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 Vectis Formation and overlies the Durlston Formation.[1] The dominant lithology of this unit is mudstone with some interbedded sandstones.

Wessex Formation
Stratigraphic range: BerriasianBarremian, 145–125 Ma
The Undercliff - geograph.org.uk - 1378574
The Undercliff near Shalcombe, Isle of Wight
TypeGeological formation
Unit ofWealden Group
  • North West section - Yellow Sandstone, Pine raft, Hanover Point Sandstone, Rough Sandstone, Shippards Sandstone, Compton Grange Sandstone, Boundary Sandstone.
  • South East section - Sudmoor Point Sandstone, Chilton Chine Sandstone, Brighstone Sandstone, Grange Chine Sandstone, Grange Chine Black band, Ship Ledge Sandstone, Barnes Chine Sandstone, Chine Farm Sandstone, Hypsilophodon Bed
UnderliesVectis Formation
OverliesDurlston Formation
Thicknessup to 1000 m near Swanage
Othersandstone, ironstone & conglomerate
RegionSouthern England
Country UK
ExtentDorset, Isle of Wight, offshore Wessex Basin



Invertebrates are commonly preserved in the Wessex Formation. Freshwater bivalves can be found including unionids such as Margaritifera, Nippononaia, and Unio. These bivalves are helpful in reconstructing what the freshwater paleoenvironment may have been like during the formation's deposition. Specimens of Viviparus, a genus of freshwater snail, have also been found. While compression fossils of insects are found in the overlying Vectis Formation, all insect fossils in the Wessex formation are found as inclusions in amber. Amber can be found present as a rare component in other plant debris beds in the Wessex formation both on the Isle of Wight and the Isle of Purbeck, however the only significant concentration and where all of the inclusions have been found is a lag channel in the L6 plant debris horizon just south-east of Chilton Chine. Only two species from the amber have been formally described, Cretamygale chasei a mygalomorph spider, and Dungeyella gavini a chironomid midge.[2] Most of the other taxa in the table come from mentions in the paper describing the latter. However several images of some of the undescribed taxa have been released from various sources, including multiple chironomids, a therevid dipteran, and dryinid hymenopteran[3]

Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.
Invertebrates of the Wessex Formation
Genus Species Location Stratigraphic Position Abundance Note Images


C. chasei[4]

Chilton Chine L6 Plant debris bed Single specimen Mygalomorph spider, has been described from a specimen found in amber. See article
Dungeyella D. gavini[5] Chilton Chine L6 Plant debris bed Single specimen a tiny buchonomyiine/podonomian chironomid See article


Chilton Chine L6 Plant debris bed 44% of all arthropod inclusions Uncertain how many taxa represented, likely at least two. At least one is a tanypodian with a wingspan twice that of Dungeyella.
Therevidae Indeterminate Chilton Chine L6 Plant debris bed At least one specimen At least one specimen figured Wealden Therevid
Diptera Indeterminate Chilton Chine L6 Plant debris bed Multiple specimens Uncertain how many taxa represented
Dryinidae Indeterminate Chilton Chine L6 Plant debris bed At least one specimen At least one specimen figured, presumably male due to presence of wings Wealden Dryinid


Chilton Chine L6 Plant debris bed Multiple specimens Uncertain how many taxa represented


Chilton Chine L6 Plant debris bed Single specimen


Chilton Chine L6 Plant debris bed Single specimen


Represented by a boring in a gymnospermous seed.[6]

Cartilaginous fishes

Cartilaginous fishes of the Wessex Formation
Genus Species Location Stratigraphic Position Abundance Note Images


H. basanus


Hybodus fraasi (fossil)


