Bishanopliosaurus

Post author:Adam S. Smith
Post published:18/10/2020
Post category:Genus page Plesiosauria Pliosauroidea Rhomaleosauridae

Photo of Bishanopliosaurus on display in the Zigong Dinosaur Museum. Photo by Zhangzhugang. Used here under a CC BY 4.0 licence. The label says it is from "Dashanpu, Zigong", suggesting it isn't the type specimen (from Bishan County, Chongqing), but this could be a mistake.

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…

Hauffiosaurus

Post author:Adam S. Smith
Post published:17/10/2020
Post category:Genus page Plesiosauria Pliosauridae Pliosauroidea

Holotype (Hauff Uncatalogued) of Hauffiosaurus zanoni as preserved in ventral view. Scale bar = 1 m. From Vincent (2011)

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

Post author:Adam S. Smith
Post published:17/10/2020
Post category:Genus page Plesiosauria Pliosauroidea

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…

Avalonnectes

Post author:Adam S. Smith
Post published:16/10/2020
Post category:Genus page Plesiosauria Rhomaleosauridae

The holotype specimen of Avalonnectes (NHMUK OR 14550), on display in the Natural History Museum, London. Photo by Chris Crump.

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…

Eretmosaurus

Post author:Adam S. Smith
Post published:22/07/2018
Post category:Genus page Plesiosauria

Skeleton of Eretmosaurus. Lithograph from Owen (1865).

The genus Eretmosaurus was erected for 'Plesiosaurus' rugosus by Seeley (1874). Eretmosaurus is a rogue taxon in cladistic analyses and researchers have been in disagreement about its taxonomic affinity. Eretmosaurus has been included in several different families: the Rhomaleosauridae based on the anatomy of its girdles (Persson 1963); the Pliosauridae (Brown 1981), the…

Atychodracon

Post author:Adam S. Smith
Post published:22/07/2018
Post category:Genus page Plesiosauria Pliosauroidea Rhomaleosauridae

Holotype specimen of Atychodracon megacephalus in the Bristol City Museum and Art Gallery (from Swinton, 1948). The specimen was destroyed during the Second World War.

The genus Atychodracon was erected by Smith (2015) to accommodate 'Rhomaleosaurus' megacephalus, because it is generically separarate from Rhomaleosaurus sensu stricto (Smith and Dyke 2008). A. megacephalus is closely related to Eurycleidus and some authors have regarded A. megacephalus as a distinct species of Eurycleidus. Three dimensional scan with texture (colour) removed…

Attenborosaurus

Post author:Adam S. Smith
Post published:22/07/2018
Post category:Attenborosaurus Genus page Plesiosauria Pliosauridae Pliosauroidea

Photograph of the holotype of Attenborosaurus, before it was destroyed. The skeleton was mounted in a block together with a cast of the opposite side of the body and the opposite side of the head (from Swinton, 1949)

Attenborosaurus is an unusual plesiosaur because it combines a long neck with a relatively large head. It is classified as a pliosaur in some classifications, but some phylogenies place it in a more basal position. The genus was introduced for 'Plesiosaurus' conybeari, a species originally described by Sollas (1881). Bob Bakker coined…

Archaeonectrus

Post author:Adam S. Smith
Post published:21/07/2018
Post category:Genus page Plesiosauria Pliosauroidea Rhomaleosauridae

Archaeonectrus illustration (From Novozhilov 1964)

The genus Archaeonectrus was proposed by Novozhilov (1964) for 'Plesiosaurus' rostratus, a species named by Owen (1865). By modern standards, Owen's (1865) original description is rather inadequate. One notable characteristic of Archaeonectrus rostratus is the relatively small size of the limbs relative to its body. It has been classified as a pliosauroid,…