Calamosaurus was a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of small theropod dinosaur

Dinosaur

Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

 from the Barremian

Barremian

The Barremian is an age in the geologic timescale between 130.0 ± 1.5 Ma and 125.0 ± 1.0 Ma). It is a subdivision of the Early Cretaceous epoch...

-age Lower Cretaceous Wessex Formation

Wessex Formation

The Wessex Formation is an English fossil site and geological formation that dates to the Barremian stage of the Early Cretaceous. It is part of the Wealden Group and underlies the younger Vectis Formation.-Invertebrates:...

 of the Isle of Wight

Isle of Wight

The Isle of Wight is a county and the largest island of England, located in the English Channel, on average about 2–4 miles off the south coast of the county of Hampshire, separated from the mainland by a strait called the Solent...

, England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

. It is based on two cervical

Neck

The neck is the part of the body, on many terrestrial or secondarily aquatic vertebrates, that distinguishes the head from the torso or trunk. The adjective signifying "of the neck" is cervical .-Boner anatomy: The cervical spine:The cervical portion of the human spine comprises seven boney...

 vertebrae (BMNH R901), collected by Reverend William Fox

William Fox (palaeontologist)

William D. Fox was an English clergyman and palaeontologist who worked on the Isle of Wight and made some significant discoveries of dinosaur fossils....

.

History and taxonomy

Richard Lydekker

Richard Lydekker

Richard Lydekker was an English naturalist, geologist and writer of numerous books on natural history.-Biography:...

 ran across these bones when cataloguing the Fox collection and named them Calamospondylus

Calamospondylus

Calamospondylus was a theropod dinosaur genus. It lived during the Early Cretaceous, and its fossils were found in England. The type species, Calamospondylus oweni, was described by amateur paleontologist Reverend William D. Fox in 1866, but is based on fragmentary material...

, noting their similarity to those of Coelurus

Coelurus

Coelurus is a genus of coelurosaur dinosaur from the Late Jurassic period . The name means "hollow tail", referring to its hollow tail vertebrae...

. Unfortunately, Calamospondylus

Calamospondylus

Calamospondylus was a theropod dinosaur genus. It lived during the Early Cretaceous, and its fossils were found in England. The type species, Calamospondylus oweni, was described by amateur paleontologist Reverend William D. Fox in 1866, but is based on fragmentary material...

had already been coined in 1866 (ironically by Reverend Fox himself, the very man honored in Lydekker's species name). Lydekker renamed it in 1891 to its present title. He also at this time provisionally referred to it a tibia

Tibia

The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....

, BMNH R186, which may be from a basal

Basal (phylogenetics)

In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...

 coelurosauria

Coelurosauria

Coelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. In the past, it was used to refer to all small theropods, although this classification has been abolished...

n like a compsognathid

Compsognathidae

Compsognathidae is a family of small carnivorous dinosaurs, generally conservative in form, from the Jurassic and Cretaceous Periods. Compsognathids lie at or near the origin of feathers—skin impressions are known from four genera, Compsognathus, Sinosauropteryx, Sinocalliopteryx, and Juravenator...

.

Because of its sparse remains, it has received little attention. Often, it has been synonymized with Calamospondylus as part of a long, confusing taxonomic tangle, although there is no comparable material between the two genera. Modern reviews have regarded it as a dubious theropod

Nomen dubium

In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...

, although potentially a valid coelurosaurian.

Paleobiology

As a possible basal coelurosaur, Calamosaurus would have been a small, agile

Agile

Agile can refer to:*Agility*Agile , an American Thoroughbred racehorse* Agile management*Association of Geographic Information Laboratories for Europe *Agile Software Corporation, a provider of product lifecycle management solutions...

, biped

Biped

Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs, or legs. An animal or machine that usually moves in a bipedal manner is known as a biped , meaning "two feet"...

al carnivore

Carnivore

A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...

. Naish et al. (2001) estimate the living animal would have been around 3–5 meters long (9.8-16.4 feet), with a small head given the build of the neck vertebrae.