Retrosaur Challenge 18: Inedible Herbivore

    Crassusaurus enigmatus (“enigmatic thick lizard”) of the late Jurassic of North America has presented quite a mystery for paleontologists. The first of these mysteries is its placement within the phylogeny of retrosaurs as it seems to be a very basal creature containing ancestral features of both duck billed and spike tailed goliaths. The second mystery is its placement within the food chain of its environment. Sites where Crassusaurus fossils are found are unusually devoid of predators and highly abundant in cycad fossils. A few specimens had the contents of their guts preserved revealing a diet that consisted mostly, if not entirely, of cycad cones, seeds, leaves and stems. Although cycads are toxic to many mammals today they were an important part of the diets of most low grazing retrosaurs. It is unknown what effect cycad toxin would have had on carnivorous retrosaurs but it is entirely possible that through its diet Crassusaurus could have concentrated this poison making it highly toxic to potential predators. This might explain the basal or degenerate appearance of this creature as it would not need the running and swimming speed of a duck billed goliath or the armor and spikes of a spike tailed goliath to avoid predation.

    I wanted to take the word inedible literally for this entry. Based on Camptosaurus a dinosaur that, as a child, I felt had few distinguishing features and even fewer defences against predators. Link to challenge: tyrantisterror.tumblr.com/post…