Indeterminate 1

Yaverland bed 38, L9

Indeterminate 2

Yaverland bed 38, L9

Indeterminate 3

Yaverland bed 38, L9


L. breve

Yaverland bed 38

L. striatum

Yaverland bed 38, L9

51.43% of total chondrichthyan taxa in L9

Indeterminate 1

Yaverland bed 38, L9

Indeterminate 2

Yaverland bed 38, L9

35.86% of total chondrichthyan taxa in Yaverland bed 38

Indeterminate 3

Yaverland bed 38, L9


H. problematica




P. heterodon




V. ornatus

Ray-finned fish

Ray-finned fishes of the Wessex Formation
Genus Species Location Stratigraphic Position Abundance Notes Images





Caturus NT















Scheenstia maximus


Amphibians of the Wessex Formation
Genus Species Location Stratigraphic Position Abundance Notes Images
Wesserpeton[7] W.evansae L2 and Yaverland 38 Albanerpetontid amphibian



Multiple 1: Yaverland 38 2: L2 and Yaverland 38 3: L2 and Yaverland 38 4: Yaverland 38 5: Yaverland 38 At least 5 distinct taxa distinguished by characters in their ilium
Urodela Indeterminate Multiple 1: L2, L14 and Yaverland 33 and 38 2: L9 and Yaverland 38 3: unnamed bed in Compton bay and Yaverland 38 At least 3 distinct taxa distinguished by their atlas vertebrae


Squamates of the Wessex Formation
Genus Species Location Stratigraphic Position Abundance Notes Images
Meyasaurus Indeterminate Yaverland Yaverland bed 38 Teeth and a partial lower jaw Genus also known from Spain


Multiple plant debris beds 1st taxon L14 and L2, 2nd L2 and Yaverland bed 38, 3rd Yaverland bed 38 At least 3 distinct taxa represented by isolated teeth, maxilla and lower jaw fragments


Multiple plant debris beds 1: L14 and Yaverland 38 2: Yaverland 38, 3: L2 and Yaverland 38 4,5: Yaverland bed 38 6:L2, L14 and Yaverland 38 7,8,9: Yaverland 38 10: L2, L14 and Yaverland 38 At least 10 distinct taxa represented by isolated teeth, maxilla and lower jaw fragments, some of which are paramacellodids based on

the common occurrence of osteoderms typical of this clade.


Turtles of the Wessex Formation
Genus Species Location Stratigraphic Position Material Notes Images


H. nopcsai

Shell and skull material

Helochelydra skull



Shell fragments

Housed at the Dinosaur Farm Museum, Isle of Wight




Housed at the Dinosaur Isle Museum, Isle of Wight

Pleurosternon Indeterminate


B. brodiei


Crurotarsans of the Wessex Formation
Genus Species Location Stratigraphic Position Abundance Notes Images


A. hooleyi

Disputed, either uppermost Wessex or lowermost Vectis


A. epikrator[10] Hanover Point Mostly complete skull and partial dentaries and associated postcranial material
Bernissartia Indeterminate 40 Isolated teeth

Bernissartia BW


H. willetti


K. aprosdokiti[11]




Vectisuchus V. leptognathus Barnes High Just below base of Vectis formation "Partial semi-articulated skeleton"


Plesiosaurs of the Wessex Formation
Genus Species Location Stratigraphic Position Abundance Notes Images



Compton Bay




Tie pits, atherfield




Mammals of the Wessex Formation
Genus Species Location Stratigraphic Position Material Notes Images



Multiple debris beds L9, Yaverland bed 38 and CL3


?Gobiconodon Indeterminate Yaverland Yaverland bed 38 Teeth GobiconodonDB15






Multiple debris beds Mandible from Yaverland bed 38, isolated teeth from L2, L9 and L14

Mandible Fragment and isolated teeth




Multiple debris beds Yaverland bed 38 and L9 Two lower molars, likely belonging to the same taxon, distinct from other dryolestid teeth so likely to be a new genus and species.
Eutriconodonta Indeterminate Yaverland Yaverland bed 38 Lower left molariform






Pterosaurs of the Wessex Formation
Genus Species Location Stratigraphic Position Material Notes Images


