Saturday, September 11, 2010

My Trilobite

Sometime last year I was looking for a book to read.  I picked up Leslie's copy of Trilobite, Eyewitness to Evolution by Richard Fortey.  Fortey is a trilobite expert and a highly praised author of books about science for non-scientists.  I found his writing to be equally fascinating and wearisome.
  • Trilobites are extinct marine arthropods. 
  • Arthropods are animals. 
  • Living arthropods include shrimp, crabs and insects. 
  • Marine arthropods live in the sea. 
  • Extinct arthropods are known only through their fossil remains. 
  • People who study fossils are called paleontologists. 
  • Richard Fortey is a paleontologist who works at a natural history museum.  
  • Leslie, my resident biologist, also works at a natural history museum.
  • She can explain these things much better than I can.
Fortey's best known work is Life, An Unauthorized Biography. It deals with 4 billion years of evolution, beginning with one-celled critters and ending with you and me.  In the preface Fortey says that he wrote Trilobite because in Life he could only give "a page or two" to his passion for trilobites.  That gives you an idea of how important trilobites, which existed for about 275 million years, were to evolution.  Can you say "dead end"?

Trilobite impressed on me just how strange these animals must have been.  And of course I have a strong affinity for "strange".  Pictures of trilobite fossils show bizarre, segmented, armored, tentacled little creepy crawlies perfect to be cast in a horror movie or as some threatening species on an alien planet where astronauts accidentally crash their spaceship.

I wanted one of my own.  Leslie picked up on a few hints that I dropped.  She's very good that way.  For my recent birthday she presented me with a genuine trilobite fossil.  Here it is.  (Click any of the pictures for enlargements.)

My little guy came with this scant information:
  • Fossil Trilobite Phacops speculator
  • Age: Devonian Period
  • Classification: Phacops speculator
  • Location: Anti-Atlas Mountains Alnif, Morocco
  • Origin: Hammar L'aghdad Limestone
"Anti-Atlas" mountains?  Are there Pro-Atlas mountains somewhere?   And where is Alnif?  Here are more pictures of fossils from Alnif.

You'll notice that this particular Pracops speculator is curled up in a ball.  Trilobitologists say it is "enrolled" - although they never talk about trilobite schools.  It's likely that trilobites which were afraid something was about to kill them curled up to protect their soft undersides.  Getting encased in muck was probably a pretty traumatic experience.

Whoever chipped away the limestone in which this particular critter was discovered left a little base for it to stand up upon.  It's like a small statue.  A trilobite bust.

I have no clue about the phrase "Hammar L'aghdad Limestone".  The Internet is no help.

So when was the Devonian Period?  Well, roughly it was 416 to 359.2 million years ago.  That's how long it has been since my Pracops speculator curled up in a ball and died.   That long ago Morocco could have been almost anywhere.  And the Anti-Atlas mountains didn't even exist yet.

I now present The Mixed Meters Method for Conceptualizing How Long Ago My Trilobite Lived.

STEP ONE: Imagine all the things which have happened since the year one, 2010 years ago, from Jesus to Justin Bieber.  Think carefully about the changes in religion, technology, society, language and government since then.  Think of all the people who have lived and died.  Think of all the arthropods which have lived and died.  Remember that there have been 734,406 days since the beginning of year one, days just like today.  A lot has happened since the year one.

STEP TWO: Count to 500.  For each number from one to five hundred, repeat STEP ONE.  This may take you a while.  If each number between one and five hundred represents two millennia, which you considered in step one, then when you get to 500 you have thought about one million years.

STEP THREE:  Repeat steps one and two each day for one entire year.

Have you done all that?  Once you successfully complete steps one, two and three you have conceptualized 365 million years.  That long ago would put you back near the end of the Devonian period  when my trilobite lived.

For a guy celebrating his birthday, the last birthday before the first digit of his age number increments yet again, this little fossil was a really good gift.  Envisioning how extremely old it is makes me feel quite young by comparison.

Thanks, Leslie.  Love you.

I took the first three pictures with Leslie's fancy schmancy camera.  The last two were taken with the point and shoot in my pocket.  They're not as good but I always say "you can never have too many pictures of your own personal trilobite."

Pracops speculator Tags: . . . . . .