Fossil Friday – sloth mandible

Greg McDonald’s visit last month to look at sloth remains gave us a reason to open our display cases, which include some of our best sloth fossils.

One of the exhibit specimens is a nearly complete mandible of Paramylodon harlani, the most common sloth from Diamond Valley Lake. The image is a dorsal view, with anterior to the right. The mandible is nearly complete, if a bit crushed. It’s missing the articulation on the right side, part of the anterior end, and all the teeth, but is otherwise in good shape.

Paramylodon lower jaws are scoop-shaped and toothless at the tip. This is very different from their distant relative Megalonyx, that has a pair of huge chisel-like teeth at the tip. Even though the teeth are missing, the shape of the sockets also reveals a different cross-section that the more rectangular teeth of Megalonyx. For additional examples of Paramylodon jaws, see our earlier Fossil Friday posts here and here.

This weekend I’ll be at the Western Association of Vertebrate Paleontology meeting at Yavapai College in Arizona, presenting on the Mastodons of Unusual Size project and on the Stepping Out of the Past exhibit. Follow @MaxMastodon on Twitter for updates.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s