C. trimicrodon

Skull and rostrum fragments

An ornithocheirid

Caulkicephalus trimicrodon


I. latidens

Partial skeleton and skull, and referred mandible fragment

An istiodactylid




Found throughout the sub basin


Two other species, distinct from I.latidens



Rostrum fragment

An ornithocheirid

Coloborhynchus piscator jconway






Tooth, potentially a gnathosaurine



Ornithischians reported from the Wessex Formation
Genus Species Synonyms Location Stratigraphic Position Material Notes Images


H. foxii

Hypsilophodon bed Many partial skeletons




Teeth Closely resemble the cheek teeth of the heterodontosaurid Tianyulong


I. bernissartensis

Specimens classified as Iguanodon seelyi are referable to this species

Iguanodon new NT


M. atherfieldensis

Dollodon bampingi, Proplanicoxa?[15]

Mantellisaurus atherfieldensis Steveoc


P. foxii

Polacanthoides ponderosus?

Polacanthus foxii



Distinct from P. foxii.[16]


V. canaliculatus

Multiple partial skeletons A dryosaurid



Sauropods reported from the Wessex Formation
Genus Species Location Stratigraphic Position Material Notes Images


C. gigas

"Several cervical vertebrae."[17]


E. foxi

"Dorsal vertebra."[17]

Perhaps a somphospondylan?[18]


I. valdensis

"Several caudal vertebrae."[17]


O. armatus



O. eucamerotus

"Ischia and pubis.",[17] regarded as an "undiagnostic titanosauriform of uncertain affinities."

O. hulkei

One dorsal vertebra.[20]

Undescribed Sauropod Indeterminate "Partial postcranial skeleton, including presacral vertebrae, anterior caudal vertebrae, girdle and limb elements" Currently in private collection and unavailable to researchers. Known informally as "the Barnes High sauropod"
Sauropoda Indeterminate One cervical vertebra and possible associated centrum Represents a large animal 20 metres or greater in length. Known informally as "Angloposeidon". Perhaps a somphospondylan?



Scapula, vertebra, and isolated teeth

Similar in proportions to Demandasaurus



Two isolated large middle caudal vertebra, one isolated large cervical vertebra


Theropods reported from the Wessex Formation
Genus Species Location Stratigraphic Position Material Notes Images



Isolated teeth

Possibly an Enantiornithe and a Hesperornithid present


A. pusillus

"Sacrum and pubes."[21]

A compsognathid

Aristosuchus restoration



Isolated teeth, manus bones, vertebrae and skull material

A spinosaurid possibly synonymous with Suchosaurus cultridens

Baryonyx walkeri restoration


C. foxi


A compsognathid


C. oweni


A possible oviraptorosaur


E. lengi

"Partial skull and skeleton."[23]

A tyrannosauroid


N. salerii

"Partial skull and skeleton."[24]

A carcharodontosaurian



O. cluniculus

A dubious species of dromaeosaurid, once misidentified as a pterosaur




Dubious, uncertain referral on the genus level

Tetanurae Indeterminate Chilton Chine Partial pubes and femur[25] Distinct from Neovenator and Baryonyx. Currently in private collection.


T. daviesi

"Cervical vertebrae."[26]

A theropod of uncertain classification, possibly an ornithomimosaur (this assignment has been questioned by both Mortimer and Naish).[27][28]

Undescribed coelurosaur Indeterminate Partial associated skeleton Apparently small. In private collection and undescribed.



Isolated teeth

May belong to a proceratosaurid.[29]


Y. bitholus

Yaverland Known from a "partial skull roof comprising both frontals and parts of the right postorbital and left orbitosphenoid". A second specimen is known but what elements are represented have not been published as of 2018.

A maniraptoran of uncertain classification, originally identified as an ornithischian.



