Hubbry Logo
MetriacanthosaurusMetriacanthosaurusMain
Open search
Metriacanthosaurus
Community hub
Metriacanthosaurus
logo
8 pages, 0 posts
0 subscribers
Be the first to start a discussion here.
Be the first to start a discussion here.
Metriacanthosaurus
Metriacanthosaurus
Metriacanthosaurus
View on Wikipedia
from Wikipedia

Metriacanthosaurus
Temporal range: Late Jurassic,
~160 Ma
↓
 Oxfordian
Part of the holotype of Metriacanthosaurus parkeri (individual fossils not to scale)
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Family: †Metriacanthosauridae
Subfamily: †Metriacanthosaurinae
Genus: †Metriacanthosaurus
Walker, 1964
Type species
†Metriacanthosaurus parkeri
(von Huene, 1923) Walker, 1964
Synonyms

Metriacanthosaurus (meaning "moderately-spined lizard") is a genus of metriacanthosaurid dinosaur from the Oxford Clay Formation of England, dating to the Late Jurassic period, about 160 million years ago (lower Oxfordian). It is the only metriacanthosaurid currently named from outside of Asia.

History of discovery

[edit]
Image (left) and reconstruction (right) of the ilium of the holotype

The holotype of Metriacanthosaurus parkeri, specimen OUM J.12144, was discovered in 1871 by W. Parker at Jordan's Cliff, near Weymouth, Dorset, on the southwest coast of England.[1] The specimen includes an incomplete hip, a leg bone, and part of a backbone; the geologist John Phillips briefly commented on the specimen during the same year.[2] These bones were from the Oxford Clay Formation, which dates to the Upper Jurassic.[3]

In 1923, German paleontologist Friedrich von Huene wrote a paper on Jurassic and Cretaceous European carnivorous dinosaurs within Saurischia. In this paper, he examined OUM J.12144, assigning it to a new species of Megalosaurus: Megalosaurus parkeri.[1] The specific name honours W. Parker. In 1932, however, von Huene concluded it was a species of Altispinax, A. parkeri.[4]

In 1964, scientist Alick Walker decided these fossils were too different from Altispinax, as they lacked the long vertebral spines, and named the new genus Metriacanthosaurus.[5] The generic name is derived from Greek metrikos, "moderate", and akantha, "spine". Metriacanthosaurus thus gets its name from its vertebrae, which are taller than typical carnosaurs, like Allosaurus, but lower than other high-spined dinosaurs like Acrocanthosaurus.

Description

[edit]
Life restoration

Metriacanthosaurus was a medium-sized theropod with a femur length of 80 cm (31 in). Gregory S. Paul in 1988 estimated its weight at 1 tonne (1.1 short tons).[6] Thomas Holtz gave a length of 8 meters (26.2 feet).[7] Metriacanthosaurus was named for the height of its neural spines, which are actually not overly tall for theropods.[3] They are similar to other theropods such as Megalosaurus, Sinraptor, and Ceratosaurus in being 1.5 times the height of the centrum.[8]

Classification

[edit]

Originally named as a species of Megalosaurus in Megalosauridae, Metriacanthosaurus has since been reclassified in Metriacanthosauridae. It is thought to be related to genera such as Yangchuanosaurus, and in 1988 Paul synonymized the two genera. However, a 2007 review of British dinosaurs by Darren Naish and David Martill defending keeping the two genera taxonomically separate.[3] Metriacanthosaurus is considered a member of the subfamily Metriacanthosaurinae.[9]

Below is a simplified cladogram of Tetanurae by Matthew Carrano et al. (2012).[9]

