Living Fossil: A New Jersey Native

Living fossils are a really important factor when studying paleontology.  The term "living fossil" shouldn't be taken literally (since fossils are mostly made of rock and therefore can't be alive).  The term is used to describe an organism that exists today that existed in the same form a very very very long time ago.  Lets say over ten million years since that's how long it usually takes for most species to rise and go extinct.  As far as animals are concerned there are plenty of living fossils around us.  Many of them you may be familiar with already such as crocodiles, sharks, cockroaches, scorpions and even opossums haven't really changed much since the Mesozoic.  Today, however, I am going to talk to you about an animal that was around long before the first dinosaurs even and just to add a little kicker, its native to the shores of New Jersey as well.  Ladies and gentlemen, please welcome Limulus polyphemus or the Atlantic Horseshoe Crab.  

When it comes to living fossils, horseshoe crabs put other animals to shame.  To put it into perspective, the oldest known dinosaur fossils are from about 250 million years ago (nothing to scoff at).  The oldest known horseshoe crab fossil?  455 MILLION YEARS OLD.  That's four hundred and fifty five...times a million.  455 million!  That's almost double the age of the oldest dinosaur fossil!  The impressive part is these fossils don't look different at all from their modern descendants.  If an animal that hasn't changed its design in 455 million years isn't considered a successful animal then I don't know what is. 

A painting I did of a prehistoric creature that was alive hundreds of millions of years ago...with a dinosaur.  (Baby Dryptosaurus to be exact.)

455 million year old horseshoe crab fossil.  It was named Lunataspis aurora.

Lets learn a little about this hugely successful creature shall we?  Luckily for you I get to work with Atlantic Horseshoe Crabs for my job at the zoo.  First off, despite the name, they are not crabs.  They aren't even crustaceans.  Horseshoe crabs belong to a subphylum called chelicerata and are therefore more closely related to arachnids like spiders and scorpions than they are to crabs.  However, the horseshoe crab's closest relative is an animal that is long extinct, the trilobite. 

Trilobite fossil

Another common misconception about horseshoe crabs is that they possess a stinger on the ends of their tails.  Horseshoe crabs are actually completely harmless to humans and only use their rather blunt tails to steer while swimming or to flip themselves over if turned on their backs.  This misconception could be due to the horseshoe crab's superficial resemblance to a stingray which does have a dangerous barb on its tail.  Stingrays are fish, however and aren't related to horseshoe crabs nor do the two animals share anything in common beyond living in the ocean together.

Stingray: a type of fish.  Not even close to a horseshoe crab.

The horseshoe crab's scientific name, Limulus polyphemus, literally translates to "side-looking cyclops" and refers to the cyclops from the Greek myth "The Odyssey", who's name was Polyphemus.  Ironically enough, horseshoe crabs actually possess ten eyes while the cyclops is only said to have one.  Oops.  

Hey, Polyphemus!  No, not you.  The other Polyphemus.

There is a LOT more I could discuss with you about this fantastic animal but I really want to keep my posts on here short and sweet.  If you have any inquiries about this subject feel free to do some research of your own including checking out some of the sources I included under my works cited for this post.  Also as you should know, myself as well as the other members of the Jersey Boys Hunt Dinosaurs crew are always more than willing to talk and answer questions on here or on our facebook page as well.  Let me know what you think about this post.  I have a lot of other cool living fossils I work with that I could do posts about in the future!  

From left to right: Atlantic Horseshoe crab, yours truly, Gary Vechiarelli's son, Joey. 

Works Cited

"Oldest Horseshoe Crab Fossil Found, 445 Million Years Old." ScienceDaily. ScienceDaily, 08 Feb. 2008. Web. 09 Aug. 2012. <http://www.sciencedaily.com/releases/2008/02/080207135801.htm>.

"About the Species." Natural History: The Amazing Horseshoe. N.p., n.d. Web. 09 Aug. 2012. <http://www.horseshoecrab.org/nh/species.html>.