Spermatophytes reported from the Wessex Formation
Genus Species Location Stratigraphic Position Material Notes Images



Stem fragment (IWCMS.2010.7)



Dubious referral




P. parceramosa

Member of Cheirolepidiaceae. Incredibly abundant, sometimes found as entire segments of the trunk

Brachyphyllum B. obesum
Pityites P. solmsii


Pteridophytes reported from the Wessex Formation
Genus Species Location Stratigraphic Position Material Notes Images






W. reticulata

Multiple specimens

See also


  1. ^ "Wessex Formation". The BGS Lexicon of Named Rock Units. British Geological Survey.
  2. ^ Jarzembowski, E.; Azar, D.; Nel, A. (2009-04-24). "A new chironomid (Insecta: Diptera) from Wealden amber (Lower Cretaceous) of the Isle of Wight (UK)". Geologica Acta. 6 (3): 285–291. doi:10.1344/105.000000257. ISSN 1696-5728.
  3. ^ Jarzembowski, E. A. (27 March 2015). "Fossil resins from England (Conference abstract)" (PDF). Amberif 2015: SUCCINITE AND SELECTED FOSSIL RESINS OF EUROPE: LOCALITIES, PROPERTIES, ARCHAEOLOGY: 18–20.
  5. ^ "Fossil specimen : MIWG IWCMS.1994.99 – Holotype". GB3D Type Fossils.
  6. ^ Legalov, A & A. Jarzembowski, Edmund. (2017). First record of a weevil (Coleoptera: Nemonychidae) from the Lower Cretaceous (Wealden) of southern England. Cretaceous Research. 82. 10.1016/j.cretres.2017.10.006.
  7. ^ "A new albanerpetontid amphibian from the Barremian (Early Cretaceous) Wessex Formation of the Isle of Wight, southern England - Acta Palaeontologica Polonica". www.app.pan.pl. Retrieved 2017-10-11.
  8. ^ a b c d e Sweetman, S. C. 2006. The tetrapod microbiota of the Wessex Formation (Lower Cretaceous, Barremian) of the Isle of Wight, UK. 127-129. In: Barrett, P. M. and Evans, S. E. (eds.) 2006. Ninth international symposium on Mesozoic terrestrial ecosystems and biota, abstracts and proceedings. 187 pp.
  9. ^ Salisbury, S.W.; Naish, D. (2011). "Crocodilians". In Batten, D.J. (ed.). English Wealden Fossils. The Palaeontological Association. pp. 305–369.
  10. ^ Ristevski, Jorgo; Young, Mark T.; de Andrade, Marco Brandalise; Hastings, Alexander K. (April 2018). "A new species of Anteophthalmosuchus (Crocodylomorpha, Goniopholididae) from the Lower Cretaceous of the Isle of Wight, United Kingdom, and a review of the genus". Cretaceous Research. 84: 340–383. doi:10.1016/j.cretres.2017.11.008. ISSN 0195-6671.
  11. ^ a b Sweetman, S.C.; Pedreira-Segade, U.; Vidovic, S.U. (2014). "A new bernissartiid crocodyliform from the Lower Cretaceous Wessex Formation (Wealden Group, Barremian) of the Isle of Wight, southern England" (PDF). Acta Palaeontologica Polonica. doi:10.4202/app.00038.2013.
  12. ^ a b KEAR, B. P. and BARRETT, P. M. (2011), Reassessment of the Lower Cretaceous (Barremian) pliosauroid Leptocleidus superstes Andrews, 1922 and other plesiosaur remains from the nonmarine Wealden succession of southern England. Zoological Journal of the Linnean Society, 161: 663–691. doi:10.1111/j.1096-3642.2010.00648.x
  13. ^ Sweetman, Steven C. (September 2009). "A New Species of the Plagiaulacoid Multituberculate MammalEobaatarfrom the Early Cretaceous of Southern Britain". Acta Palaeontologica Polonica. 54 (3): 373–384. doi:10.4202/app.2008.0003. ISSN 0567-7920.
  15. ^ McDonald, Andrew T. (2011). "The status of Dollodon and other basal iguanodonts (Dinosauria: Ornithischia) from the upper Wealden beds (Lower Cretaceous) of Europe". Cretaceous Research. 33: 1–6. doi:10.1016/j.cretres.2011.03.002.
  16. ^ Pond, Stuart, et al. A critical new ankylosaur specimen from the Wessex Formation of the Isle of Wight. No. e1742. PeerJ PrePrints, 2015.
  17. ^ a b c d "Table 13.1," in Weishampel, et al. (2004). Page 271.
  18. ^ Campbell, Amy, Paul Upchurch, and Phillip D. Mannion. The anatomy and relationships of Eucamerotus foxi (Dinosauria, Sauropoda) from the Early Cretaceous of England. No. e3247v1. PeerJ Preprints, 2017.
  19. ^ "Table 13.1," in Weishampel, et al. (2004). Page 261.
  20. ^ "Table 13.1," in Weishampel, et al. (2004). Page 266.
  21. ^ "Table 4.1," in Weishampel, et al. (2004). Page 76.
  22. ^ a b "Table 4.1," in Weishampel, et al. (2004). Page 78.
  23. ^ "Table 5.1," in Weishampel, et al. (2004). Page 112.
  24. ^ "Table 4.1," in Weishampel, et al. (2004). Page 75.
  25. ^ Benson, Roger B. J.; Brusatte, Stephen L.; Hutt, Stephen; Naish, Darren (2009). "A new large basal tetanuran (Dinosauria: Theropoda) from the Wessex Formation (Barremian) of the Isle Of Wight, England". Journal of Vertebrate Paleontology. 29 (2): 612–615. doi:10.1671/039.029.0202. ISSN 0272-4634.
  26. ^ "Table 8.1," in Weishampel, et al. (2004). Page 167.
  27. ^ Naish, D. (2014, June 3). "Ostrich dinosaurs invade Europe! Or do they?". Retrieved from https://blogs.scientificamerican.com
  28. ^ Mortimer, M. (2014, May 26). "Is Thecocoelurus an ornithomimosaur?". Retrieved from http://theropoddatabase.blogspot.co.uk
  29. ^ Rauhut, O.W.M.; Milner, A.C.; Moore-Fay, S. (2010). "Cranial osteology and phylogenetic position of the theropod dinosaur Proceratosaurus bradleyi (Woodward, 1910) from the Middle Jurassic of England". Zoological Journal of the Linnean Society. 158 (1): 155–195. doi:10.1111/j.1096-3642.2009.00591.x.
  • Batten, D. J. (ed.) 2011. English Wealden Fossils. The Palaeontological Association, London.

