Genus
Valid Extinct

Rhomaleosaurus

Seeley 1874

Rhomaleosaurus is an extinct genus of Early Jurassic rhomaleosaurid pliosauroid known from Northamptonshire and from Yorkshire of the United Kingdom. It was first named by Harry Seeley in 1874 and the type species is Rhomaleosaurus cramptoni. It was one of the earliest large marine reptile predators which hunted in the seas of Mesozoic era, measuring about 7 metres (23 ft) long. Like other pliosaurs, Rhomaleosaurus fed on ichthyosaurs, ammonites and other plesiosaurs.

Temporal range
Triassic
Jurassic
Cretaceous
Paleogene
Neogene
252 201 145 66 0 Ma
PBDB occurrences
15
Group
Sauroptérygiens
Carnivore aquatic, depth=surface Marine
Rhomaleosaurus
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Rhomaleosaurus cramptoni fossil, Natural History Museum, London © APK · CC BY 4.0 · Wikimedia
Rhomaleosaurus
Rhomaleosaurus
Rhomaleosaurus
PBDB ↗ Wikipedia ↗
Classification
Sauropterygia Suborder
›
Plesiosauria Order
›
Rhomaleosauridae Family
›
Rhomaleosaurus Genus
Measurements
Length
7 m ⓘ
Fossil sites 15 geolocated sites
Distribution
Top countries
🇬🇧 United Kingdom
15
Geological formations
Whitby Mudstone
4
Blue Lias
3
Alum Shale
3
Westbury
1
Marlstone Rock
1
Temporal distribution
Toarcian (184.2–174.7 Ma)
11
Hettangian (201.4–199.5 Ma)
4
Species (6)
Plesiosaurus propinquus subjective synonym of Rhomaleosaurus zetlandicus 193 Ma
Plesiosaurus simpsoni subjective synonym of Rhomaleosaurus zetlandicus 193 Ma
Rhomaleosaurus cramptoni 184 Ma
Rhomaleosaurus megacephalus 201 Ma
Rhomaleosaurus thorntoni subjective synonym of Rhomaleosaurus zetlandicus 193 Ma
Rhomaleosaurus zetlandicus 193 Ma
Images 4
Bibliography
Original description
H. G. Seeley. 1874. Note on some generic modifications of the plesiosaurian pectoral arch. Quarterly Journal of the Geological Society of London 30:436-449 DOI ↗
Bibliography (8)
A. S. Smith and G. J. Dyke. 2008. The skull of the giant predatory pliosaur Rhomaleosaurus cramptoni: implications for plesiosaur phylogenetics. Naturwissenschaften 95:975-980 DOI ↗
G. W. Storrs and M. A. Taylor. 1996. Cranial anatomy of a new plesiosaur genus from the lowermost Lias (Rhaetian/Hettangian) of Street, Somerset, England. Journal of Vertebrate Paleontology 16(3):403-420 DOI ↗
A. R. I. Cruickshank. 1994. Cranial anatomy of the Lower Jurassic pliosaur Rhomaleosaurus megacephalus (Stutchbury) (Reptilia: Plesiosauria). Philosophical Transactions of the Royal Society of London B 343:247-260 DOI ↗
M. J. Benton and M. A. Taylor. 1984. Marine reptiles from the Upper Lias (Lower Toarcian, Lower Jurassic) of the Yorkshire coast. Proceedings of the Yorkshire Geological Society 44(4):399-429 DOI ↗
S. Melmore. 1946. Catalogue of types and figured specimens in the Geological Department of the Yorkshire Museum. The North Western Naturalist 20(3/4):207-221
C. W. Andrews. 1922. Note on the skeleton of a large plesiosaur (Rhomaleosaurus thorntoni, sp. n) from the Upper Lias of Northamptonshire. Annals and Magazine of Natural History 10:407-415 DOI ↗
R. Lydekker. 1889. Catalogue of the Fossil Reptilia and Amphibia, Part II. Containing the orders Ichthyopterygia and Sauropterygia DOI ↗
T. Wright. 1860. On the Zone of Avicula contorta, and the Lower Lias of the South of England. Quarterly Journal of the Geological Society 16:374-411 DOI ↗