Astragalus

[rplopes]

Hi people! A friend of mine collected the astragalus of the photo from a fossiliferous site with Pleistocene mammals in southern Brazil. Although we have a large collection of fossils at the university, we couldn't identify it. We have already excluded horses, tapirs, ground sloths, sabertooth cats...could it be a bear or possibly a mastodont?

[Harry Pristis]

Hi people! A friend of mine collected the astragalus of the photo from a fossiliferous site with Pleistocene mammals in southern Brazil. Although we have a large collection of fossils at the university, we couldn't identify it. We have already excluded horses, tapirs, ground sloths, sabertooth cats...could it be a bear or possibly a mastodont?

It may be that this astragalus is from a taxon no familiar to North American collectors. Have you looked at some of the giant armadillos?

What you must do, if you can't find a match for this bone, is eliminate the possibilites among the known medium-large mammals. Try mating it with calcanea and tibiae from known animals. Whatever taxon you can't eliminate is likely to be the correct answer. (Of course, it is always possible that this is the only known astragalus of whichever animal it may be. However, if it is a Pleistocene mammal, it is unlikely to be unique.)

Let us know what you conclude.

Edited August 3, 2012 by Harry Pristis

[LordTrilobite]

I'd say the size is similar to bear, but the shape is very different to a cave bear astragalus I have.

[Harry Pristis]

I'd say the size is similar to bear, but the shape is very different to a cave bear astragalus I have.

I don't think it's any sort of carnivore:

[LordTrilobite]

Yes that's what I meant. It's not bear. But similar in size.