Crunchy on the outside, chewy on the inside.

I was going to turn that into a joke about deep frying and salamanders, but I thought better of it, so I won’t. Instead I’ll just let you all think I was talking about the trilobite pictured above.

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Wait.....a trilobite? Why, that must mean today is Friday Rocks!. And if it’s Friday Rocks, that must mean I’m about to tell you about some sort of dead thing in a rock. So, don’t mind if I do.

For the last few weeks I’ve been featuring crinoids and teeth. Why? Because you all deserve to know about crinoids and teeth. Plus I wanted to give trilobites a rest. I mean, they’ve only been dead for a minimum, a minimum, of 250 million years. And I figured they might be getting tired. (and you thought cats slept a lot).

Trilobites have been known to science for a long time. the first written description of a trilobite comes from 1698 when a Reverend Edward Lhwyd described the specimen he found in Wales. Of course, he was a priest and not a paleontologist, or an anthropologist, so he mis-identified it as some sort of flat fish. But over the next one hundred and fifty years, enough other examples of trilobites were discovered to properly place them with the other arthropods where they belong.

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When they were first being found and noticed, it wasn’t because of their wide ranging diversity, or the important role they play in teaching us about how species adapt and evolve. They were primarily studied because they were one of the best methods of dating rocks by their geological age.

But in the late 19th century, people started to really look at trilobites. They started to realize exactly how diverse they were. Over 17,000 species had been described. And, when you looked at some of the examples being found, they were really an incredible little creature. So people started paying more attention to them.

And then in the early 20th century, Charles Walcott found a few unusual fossils while exploring the Canadian Rockies. He investigated back to see where they had come from, and found the Burgess Shale formation. Here, for the first time, were fossils from the early Cambrian found in large quantities. And about half of them were trilobites.

Since the Burgess find there have been more, earlier Cambrian sites located. And there have been locations, like the Atlas Mountains in Morocco, where huge amounts of stunningly well preserved trilobites have been found. And the diversity of the Moroccan trilobites rivals that of any other location in the world.

Which brings me to todays trilobite. This is a good example of a trilobite that was found in the Atlas mountains. It is a Koneprusia dahmani. And, as you can see, it’s a pointy little bastard.

In the past I’ve mentioned how one of the defensive maneuvers the trilobite used was to enroll. That is, to roll up in a ball, like an armadillo. Many trilobites had a smooth shell, and they relied on their hard armor to protect them. But some trilobites lived in areas where predators could crunch right through their armor. So they grew spines.

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Imagine what this Koneprusia would have looked like in a defensive ball. I’m sure a predator tried to eat one. My mother tried to eat one once. Once. (tee-hee). I doubt many tried to eat them a second time. Because a small ball of ouch probably wasn’t too tasty.

And this was a small one. At least, small when compared to us. The total length of this example is about an inch from tip of the cephalon to the tip of the pygidium. The spines vary in length from 1/4 inch to about 3/4 inch. So when enrolled, it would have been dangerous for a predator to eat.

The rock that the trilobites from Morocco are encased in is very hard. It takes many hours of patient work to free them from the matrix. In the course of the preparation, it’s not unusual for some of the delicate spines to be broken. This is normal. The broken piece of the spine is freed from the matrix and it’s glued back into place. This type or repair does not alter the value of a trilobite. If one of the spines was lost in the mists of time, and the person doing the prep work replaces it with a man made spine, that’s considered a restoration and it can affect the value. The more restoration, the less it’s worth.

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While this Koneprusia might look incredibly detailed to the untrained eye, it actually isn’t. While mine has all the primary spines intact, a truly well preserved example will show that the main spines also have sub-spines, like this example:

Both of these came from the same formation in the Atlas mountains. While mine will run you in the hundreds of dollars, the prime example I showed, (that I really, really wish was mine), would run you into the thousands. Mine probably took 30 hours to prepare. The nicer example, (for the love of all that’s holy, some rich person buy it for me!), took at least 100 hours to prepare.

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Now, I’m going to leave you with a special treat. This is a short clip from the first episode of “First Life”, a BBC mini-series hosted by David Attenborough. It deals with trilobites. He touches on the evolution of the eye and how later trilobites with the more complex eyes could see more than the less developed ones. He also visits the Atlas Mountains with Richard Fortey, and they show some incredible examples of the trilobites found there. (Richard Fortey is one of the leading experts on trilobites, and if you have any interest in them, I suggest you read ‘Trilobite: Eyewitness To Evolution’, which is a very good read).