Metriacanthosauridae

Paleobiogeography and paleoecology

[edit]
Paleogeographic map of Europe during the early Oxfordian

Metriacanthosaurus is the only known member of Metriacanthosauridae outside of Asia (other than possible fragmentary records from the geographically close Falaises des Vaches Noires locality of northern France, which is probably similar in age to Metriacanthosaurus[10]). The earliest records of metriacanthosaurids in Asia are from the early Middle Jurassic, with Metriocanthosaurus being nested within the diversity of Asian metriacanthosaurids. Metriacanthosaurus thus likely represents a dispersal event from Asia into Europe during the early Late Jurassic. Metriacanthosaurus appears to have lived alongside other large theropods belonging to the family Megalosauridae.[11] Other dinosaurs known from the Oxford Clay (which both spans the preceding Callovian and the Oxfordian) include the megalosaurid theropod Eustreptospondylus, the sauropod Cetiosauriscus, the stegosaurs Lexovisaurus and Loricatosaurus, the ankylosaur Sarcolestes, and the iguanodontian Callovosaurus.,[12] with the poorly known ankylosaur Cryptosaurus also being known from Oxfordian aged sediments in Britain.[13][14] During this time, Europe formed an archipelago of islands surrounded by shallow seas, explaining the findings of these dinosaurs in marine sediments.[10]

References

[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Metriacanthosaurus

View on Grokipedia
from Grokipedia
Metriacanthosaurus is a genus of large, carnivorous theropod dinosaur belonging to the family Metriacanthosauridae, known from the Late Jurassic Oxford Clay Formation in England, dating to approximately 159–154 million years ago. It was a bipedal predator estimated to reach lengths of 8.2 meters, with a robust build similar in proportions to the North American Allosaurus, though reconstructions rely on comparisons due to the fragmentary nature of its remains. The type and only species, M. parkeri, was first described by German paleontologist Friedrich von Huene in 1923 as a species of Megalosaurus based on fossils including several dorsal vertebrae, a partial pelvis, and hindlimb elements collected from the Oxford Clay near Weymouth, Dorset. In 1964, British paleontologist A.D. Walker erected the genus Metriacanthosaurus to accommodate these remains, noting the moderately elevated neural spines on the vertebrae—translating to "moderately-spined lizard"—which distinguished it from other theropods like the taller-spined Altispinax. No cranial material has been found, limiting direct knowledge of its skull, but its postcranial skeleton suggests a body mass around 1 tonne, with a femur length of approximately 80 cm indicating a hip height of about 2 meters. Phylogenetically, Metriacanthosaurus is classified within , a basal clade of tetanuran theropods in the larger Allosauroidea superfamily, closely related to Asian genera such as Yangchuanosaurus and Sinraptor. This family is characterized by features like sheet-like neural spines and moderately pneumatized vertebrae, though Metriacanthosaurus represents the sole European member and one of the earliest known, highlighting faunal connections between and during the Middle to . As a top predator in its lagoonal, marine-influenced environment, Metriacanthosaurus likely hunted large prey such as ornithopods and smaller theropods, with its robust limbs adapted for agile pursuit rather than extreme speed. Its discovery underscores the diversity of large theropods in the European , contributing to understandings of early tetanuran before the dominance of advanced allosauroids in the .

Discovery

Fossil Material

The specimen of Metriacanthosaurus, cataloged as OUM J.12144, was discovered in 1871 at Jordan's Cliff near Weymouth in Dorset, , by W. Parker. This partial skeleton includes elements of the pelvic girdle (right ilium, right and left pubes, fragments of right and left ), hindlimb bones (, , ), and components (three anterior dorsal vertebrae, one posterior dorsal vertebra, partial , and four proximal caudal vertebrae). The fossils are weathered and incomplete, lacking a , forelimbs, and most of the axial column; the preserved measures 80 cm in length. The specimen is currently housed at the Oxford University Museum of Natural History. No additional specimens are definitively referred to Metriacanthosaurus, although some isolated theropod bones from the Formation have been tentatively attributed to the genus in broader studies of the formation's vertebrate assemblage.

