Article · Wikipedia archive · Last revised Jun 6, 2026

Coniasaurus

Coniasaurus is an extinct genus of Late Cretaceous marine squamates that range in age from Cenomanian to Santonian. It was first described by Richard Owen in 1850 from lower Cenomanian chalk deposits in South East England (Sussex). Two species have been described from this genus: C. crassidens, known from Cenomanian to Santonian deposits from South East England, Germany and North America, and C. gracilodens from the Cenomanian of southeast England.

Last revised
Jun 6, 2026
Read time
≈ 1 min
Length
327 w
Citations
8
Source
Coniasaurus
Temporal range: Late Cretaceous,
C. crassidens holotype, drawn by James Erxleben in 1850
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Dolichosauridae
Genus: Coniasaurus
Owen, 1850
Species
  • C. crassidens Owen, 1850 (type)
  • C. gracilodens Caldwell, 1999

Coniasaurus is an extinct genus of Late Cretaceous marine squamates that range in age from Cenomanian to Santonian.1 It was first described by Richard Owen in 1850 from lower Cenomanian chalk deposits in South East England (Sussex).23 Two species have been described from this genus: C. crassidens (Owen, 1850), known from Cenomanian to Santonian deposits from South East England, Germany and North America, and C. gracilodens (Caldwell, 1999) from the Cenomanian of southeast England.1

Coniasaurus has only been described from incomplete specimens, but it is known to have had a relatively elongate skull with specialised teeth.1 By comparison with Dolichosaurus, it may have had four short limbs and an elongate neck and body. A maximum length between 0.5–1 m (1.6–3.3 ft) has been proposed.34

Phylogenetic analysis suggests that Coniasaurus is a sister group to the Mosasauroidea within the clade Pythonomorpha.5

References

References

  1. Shimada K. & Bell G.L.Jr (2006). "Coniasaurus Owen, 1850 (Reptilia: Squamata), from the Upper Cretaceous Niobrara Chalk of western Kansas". Journal of Paleontology. 80 (3): 589–593. doi:10.1666/0022-3360(2006)80[589:corsft]2.0.co;2.
  2. Owen, R. (1850). Descriptions of the fossils of the Chalk Formation. Description of the fossil reptiles of the Chalk Formation. The Geology and Fossils of the Tertiary and Cretaceous Formations of Sussex 378-404
  3. Caldwell M.W. & Cooper J.A. (1999). "Redescription, palaeobiogeography and palaeoecology of Coniasaurus crassidens Owen, 1850 (Squamata) from the Lower Chalk (Cretaceous; Cenomanian) of SE England" (PDF). Zoological Journal of the Linnean Society. 127 (4): 423–452. doi:10.1111/j.1096-3642.1999.tb01380.x.
  4. Bardet, Nathalie (2008). "The Cenomanian-Turonian (late Cretaceous) radiation of marine squamates (Reptilia): the role of the Mediterranean Tethys". Bulletin de la Société Géologique de France. 179 (6): 605–623. doi:10.2113/gssgfbull.179.6.605.
  5. Caldwell M.A. (1999). "Squamate phylogeny and the relationships of snakes and mosasauroids" (PDF). Zoological Journal of the Linnean Society. 125 (1): 115–147. doi:10.1111/j.1096-3642.1999.tb00587.x.