Muraenosaurus fossil map
Where fossils of Muraenosaurus have been found, shown on the Earth as it looked about 160 million years ago and on today’s map.
Dots are fossil collections recorded in the Paleobiology Database. The “then” view moves today’s fossil sites back to their positions 160 million years ago (the time slice nearest the median age of the fossils) using the Merdith et al. (2021) plate model; positions are approximate. Open on the timeline map →
| Group | Plesiosaurs & kin |
|---|---|
| Lived | 165.3–154.8 million years ago (Callovian to Oxfordian) |
| Periods | Jurassic |
| Family | Cryptoclididae |
| Named by | Seeley 1874 |
| Fossil records | 11 occurrences at 7 locations (PBDB) |
| Found in | United Kingdom, Argentina, France |
| Rock formations | Oxford Clay, Lajas, Argiles de Montaubert |
About Muraenosaurus
Muraenosaurus (from the Latin "Muraena" meaning "eel" and "Sauros" meaning lizard) is an extinct genus of cryptoclidid plesiosaur reptile from the Oxford Clay of Southern England. The genus was given its name due to the eel-like appearance of the long neck and small head. Muraenosaurus grew up to 5.2 metres (17 ft) in length and lived roughly between 160 Ma (million years ago) and 164 Ma in the Callovian of the middle Jurassic. Charles E. Leeds collected the first Muraenosaurus which was then described by H. G. Seeley. The specimen may have suffered some damage due to the casual style of Charles Leeds’ collection. The first muraenosaur was recovered with pieces missing from the skull and many of the caudal vertebrae absent. Because the animal was described from Charles Leeds’ collection it was given the name Muraenosaurus Leedsii. M. leedsii is the most complete specimen belonging to the genus Muraenosaurus and also the only species that is undoubtedly a member of the genus. Two other species have been tentatively referred to as members of the genus Muraenosaurus: M. reedii and Muraenosaurus beloclis Seeley 1892, which in 1910 became the separate genus Picrocleidus.
Text in “About” is quoted from the Wikipedia article Muraenosaurus (revision 1363704460), licensed under CC BY-SA 4.0; introduction excerpted verbatim, formatting removed. Ages, family, authority and fossil records: Paleobiology Database, accessed 23 October 2026. Ages are those of the rock layers the fossils were found in. Wikidata: Q1179905.
