Libonectes (meaning "southwest swimmer") is an extinct genus of sauropterygian reptile belonging to the plesiosaur order. It is known from specimens found in the Britton Formation of Texas (USA) and the Akrabou Formation of Morocco, which have been dated to the lower Turonian stage of the late Cretaceous period.[1]

Temporal range: Late Cretaceous, 93 Ma
Libonectes atlasense skull.jpg
Skull SMNK PAL 3978
Scientific classification edit
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Superorder: Sauropterygia
Order: Plesiosauria
Family: Elasmosauridae
Genus: Libonectes
Carpenter, 1997
L. morgani
Binomial name
Libonectes morgani
(Welles, 1949)
[originally Elasmosaurus]
  • Elasmosaurus morgani Welles, 1949
  • Libonectes atlasense Buchy, 2005
Life restoration


The animal was very similar to the related Thalassomedon, though the structure of the neck vertebrae were different, with taller neural spines and longer supporting processes of the bone, and its nostrils were slightly closer to the tip of the skull. The skull of the type specimen, which also contains the 5.06 metres (16.6 ft) neck[2] and gastroliths, is the best preserved elasmosaurid skull known. A shoulder girdle and flipper were also found but were apparently discarded at some point in the past.[1]

The specimen was originally named Elasmosaurus morgani by Welles in 1949, but it was reclassified to its own genus by Carpenter in 1997.[1] A second species, L. atlasense, was named in 2005 from deposits in Morocco, but a 2017 redescription of the material recognized it as a junior synonym of L. morgani.[3]

See alsoEdit


  1. ^ a b c Carpenter, K. (1999). "Revision of North American elasmosaurs from the Cretaceous of the western interior." Paludicola, 2(2): 148-173.
  2. ^ O'Gorman, J.P. (2016). "A Small Body Sized Non-Aristonectine Elasmosaurid (Sauropterygia, Plesiosauria) from the Late Cretaceous of Patagonia with Comments on the Relationships of the Patagonian and Antarctic Elasmosaurids". Ameghiniana. 53 (3): 245–268. doi:10.5710/AMGH.29.11.2015.2928.
  3. ^ Sachs, S.; Kear, B.P. (2017). "Redescription of the elasmosaurid plesiosaurian Libonectes atlasense from the Upper Cretaceous of Morocco". Cretaceous Research. 74: 205–222. doi:10.1016/j.cretres.2017.02.017.

External linksEdit