Plesiosaurs, the best known of the world’s extinct marine reptiles, were found worldwide. They lived millions of years ago through the Jurassic and Cretaceous periods until all dinosaurs were wiped out in what is known as the K/T extinction (65 million years ago).

The plesiosaur’s head is quite triangular in shape with a short snout. They had approximately 86 upper teeth and 84 lower. The shape of the skull suggests the creature had powerful jaw muscles and forward facing eyes. This may have helped the creature to see its prey while it swam with its mouth open. They ate soft-bodied prey like squid, which is where the genus name Kaiwhekea derives: kai – food, and whekea – squid. Large eyes may have helped the plesiosaur to see its prey in low light or great depths. The plesiosaur has been described as a snake threaded through a turtle’s body. It was highly adapted for marine life. It was a fast swimming reptile and moved by using its paddle-like hind flippers.

The Otago Museum’s Plesiosaur

Plesiosaur fossils occur worldwide, but the one displayed in the Otago Museum establishes a new genus and species. Located in the ‘Southern Land, Southern People’ gallery, it is the imprint which remained in the rock when all the bones of a plesiosaur dissolved. It lived during the late Cretaceous period, around 70 million years ago (very close to the K/T boundary) so is considered relatively recent. It inhabited one of the southern-most localities in which a Cretaceous plesiosaur has ever been found.

The Otago Museum’s plesiosaur fossil was found at Shag Point below a 10 metre cliff. It displays a life-like position, with skull and bones together, which leads us to believe it died a natural death as most body parts are present. Found in 1983 by fossil collector Gary Raper, it is the largest fossil discovered in New Zealand at 8 metres long. Only the forelimbs and pectoral girdle are missing.