a set of six fused vertebrae from the hip (sacrum), specimen number BMNH R187, found by William D. Fox in the Wessex Formation of Brook Bay. Seeley thought the bones came from a primitive bird, and gave it a name meaning "bird link", from Greek ὄρνις (ornis), "bird", en δεσμός (desmos), "link". The specific name cluniculus means "little buttock" in Latin, a reference to the small thighs indicated by the size of the specimen.
Later that year, John Hulke (in an anonymous paper) suggested the remains actually belonged to a pterosaur. Seeley himself later changed his opinion when he described the complete skeleton (specimen number BMNH R176) of a new pterosaur species he believed was closely related to O. cluniculus. He named this new species Ornithodesmus latidens in 1901. Although he now considered it a pterosaur, Seeley at the time still considered Ornithodesmus close to the origin of birds, and suggested the (now defunct) theory that birds and pterosaurs shared a close common ancestry. For over a century following this, the pterosaur O. latidens was used as the standard example of Ornithodesmus, and the fragmentary type specimen was largely ignored. In 1913, Reginald Walter Hooley named a new family to distinguish Ornithodesmus from other large pterosaurs known at the time, Ornithodesmidae.