Chondrosteosaurus
Encyclopedia
Chondrosteosaurus was a sauropod from Early Cretaceous
England
.
The type species
, Chondrosteosaurus gigas, was described and named by Richard Owen
in 1876. The fossils of Chondrosteosaurus were discovered in the Wessex Formation
on the Isle of Wight
. C. gigas is known only from two neck vertebrae (specimens BMNH 46869, the holotype
, and BMNH 46870), with distinctive hollows and internal passages now interpreted as evidence of pneumatic air sacs. Paleontologist Harry Seeley
had interpreted similar structures as pneumatic in his specimen of Ornithopsis
. Owen disagreed with Seeley's concept of a giant creature bridging the gap between bird
s or pterosaur
s (Owen considered sauropods to be whale-like marine reptiles), and while he acknowledged that the external cavities on the vertebrae may have been connected to the lung
s, he interpreted the internal passages as having been filled with cartilage
(hence his name for the genus, Chondrosteosaurus or "cartilage and bone lizard").
Owen also named a second species, Chondrosteosaurus magnus, that today no longer is considered to belong to Chondrosteosaurus.
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
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...
.
The type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
, Chondrosteosaurus gigas, was described and named by Richard Owen
Richard Owen
Sir Richard Owen, FRS KCB was an English biologist, comparative anatomist and palaeontologist.Owen is probably best remembered today for coining the word Dinosauria and for his outspoken opposition to Charles Darwin's theory of evolution by natural selection...
in 1876. The fossils of Chondrosteosaurus were discovered in the 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:...
on 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...
. C. gigas is known only from two neck vertebrae (specimens BMNH 46869, the holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
, and BMNH 46870), with distinctive hollows and internal passages now interpreted as evidence of pneumatic air sacs. Paleontologist Harry Seeley
Harry Seeley
Harry Govier Seeley was a British paleontologist.-Career:Seeley was born in London, the son of Richard Hovill Seeley, goldsmith, and his second wife Mary Govier. He attended classes at the Royal School of Mines, Kensington before becoming an assistant to Adam Sedgwick at the Woodwardian Museum,...
had interpreted similar structures as pneumatic in his specimen of Ornithopsis
Ornithopsis
Ornithopsis was a medium-sized Early Cretaceous sauropod dinosaur, from England. It has been considered a synonym of the wastebasket taxon Pelorosaurus, but recent research suggests that this is not as clear-cut as supposed...
. Owen disagreed with Seeley's concept of a giant creature bridging the gap between bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s or pterosaur
Pterosaur
Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight...
s (Owen considered sauropods to be whale-like marine reptiles), and while he acknowledged that the external cavities on the vertebrae may have been connected to the lung
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
s, he interpreted the internal passages as having been filled with cartilage
Cartilage
Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...
(hence his name for the genus, Chondrosteosaurus or "cartilage and bone lizard").
Owen also named a second species, Chondrosteosaurus magnus, that today no longer is considered to belong to Chondrosteosaurus.