1 2. 1 Ichthyopterygian Diversity

Welcome back to Marine Reptiles. In lesson two, we ll examine the diversity of form and function for Ichthyopterygians and their closest relatives. The Ichthyopterygians are a distinctive and highly specialized group of marine reptiles that lived from the early Triassic to the midcretaceous, over a span of nearly 150 million years. They all had the same basic body plan but were specialized in a variety of ways ranging in length from 1 to 21 meters. Some were small and snubnosed, others had long pincerlike jaws and still others had an overhanging upper jaw like a swordfish. The derived members were streamlined like the fastest fishes. They breathe through nostrils located between their eyes and propel themselves through the water using their crescent shape tail flukes. They are an incredible example of convergent evolution, being similar in shape to sharks, tuna, and dolphins. If a casual observer looked at a drawing of a Icthyosaur and identified it as a dolphin, this mistake could easily be forgiven. You