Dacentrurus
Encyclopedia
Dacentrurus originally known as Omosaurus, was a large stegosaur
of the Late Jurassic
Period (154 - 150 mya).
This dinosaur measured around 8 metres (26.2 ft) in length. It had paired triangular plates down its spine, with four pairs of spikes on the end of the tail. This configuration closely resembles that of its relative, Kentrosaurus
(see also: thagomizer
). Many books claim that Dacentrurus was a small stegosaur, when in fact finds such as a 1.5 metres (4.9 ft) pelvis
(measured at the acetabula
) suggest that Dacentrurus was among the largest of them. Although Dacentrurus is considered to have the same proportions as a Stegosaurus
, Dacentrurus plate and spike configuration is known to be rather different, as Dacentrurus has both two rows of small plates and two rows of longer spines along its back. Its closest relative within Stegosauria is Miragaia
, and the two are united in the subfamily Dacentrurinae.
in 1875 as Omosaurus armatus, it was the first stegosaur ever discovered, although the genus name had to be changed as the name Omosaurus was preoccupied.
Other proposed species of Dacentrurus include D. durobrivensis (included
with Lexovisaurus
durobrivensis), D. phillipsi (sometimes mistakenly included with Priodontognathus phillipsi, due to having the same species name and a confused history), and D. vetustus (included with Lexovisaurus
vetustus).
and Dorset
(including a vertebra ascribed to D. armatus in Weymouth) in southern England, France and Spain and five more historically recent skeletons from Portugal.
Eggs attributed to Dacentrurus have also been discovered in Portugal.
Stegosauria
Known colloquially as stegosaurs, the Stegosauria are a group of herbivorous dinosaurs of the Jurassic and Early Cretaceous Periods, being found mostly in the Northern Hemisphere, predominantly in what is now North America and China....
of the Late Jurassic
Late Jurassic
The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 161.2 ± 4.0 to 145.5 ± 4.0 million years ago , which is preserved in Upper Jurassic strata. In European lithostratigraphy, the name "Malm" indicates rocks of Late Jurassic age...
Period (154 - 150 mya).
Description
Kentrosaurus
Kentrosaurus is a genus of stegosaurid dinosaur from the Late Jurassic of Tanzania. Its fossils have been found only in the Tendaguru Formation of Tanzania, dated to the Kimmeridgian stage, between about 155.7 ± 4 Ma and 150.8 ± 4 Ma . Apparently, all finds belong to one species, K...
(see also: thagomizer
Thagomizer
Thagomizer is an informal name for the distinctive arrangement of four to ten spikes on the tails of stegosaurid dinosaurs. These spikes are believed to have been a defensive measure against predators.-Paleobiology:...
). Many books claim that Dacentrurus was a small stegosaur, when in fact finds such as a 1.5 metres (4.9 ft) pelvis
Pelvis
In human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...
(measured at the acetabula
Acetabulum
The acetabulum is a concave surface of the pelvis. The head of the femur meets with the pelvis at the acetabulum, forming the hip joint.-Structure:...
) suggest that Dacentrurus was among the largest of them. Although Dacentrurus is considered to have the same proportions as a Stegosaurus
Stegosaurus
Stegosaurus is a genus of armored stegosaurid dinosaur. They lived during the Late Jurassic period , some 155 to 150 million years ago in what is now western North America. In 2006, a specimen of Stegosaurus was announced from Portugal, showing that they were present in Europe as well...
, Dacentrurus plate and spike configuration is known to be rather different, as Dacentrurus has both two rows of small plates and two rows of longer spines along its back. Its closest relative within Stegosauria is Miragaia
Miragaia (dinosaur)
Miragaia is a genus of stegosaurid dinosaur. Its fossils have been found in Upper Jurassic rocks in Portugal...
, and the two are united in the subfamily Dacentrurinae.
Discovery and species
When it was described by Richard OwenRichard 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 1875 as Omosaurus armatus, it was the first stegosaur ever discovered, although the genus name had to be changed as the name Omosaurus was preoccupied.
Species
Inclusion (taxonomy)
In taxonomy, inclusion is the process whereby two species that were believed to be distinct are found in fact to be the same and are thus combined as one species...
with Lexovisaurus
Lexovisaurus
Lexovisaurus was one of the first dinosaurs from mid-to-Late Jurassic Europe, 164.7 mya to be discovered. It was a stegosaur. Its fossils have been found in France and northern England....
durobrivensis), D. phillipsi (sometimes mistakenly included with Priodontognathus phillipsi, due to having the same species name and a confused history), and D. vetustus (included with Lexovisaurus
Lexovisaurus
Lexovisaurus was one of the first dinosaurs from mid-to-Late Jurassic Europe, 164.7 mya to be discovered. It was a stegosaur. Its fossils have been found in France and northern England....
vetustus).
Distribution
Fossil evidence has been found in WiltshireWiltshire
Wiltshire is a ceremonial county in South West England. It is landlocked and borders the counties of Dorset, Somerset, Hampshire, Gloucestershire, Oxfordshire and Berkshire. It contains the unitary authority of Swindon and covers...
and Dorset
Dorset
Dorset , is a county in South West England on the English Channel coast. The county town is Dorchester which is situated in the south. The Hampshire towns of Bournemouth and Christchurch joined the county with the reorganisation of local government in 1974...
(including a vertebra ascribed to D. armatus in Weymouth) in southern England, France and Spain and five more historically recent skeletons from Portugal.
- Argiles d'OctevilleArgiles d'OctevilleThe Argiles d'Octeville is a geological formation in Europe. It dates back to the Late Jurassic.-Vertebrate fauna:...
- Camadas de AlcobaçaCamadas de AlcobaçaThe Camadas de Alcobaça is a geological formation in Portugal. It dates back to the Oxfordian stage of the Late Jurassic.-Vertebrate fauna:Dinosaur eggs are geographically located in Distrito do Lisboa, Portugal. Dinosaur tracks are geographically located in Distrito do Leiria,...
- El Collado FormationEl Collado FormationThe El Collado Formation is a geological formation in Cuenca, Spain whose strata date back to the Early Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.-References:...
- Kimmeridge ClayKimmeridge ClayThe Kimmeridge Clay Formation is a sedimentary deposit of fossiliferous marine clay which is of Jurassic age. It occurs in Europe.Kimmeridge Clay is arguably the most economically important unit of rocks in the whole of Europe, being the major source rock for oil fields in the North Sea hydrocarbon...
- Unidade Amoreira-Porto NovoUnidade Amoreira-Porto NovoThe Amoreira Member and Porto Novo Member is a subdivision of the Lourinhã Formation, a geological formation in Portugal. It dates back to the Late Jurassic....
- Unidade BombarralUnidade BombarralThe Unidade Bombarral is a geological formation in Europe. It dates back to the Late Jurassic.-Vertebrate fauna:Indeterminate stegosauridae remains once referred to Dacentrurus armatus were located in Distrito do Leiria, Portugal. Theropod tracks have been located in Distrito do Lisboa, Portugal....
- ?Unidade Castehanos
- Unidade SobralUnidade SobralThe Sobral Unit or Sobral Member is a subdivision of the Lourinhã Formation, a geological formation in Portugal. It dates back to the Late Jurassic.-Vertebrate fauna:...
Eggs attributed to Dacentrurus have also been discovered in Portugal.