Is this the real story behind the Atacama 'alien' mystery?S

Last week we told you about the surprising conclusion reached by a Stanford University professor suggesting that the remains of the alien-like Atacama skeleton belonged to a human between the ages of 6 to 8 — an assertion that seemed impossible to believe given its size. And indeed, a simpler explanation may finally put the mystery to rest.

The preliminary examination was performed by Garry Nolan, professor of microbiology and immunology at Stanford School of Medicine. In addition to concluding that the specimen belonged to a young human child, Nolan suggested that its other deformations, like the elongated head and two missing ribs, were on account of a birth detect.

But according to Paolo Viscardi, a natural history curator at the Horiman Museum in London, there’s no way this skeleton could have come from a child between 6 and 8.

Is this the real story behind the Atacama 'alien' mystery?

“This seems quite remarkable to me, since I’ve dealt with skeletal foetus specimens rather similar to this in museum collections,” he wrote at his blog, Zygoma.

Rather, the Atacama specimen was probably an aborted 14-16 week fetus that was unceremoniously dumped in the desert, where it underwent a natural mummification process. Viscardi writes:

The main differences I can discern by looking at the high quality photos, X-rays and CT scan...are that the Atacama specimen is from a slightly earlier stage foetus...it has mummified soft tissue that has shrunk tight...pulling the ribcage into a more narrow configuration; and the head has been distorted, probably as a result of an illegal back-street abortion where a hook has been used to extract the foetus...causing damage to the back of the skull and stretching the pliable head.

Viscardi admits that the hole in the head may have occurred during the scientists' examinations, which would be consistent with other images showing a skull without a hole.

Is this the real story behind the Atacama 'alien' mystery?S

Viscardi’s fetus hypothesis would also explain not just the small size, but why there are only 10 pairs of ribs; the lower ‘floating ribs’ were still under development and had not yet fully formed.

“It would also explain why there is no evidence in the x-rays of the deciduous or unerupted permanent dentition that you would expect to find in a 6-8 year old,” he writes.

Is this the real story behind the Atacama 'alien' mystery?

Viscardi also argues that the age estimate was overly influenced by the high density of the bone in the x-rays of the specimen, which is typical of mummified specimens.

Read more at Zygoma, including Viscardi’s remarks about Chile’s restrictive abortion laws.

H/t to io9 reader ParticleNoun!

Images: Atacama Humanoid © 2013 Sirius Disclosure.