Category Archives: Paramylodon

Fossil Friday – Paramylodon claw

Sloths are fascinating animals, with all kinds of strange anatomical features. One of their signature characters is their enormous claws. 
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Fossil Friday – Paramylodon skull

Even if a bone is lucky enough to be preserved as a fossil, time is not always kind. There are numerous ways a bone can be altered after burial, including being smushed by the weight of overlying sediment. Continue reading

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. Continue reading

Fossil Friday – sloth thoracic vertebra

Earlier this week, sloth expert Greg McDonald spent several days at the Western Science Center looking at ground sloth material in our collection. I spent that time peering over his shoulder and asking lots of questions. This made the work go more slowly, but it also greatly improved my understanding of ground sloths. Continue reading

Fossil Friday – sloth dermal bones

Next Tuesday evening, Greg McDonald is going to give a lecture at Western Science Center on fossil sloths, so for this week’s Fossil Friday we have sloth bones! Continue reading

Fossil Friday – sloth jaw

Yesterday was International Sloth Day (with sloth in this case being a noun, not an adjective)! That’s a nice day to celebrate at Western Science Center, because Diamond Valley Lake is the only locality in California with three different species of ground sloths.  Continue reading

Fossil Friday – sloth ulna

IMG_3670 Last Saturday the Western Science Center was visited by Eric Scott from The Cooper Center and high school student Santiago Hernandez. They came with a specific goal in mind, to look at fossil horses from a small, understudied collection, called the Harveston Collection, from western Riverside County. Continue reading

Fossil Friday – sloth vertebra

Paramylodon harlani (1)One of the most enjoyable things about writing this blog is that I have the chance to learn about the anatomy of animals that are relatively unfamiliar to me. While I’ve done a little work on sloths in the past, their somewhat unusual skeletal anatomy can be tricky for someone who has mostly worked on other animals. Continue reading

Fossil Friday – Harlan’s ground sloth femur

There are three different species of ground sloths known from the Pleistocene Diamond Valley Lake fauna. By far the most common of the three is Harlan’s ground sloth, Paramylodon harlani. For this week’s Fossil Friday we have a Paramylodon femur. Continue reading

Fossil Friday – Harlan’s ground sloth jaw


For this week’s Fossil Friday we have a partial lower jaw of Harlan’s ground sloth, Paramylodon harlani, collected near the eastern end of Diamond Valley not far from the museum’s current location.

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