Calamosaurus

Lydekker, 1891 kal-uh-mo-SOR-us

From Greek kalamos (κάλαμος) meaning 'reed' + Greek sauros (σαῦρος) meaning 'lizard'; overall meaning 'reed lizard', likely referring to the slender, hollow vertebrae.

125.8–121.4 million years ago Barremian, Early Cretaceous
Early Cretaceous stages

Calamosaurus is a genus of small theropod dinosaur, from the Early Cretaceous of the Isle of Wight, England. It is based on two cervical vertebrae (NHMUK PV R 901), collected by Reverend William Fox. These fossils come from sedimentary rocks of the Wessex Formation and are Barremian in age. The type species of Calamosaurus, named Calamospondylus foxi by Richard Lydekker, was named in honor of Fox. Calamospondylus, however, was a preoccupied name, forcing Lydekker to change the genus name to Calamosaurus. This has subsequently led to immense confusion, with some authors believing the two genera to be synonymous. The systematic position of Calamosaurus within theropods has been controversial, and placements within Compsognathidae and Ornithomimosauria have been suggested. More recently, researchers have suggested affinities with the Tyrannosauroidea and Alvarezsauroidea.

Diagnosis

  1. Cervical vertebrae shorter than those of Coelurus (C. daviesi)
  2. All cervicals probably opisthocœlous (vs. amphicœlous middle and posterior cervicals in Coelurus)
  3. Cervical vertebrae with pneumatic foramina, indicating highly pneumatic skeleton
  4. Characteristic brown coloration distinguishing them from black-stained Coelurus daviesi and Aristosuchus pusillus types

Species

Calamosaurus foxi Lydekker, 1891

Type species

Named for Reverend William Fox, the collector who gathered the type specimens.

Holotype
BMNH R901 , Natural History Museum
Material
Two associated cervical vertebrae.
Horizon
Wessex Formation, Barremian, Early Cretaceous , 125.8–121.4 million years ago
Locality
Isle of Wight, United Kingdom

Synonyms of the genus

Name Type Reason
Calamospondylus preoccupied Name preoccupied by Calamospondylus oweni Fox, 1866.

References

  1. Lydekker, R. (1891). On certain Ornithosaurian and Dinosaurian Remains. Quarterly Journal of the Geological Society of London 47(1-4): 41-44. Geological Society of London. doi:10.1144/gsl.jgs.1891.047.01-04.06 lydekker1891a