Jurassic Hermit Crabs Are Even More Awesome Than You Can Envision

In case it ever comes up in a Jeopardy Daily Double question, the fossil record does not contain many hermit crab fossils.  That’s right, those cute little beasties, so abundant you can buy them in magnitudes at your local pet store, are rarely found as fossils.  It’s not that hermit crabs haven’t been around long enough.  Fossil hermit crabs date back at least to the Early Jurassic 200 million years ago.  That’s plenty of time for hermit crab of finding itself in the right, or wrong if you are the hermit crab, situation to be fossilized.

Screen Shot 2015-11-16 at 2.30.03 PMDespite the relative paucity of fossilized hermit crabs, the known fossils are amazing.  Tim Ziegler on Twitter brought to my attention to the most amazing of them all, fossil hermit crabs in ammonoid shells.  To recap, ammonoids are an extinct group of cephalopods.  Ammonoids are unique in having full exoskeletal spiraled shells, as opposed to squids and octopuses.  However, despite having an external shell like modern Nautiluses, they are evolutionarily more related to the squids and octopuses.

Well old ammonoid shells work just a perfectly as snail shell.

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From Fraaije et al. 2003. In D you can see the fossilized claw sticking out of the shell.

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From Jagt et al. 2006.

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This illustration too cute for a scientific publication. From Fraaije 2003


Dr. M (1801 Posts)

Craig McClain is the Executive Director of the Lousiana University Marine Consortium. He has conducted deep-sea research for 20 years and published over 50 papers in the area. He has participated in and led dozens of oceanographic expeditions taken him to the Antarctic and the most remote regions of the Pacific and Atlantic. Craig’s research focuses on how energy drives the biology of marine invertebrates from individuals to ecosystems, specifically, seeking to uncover how organisms are adapted to different levels of carbon availability, i.e. food, and how this determines the kinds and number of species in different parts of the oceans. Additionally, Craig is obsessed with the size of things. Sometimes this translated into actually scientific research. Craig’s research has been featured on National Public Radio, Discovery Channel, Fox News, National Geographic and ABC News. In addition to his scientific research, Craig also advocates the need for scientists to connect with the public and is the founder and chief editor of the acclaimed Deep-Sea News (http://deepseanews.com/), a popular ocean-themed blog that has won numerous awards. His writing has been featured in Cosmos, Science Illustrated, American Scientist, Wired, Mental Floss, and the Open Lab: The Best Science Writing on the Web.

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