Rhaeticosaurus

Rhaeticosaurus is the first plesiosaur skeleton ever found from the Triassic period, showing that plesiosaurs were already around before the Jurassic.2

Its name means 'Rhaetian lizard' because it lived during the Rhaetian age, the last stage of the Triassic.1

Rhaeticosaurus had very short lower arm and leg bones compared to its upper limb bones, with a humerus-to-radius ratio of 3.8 and a femur-to-tibia ratio of 4.3.2

The holotype skeleton was discovered in 2013 by Michael Mertens, a private collector who reported it to authorities.1

Rhaeticosaurus was a basal member of the Pliosauridae, a group of plesiosaurs with large heads and short necks.2

Its teeth had sharp ridges on the enamel, a feature that helped scientists identify it as a plesiosaur.2