External links

1887 in paleontology

Paleontology or palaeontology (from Greek: paleo, "ancient"; ontos, "being"; and logos, "knowledge") is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1887.


The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 125.0 ± 1.0 Ma). It is a subdivision of the Early Cretaceous epoch (or Lower Cretaceous series). It is preceded by the Hauterivian and followed by the Aptian stage.


Calamosaurus (meaning "reed lizard") was a genus of small theropod dinosaur from the Barremian-age Lower Cretaceous Wessex Formation of the Isle of Wight, England. It is based on two cervical vertebrae (BMNH R901), collected by Reverend William Fox.


Caulkicephalus is a genus of Ornithocheirid pterosaur, from the Isle of Wight off the coast of England.


Cedarosaurus (meaning "Cedar lizard" - named after the Cedar Mountain Formation, in which it was discovered) was a nasal-crested macronarian dinosaur genus from the Early Cretaceous Period (Barremian). It was a sauropod which lived in what is now Utah. It was first described by Tidwell, Carpenter and Brooks in 1999.It shows similarities to the brachiosaurid Eucamerotus from the Wessex Formation of southern England, as well as to Brachiosaurus from the Morrison Formation.


Chondrosteosaurus (meaning "cartilage and bone lizard") was a sauropod from Early Cretaceous England.