Naming History

The holotype fossils of Metriacanthosaurus were collected from the Formation at Jordan's Cliff near Weymouth in Dorset, , by W. Parker in 1871. In 1871, briefly described several of these remains—including three dorsal vertebrae, a partial ilium, and a —as belonging to an indeterminate species of , noting their similarity to the M. bucklandii but without assigning a specific . In 1923, Friedrich von Huene provided a more detailed examination of the material, formally naming the species Megalosaurus parkeri in honor of its discoverer, W. Parker; this designation was based on the distinctive morphology of the neural spines and pelvic elements, which von Huene interpreted as indicative of a large theropod closely related to . The genus remained classified under Megalosaurus until 1964, when Alick D. Walker re-evaluated the (Oxford University of specimen J.12144) and erected the new genus Metriacanthosaurus for M. parkeri, emphasizing the moderately elongated neural spines (reaching about 20% of vertebral height) that distinguished it from other megalosauroids. Subsequent taxonomic work in the late validated Metriacanthosaurus parkeri as the of the family , first proposed by in 1988 to encompass theropods with similar vertebral and pelvic features; this classification was reinforced through phylogenetic analyses in the , such as those by Holtz (1994) and Sereno (1998), which positioned it as a basal allosauroid.

Description

Size Estimates

Metriacanthosaurus is estimated to have reached a total body length of 7.5 to 8 meters, derived from scaling the preserved length of 80 cm using theropod regression formulas that relate dimensions to overall size. One such approach involves applying allometric equations to measurements, such as body mass approximations from length-based models, though circumference-based methods are also considered for refinement. Due to the fragmentary of the remains, these estimates rely on comparisons to related theropods like . Body mass estimates for Metriacanthosaurus center around 1 tonne (approximately 1000 kg), obtained through volumetric modeling of the elements and direct comparisons to the similarly proportioned , which shares comparable femoral robusticity and pelvic structure. These calculations account for the dinosaur's bipedal stance and estimated distribution, yielding a robust predator of medium size within its . Hip height is inferred to be around 2 meters, based on proportional relationships between the length and the preserved ilium, which indicate a relatively upright posture typical of basal tetanurans. The specimen likely represents an adult individual, based on its overall size and robusticity.

Anatomical Features

Metriacanthosaurus exhibits several key osteological characteristics in its postcranial skeleton that highlight its position among basal tetanuran theropods. Due to the fragmentary , details are supplemented by comparisons to related genera. The dorsal vertebrae feature moderately elongated neural spines, approximately 1.5 times the height of the centrum, which contribute to a "moderately spiny" dorsal profile. These spines are taller than those in but shorter than the exaggerated structures seen in spinosaurids like , reflecting an intermediate morphology among theropods. The pelvic girdle of Metriacanthosaurus is robust, with the ilium displaying an elongated preacetabular process that extends anteriorly, providing attachment for powerful musculature. The pubis and are notably sturdy, characterized by twisting shafts that enhance structural integrity during locomotion. These features suggest adaptations for supporting a medium-sized bipedal frame capable of bursts of speed. In the , the is straight along its shaft and bears a prominent fourth , a ridge for major retractor muscle attachment typical of theropods. The exceeds the in length, a proportion indicative of agile, capabilities suited to navigating varied terrains. Additionally, the cervical and dorsal vertebrae include pneumatic foramina, openings that imply invasion by , a trait consistent with advanced theropod respiratory systems.

Classification

Taxonomic History

The taxonomic history of Metriacanthosaurus began in the with the collection of its material (OUM J.12144) by W. Parker in 1871 from the Formation at Jordan's Cliff near , ; these remains, including parts of the , , and vertebrae, were initially regarded as belonging to a large carnivorous referable to . In 1923, Friedrich von Huene formally described the specimen as a new species, Megalosaurus parkeri, retaining it within but noting distinctive features such as moderately tall neural spines and robust limb bones that set it apart from the type Megalosaurus bucklandii. By 1932, von Huene had reclassified it as parkeri due to the prominent dorsal spines, emphasizing its similarities to other European theropods with elongated neural processes. In the mid-20th century, Alick D. Walker revisited the material in 1964, erecting the new genus Metriacanthosaurus ( M. parkeri) to accommodate the Dorset specimen, which he distinguished from both and based on its moderate neural spine height, allosauroid-like pelvic structure, and overall proportions; Walker suggested close affinities with Asian theropods, including forms later synonymized under Metriacanthosaurus such as M. "huxleyi". This reclassification highlighted Metriacanthosaurus as a distinct Middle to tetanuran, bridging European and Asian theropod faunas. By the late , taxonomic views shifted from broad carnosaur groupings to more refined theropod phylogenies. Gregory S. Paul in 1988 interpreted Metriacanthosaurus as a member of , synonymizing the Asian genus with it and emphasizing shared cranial and postcranial traits indicative of a robust, apex-predatory . Thomas R. Holtz Jr. in 2000 further refined this placement within a cladistic framework, positioning Metriacanthosaurus as a basal allosauroid outside advanced carcharodontosaurids, based on comparative analyses of morphology and vertebral architecture that underscored its tetanuran affinities.

