Comments on: Toxodonts Traveled North

By: Stefanus Sutopo

Stefanus Sutopo — Fri, 18 Jan 2013 11:17:39 +0000

I think that the reason why toxodonts and phorusrhacids never make it up north is that they just weren’t adapted for high latitude life from the start (AFAIK, no toxodont or phorusrhacid fossils have been found from South America’s far south; correct me if I’m wrong)

Still, this is still a very big “IF”, and perhaps some of the more established, adult, scientists can enlighten me on this

By: Steve

Steve — Thu, 17 Jan 2013 04:33:07 +0000

Great post.
One thing to bear in mind when writing about southern US coastal areas is that what constitutes the coast would have been completely different at the height of the last ice age. For example, a lot of the area between Yucatan and Florida would have been dry.

Therefore the S American beasts found from Texas to Florida would have had a lot more land to roam at that time.

By: Hai~Ren

Hai~Ren — Wed, 16 Jan 2013 10:27:40 +0000

I think the North American porcupine counts as one of the more successful southern species. It seems like most other southern species, such as capybara, terror birds, and other xenarthrans like anteaters, glyptodonts, pampatheres and armadillos did not manage to spread very far north.

By: Ross

Ross — Wed, 16 Jan 2013 10:13:05 +0000

Thanks for the reply! I guess sloths are just weird. The image of Megalonyx in the snowy North is just bizarre. I guess it works the other way as well. Coelodonta never made it over Beringia, while Mammuthus, Cervus, Alces and others did. Without knowledge of the environmental and ecological constraints on the living animals we’ll probably never know.

By: Brian Switek

Brian Switek — Tue, 15 Jan 2013 19:55:47 +0000

Great question, Ross! I don’t think any of the South American mammal lineages made it as far as the sloths, although I’m not entirely sure of their entire distribution. It seems that some SA lineages – toxodonts, terror birds – stuck to coastal areas in southern North America. I wonder why that is, and why the sloths were so much more widespread.

By: Ross

Ross — Tue, 15 Jan 2013 11:00:41 +0000

Fascinating stuff. Do any other South American endemics make it further than Megalonyx jeffersoni in Alaska? http://pubs.aina.ucalgary.ca/arctic/Arctic53-3-213.pdf