Mammathus, thanks for the article. You're a prime genius! Thanks, too, for the PubMed links to all this great info.
Since we can't all be Svante Paabo, examining ancient mtDNA or even the occasional nuclear DNA, can you give us the morphological scoop on any of these fossils, particularly regarding the cervical vertebrae? When I read your article, I recalled one of the few interesting things I previously learned about sloths - they don't have the standard 7 cervical vertebrae that mammals typically have (manatees are the other exception I recall - they have 6). I went digging for more info, and one site said that the 2-toed sloths generally have 6, while the 3-toed guys have 9 or 10.
Basically, I'm curious as to whether the molecular phylogenetics correlates with any relationships of fossil and modern sloths based on the cervical vertebrae. Please excuse my ignorance on the topic, and sorry if it sounds like I'm asking you to do all the research on my question, I just thought you might have already tracked down the info on the cervical vertebrae in the fossil sloths, and have a ready answer.
Besides, it gives us something to do while waiting for all those creationist responses that are sure to be rolling in any day now.
Thanks again for the interesting info. I'm learning more about sloths and coprolites than I have in many years. (My only other experience with a coprolite is a dino coprolite I own - I called it the "Barney Stone").