Tym The Trilobite: Why three is my favourite number…
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How better to understand what fossils can tell us than by listening to one's inner thoughts? Meet Tym The Trilobyte
Welcome back - I’m Tym the Trilobite…
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If you missed my blog last week, you might want to catch up with part one.
Physiology
Before I tell you how I died (and forgive me if I don’t hurry forward to that bit) I should really tell you a bit about myself and how I lived…
Trilobites first came in being about 540 million years ago. We were a fantastically successful group of critters that stuck it out on earth for an awesome 300 million years. In comparison, that makes you humans look like just a ‘blip’ on the evolutionary radar - let’s face it, you’ve only been around for about 200 thousand years!
I look a bit like a large ‘woodlouse’
Ok, understood. that probably doesn’t ‘do it’ for you – but hey, that whole ‘evolution’ thing was only just getting going back then and we didn’t have that many options. No face lifts available, and the only kind of cosmetic surgery available was having your head bitten off by a passing predator (and that, lets face it, doesn’t exactly improve one's looks!).
So, we just had to live with the way we were… anyway, I never had any trouble attracting lady trilobites, but more on that later in my blog!
In terms of the bigger picture, we trilobites are arthropods (albeit extinct ones), that is; “critters with a hard external shell, called an‘exoskeleton, multiple body segments and jointed legs”. Other ‘modern’ arthropods that you humans might be more familiar with are; insects, spiders, centipedes, shrimps and crabs.
Lots of scientists have tried to fit us into to one of these smaller modern groups. I suppose you could think of us as distant cousins to crustaceans, and we do have one close living relative which is the horseshoe crab) – and you can see the similarities.
But hey, they are only similarities. In fact, we’re unique, and we have our own branch on the big old ‘Tree of Life’ – just like you humans!
Trilobites come in all shapes and sizes, and lots of different species. In fact, at the last count there were over 17,000 species of trilobite, with new ones being discovered every year.
In terms of size? Well, the smallest species they taught us about at ‘trilobite school’ were less than millimetre long, right up to big-daddy behemoths at over 70cm long (believe me, you wouldn’t want to meet one of those in the playground!) Most of us, however, were just a few centimetres long – think giant cockroach, but with a much nicer personality!
It’s true we come in lots of different shapes too – but I should be clear, we’re all just variations on a single theme. The clue to that is in our name ‘Tri-lobeite’- it means: three lobes, and if you take a look at me and some of my mates , it’s pretty obvious really.
We’re divisible into threes in two ways: from top to bottom, we have three main parts; a head, a body and a ‘shake-your-tail’ piece; but we don’t get our name from that.
We’re actually divided into three along the length of our bodies as well; we have a left lobe, a middle or axial lobe, and a right lobe…pretty distinctive huh? So we’re easy to recognise, with an easy name to remember – in fact, we’re the perfect dinner guest!
Content last updated: 07/08/2008