Phylogenetic Relationships

Metriacanthosaurus serves as the and occupies a basal position within , a family of allosauroid theropods nested in the larger clade Allosauroidea and often aligned with Carcharodontosauria based on shared cranial and postcranial features. This family is diagnosed by several synapomorphies, including moderately elongated neural spines on the dorsal vertebrae that exceed twice the height of the centra and distinct pelvic morphology, such as a pubis-boot angle less than 60° and distally fused ischia, traits shared with Asian relatives like and Sinraptor. Phylogenetic analyses by Rauhut et al. (2024) recover as a diverse clade with a broad distribution, originating in South-East and dispersing westward to (e.g., the Kyrgyzstani taxon Alpkarakush kyrgyzicus) and eventually (), highlighting faunal connections across during the Jurassic. The 2025 description of Yuanmouraptor jinshajiangensis by Zou et al. further strengthens the of , placing Yuanmouraptor as the most basal member in a with Xuanhanosaurus and the clade comprising and Sinraptor, based on shared features such as vertebral pneumatization. In comparisons to outgroups, Metriacanthosaurus differs from notably in possessing a less pronounced without the distinct neck separation seen in , underscoring its position as a metriacanthosaurid rather than an allosaurid.

Paleobiology

Geological Context

Metriacanthosaurus fossils date to the Epoch, specifically the Oxfordian stage, approximately 163 to 160 million years ago. The primary fossil material, including the specimen, originates from the Formation, a sequence of predominantly mudstones and minor limestones deposited across . This formation represents a low-energy, offshore marine shelf environment influenced by lagoonal conditions, with evidence of periodic marine incursions into more restricted, brackish settings. The fossils were discovered along the Dorset coast, particularly at sites like Furzy Cliff near Weymouth, within the broader context of the European Jurassic archipelago—a fragmented of islands and shallow seas during the Oxfordian. Sedimentary evidence from the indicates a subtropical, humid in this region, characterized by warm temperatures and seasonal rainfall that supported diverse terrestrial and . Taphonomic preservation of Metriacanthosaurus remains occurs primarily in fine-grained mudstones of the formation, reflecting deposition in a quiet, anoxic bottom environment that favored the accumulation of disarticulated bones with minimal disturbance or scavenging. This low-energy setting contributed to the incomplete but well-mineralized nature of the specimens, often found in association with and occasional terrestrial debris washed into the lagoonal system.

Ecological Interactions

Metriacanthosaurus likely occupied the role of an within the Formation ecosystem of , preying upon medium-sized herbivores such as the sauropod Cetiosauriscus and the stegosaur Lexovisaurus. These prey items were part of a diverse terrestrial assemblage that included other sauropods like Cetiosaurus and various ornithischians, reflecting a coastal where terrestrial remains were occasionally transported into marine deposits. Fossil associations indicate that Metriacanthosaurus likely targeted herbivores of comparable size, using its robust build to inflict lethal wounds during hunts. The genus coexisted with the fellow theropod , another large carnivore in the fauna, as well as marine reptiles such as the ichthyosaur and abundant fish taxa including and Hypsocormus. This sympatric theropod assemblage suggests niche partitioning, with no direct evidence of intense competition between Metriacanthosaurus and larger megalosaurids, which were more prominent in contemporaneous European formations elsewhere. The overall ecosystem balanced terrestrial predators with a rich marine component, where Metriacanthosaurus may have scavenged marine carcasses opportunistically alongside active predation on land. Paleoecological inferences portray Metriacanthosaurus as an ambush or pursuit predator adapted to the vegetated coastal floodplains of the environment, leveraging its bipedal agility to chase or surprise prey in forested or open terrains. Studies from 2025 on related metriacanthosaurids, including new Asian taxa, highlight potential gregarious behaviors inferred from bonebed associations in relatives like , suggesting pack-hunting as a plausible , though direct evidence for this in Metriacanthosaurus remains absent. Biogeographically, the isolated European occurrence of Metriacanthosaurus points to a relic population stemming from an early dispersal across from Asian origins, underscoring the fragmented island geography of the time.

