''Oplosaurus'' (meaning "armed or weapon lizard" or "armoured lizard"; see below for discussion) was a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

sauropod Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their bo ...

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

from the

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 121.4 ± 1.0 Ma). It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is precede ...

-age

Lower Cretaceous Lower may refer to: *Lower (surname) *Lower Township, New Jersey *Lower Receiver (firearms) *Lower Wick Lower Wick is a small hamlet located in the county of Gloucestershire, England. It is situated about five miles south west of Dursley, eig ...

Wessex Formation The Wessex Formation is a fossil-rich English geological formation that dates from the Berriasian to Barremian stages (about 145–125 million years ago) of the Early Cretaceous. It forms part of the Wealden Group and underlies the younger Vect ...

of the

Isle of Wight The Isle of Wight ( ) is a county in the English Channel, off the coast of Hampshire, from which it is separated by the Solent. It is the largest and second-most populous island of England. Referred to as 'The Island' by residents, the Isle of ...

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

. It is known from a single tooth usually referred to the contemporaneous "

wastebasket taxon Wastebasket taxon (also called a wastebin taxon, dustbin taxon or catch-all taxon) is a term used by some taxonomists to refer to a taxon that has the sole purpose of classifying organisms that do not fit anywhere else. They are typically defined ...

" ''

Pelorosaurus ''Pelorosaurus'' ( ; meaning "monstrous lizard") is a genus of titanosauriform sauropod dinosaur. Remains referred to ''Pelorosaurus'' date from the Early Cretaceous period, about 140-125 million years ago, and have been found in England and Port ...

'', although there is no solid evidence for this.

History and taxonomy

In 1852

geologist A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althou ...

Thomas Wright reported the find of a large reptilian tooth from the ''Wealden Clay'' near Brixton Bay on Wight. Wright had presented the find to several experts, among them

Richard Owen Sir Richard Owen (20 July 1804 – 18 December 1892) was an English biologist, comparative anatomist and paleontologist. Owen is generally considered to have been an outstanding naturalist with a remarkable gift for interpreting fossils. Owe ...

, David Forbes,

George Robert Waterhouse George Robert Waterhouse (6 March 1810 – 21 January 1888) was an English natural history, naturalist. He was a keeper at the department of geology and later curator of the Zoological Society of London's museum. Early life George was born ...

and

Samuel Pickworth Woodward Samuel Pickworth Woodward (17 September 1821 – 11 July 1865) was an English geologist and malacologist. Biography He was the son of the geologist Samuel Woodward. In 1845, S. P. Woodward became the professor of geology and natural history in ...

but only

Gideon Mantell Gideon Algernon Mantell MRCS FRS (3 February 1790 – 10 November 1852) was a British obstetrician, geologist and palaeontologist. His attempts to reconstruct the structure and life of ''Iguanodon'' began the scientific study of dinosaurs: in ...

came with a useful suggestion pointing to a similarity with the teeth of the dinosaur ''

Hylaeosaurus ''Hylaeosaurus'' ( ; Greek: / "belonging to the forest" and / "lizard") is a herbivorous ankylosaurian dinosaur that lived about 136 million years ago, in the late Valanginian stage of the early Cretaceous period of England. It was found ...

''. Not convinced by this, Wright concluded that the tooth, in view of its sharpness, belonged to a carnivorous reptile of unknown affinities.Wright, T. (1852). Contributions to the palaeontology of the Isle of Wight. ''Annals and Magazine of Natural History'' 2:87-93. Wright had also asked the French paleontologist

Paul Gervais Paul Gervais full name François Louis Paul Gervais (26 September 1816 – 10 February 1879) was a French palaeontologist and entomologist. Biography Gervais was born in Paris, where he obtained the diplomas of doctor of science and of medicine ...

for his opinion on the fossil. Gervais in 1852 based the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

''Oplosaurus armatus'' on it. The generic name would normally read as "armoured lizard" from the Greek ''hoplon'', "body armour". The usual story about the — given the fact that ''Oplosaurus'' is not known to be armoured — odd choice of name is that Gervais named this large, well-preserved tooth (

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

BMNH R964) under the mistaken belief that its owner was an armoured dinosaur like ''Hylaeosaurus'' following Mantell's suggestion.Naish, D., and Martill, D.M. (2001). Saurischian dinosaurs 1: Sauropods. In: Martill, D.M., and Naish, D. (eds.). ''Dinosaurs of the Isle of Wight''. The Palaeontological Association:London 185-241. However
recent research
by Ben Creisler shows that Gervais compared it to ''

Mosasaurus ''Mosasaurus'' (; "lizard of the Meuse River") is the type genus (defining example) of the mosasaurs, an extinct group of aquatic squamate reptiles. It lived from about 82 to 66 million years ago during the Campanian and Maastrichtian sta ...

'', not ''Hylaeosaurus'', and that the name may have been intended as "armed lizard", with the teeth as the weapons of a

carnivore A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...