The type species, Chondrosteosaurus gigas, was described and named by Richard Owen in 1876. The fossils of Chondrosteosaurus were discovered in the Wessex Formation on the Isle of Wight. C. gigas is known only from two neck vertebrae (specimens BMNH 46869, the holotype, and BMNH 46870), with distinctive hollows and internal passages now interpreted as evidence of pneumatic air sacs. Paleontologist Harry Seeley had interpreted similar structures as pneumatic in his specimen of Ornithopsis. Owen disagreed with Seeley's concept of a giant creature bridging the gap between birds or pterosaurs (Owen considered sauropods to be whale-like marine reptiles), and while he acknowledged that the external cavities on the vertebrae may have been connected to the lungs, he interpreted the internal passages as having been filled with cartilage (hence his name for the genus, Chondrosteosaurus or "cartilage and bone lizard").Owen also named a second species, Chondrosteosaurus magnus, that today no longer is considered to belong to Chondrosteosaurus.

Darren Naish

Darren Naish is a British vertebrate palaeontologist and science writer. He obtained a geology degree at the University of Southampton and later studied vertebrate palaeontology under British palaeontologist David Martill at the University of Portsmouth, where he obtained both an M. Phil. and PhD. He is founder of the blog Tetrapod Zoology, created in 2006.


Darwinsaurus (meaning "Darwin's lizard") is a genus of herbivorous styracosternan ornithopod dinosaur.

In the early nineteenth century dinosaur remains were discovered in the Shornden Quarry at Shorden near Hastings in East Sussex. These were first reported by Richard Owen in 1842. In 1889 they were referred to Iguanodon fittoni by Richard Lydekker. They were then assigned to Hypselospinus fittoni by David Bruce Norman in 2010.

In 2012 Gregory S. Paul named them as a separate genus and species. The type species is Darwinsaurus evolutionis. The generic name honours Charles Darwin for his theory of evolution. The specific name refers to evolution in general and specifically to the strong evolutionary radiation that iguanodonts, according to Paul, are a prime example of. The holotype, as indicated by Paul, is an associated skeleton that includes material catalogued under the numbers NHMUK R1831, R1833, and R1835 (Paul mistakenly included NHMUK R1836 in the genus, unaware that it came from the younger Wessex Formation). Included by Lydekker and Norman was also specimen NHMUK R1832, lower arm elements.

Paul in 2012 provided a short diagnosis of Darwinsaurus. The dentary, the front bone of the lower jaw, is straight. An elongated diastema is present between the beak and the row of teeth. The dentary is shallow below the diastema and deeper below the teeth. The foremost dentary teeth are smaller. The arm is very robust. The olecranon of the ulna is well-developed. Some carpalia are very large. The metacarpals are rather elongated. The thumb spike, the claw of the first finger, is massive.Paul and Norman are in disagreement about the form of the diastema. According to Paul, an illustration in Lydekker (1889) shows that the fossil originally possessed a long and low gap between the tooth battery and the beak; subsequent damage would have removed three or four very small teeth in front of the main row. Norman, however, disputes this and thinks damage has considerably lowered the jaw, the front teeth originally having been large, resulting in a narrow diastema.Paul considered Darwinsaurus a basal member of the Iguanodontia.Norman (2013) considered Paul's description of Darwinsaurus to be inadequate, treating D. evolutionis as a junior synonym of Hypselospinus fittoni, and noting that NHMUK 1836, an associated partial skeleton from the late Barremian of the Isle of Wight, can referred to the species Mantellisaurus atherfieldensis. In a recent SVP abstract, Karen Poole considered Darwinsaurus a possible junior synonym of Huxleysaurus based on unpublished cladistic results.


Eotyrannus (meaning "dawn tyrant") is a genus of tyrannosauroid theropod dinosaur hailing from the Early Cretaceous Wessex Formation beds, included in Wealden Group, located in the southwest coast of the Isle of Wight, United Kingdom. The remains (MIWG1997.550), consisting of assorted skull, axial skeleton and appendicular skeleton elements, from a juvenile or subadult, found in a plant debris clay bed, were described by Hutt et al. in early 2001. The etymology of the generic name refers to the animals classification as an early tyrannosaur or "tyrant lizard", while the specific name honors the discoverer of the fossil.


