Weekly Spotlight (Mini Version): Scelidotherium

6 02 2010

Good tidings and well-wishes! 

Due to the advent of recent academic pressures, this is going to be one of my shorter entries. 

I’ve often utilized the opening segment of this space to lament the neglect of whichever prehistoric critter I’ve opted to feature during the course of that particular week by the public and/or the scientific community. However, I’m glad to say that I cannot do so whilst discussing a giant ground sloth, for last year’s article on Eremotherium is by far one of my most popular to date.  Nevertheless, as in any group, the ground sloth clan maintains its fair share of lesser-known members, my favorite of which being the long-faced Scelidotherium sp. (“a Scelidotherium walks into a bar…”). 

Scelidotherium skeletal reconstruction.

Scelidotherium is, amazingly, the namesake genus of the South American Scelidotheriinae subfamily (which in turn belongs to the Mylodontidae family); a group that also contains such stellar sloths as Catonyx & Valgipes and which is defined by, among others, the following characteristics: 

-Like all Mylodonts, they possess lobate teeth (which, by definition, are riddled with projections or ‘lobes’) however, the Scelidotheres are unique in being transversely compressed (flattened from side to side). 

-As I mentioned earlier, the skulls of these animals are notably elongate. More specifically, the nasals and maxillae were particularly long: the former stretched for at least half the length of the skill in these beasts! 

-Their femurs were famously short and wide, leading Sir Richard Owen to create the name ‘Scelidotherium‘, which roughly translates to ‘femur beast’. 

-The astragalus sported a depression on the surface with which it touched the tibia. 

Scelidotherium skeletal mount.

 Scelidotherium itself was discovered by a Mr. Charles Darwin near Punta Alta, Argentina in 1832 during his famous voyage, though he initially assumed the remains belonged to the larger Megatherium. According to “The Cambridge Natural History, Volume 10”, Scelidotherium has “four properly-developed toes in the fore-foot, the thumb being rudimentary; of these, the first two bear claws. The hind feet are also four-toed.” It’s also been theorized that Scelidotherium may have had a strong, muscular tongue (ideally, like many ground sloths) and that the beast probably maintained a more diverse diet than did most Megalonychids, Megatheriids, and Mylodontids. 

Scelidotherium reconstruction.

May the fossil record continue to enchant us all!




3 responses

6 02 2010

Hooray for sloths! I’d say my favorite unknown sloth is Thalasocnus. And i peeked over at your Eremotherium post and would like to add that Berkeley’s online atabase says they have a vertebra of Megatherium americanum from Santa Barbara County, CA (the county right below mine).

Also, i think you should do Capricamelus for one of these spotlights!

7 02 2010

I’d love to cover the camelid, assuming that I can locate enough information concerning it…

You may be interested in my article dedicated to Titanotylopus, which can be found here: https://tanystropheus.wordpress.com/2009/07/15/wednesday-wonders-titanotylopus/

7 02 2010

Thanks, twas a good article. I noticed you used my shot of Titanotylopus from the LA Museum (a little odd, given the annoying flash spots and the fact that the specimen was only 6-7 feet at the shoulder, much smaller than the sizes i have heard). I have tried to find more info on Capricamelus (because it’s the wierdest and most amazing camel i’ve come across) but have not had much success. I’ll try sending you the original paper tomorrow, which is lengthy.

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