References

  1. https://www.nhm.ac.uk/discover/dino-directory/metriacanthosaurus.html
  2. https://www.3d-fossils.ac.uk/fossilType.cfm?typSampleId=15000859
  3. https://royalsocietypublishing.org/doi/10.1098/rstb.1964.0009
  4. https://www.prehistoric-wildlife.com/species/m-etriacanthosaurus/
  5. https://peerj.com/articles/19218/
  6. https://webapps.bgs.ac.uk/lexicon/lexicon.cfm?pub=OXC
  7. https://oumrp.nsms.ox.ac.uk/cgi-bin/jurassic.cgi?detail_oid=J.12144
  8. http://www.paleofile.com/Dinosaurs/Theropods/Metriacanthosaurus.asp
  9. https://www.prehistoric-wildlife.com/species/metriacanthosaurus/
  10. https://www.emgs.org.uk/uploads/1/4/9/1/149143154/mg11_3_1988_171_martill_review_of_terrestrial_vertebrate_fossils_of_the_oxford_clay_2.pdf
  11. https://www.researchgate.net/publication/230808558_The_phylogeny_of_Tetanurae_Dinosauria_Theropoda
  12. https://paleobiodb.org/classic/basicTaxonInfo?taxon_no=38584
  13. https://paleobiodb.org/classic/basicTaxonInfo?taxon_no=39100
  14. https://besjournals.onlinelibrary.wiley.com/doi/10.1111/2041-210X.12226
  15. https://pmc.ncbi.nlm.nih.gov/articles/PMC11971988/
  16. https://royalsocietypublishing.org/doi/10.1098/rsos.230481
  17. https://academic.oup.com/zoolinnean/article/201/4/zlae090/7736730
  18. https://theropoddatabase.github.io/Carnosauria.htm
  19. https://data.jncc.gov.uk/data/574eac76-683c-47c6-a1de-b22439031f4c/gcr-v10-fossil-reptiles-of-great-britain-c7.pdf
  20. https://pubs.geoscienceworld.org/gsl/jgs/article/151/1/153/112442/Petrographic-analyses-of-organo-mineral
  21. https://data.jncc.gov.uk/data/d249bbc2-220e-4e39-afa6-1019ee91917e/gcr-v22-mesozoic-tertiary-palaeobotany-c4.pdf
  22. https://www.sciencedirect.com/science/article/abs/pii/S0921818101001011
  23. https://peerj.com/articles/6404/
  24. https://www.tandfonline.com/doi/full/10.1080/02724634.2021.1995737
  25. https://www.researchgate.net/publication/331088857_Additional_sauropod_dinosaur_material_from_the_Callovian_Oxford_Clay_Formation_Peterborough_UK_Evidence_for_higher_sauropod_diversity
  26. https://pmc.ncbi.nlm.nih.gov/articles/PMC6035862/
  27. https://www.researchgate.net/publication/249545903_The_trophic_structure_of_the_biota_of_the_Peterborough_Member_Oxford_Clay_Formation_Jurassic_UK
  28. https://www.researchgate.net/publication/304988181_Multivariate_and_Cladistic_Analyses_of_Isolated_Teeth_Reveal_Sympatry_of_Theropod_Dinosaurs_in_the_Late_Jurassic_of_Northern_Germany
Add your contribution
Related Hubs
User Avatar
No comments yet.