We started off our Triassic series looking at the placodonts, a group of turtle-like marine reptiles. The placodonts existed solely during the Triassic years, becoming extincted at the end of the time period. The second group of creatures that shared Pangea with the first dinosaurs were the nothosaurs.
The nothosaurs (temporal range: 245-213 Mya) were a group of marine reptiles that first appeared in the seas of the Early Triassic. They thrived throughout the Triassic time period but eventually became extinct at the Triassic/Jurassic boundary. Unlike the placodonts however, the nothosaurs were not completely lost following their extinction. The much more commonly known plesiosaurs (temporal range: 203-66 Mya) thrived throughout the Jurassic and Cretaceous eras and are believed to have evolved from the far more primitive nothosaurs, with whom they share a number of distinct characteristics. The order Nothosauroidea was created in 1889, when paleontologist Georg Baur classified the nothosaurs within the Sauropterygia (the group which also includes the plesiosaurs and the placodonts).
It is believed that the nothosaurs would have lived their lives in a similar manner to those of modern-day seals, catching food in water but coming ashore on rocks and beaches. The nothosaurs averaged around 3 meters in length and were characterised by an elongated neck, body and tail. The limbs were paddle-like and webbed, which would have helped generate power when swimming. They sported an elongated, flattened head with nostrils situated just in front of the eyes. It is believed that the nothosaurs breathed air, needing to come up to the surface for oxygen when in the water.
It has also been recently proven that nothosaurs would have used their limbs to scoop out the soft mud whilst floating along the sea floor, possibly in an attempt to disturb prey items hiding among the seabed. The diet of a nothosaur would have consisted mainly of fish, squid and shrimp which would have been snapped up between a pair of long jaws, equipped with sharp, outward-pointing teeth.
Picture: Lariosaurus, a member of the nothosaur family.