| Diet | Herbivore |
| Height | 2m |
| Length | 4m |
| Weight | 300 kg |
| Environment | Land |
| Era | Jurassic |
| Period | Early Jurassic |
| Type | Sauropod |
| Location | South Africa |
Aetonyx palustris is a mysterious sauropod from the Early Jurassic period of southern Africa, though its identity remains highly uncertain due to the fragmentary nature of its fossils. Originally described by Robert Broom in 1911, this dinosaur was initially misidentified as a carnivorous species before being recognised as a plant-eating sauropod.
Living approximately 190 million years ago in what is now South Africa, Aetonyx inhabited the semi-arid landscapes of the upper Elliot Formation. The fossil remains suggest it was a relatively small sauropod, estimated at around 4 metres in length and 2 metres tall at the hip, making it considerably smaller than its famous relatives like Brontosaurus.
As a herbivorous sauropod, Aetonyx would have fed on early Jurassic plant life including ferns, cycads, and conifers. Its teeth and jaw structure, though poorly preserved, suggest it was adapted for processing tough plant material. Like other early sauropods, it likely moved on both two and four legs, depending on whether it was feeding or travelling.
The taxonomic history of Aetonyx has been particularly complex, with various scientists suggesting it may be synonymous with better-known genera like Massospondylus. Today, most palaeontologists consider Aetonyx a nomen dubium - a doubtful name - because the original fossils are too incomplete to definitively distinguish it from other early sauropods.
The fragmentary nature of Aetonyx fossils makes it difficult to identify specific distinguishing features. What remains suggests it was a relatively small sauropod with typical early sauropod characteristics, though no unique features can be confidently attributed to this genus.
Based on its sauropod classification, Aetonyx likely spent much of its time foraging for vegetation in the Early Jurassic landscape. It may have lived in small groups and could probably rear up on its hind legs to reach higher vegetation, a behaviour common among early sauropods.
Aetonyx was first described by Robert Broom in 1911. The original fossils were discovered at Upper Elliot Formation, Fouriesburg, Free State Province, South Africa.
