''Metriacanthosaurus'' (meaning "moderately-spined lizard") is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

metriacanthosaurid Metriacanthosauridae (Greek for "moderately-spined lizards") is an extinct family of allosauroid theropod dinosaurs that lived in Europe and Asia from the Middle Jurassic to the Early Cretaceous. The family is split into two subgroups: Metriacant ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

from the

Oxford Clay Formation The Oxford Clay (or Oxford Clay Formation) is a Jurassic marine sedimentary rock formation underlying much of southeast England, from as far west as Dorset and as far north as Yorkshire. The Oxford Clay Formation dates to the Jurassic, specific ...

England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

, dating to the

Late Jurassic The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen ...

period Period may refer to: Common uses * Period (punctuation) * Era, a length or span of time *Menstruation, commonly referred to as a "period" Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (o ...

, about 160 million years ago (lower Oxfordian). It is the only named metriacanthosaurid known outside of Asia.

History of discovery

The holotype of ''Metriacanthosaurus parkeri'', specimen OUM J.12144, was discovered in 1871 by W. Parker at Jordan's Cliff, near Weymouth,

Dorset Dorset ( ; Archaism, archaically: Dorsetshire , ) is a Ceremonial counties of England, ceremonial county in South West England. It is bordered by Somerset to the north-west, Wiltshire to the north and the north-east, Hampshire to the east, t ...

, on the southwest coast of England. The specimen includes an incomplete hip, a leg bone, and part of a backbone; the

geologist A geologist is a scientist who studies the structure, composition, and History of Earth, history of Earth. Geologists incorporate techniques from physics, chemistry, biology, mathematics, and geography to perform research in the Field research, ...

John Phillips briefly commented on the specimen during the same year. These bones were from the

, which dates to the

Upper Jurassic The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987. In European lithostratigraphy, the name ...

. In 1923, German paleontologist

Friedrich von Huene Baron Friedrich Richard von Hoyningen-Huene (22 March 1875 – 4 April 1969) was a German nobleman paleontologist who described a large number of dinosaurs, more than anyone else in 20th-century Europe. He studied a range of Permo-Carbonife ...

wrote a paper on

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

and

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

European carnivorous dinosaurs within

Saurischia Saurischia ( , meaning "reptile-hipped" from the Greek ' () meaning 'lizard' and ' () meaning 'hip joint') is one of the two basic divisions of dinosaurs (the other being Ornithischia), classified by their hip structure. Saurischia and Ornithi ...

. In this paper, he examined OUM J.12144, assigning it to a new species of ''

Megalosaurus ''Megalosaurus'' (meaning "great lizard", from Ancient Greek, Greek , ', meaning 'big', 'tall' or 'great' and , ', meaning 'lizard') is an extinct genus of large carnivorous theropod dinosaurs of the Middle Jurassic Epoch (Bathonian stage, 166 ...

'': ''Megalosaurus parkeri''. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

honours W. Parker. In 1932, however, von Huene concluded it was a species of ''

Altispinax ''Altispinax'' (; "with high spines") is a genus of large predatory theropod dinosaur from the Early Cretaceous period (Valanginian, 140 to 133 million years ago) of what is now the Wadhurst Clay Formation of East Sussex, England. History Proba ...

'', ''A. parkeri''. In 1964, scientist

Alick Walker Alick Donald Walker (26 October 1925 – 4 December 1999) was a British palaeontologist, after whom the ''Alwalkeria'' genus of dinosaur is named. He was born in Skirpenbeck, near York and attended Pocklington School from 1936 to 1943. He began ...

decided these fossils were too different from ''Altispinax'', as they lacked the long vertebral spines, and named the new genus ''Metriacanthosaurus''. The generic name is derived from Greek ''metrikos'', "moderate", and ''akantha'', "spine". ''Metriacanthosaurus'' thus gets its name from its

vertebrae Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal ...

, which are taller than typical carnosaurs, like ''

Allosaurus ''Allosaurus'' ( ) is an extinct genus of theropod dinosaur that lived 155 to 145 million years ago during the Late Jurassic period ( Kimmeridgian to late Tithonian ages). The first fossil remains that could definitively be ascribed to th ...

'', but lower than other high-spined dinosaurs like ''

Acrocanthosaurus ''Acrocanthosaurus'' ( ; ) is a genus of carcharodontosaurid dinosaurs that existed in what is now North America during the Aptian and early Albian stages of the Early Cretaceous, from 113 to 110 million years ago. Like most dinosaur genera, ...

''.

Description

''Metriacanthosaurus'' was a medium-sized theropod with a femur length of .

Gregory S. Paul Gregory Scott Paul (born December 24, 1954) is an American freelance researcher, author and illustrator who works in paleontology. He is best known for his work and research on theropoda, theropod dinosaurs and his detailed illustrations, both l ...

in 1988 estimated its weight at . Thomas Holtz gave a length of 8 meters (26.2 feet). ''Metriacanthosaurus'' was named for the height of its

neural spines Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal ...

, which are actually not overly tall for theropods. They are similar to other theropods such as ''Megalosaurus'', ''

Sinraptor ''Sinraptor'' () is a genus of metriacanthosaurid theropod dinosaur from the Late Jurassic. The name ''Sinraptor'' comes from the Latin prefix "Sino", meaning Chinese, and "raptor", meaning robber. The specific name ''dongi'' honours Dong Zhimin ...

'', and ''

Ceratosaurus ''Ceratosaurus'' (from Greek 'horn' and 'lizard') is a genus of carnivorous theropod dinosaur that lived in the Late Jurassic period (Kimmeridgian to Tithonian ages). The genus was first described in 1884 by American paleontologist Othni ...

'' in being 1.5 times the height of the centrum.

Classification

Originally named as a species of ''Megalosaurus'' in

Megalosauridae Megalosauridae is a monophyletic Family (taxonomy), family of Carnivore, carnivorous theropod dinosaurs within the group Megalosauroidea. Appearing in the Middle Jurassic, megalosaurids were among the first major radiation of large theropod dino ...

, ''Metriacanthosaurus'' has since been reclassified in

Metriacanthosauridae Metriacanthosauridae (Greek for "moderately-spined lizards") is an extinct family of allosauroid theropod dinosaurs that lived in Europe and Asia from the Middle Jurassic to the Early Cretaceous. The family is split into two subgroups: Metriacan ...

. It is thought to be related to genera such as ''

Yangchuanosaurus ''Yangchuanosaurus'' is an extinct genus of metriacanthosaurid theropod dinosaur that lived in China from the Middle Jurassic to Late Jurassic periods (Bathonian to Tithonian stages), and was similar (although slightly larger) in size and appea ...

'', and in 1988 Paul synonymized the two genera. However, a 2007 review of British dinosaurs by

Darren Naish Darren William Naish (born 26 September 1975) is a British vertebrate palaeontologist, author and science communicator. As a researcher, he is best known for his work describing and reevaluating dinosaurs and other Mesozoic reptiles, including ...

and

David Martill {{Short pages monitor