Effigia
A toothless, bipedal crocodile relative from the Late Triassic.
Effigia is an extinct genus of shuvosaurid known from the Late Triassic of New Mexico, south-western USA. With a bipedal stance, long neck, and a toothless beaked skull, Effigia and other shuvosaurids bore a resemblance to the ornithomimid dinosaurs of the Cretaceous Period. However, shuvosaurids were not dinosaurs, but were instead a specialized family of poposauroid pseudosuchians, meaning that their closest living relatives are crocodilians.
- field
- Paleontology
- known_for
- Extreme convergent evolution with ornithomimid dinosaurs; toothless beaked skull; bipedal stance
- type_species
- Effigia okeeffeae
- geological_period
- Late Triassic
- location
- New Mexico, south-western USA
Lore & Background
The holotype fossil was collected by Edwin H. Colbert's expedition aimed to recover fossils of the basal theropod dinosaur Coelophysis, and he believed no other large vertebrates were present. Nesbitt instantly recognized the remains were not a dinosaur and tracked down the rest of the blocks from that area of the quarry.
Reader's Guide
Effigia is significant for its remarkable similarity to ornithomimid dinosaurs, a case of 'extreme' convergent evolution. Nesbitt also showed that Shuvosaurus was the same animal as Chatterjeea and that Effigia belongs to an exclusive clade within Poposauroidea, forming an even more exclusive clade with Shuvosaurus and the South American Sillosuchus (Shuvosauridae). Examination of Effigia's jaws suggests it was a specialist herbivore that filled a niche as a browser feeding on softer plant material, due to its weak jaws and sharp beak. It was previously suggested that it pecked for food like ostriches, but biomechanical studies have estimated that its skull could not withstand such forces.
Did You Know?
- Its closest living relatives are crocodilians, despite its dinosaur-like appearance.
- The species name okeeffeae honors artist Georgia O'Keeffe, who spent many years at Ghost Ranch.
- Effigia's similarity to ornithomimid dinosaurs is considered a case of 'extreme' convergent evolution.
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