First bones of this mysterious creature were discovered in 1787 near Rio Lujàn (Argentinia), collected and send to Spain two years later. Zoologist Juan Bautista Bru de Ramon (1740-1799) reconstructed the bones in 1795 as a mounted skeleton for the Real Gabinete de Historia Natural de Madrid, the royal cabinet of curiosities - the first fossil vertebrate displayed in such a way.
Fig.1. The mounted skeleton of Megatherium, from Cuvier 1812 (image in public domain).
Many interested naturalists visited the strange animal , but only in 1796 and based just on some drawings, the French anatomist Georges Cuvier identified it as a giant specimen of Ice Age sloth and named it Megatherium americanum (large mammal from America). King Charles IV of Spain was so fascinated by this creature that he ordered to the colonial authorities to capture one alive, if not an adult specimen, also a younger, smaller, would do.
However Cuvier, based on the lack of historic accounts of such an animal spotted in South America, proclaimed that there was little hope to succeed:
"…we hope that nobody thinks to search them for real, it would be like searching the animals of Daniel or the beasts of the apocalypse. Let us not even search for the mythical animals of the Persians, results of an even greater imagination."
In 1870 the Argentine pioneering paleontologist and anthropologist Florentino Ameghino (born september 18, 1854 - 1911) discovered in the valley of the Rio Frias human and animal bones buried together, the animal bones showing marks left by stone tools. This was quite exceptional, at is was believed at the time that ancient Ice Age beasts, like giant sloths, and humans never coexisted. Then in 1898 Ameghino received a collection of tiny bones, extracted, so it was said, from a strange piece of skin, covered by reddish-gray fur. Ameghino identified the bones as dermal ossicles, similar to those found in the skin of Mylodon, a species of ground sloth of medium-sized proportions, known only from fossil remains excavated by geologist Charles Darwin in 1832. Ameghino published the discovery, even arguing that the new material appeared so well preserved and fresh, that it may came from a living specimen! To support this claim he added a tale by his friend Ramon Lista, politician, geographer and explorer. During an expedition in the province of Santa Cruz (south Patagonia) Lista supposedly encountered a strange cryptid. It resembled an pangolin (found however only in Asia), but instead of scales it was covered with long, reddish-grey fur. The animal was never identified, as Lista was soon killed after the supposed encounter. Ameghino, sure of the connection between the preserved skin and the mysterious sighting, named his discovery in honor of his deceased friend Neomylodon listai (the modern Mylodon of Lista).
The press was quite excited about the news of a surviving ground sloth. However many naturalists questioned the recent age of the remains and also the classification of the material, as Ameghino was known to be a bit too enthusiastic when naming new species.
Soon the source of the supposed fresh Neomylodon-skin was found. A German rancher, named Eberhardt, used a large piece of skin like a flag to mark the boundaries of his property. Many visitors cut small pieces from this supposedly cow- or lama-skin and it was such a souvenir that was later given to Ameghino. Eberhardt claimed that the skin had been discovered during the exploration of a cave, situated along the shores of the fiord of Ultima Esperanza (Last Hope Inlet, the cave today is known both as Ultima-Esperanza- or Eberhardt-cave). An archeological survey there revealed more human and animal bones, along with another piece of skin - however all fossil material, as it seemed.
In 1897 the brother of Florentino, geologist Carlos Ameghino, provided the paleontologist with some more anecdotal evidence of a late-surviving ground sloth. Carlos collected some local lore of a creature named Iemisch. He claimed that Indians often encountered a quite strong, clawed animal (able to drag horses away!) and also noted that a supposed iemisch-skin was identical to the skin recovered from the cave. However no complete carcass or living specimen was ever to be found.
Ameghino published this story as possible link between myth and reality, even altering dimensions and shape of the real fossil ground sloth to match better the vague description with the iemisch - with the result that the dispute between experts became even stranger.
Ameghino's dedication to support a seemingly lost case can be forgiven considering the time. Just three decades earlier the first incredible evidence that men and prehistoric beasts coexisted was discovered and a surviving giant, Ice Age sloth would may be highly unlikely, but not outside the realm of extreme possibilities…
BARNETT, R. & SYLVESTER, S. (2009): Does the ground sloth, Mylodon darwinii, still survive in South America? In "Bogus Science: Or, Some People Really Believe These Things (Facts Figures & Fun)" by PRICE, B. : 8-11
HEUVELMANS, B. (1995): On the Track of Unknown Animals. Kegan Paul International, London: 677
KOENIGSWALD, von W. & HOFFMAN, S. (2009): Ein berühmtes Faultier. Fossilien Nr. 5 :274-280