Pronunciation: ahr-DON-iks
Meaning: Earth claw
Author/s: Yates et al. (2010)
Synonyms: None known
First Discovery: Free State, S.Africa
Discovery Chart Position: #722
Aardonyx celestae
Described in 2009 based on the remains of two sub-adults, Aardonyx was close to the ancestor of sauropods proper and provided a missing chapter in the evolution of lumbering herbivores from bipedal (two-leg drive) to quadrupedal (four-leg drive).
Straightened thighs with muscle attachment anchors lowered to the mid-point, allowing for bigger muscles and thus increased power, strengthened bracing joints to reinforce the spine, interlocking forearm bones and non-twisting wrists, and flattened weight-bearing feet all suggest Aardonyx was becoming just as comfortable on four legs as it was on two. It was lugging around an enormous fermenting tank of a belly and had a mouth unhindered by huge-gape-restricting cheeks to fill it with, which is as good a reason as any for the shift to four-legs for even weight distribution and super-sizing that sauropods underwent. They simply ate themselves bigger.
Although Aardonyx — with an estimated adult length of 9 metres — highlighted the changes that two-legged sauropodomorphs underwent on their journey to becoming four-legged sauropods, it wasn't a missing link. At best, it was an offshoot, on its way but on a slow boat to nowhere, because true sauropods had already evolved from the same ancestor and were thriving in the Early Jurassic while "Earth Claw" was doing its own thing.
Aardonyx was a hugely unexpected bonus when National Geographic funded a research party to explore a known South African Massospondylus hot spot for juvenile specimens of this common as dust "prosauropod" in 2004. The lead author was utterly underwhelmed by that prospect, so he sent undergraduate Marc Blackbeard and volunteers to work the site. But interest was piqued when they discovered its tough-as-nuts, muck-encrusted, name-prompting claws, and Yates and co were back on board for a full description which arrived five years later.
Straightened thighs with muscle attachment anchors lowered to the mid-point, allowing for bigger muscles and thus increased power, strengthened bracing joints to reinforce the spine, interlocking forearm bones and non-twisting wrists, and flattened weight-bearing feet all suggest Aardonyx was becoming just as comfortable on four legs as it was on two. It was lugging around an enormous fermenting tank of a belly and had a mouth unhindered by huge-gape-restricting cheeks to fill it with, which is as good a reason as any for the shift to four-legs for even weight distribution and super-sizing that sauropods underwent. They simply ate themselves bigger.
Although Aardonyx — with an estimated adult length of 9 metres — highlighted the changes that two-legged sauropodomorphs underwent on their journey to becoming four-legged sauropods, it wasn't a missing link. At best, it was an offshoot, on its way but on a slow boat to nowhere, because true sauropods had already evolved from the same ancestor and were thriving in the Early Jurassic while "Earth Claw" was doing its own thing.
Aardonyx was a hugely unexpected bonus when National Geographic funded a research party to explore a known South African Massospondylus hot spot for juvenile specimens of this common as dust "prosauropod" in 2004. The lead author was utterly underwhelmed by that prospect, so he sent undergraduate Marc Blackbeard and volunteers to work the site. But interest was piqued when they discovered its tough-as-nuts, muck-encrusted, name-prompting claws, and Yates and co were back on board for a full description which arrived five years later.
[Celeste Yates' Earth Claw]
Etymology
Aardonyx is derived from the Afrikaans "aard" (earth) and the Greek "onux" (claw), referring to its earth-encrusted feet claws which were the first remains to be discovered.
The species epithet, celestae (ce-less-tie) honors Celeste Yates who was charged with removing said earth.
Discovery
The first fossils of Aardonyx were discovered in the Upper Elliot Formation at "Marc's Quarry" on the farm Spion Kop 932, just over a kilometre from "Sauropod Quarry" that yielded fellow sauropodomorphs Arcusaurus and Pulanesaura, Senekal District, Free State, South Africa, by Marc Blackbeard in 2004.
The holotype (BP/1/6254) is a maxilla (a tooth-bearing bone from the upper jaw).
Preparators
Nkosinathi Sithole, Charleton Dube and Celeste Yates.
