Simon Clabby (UK)
There was a lot written concerning the dinosaurs of the Isle of Wight through the years. For instance, Gideon Mantell, who found Iguanodon in 1821, wrote a e-book on the geology in 1847, by which he refers to its fossil fauna. Nevertheless, like all sciences, palaeontological analysis doesn’t stand nonetheless. Yearly, our information about dinosaurs adjustments as new discoveries are made. That is true even of the Isle of Wight, which, because the Eighties, has skilled a sudden upsurge in analysis, making many books on the topic now outdated.
The primary dinosaur discoveries passed off in antiquity, with native tales of “stone horses” (presumably Iguanodon, because of its horse-like cranium) being discovered within the cliffs. Nevertheless, the primary scientific discoveries passed off in 1829, when William Buckland (describer of Megalosaurus) described some Iguanodon materials from Yaverland. The mid 1800s was a time of huge curiosity in dinosaur analysis, with the Rev. William Fox, curate at Brighstone village (not removed from the fossil-rich cliffs at Brighstone bay) apparently neglecting his duties to search for fossils. In reality, he managed to find 4 new species throughout his tenure at Brighstone.
There was a little bit of a lull within the early twentieth century, with nothing new being found till the Nineteen Seventies. Nevertheless, since then, not less than three new species have been described, and an extra seven beforehand identified species being reassigned to new taxa.
The dinosaurs of the Isle of Wight virtually all come from the Wessex Formation, a gaggle of rocks that date from an age generally known as the Barremian (125 to 130 million years in the past), through the Early Cretaceous interval. Throughout this time, the Isle of Wight was a lot nearer the equator than it’s right this moment, and had a hotter local weather. The Wessex Basin, inside which the Isle of Wight is positioned, was a big floodplain, surrounded by conifer forest-covered hills.
The plain was seasonally flooded, and would fluctuate from close to desert situations to wetlands. Nevertheless, there have been loads of ferns and tree ferns to maintain the herbivore inhabitants. The panorama was coated in shallow, anoxic (oxygen-free) puddles. As well as, there was the occasional lake that may entice loads of Iguanodon herds to its waters, in addition to offering a house for turtles, crocodiles and fish, along with bivalves and different invertebrates. It was this seasonal flooding that allowed so many various genera to be preserved as fossils.
Dinosaurs will be discovered at a number of websites on the Isle of Wight. Firstly, there may be Yaverland, close to Sandown, the place a number of dinosaur species have been discovered, in addition to the occasional footprint.
Nevertheless, one of the best web site to search out dinosaurs is on the southwest coast, between Cowleaze Chine and Hanover level. This stretch of shoreline is likely one of the best for dinosaur stays within the UK, and perhaps even the world – over 20 species will be discovered right here, a lot of that are distinctive to the island. Whether or not that is as a result of depositional situations, excessive productiveness or simply the massive fossil gathering neighborhood on the Isle of Wight, it’s unattainable to say, however it might be a mixture of all these components.
Ornithopod dinosaurs
Beginning with the Ornithopod dinosaurs, the most typical dinosaur is Iguanodon, a big, herbivorous dinosaur, reaching 10m in size. Iguanodon might be essentially the most well-known of the Isle of Wight’s dinosaurs and is understood from all around the world. Iguanodon would have been a high-browser, rearing up on its hind legs to feed on excessive branches of tree-ferns and conifers, each of which have been discovered within the Isle of Wight fossil file.
| Current taxonomy work of Iguanodon |
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| Current work on the taxonomy of Iguanodon has proven that the Isle of Wight’s Iguanodon specimens belong to a few distinct genera – Iguanodon (Iguanodon bernissartensis), Mantellisaurus (beforehand Iguanodon atherfieldensis) and Dollodon (primarily based on undescribed Iguanodon materials): Iguanodon (iguana tooth) is the most important of the three, with the massive thumb spike the iguanodontids are well-known for, and a strong, brief cranium with a toothless beak. Mantellisaurus (Mantell’s reptile, after Gideon Mantell) is smaller, about 7m in size, and extra gracile, with a lowered thumb spike and an extended cranium, with increased neural spines. Dollodon (Dollo’s tooth, after Louis Dollo, who did numerous work on the Belgian Iguanodon specimens that corrected earlier restorations) is poorly identified on the island, however is understood to have had an extended snout and excessive neural spines probably forming a small sail alongside the again. There’s now some debate as as to if Iguanodon is definitely an iguanodontid. Nevertheless, till that analysis is printed, it stays as such. |
Carefully associated to the iguanodontids is Valdosaurus (Weald reptile), a dryosaurid dinosaur about 4m lengthy, with a toothless beak and slender limbs. It could have lived an identical life-style to a gazelle, searching on ferns and bushes. Valdosaurus can be identified from Africa, suggesting that Europe and Africa have been both linked or had solely lately separated.
