Umoonasaurus

Post author:Adam S. Smith
Post published:31/01/2026
Post category:Genus page Leptocleididae Plesiosauria Plesiosauroidea

Skeleton of Umoonasaurus. (Image copyright Australian Museum: https://australian.museum/blog/museullaneous/a-national-treasure/)

Umoonasaurus is a small (~2.5 m long) leptocleidid that lived during the Early Cretaceous in Southern Australia. The holotype specimen (AM F99374), a spectacular opalised skeleton including the skull, is nicknamed ‘Eric’. It is the most complete opalised plesiosaur skeleton (and fossil vertebrate) known. It was originally described briefly as Leptocleidus sp. by Kear (2006) who figured the skull and...

Vectocleidus

Post author:Adam S. Smith
Post published:19/10/2020
Post category:Genus page Leptocleididae Plesiosauria Plesiosauroidea

Vectocleidus material on display in the Dinosaur Isle Museum, Isle of Wight, UK.

The name Vectocleidus was erected by Benson et al. (2012b) for a leptocleidid from the Early Cretaceous of the Isle of Wight, UK. The type specimen was previously referred to Leptocleidus sp. Vectocleidus can be confidently identified as a leptocleidid but its position within the clade is unstable (Benson et al. (2012b). Vectocleidus material on display in the Dinosaur Isle...

Hastanectes

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

Under construction...

Gronausaurus

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

‘Gronausaurus‘ was named in 2013 (Hampe 2013). It is now regarded as a junior synonym of Brancasaurus (Sachs et al. 2016). Under construction...

Leptocleidus

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

Skull of Leptocleidus capensis in lateral view (from Cruickshank, 1997)

Lower Cretaceous plesiosaurs are rare, so Leptocleidus is important because it fills a gap in the fossil record of plesiosaurians. Leptocleidus was once considered to be a late surviving member of the family Rhomaleosauridae but it has recently been reidentified as a close relative of polycotylids. The fossils of all known species of Leptocleidus were preserved in inshore brackish or...

Brancasaurus

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

Skeleton of Brancasaurus in side view. Form Sachs et al. (2016)

Under construction Skeleton of Brancasaurus in side view. From Sachs et al. (2016) Skull of Brancasaurus in dorsal and lateral view, and showing the tip of the snout (C) in ventral view (from Wegner 1914)...