Wessex Formation

Wessex Formation Stratigraphic range: Barremian, 130–126 Ma PreЄ Є O S D C P T J K Pg N ↓
The Undercliff near Shalcombe, Isle of Wight
Type	Geological formation
Unit of	Wealden Group
Underlies	Vectis Formation
Overlies	Lower Wealden Clay Formation
Location
Region	England
Country	UK

The Wessex Formation is a fossil-rich English geological formation that dates to the Barremian stage (about 130 million years ago) of the Early Cretaceous. It is part of the Wealden Group and underlies the younger Vectis Formation.

Geological map of southeast England (Horace B. Woodward, 1904) (for index of colours see London basin map)

Fauna

Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon		Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Invertebrates

Invertebrates are commonly preserved in the Wessex Formation. Freshwater bivalves can be found including unionoids 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. Cretamygale chasei, a species of Mygalomorph spider, has been described from a specimen found in amber. It is believed to be the oldest known Nemesiid and the second oldest Mygalomorph.^[1]

Cartilaginous fishes

Cartilaginous fishes of the Wessex Formation
Genus	Species	Location	Stratigraphic Position	Abundance	Note	Images
Hybodus	H. basanus					Hybodus
Hylaeobatis	H. problematica
Palaeoscyllium	Indeterminate
Vectiselachos	V. ornatus

Ray-finned fish

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

Turtles

Turtles of the Wessex Formation
Genus	Species	Location	Stratigraphic Position	Abundance	Notes
Helochelydra	H. nopcsai
Brodiechelys	B. brodiei

Crurotarsans

Crurotarsans of the Wessex Formation
Genus	Species	Location	Stratigraphic Position	Abundance	Notes	Images
Anteophthalmosuchus[2]	A. hooleyi[2]
Hylaeochampsa	H. vectiana
Koumpiodontosuchus[3]	K. aprosdokiti[3]
Leiokarinosuchus[2]	L. brookensis[2]
Vectisuchus	V. leptognathus

Pterosaurs

Pterosaurs of the Wessex Formation
Genus	Species	Location	Stratigraphic Position	Abundance	Notes	Images
Caulkicephalus	C. trimicrodon					Caulkicephalus
Istiodactylus	I. latidens
Ornithocheirus	Indeterminate
"Ornithodesmus"	"O." latidens				Reclassified as Istiodactylus latidens

Dinosaurs

Ornithischians

Ornithischians reported from the Wessex Formation
Genus	Species	Location	Stratigraphic Position	Material	Notes	Images
Dollodon	D. bampingi				Junior synonym of Mantellisaurus atherfieldensis	Hypsilophodon foxii
Hypsilophodon	H. foxii
Iguanodon	I. seelyi				Junior synonym of Iguanodon bernissartensis
	I. bernissartensis				Specimens classified as Iguanodon seelyi are referable to this species
Mantellisaurus	M. atherfieldensis
Polacanthoides	P. ponderosus			"Tibia."[4]
Polacanthus	P. foxii
	P. rudgwickensis
Valdosaurus	V. canaliculatus

Sauropods

Indeterminate diplodicoid and rebbachisaurid remains are known from the formation.

Sauropods reported from the Wessex Formation
Genus	Species	Location	Stratigraphic Position	Material	Notes	Images
Chondrosteosaurus	C. gigas			"Several cervical vertebrae."[5]
Eucamerotus	E. foxi			"Dorsal vertebra."[5]
Iuticosaurus	I. valdensis			"Several caudal vertebrae."[5]
Oplosaurus	O. armatus			"Tooth."[6]
Ornithopsis	O. eucamerotus			"Ischia and pubis."[5]
	O. hulkei			One dorsal vertebra.[7]

Theropods

Indeterminate velociraptorine remains have been recovered from the Wessex Formation.

Theropods reported from the Wessex Formation
Genus	Species	Location	Stratigraphic Position	Material	Notes	Images
Aristosuchus	A. pussilis			"Sacrum and pubes."[8]	A compsognathid	Baryonyx walkeri Neovenator salterii
Baryonyx	B. walkeri			Isolated teeth	A spinosaurid possibly synonymous with Suchosaurus cultridens
Calamosaurus	C. foxi			"Vertebrae."[9]	A compsognathid
Calamospondylus	C. oweni			"Vertebrae."[9]	A possible oviraptorosaur
Eotyrannus	E. lengi			"Partial skull and skeleton."[10]	A tyrannosauroid
Neovenator	N. salerii			"Partial skull and skeleton."[11]	A carcharodontosaurian
Ornithodesmus	O. cluniculus				A dubious species of dromaeosaurid, once misidentified as a pterosaur
Thecocoelurus	T. daviesi			"Cervical vertebrae."[12]	A coelurosaur of uncertain classification
"Thecospondylus"	T. daviesi				Name preoccupied, renamed Thecocoelurus daviesi
Yaverlandia	Y. bitholus				A maniraptoran of uncertain classification, originally identified as an ornithischian

See also

• List of fossil sites
• List of stratigraphic units with dinosaur body fossils
• Dinosaurs of the Isle of Wight

References

1. Selden, Paul A. (2003). First British Mesozoic Spider, From Cretaceous Amber Of The Isle Of Wight, Southern England. Palaeontology 45(5): 973-983
2. Steven W. Salisbury and Darren Naish (2011). "Crocodilians". In Batten, D. J. (eds). English Wealden Fossils. The Palaeontological Association (London). pp. 305–369.
3. Sweetman, S.C., Pedreira-Segade, U., and Vidovic, S.U. 2014. A new bernissartiid crocodyliform from the Lower Cre- taceous Wessex Formation (Wealden Group, Barremian) of the Isle of Wight, southern England. Acta Palaeontologica Polonica. http://www.app.pan.pl/archive/published/app59/app000382013_acc.pdf
4. "Table 17.1," in Weishampel, et al. (2004). Page 368.
5. "Table 13.1," in Weishampel, et al. (2004). Page 271.
6. "Table 13.1," in Weishampel, et al. (2004). Page 261.
7. "Table 13.1," in Weishampel, et al. (2004). Page 266.
8. "Table 4.1," in Weishampel, et al. (2004). Page 76.
9. "Table 4.1," in Weishampel, et al. (2004). Page 78.
10. "Table 5.1," in Weishampel, et al. (2004). Page 112.
11. "Table 4.1," in Weishampel, et al. (2004). Page 75.
12. "Table 8.1," in Weishampel, et al. (2004). Page 167.

• Batten, D. J. (ed.) 2011. English Wealden Fossils. The Palaeontological Association, London.

External links

• Discovery of shark teeth