Eocursor: Prehistoric Beast of the Week

This week we are going to check out a little dinosaur that gives us insight into the origins of some of the most iconic dinosaurs, Eocursor parvus!  

Eocursor translates to "Dawn Runner" because it was a very early dinosaur and its extremely long legs show us that it was probably a fast runner.  From snout to tail it only measured about 3 feet (roughly 1m) and was a plant-eater.  It lived during the early Jurassic period, somewhere between 200 and 191 million years ago in what is now South Africa and was discovered in the 1990s but wasn't formally described until 2007.

Watercolor life reconstruction of Eocursor by Christopher DiPiazza.

Eocursor was tiny and had no special armor, horns, spikes, large teeth or anything else that some other extinct dinosaurs had that would make it formidable but it is nonetheless an extremely important discovery.  This is because it is one of the very earliest known members of the group of plant-eating, beaked dinosaurs like ceratopsians, thyreophorans and ornithopods, called the ornithischian dinosaurs or "bird hipped dinosaurs" (ironic because they're not the dinosaurs that include birds, it's the other "lizard hipped" group that includes theropods that were).  It may not look like much, but Eocursor's lineage would evolve into some of the most successful and widespread dinosaurs of the Mesozoic!

Eocursor parvus bones

Like I said before, Eocursor had extremely long legs which would have come in handy(or leggy) when avoiding all those hungry meat-eating theropods of its time.  We can tell this because its tibia(lower leg bone right below the knee) was much longer than its femur (thigh bone) which is a characteristic of swift-runners.  It also would have had strong arms with five grasping fingers on each hand.  This might have aided it when foraging for plants to eat.  Its head was small and possessed small teeth that look like they would have been suitable for cutting leaves and other such plant material.  Even though the top of its skull was never discovered, I would be willing to bet Eocursor also had large eyes, which is a trait common in small, fast-moving, plant-eating dinosaurs.

References

Butler, Richard J.; Roger M. H. Smith and David B. Norman (2007). "A primitive ornithischian dinosaur from the Late Triassic of South Africa, and the early evolution and diversification of Ornithischia". Proceedings of the Royal Society B: Biological Sciences 274 (1621): 2041. 

Mcphee, Blair W.; Bordy, Emese M.; Sciscio, Lara; Choiniere, Jonah N. (2017). "The sauropodomorph biostratigraphy of the Elliot Formation of southern Africa: Tracking the evolution of Sauropodomorpha across the Triassic–Jurassic boundary". Acta Palaeontologica Polonica. 62 (3): 441–465.