Eucamerotus (meaning "well-chambered" in reference to the hollows of the vertebrae) was a genus of sauropod dinosaur from the Barremian-age Lower Cretaceous Wessex Formation (Wealden) of the Isle of Wight, England.


Istiodactylus is a genus of pterosaur that lived during the Early Cretaceous period, about 120 million years ago. The first fossil was discovered on the English Isle of Wight in 1887, and in 1901 became the holotype specimen of a new species, O. latidens (Latin for "wide tooth"), in the genus Ornithodesmus. This species was moved to its own genus, Istiodactylus, in 2001; this name is Greek for "sail finger". More specimens were described in 1913, and Istiodactylus was the only pterosaur known from three-dimensionally preserved fossils for much of the 20th century. In 2006, a species from China, I. sinensis, was assigned to Istiodactylus, but it has since been found to belong to a different genus.

Istiodactylus was a large pterosaur; estimates of its wingspan range from 4.3 to 5 metres (14 to 16 ft). Its skull was about 45 centimetres (18 in) long, and was relatively short and broad for a pterosaur. The front of the snout was low and blunt, and bore a semicircle of 48 teeth. The triangular teeth were closely spaced, interlocked, and formed a "razor-edged" outline. The lower jaw also had a tooth-like projection that occluded with the teeth. The skull had a very large naso-antorbital opening (which combined the antorbital fenestra and the opening for the bony nostril) and a slender eye socket. Some of the vertebrae were fused into a notarium, to which the shoulder blades connected. It had very large forelimbs, with a wing-membrane distended by a long wing-finger, but the hindlimbs were very short.

Until the 21st century, Istiodactylus was the only known pterosaur of its kind, and was placed in its own family, Istiodactylidae, within the group Ornithocheiroidea. Istiodactylus differed from other istiodactylids in having a proportionally shorter skull. The distinctive teeth of Istiodactylus indicate that it was a scavenger that may have used its teeth to sever morsels from large carcasses in the manner of a cookie cutter. The wings of Istiodactylus may have been adapted for soaring, which would have helped it find carcasses before terrestrial carnivores. Istiodactylus is known from the Wessex Formation and the younger Vectis Formation, which represent river and coastal environments that were shared with various pterosaurs, dinosaurs, and other animals.


Iuticosaurus (meaning "Jute lizard") is the name given to a genus of dinosaur from the Early Cretaceous of the Isle of Wight. Iuticosaurus was a sauropod, specifically a titanosaur.

In 1887 Richard Lydekker described two sauropod tail vertebrae found by William D. Fox near Brook Bay on Wight, BMNH R146a and BMNH 151, and referred them to the genus Ornithopsis, despite indicating their similarity to Titanosaurus, because the tail of Ornithopsis was unknown. On reading the paper to the Geological Society of London, Lydekker was criticised by Harry Govier Seeley and John Hulke for his choice and in 1888 he referred to the fossils as Titanosaurus sp. a, Titanosaurus sp. b being a third vertebra, BMNH 32390.In 1929 Friedrich von Huene named both taxa as full species. The first became Titanosaurus Valdensis, the specific name referring to the Wealden, the second Titanosaurus Lydekkeri, its specific name honouring Lydekker. By present convention both specific names would be spelled as T. valdensis and T. lydekkeri respectively.

In 1993 Jean le Loeuff redescribed the material and named a separate genus: Iuticosaurus, the generic name referring to the Jutes who settled the island in the fifth century and established a Jute dynasty in the sixth century. Le Loeuff made Iuticosaurus valdensis the type species, and chose BMNH 151 as the lectotype. Another vertebra, BMNH R 1886, was referred by him to this species. The second species, though formally named by him as Iuticosaurus lydekkeri, he considered a nomen dubium.I. valdensis was found in the Wessex Formation and I. lydekkeri in the younger Upper Greensand.

