Lusonectes
Lusonectes is a poorly known microcleidid the Toarcian (Lower Jurassic) of Portugal. It is known from a single holotype specimen (MG33), a partial skull in the Museu Geológico, Lisbon, Portugal. It was described and named by Smith et al. (2012) as the first diagnostic plesiosaur species from Portugal, and the westernmost occurrence…
Bishanopliosaurus
Bishanopliosaurus is the most complete plesiosaur known from the Jurassic of Asia (Sato et al. 2003). The holotype specimen of the type species, B. youngi, is a partial postcranial skeleton of a juvenile individual from the Dongyuemiao Member of the Ziliujing Formation (Lower or Mid Jurassic) of Bishan County, Chongqing, China. It…
Microcleidus
Microcleidus is a medium (4.27 m) to large (5.03 m) plesiosauroid with a small head and a long neck containing 38–39 cervical vertebrae. Watson (1909) erected Microcleidus to accommodate fossil material belonging to 'P.' homalospondylus and 'P.' macropterus (Watson 1911). Both species were considered valid by Seeley (1865), Blake (1876) and Watson (1911) on…
Hauffiosaurus
Hauffiosaurus is a basal pliosaurid known from the Lower Jurassic (Toarcian) of the UK and Germany. Hauffiosaurus is a medium to large sized plesiosaur (H. zanoni = 3.4 m, H. tomistomimus, 4.23 m, H. longirostris = 4.83 m) (Smith and Lomax 2019), with a relatively long neck for a pliosaur, and an…
Anningasaura
Anningasaura is a basal plesiosaur from the Lower Jurassic of Lyme Regis, UK, known from a single three-dimensionally preserved skull. The specimen, NHMUK OR49202, was originally described and figured by Andrews (1896), who referred it to 'Plesiosaurus' macrocephalus. It was redescribed and named as the holotype of Anningasaura lymense by Vincent and…
Thaumatodracon
Thaumatodracon is a relatively large rhomaleosaurid from the Lower Jurassic (Sinemurian) of Lyme Bay – the coast between Lyme Regis and Charmouth – UK. The holotype specimen (NLMH 106.058) is an almost complete skull and cervical (neck) series. It has a 60 cm long skull, and based on comparison with other rhomaleosaurids I…
Avalonnectes
Avalonnectes is a small-bodied basal rhomaleosaurid. Avalonnectes was named by Benson, Evans and Druckenmiller (2012) for a partial skeleton including the rear part of the skull from the lowermost Jurassic of Street, Somerset, UK. The specimen (NHMUK PV OR 14550) was previously referred to Thalassiodracon hawkinsii and is one of many historical…
Stratesaurus
Stratesaurus is a very small-bodied basal plesiosaur known from the lowermost Jurassic (Blue Lias Formation) of Street, Somerset . Stratesaurus is represented by three specimens. The holotype specimen (OUMNH J.10337) was named and briefly described by Benson, Evans and Druckenmiller (2012), and later described in detail along with two referred specimens by…
Thalassiodracon
The species Plesiosaurus hawkinsii was introduced in 1838 for a small plesiosaurian from Street, Somerset. The new genus name Thalassiodracon was erected decades later following an examination of a referred skull in Cambridge (CAMSM J.46986). Thalassiodracon is from the Rhaetian-Hettangian boundary, so it is latest Triassic or earliest Jurassic in age. Thalassiodracon…
Rhomaleosaurus
Rhomaleosaurus is the largest known Lower Jurassic pliosaur and was the top predator in early Jurassic marine ecosystems. It has a reinforced skull to help resist torsion and a ferocious set of teeth, a combination of characters perfect for snatching and killing cephalopods, fish, and other marine reptiles. Historically, the genus Rhomaleosaurus…
Plesiosaurus
Plesiosaurus was the first plesiosaur discovered and named (De la Beche and Conybeare 1821). The first 1821 description was based on partial remains so the anatomy of Plesiosaurus - particularly the identity of the isolated bones and how they articulated together – involved some guesswork. An attempted reconstruction of the forelimb of…
Occitanosaurus
'Occitanosaurus' was described by Sciau et al. (1990) and Bardet et al. (1999). The genus name was erected for 'Plesiosaurus' tournemirensis by Bardet et al. (1999). The taxon was originally regarded as an early elasmosaurid but is now considered a member of the Microcleididae. 'Occitanosaurus' was approximately 3.9 meters long. The type…
Meyerasaurus
M. victor was originally described and figured by Fraas (1910). Historically, M. victor has been regarded as a species of Rhomaleosaurus and is often associated in the literature under the defunct name 'Thaumatosaurus'. See my article about this history of 'Thaumatosaurus' here. Smith and Vincent (2010) identified M. victor as generically distinct from…