Aardonyx celestae had many characteristics of two-legged herbivore dinosaurs, but also could drop down on all fours and move about like the huge sauropods that would evolve later on. This distinct feature is thought to have contributed to what later allowed the sauropods to become the largest dinosaurs that ever existed. The bones in the forearms of Aardonyx celestae would interlock when it walked on four legs, a feature that it’s descendants all had, and it allowed it to be able to safely support it’s weight.

Despite limb proportions that showed Aardonyx celestae to be mostly bipedal, meaning it mostly walked on two legs, it had already developed several features that would become evident in sauropods. The femur (thigh bone) had straightened out for strong vertical weight support, the backbone developed specialized bracing-joints to strengthen it, the feet had flattened and became more robust, the jaw had a wide gape, and of course, the previously mentioned forearm bones that interlocked.

These findings were published in the Proceedings of the Royal Society B, a peer-reviewed journal based in London, England. If you want to read the full report, click here.

So remember, if you ever find yourself arguing with someone who believes that no transitional fossils exist, Aardonyx celestae is yet another example you could politely point them to ;)

Dr. Bonnan talks about Aardonyx celestae:

Aardonyx celestae FACTS:

• discovered in Free State, South Africa
• lived in early Jurassic era (roughly 195 million years ago)
• grew to 7m (20ft)
• fossil specimen believed to have died early at 10 years old
• “Aardonyx” means “Earth Claw,” named because the earth filled claws were amongst the first bones discovered of the specimen
• “celestae” is derived from Celeste Yates, the fossil preparator for the team that made the discovery
• the research team included Dr. Adam Yates, Dr. Matt Bonnan, Dr. Johann Neveling, Dr. Anusuya Chinsamy, Marc Blackbeard, and Celeste Yates