The smallest ornithopod is Hypsilophodon (high-ridged tooth) that was about 2m in size and which will be present in giant numbers in a layer generally known as the Hypsilophodon beds. This layer is believed to have been laid down by sudden flooding, washing the poor Hypsilophodon away. An uncommon side of the Hypsilophodon beds it that many of the specimens are juveniles, and some appear to have been preserved in a resting place. There’s additionally anecdotal proof for them being present in pairs. The big numbers discovered suggests Hypsilophodon lived in communes, transferring by way of areas like sheep, grazing on ferns and cycads, and probably even small mammals. Hypsilophodon had a brief cranium, with a toothed beak, and extremely developed muscle attachments within the hind legs. This implies that it may handle fairly a great pace, enabling it to get away from predators.
These of you who learn about dinosaurs could also be questioning about just a few lacking dinosaurs from this record.Vectisaurus, which was believed to have been a small ornithopod, is definitely Iguanodon (probably even Mantellisaurus) and, as for Yaverlandia, the ‘earliest identified pachycephalosaur’, we’ll be seeing it once more later …
Thyreophoran (armoured) dinosaurs
It was not simply ornithopods grazing on the Isle of Wight. There was an ankylosaur too – Polacanthus. Polacanthus (many-spined) has often been attributed to the nodosaurids, because of its club-less tail. Nevertheless, comparisons with different comparable genera, resembling Gastonia from the US, present it will have had a extra squared off, triangular head, extra like ankylosaurids than the narrow-snouted nodosaurs. There have even been solutions of inserting Polacanthus in its personal group, the polacanthids, because of its distinctive nature. Polacanthus was about 4m lengthy, with giant spines alongside the again and shoulders, and a big bony protect throughout the sacrum (a triangular bone on the base of the backbone).
A braincase discovered close to Brighstone bay and allotted to Polacanthus primarily based on similarities to Gastonia, has proven that Polacanthus was extra conscious than most ankylosaurs. This implies that it had a extra energetic methodology of avoiding predators. The positioning of the spines on the shoulders hints that Polacanthus might have used them to “shoulder-barge” any menace, if a show of the massive dorsal spikes didn’t put them off. The comparatively unprotected flanks and hind legs low cost any suggestion of Polacanthus utilizing the “duck and canopy” methodology favoured by kids’s books for the final 50 years. It could have been a low browser, probably following the Iguanodon herds, as there are Iguanodon and Polacanthus footcasts discovered collectively at Hanover level.
Lastly, there’s a stegosaur, tentatively attributed to Regnosaurus (Regni reptile, after the Romano-British Regni tribe of West Sussex), because of diagnostic options within the single specimen (a partial pelvis) which are distinctive to huayangosaurid stegosaurs. Little is understood of Regnosaurus, aside from it was a huayangosaurid. Nevertheless, it may be inferred that it was a low browser, with dorsal spines and solitary spines on the shoulders.
Sauropod dinosaurs
Sauropods appear to have been fairly various on the Isle of Wight, main some to take a position that they have been simply passing by way of. Nevertheless, it has been recommended that there was appropriate vegetation for them to thrive there.
The most important is MIWG 7306, which is the specimen variety of a single neck vertebra belonging to a brachiosaurid. This explicit brachiosaur was about 20m lengthy, making it the most important dinosaur identified in Europe, and is comparable in measurement to Brachiosaurus from Africa and Sauroposeidon from the US. MIWG 7306 would have been a excessive browser, biting off branches from conifer timber and grinding them up within the intestine with gastroliths from the close by cliffs.
MIWG 7306 was not the one brachiosaur. There was additionally Eucamerotus (nicely chambered) at 15m lengthy, Ornithopsis (bird-like) at 15m to 18m and Pelorosaurus (Peloros’s reptile, after the Tessalian identify for Saturn) at 15m. Nevertheless, Eucamerotus and Ornithopsis are each identified from vertebrae, none of that are precisely the identical bone. Due to this fact, it’s doable that they could possibly be the identical genus, and even the identical species. Work that’s nonetheless ongoing with the Barnes Excessive Sauropod, being carried out by consultants from each Dinosaur Farm Museum and Dinosaur Isle, ought to assist to kind out this taxonomic mess. The Barnes Excessive Sauropod is attention-grabbing in that it seems to have fallen right into a pure lure, by wandering into mud and getting caught. This might clarify the close to completeness of the skeleton, though the cranium is lacking.
Different sauropods discovered on the Isle of Wight embody the titanosaurs, Iuticosaurus, and Pleurocoelus. Luticosaurus (Jute reptile, after the Jute tribe that lived in Kent, Sussex and the Isle of Wight) was between 15 to 20m lengthy, and is understood from a single caudal vertebra (titanosaur vertebrae are convex on the rear and concave on the entrance, and the neural course of is in the direction of the rear, making identification simpler).
Pleurocoelus (hole sided) is understood from a single, peg-like tooth, which, by comparability with different titanosaurs, exhibits it to be comparatively small, simply 8m lengthy.
There have been additionally just a few problematic sauropods. Chondrosteosaurus (cartilaginous-boned reptile) was as soon as attributed to the camarasaurs, however the options used to diagnose it as such have proved to be extra frequent amongst sauropods than beforehand thought. It was 18m lengthy.