, as ''hoplon'' can also mean "weapon" (although this would make the specific name redundant, as ''armatus'' too means "armed" in

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

).Gervais, P. (1852). ''Zoologie et paléontologie française (animaux vertébrés)'' (1st edition). A. Bertrand:Paris, 271 p.

rench The Rench is a right-hand tributary of the Rhine in the Ortenau ( Central Baden, Germany). It rises on the southern edge of the Northern Black Forest at Kniebis near Bad Griesbach im Schwarzwald. The source farthest from the mouth is that of the ...

/ref>

Richard Lydekker Richard Lydekker (; 25 July 1849 – 16 April 1915) was an English naturalist, geologist and writer of numerous books on natural history. Biography Richard Lydekker was born at Tavistock Square in London. His father was Gerard Wolfe Lydekker, ...

(1888) suggested that a

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...

with a tooth (BMNH R751), also from the Isle of Wight, was another exemplar of this animal, but this opinion has not been substantiated. Lydekker also used the improved spelling "Hoplosaurus" but the original ''Oplosaurus'' has priority. The tooth is large, 85 mm (3.35 in) tall in total, with a

spatula A spatula is a broad, flat, flexible blade used to mix, spread and lift material including foods, drugs, plaster and paints. In medical applications, "spatula" may also be used synonymously with tongue depressor. The word ''spatula'' derives f ...

te crown 52 mm (2.05 in) tall, comparable to ''

Brachiosaurus ''Brachiosaurus'' () is a genus of sauropod dinosaur that lived in North America during the Late Jurassic, about 154to 150million years ago. It was first described by American paleontologist Elmer S. Riggs in 1903 from fossils found in th ...

''; it has a pointed tip, a slightly compressed form "cheek" to

tongue The tongue is a muscular organ (anatomy), organ in the mouth of a typical tetrapod. It manipulates food for mastication and swallowing as part of the digestive system, digestive process, and is the primary organ of taste. The tongue's upper surfa ...

, a slight

convex Convex or convexity may refer to: Science and technology * Convex lens, in optics Mathematics * Convex set, containing the whole line segment that joins points ** Convex polygon, a polygon which encloses a convex set of points ** Convex polytope ...

ity to the base of the tongue-facing side, and wear facets. It is vaguely like a ''Brachiosaurus'' tooth, which is why the genus has for a time been referred to the

Brachiosauridae The Brachiosauridae ("arm lizards", from Greek ''brachion'' (βραχίων) = "arm" and ''sauros'' = "lizard") are a family or clade of herbivorous, quadrupedal sauropod dinosaurs. Brachiosaurids had long necks that enabled them to access the ...

.McIntosh, J.S. (1990). Sauropoda. In: Weishampel, D.B., Dodson, P., and Osmólska, H. (eds.). ''The Dinosauria''. University of California Press:Berkeley 345-401. Earlier, ''Oplosaurus'' was typically referred to ''

'' following an opinion of Friedrich von Huene in 1909, although ''Pelorosaurus'' is based on fragmentary remains that do not include teeth, making it impossible to prove the identity. (See Naish and Martill (2001) for a good review of ''Oplosaurus'' and Wealden sauropods in general
here
is a more recent informal summation of the state of work.) Given how poor the ''

material is, and that it doesn't include teeth, recent reviews have retained ''Oplosaurus'' as a potentially valid but poorly known genus.Upchurch, P.M., Barrett, P.M., and Dodson, P. (2004). Sauropoda. In: Weishampel, D.B., Dodson, P., and Osmólska, H. (eds.). ''The Dinosauria'' (2nd edition). University of California Press:Berkeley 259-322.

Darren Naish Darren William Naish 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 '' Eotyrannus'', '' Xenop ...

, a

British British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories, and Crown Dependencies. ** Britishness, the British identity and common culture * British English, ...

palaeontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

familiar with Wealden sauropods, ha
suggested informally
that the genus may be a turiasaur but also co-authored an article concluding it was a member of the

Camarasauridae Camarasauridae is a family of sauropod dinosaurs. Among sauropods, camarasaurids are small to medium-sized, with relatively short necks. They are visually identifiable by a short skull with large nares, and broad, spatulate teeth filling a thick ...

. In any case, it likely belongs to the more general

Macronaria Macronaria is a clade of sauropod dinosaurs. Macronarians are named after the large diameter of the nasal opening of their skull, known as the external naris, which exceeded the size of the orbit, the skull opening where the eye is located (hence ...

. A 2022 review considered it to be a potential turiasaur, echoing Naish's suggestion.

Paleobiology

As Naish and Martill point out, the tooth is comparable in size to that of ''

'', indicating that the owner was a large sauropod; as a possible turiasaur, the size should not change drastically. It would have been a

quadruped Quadrupedalism is a form of locomotion where four limbs are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four limbs is said to be a quadruped (from Latin ''quattuor' ...

herbivore A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

, possibly around 25 m (82 ft) long.

References

External links

Darren Naish on Wealden sauropod diversity (pre-turiasaurs)
{{Taxonbar, from=Q4765905 Macronarians Early Cretaceous dinosaurs of Europe Fossil taxa described in 1852 Taxa named by Paul Gervais