Gosh, I thought, this is one ancient creature that may not have gone extinct! I even paid homage on-site once, with little luck of course.
Plesiosauria – including Plesiosaurs and their shorter-necked cousins the Pliosaurs – were cold-blooded, lung breathing marine reptiles (technically not dinosaurs as they lacked antorbital fenestrae, did not share the erect limb postures that gave dinosaurs greater mobility and stamina, and of course did not live on land as dinosaurs did) which lived from the early Jurassic to the Cretaceous periods, and were particularly populous during the Jurassic. Ranging in size from 2m to 20m, they replaced the Ichthyosaurs as the top aquatic predators, and were themselves replaced by the Mosasaurs in the last 20 million years of the Cretaceous era.
Behaviorally, Plesiosaurs had a unique swimming style involving up-down flapping of their flippers. Their still, long necks possibly helped them bottom-feed. They ate ammonites, belemites, and fish, had gastroliths to help in their digestion, and gave birth to live young.
It was mildly sobering to see that (i) recent expeditions to Loch Ness did not turn up anything; (ii) that a famous rotting carcass found by Japanese trawler near New Zealand really belonged to a basking shark; (iii) to learn in 1994 that the famous Nessie photo above taken by respected gynaecologist Colonel Robert Wilson was really a hoax; (iv) that a Plesiosaur fossil found at Loch Ness was in fact brought there from elsewhere; and that (v) Loch Ness itself is only 12,000 years old.
Still, Plesiosaur fossils are spectacular to marvel at. The largest collection I’ve seen lies in Britain’s Natural History Museum (below). By the way, it was also in Britain’s Lyme Regis area that the very first Plesiosaur was discovered.
Plesiosaurs were found in many countries, ranging from Argentina, Australia, Canada, , China, Colombia, and Cuba, to Germany, Japan, New Zealand, Morocco, Pakistan, the US, and the UK. Here’s my own humble collection of Plesiosaur-related fossils. Enjoy!