Cionodon Facts
| Diet | Herbivore |
| Height | 3m |
| Length | 8m |
| Weight | 3 tonnes |
| Environment | Land |
| Era | Cretaceous |
| Period | Late Cretaceous |
| Type | Ornithopod |
| Location | North America |

| Diet | Herbivore |
| Height | 3m |
| Length | 8m |
| Weight | 3 tonnes |
| Environment | Land |
| Era | Cretaceous |
| Period | Late Cretaceous |
| Type | Ornithopod |
| Location | North America |
Cionodon is a controversial ornithopod dinosaur that lived during the Late Cretaceous period, approximately 94 to 72 million years ago. However, palaeontologists consider it a 'nomen dubium' - meaning its identity remains doubtful due to the extremely fragmentary nature of the fossil evidence. The original specimens consist of just a few teeth and bone fragments, making it nearly impossible to determine what this dinosaur actually looked like or how it lived.
First discovered in Colorado's Denver Formation in 1873 and described by the famous palaeontologist Edward Drinker Cope the following year, Cionodon was initially thought to be a duck-billed ornithopod. The fragmentary remains suggest it was likely a plant-eating dinosaur that may have walked on both two and four legs, as was typical of many ornithopods of this period.
Two additional species were later assigned to Cionodon: one from Canada and another from Uzbekistan. However, the Uzbekistan specimen has since been reclassified as belonging to a different genus entirely, Bactrosaurus. This highlights the ongoing confusion surrounding Cionodon and demonstrates why palaeontologists are so cautious about the genus.
The mystery of Cionodon serves as an important reminder of how challenging palaeontology can be. With only teeth and small bone fragments to work with, scientists cannot confidently reconstruct this dinosaur's appearance, behaviour, or even confirm whether the fossils all belong to the same type of animal.
Due to the extremely fragmentary nature of Cionodon fossils, consisting mainly of isolated teeth and small bone pieces, no reliable distinguishing features can be identified. The teeth appear to be typical of ornithopod dinosaurs but lack unique characteristics.
The behaviour of Cionodon cannot be determined due to the fragmentary nature of the fossil evidence. If it was indeed an ornithopod as suggested, it would likely have been a herbivore that fed on plants close to the ground.
Cionodon was first described by Edward Drinker Cope in 1874. The original fossils were discovered at Denver Formation, Lodge Pole Creek, Colorado, USA.