Evolution of MARINE REPTILES

Plesiosaurs and pliosaurs were marine reptiles within Sauropterygia that evolved from land-dwelling ancestors and returned to the oceans by the Early Jurassic. Over time they diversified into two classic body plans: long-necked, small-headed plesiosauroids and short-necked, large-skulled pliosaurids. These differences reflect evolutionary specialization, with many long-necked forms adapted for snapping up smaller prey and many pliosaurids evolving into powerful macropredators. Both groups converged on the same efficient swimming solution, four large flippers used for underwater “flight”, while experimenting with neck length, skull shape, and body size as marine ecosystems changed. During the Cretaceous, giant pliosaurids became rarer, while lineages like elasmosaurids and polycotylids flourished, showing that plesiosaur evolution continued to reshape their roles alongside other marine hunters. They ultimately disappeared in the end-Cretaceous mass extinction, when rapid global environmental disruption collapsed the food webs that sustained these ocean giants. Compilation of these 2 videos : Part one - https://www.youtube.com/watch?v=ULOn1-pdquY Part two - https://www.youtube.com/watch?v=s87IG7spx8g Music by Karl Casey Illustrations by Satoshi Kawasaki, Mario Lanzas, Gabriel Ugueto, Fabio Alejandro, Thomas Sutton and Ceri Thomas Icons next to names indicate the diet : 🌱Seaweed / 🦪Shelly mollusks / 🦀Aquatic arthropods / 🦐Micro-organisms/Plankton / 🐟Fish / 🥩Meat / 🦑Cephalopods