Shonisaurus

Shonisaurus is an ichthyosaur from the late Triassic period and is notable for its incredible size – it is one of the largest marine reptiles in history, growing up to 15m in length and nearly 30 tonnes in weight. This genus has a slim body and a long snout, and is a relatively slow swimmer despite having large flippers. While a juvenile Shonisaurus displays small teeth, these grow out by the time the genus reaches adulthood.

Discovery

Named after the location of its discovery – the Shoshone Mountains in Nevada, USA – the first Shonisaurus remains were unearthed in 1920. The genus wasn’t properly investigated until much later, though – respected palaeontologists Charles Camp and Samuel Welles began excavating the site in 1954, finding the remains of 37 large specimens through the late 1950s and 1960s. The genus was formally named in 1976, a full 56 years after it was first discovered.

Palaeoecology

Shonisaurus lived around 225-240 million years ago, swimming in deep oceans that were more suited to its large size than shallower waters. Its lack of teeth meant that it fed on soft-bodied prey such as squid and soft fish, eating them in huge quantities and often swallowing them whole.