Iuticosaurus was probably similar to Titanosaurus. It measured 15 to 20 metres (49–65 feet) long.

Most researchers have concluded that I. valdensis cannot be distinguished from other titanosaurs and is therefore a nomen dubium also.


Koumpiodontosuchus is an extinct genus of neosuchian crocodyliform that lived in the Early Cretaceous. The only species is K. aprosdokiti.


Meyasaurus is an extinct genus of Teiid lizard known from the Barremian of Spain and the Isle of Wight, UK. Four species are known from Spain, from the La Huérguina, Camarillas and La Pedrera de Rúbies Formations while an indeterminate taxon is known from the Wessex Formation of Isle of Wight. It is a possible close relative of Barbatteius and other members of Barbatteiidae.


Oplosaurus (meaning "armed or weapon lizard" or "armoured lizard"; see below for discussion) was a genus of sauropod dinosaur from the Barremian-age Lower Cretaceous Wessex Formation of the Isle of Wight, England. It is known from a single tooth usually referred to the contemporaneous "wastebasket taxon" Pelorosaurus, although there is no solid evidence for this.


Proplanicoxa is a genus of iguanodont dinosaur which existed in what is now England during the Early Cretaceous period (late Barremian stage, around 126 mya).The holotype and only specimen of Proplanicoxa, BMNH R 8649, is composed of thirteen dorsals, a sacrum with ilia, parts of the pubis and ischium. The fossils were found in 1916 by Reginald Walter Hooley on the Isle of Wight from the upper Wessex Formation of England. BMNH R 8649 was originally assigned to Vectisaurus valdensis Hulke 1879 (=Mantellisaurus atherfieldensis) by Galton in 1976. The specimen was assigned to its own genus and species by Kenneth Carpenter and Yusuke Ishida in 2010, and the type species is Proplanicoxa galtoni. The generic name is derived from “before” (pro in Greek) and Planicoxa in reference to the postacetabular process of the ilium trending towards the horizontal as seen even stronger in Planicoxa, and the specific name honors Peter Galton. It may be synonymous with Mantellisaurus.

Wealden Group

The Wealden Group is a group (a sequence of rock strata) in the lithostratigraphy of southern England. The Wealden group consists of paralic to continental (freshwater) facies sedimentary rocks of Berriasian to Aptian age and thus forms part of the English Lower Cretaceous. It is composed of alternating sands and clays. The sandy units were deposited in a flood plain of braided rivers, the clays mostly in a lagoonal coastal plain.The Wealden Group can be found in almost all Early Cretaceous basins of England: its outcrops curve from the Wessex Basin in the south to the Cleveland Basin in the northeast. It is not found in northwest England and Wales, areas which were at the time tectonic highs where no deposition took place. The same is true for the London Platform around London and Essex. Offshore, the Wealden Group can reach a thickness of 700 metres.


Yaverlandia is a genus of maniraptoran dinosaur. Known from a partial fossil skull found in Lower Cretaceous strata of the Wessex Formation on the Isle of Wight, it was described as the earliest known member of the pachycephalosaurid family, but recent research by Darren Naish shows it to have actually been a theropod, seemingly a maniraptoran. Yaverlandia was named from where it was found, Yaverland Point/ Yaverland Battery.

It was about 3 ft ( 1 m ) in length and 1 ft ( 30 cm ) in height.

Its fossils were discovered in 1930, in Egland.


Yaverlestes gassoni is an extinct mammal which dates to the early Cretaceous period, 130 million years ago. It is part of the Wessex Formation from the Isle of Wight, England. The holotype, BMNH M 54386, is a partial jaw discovered near Yaverland.

The genus name, Yaverlestes, is derived from Yaverland, the location of its discovery, and lestes, Greek for thief. The specific epithet, gassoni, is in honour of Brian Gasson, its discoverer.


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