Oplosaurus (hoplon lizard, after the traditional Greek protect), which was in all probability between 20 to 25m lengthy and is understood from a single tooth, is taken into account by the bulk to be camarasaurid in nature. Nevertheless, there are some who imagine it to be indeterminate.
Lastly, we’ve just a few undescribed sauropods. There are not less than two diplodocids and a rebbachisaurid, identified from remoted fragments.
Theropod dinosaurs
And eventually, we get to the theropods …
The most important described theropod is Baryonyx (heavy claw), a spinosauroid higher identified from Sussex. It’s presumed to be a piscivore, because of its lengthy, crocodilian snout, conical enamel and the presence of acid-etched fish scales within the intestine space. There have been additionally juvenile Iguanodon bones discovered within the intestine or a Baryonyx specimen present in Sussex, suggesting it not less than scavenged on this herbivore. Nevertheless, Baryonyx is most well-known for the massive claw on its first digit, which can have been used to catch fish by “gaffing” them within the method of a bear. Evaluation of Baryonyx materials from the Isle of Wight has proven that it’s in all probability the identical genus as Suchomimus, a bigger spinosauroid from Africa. (There might also be one other spinosauroid on the Isle of Wight, identified from enamel beforehand attributed to the crocodilian, Suchosaurus, though there may be nonetheless work to be completed on these.)
In the event you contemplate that Baryonyx was a scavenging piscivore, the most important predator discovered on the Isle of Wight was Neovenator (new hunter). This was an 8m-long carcharodontosaur, much like allosaurs. It had a particular, puffin-beak formed snout, and would have preyed on Iguanodon and, probably, the occasional smaller sauropod. There’s additionally a bigger, undescribed theropod, identified solely from just a few hand bones, however they’re non-diagnostic and so can not but be attributed to any identified group.
The Isle of Wight’s most well-known theropod is Eotyrannus (early tyrant), at 4m lengthy. Whereas it isn’t the largest, it is vital because it is likely one of the earliest tyrannosauroids. It was present in affiliation with some Valdosaurus bones, which may counsel that Valdosaurus was not less than a part of Eotyrannus’ eating regimen.
Thecocoelurus (sheath hole type) was an oviraptorsaur, which is unusual in Europe. At 7m in size, additionally it is unusually giant. Thecocoelurus is simply identified from a single partial vertebra, which luckily has sufficient diagnostic options to permit its attribution to the oviraptorsauria, though, for some time, it was thought of by some to be a therizinosaur. As virtually all oviraptorsaurs have been toothless, it’s doable that Thecocoelurus was too, though this doesn’t preclude it from a carnivore life-style.
Aristosuchus (superior crocodile) was, till lately, additionally an unusually giant instance of its taxon, on this case the compsognathids, greatest identified from the tiny Compsognathus from Bavaria. Presumably, Aristosuchus would have eaten lizards and small mammals.
Calamosaurus (reed reptile) was a coelurosaur, which is, in lots of circumstances, a really obscure time period for a small theropod. Work is being completed on the prevailing specimens, however nothing has been printed but.
Calamospondylus (reed vertebrae) is an indeterminate theropod, identified from a sacrum that was described as soon as then misplaced, with out being photographed or drawn, so no extra info is forthcoming sadly. It was as soon as thought to have been a synonym of Calamosaurus, however examination of the Calamosaurus materials exhibits it to be one thing else.
Ornithodesmus (fowl hyperlink) has had a vibrant previous. Initially classed as a pterosaur, in 1992 it was found that the kind specimen, a sacrum, was not from a pterosaur, however from a theropod dinosaur, particularly a troodontid Nevertheless, later examination linked it to the dromaeosauridae. All of the pterosaur materials attributed to Ornithodesmus was assigned to a brand new taxon, Istiodactylus. One other dromaeosaur was the massive velociraptorine that has been recognized by some enamel discovered by sieving sediments. The sizes of the enamel counsel a full size of about 6m.
Lastly, there’s a reappearance by Yaverlandia (from Yaverland). Initially, this was thought of to be a pachycephalosaur, primarily based on a slight thickening of the frontals. Nevertheless, additional examination in the previous few years has proven it to have theropod affinities. The reply to the query, “Which explicit kind of theropod”, I’m afraid, must wait till it’s printed.
Present work on the fauna of the Wessex Formation is ongoing, with scientists sieving by way of tonnes of clay looking for microscopic bones. By these means, they have uncovered teeth and even fragments of eggshell and, with fossil hunters scouring the beaches every day, there is bound to be more discoveries to come in the future.
Further reading
Dinosaurs of the Isle of Wight: Guide No 10, edited by David M Martill and Darren Naish, The Palaeontological Association, London (2001), 433 pages (paperback), ISBN: 0901702722
Dinosaurs of the British Isles, by Dean R Lomax and Nobumichi Tamura, Siri Scientific Press, Manchester (2014), 414 pages (paperback), ISBN: 978-0-9574530-5-0
Isle of Wight: Landscape and Geology, by John Downes, The Crowood Press Ltd (2021), 112 pages (paperback), ISBN: 978-1785008924
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