It's the world's most famous living fossil! Or is it? A living fossil, I mean. Because the Coalacanth is so ridiculously famous that whatever it is, it's probably the most famous one.
A guy from the future just gave me his time machine! He says it works quite well most of the time, and people usually don't die when they use it! And we'll probably come back with almost all our limbs, at least 40% of our face and only moderate burns. Sounds good to me! So I thought we could go back in time.
We won't go back millions of years to find a real, live Coelacanth... we'd only end up stepping on a butterfly and causing the world's languages to change slightly and all the world leaders would be different. That'd just be annoying.
Instead, let's go to 1836. Charles Darwin is off on his round-the-world adventure on the HMS Beagle and he will return this year. A young journalist called Charles Dickens is taking his first steps in fiction, publishing a novel called The Pickwick Papers as a monthly serial. He'll start work on Oliver Twist at the end of the year.
|Image: Alberto Fernandez Fernandez|
So it's a fascinating year, full of opportunity and adventure for the scientist, the writer and the idealist. And if you just want to try out killing people, you can do that, too. But we're not going to any of those exciting, dangerous places. We're going to Switzerland.
|Image: Jim O'Donnell|
Leafing through the pages of the second volume of Recherches sur les poissons fossiles by celebrated, Swiss paleontologist Louis Agassiz, we find a fish. Actually we find lots of fossil fish, also known as les poissons fossiles. The book title is not imaginative.
|Coelacanthus granulatus in the the book by Louis Agassiz|
C. granulatus fossil
That will change in 1938, when a new picture of the Ceolacanth will emerge.
|World's first sketch of a living Coelacanth, by Marjorie Courtenay-Latimer|
There might have been loads of interesting fish staring up at her that day, but one of them was 1.5 m (5 ft) long and looked prehistoric and weird so it duly monopolised her attention. From there, everything becomes a hilarious farce.
She and her giant, dead fish took a taxi back to the museum. The day was hot and she needed to preserve the thing, so when the morgue refused to accept a fish no matter how interesting it was, and when it wouldn't fit in her bath, she drenched some clothes in formalin and wrapped them around the corpse, instead.
|The stuffed specimen. Neither living nor fossil|
Meanwhile Courtenay-Latimer had sent a letter and "good enough" sketch to J. L. B. Smith, a university lecturer who had offered his expertise in identifying fish for her collection. He probably dropped his pipe into his corn flakes, because he knew what he was looking at. At long last, on 3rd January, 1939, Courtenay-Latimer received his reply by telegram:
MOST IMPORTANT PRESERVE SKELETON AND GILLS = FISH DESCRIBED
I can almost see her rolling her eyes and sighing, "you don't say..."
Her efforts were rewarded with the naming of the fish, Latimeria chalumnae, named after herself and the river near to which it was found.
|J. L. B. Smith lovingly strokes a Coelacanth, 1952|
A lot more is known about these Coelacanths today. Not least that there is another species near Indonesia that was discovered in 1997. They can reach 1.8 metres (6 feet) long and live in deep, dark waters where they conserve energy by mostly not doing anything at all.
They have a whole host of interesting and unique characteristics:
- Firstly, those extraordinary lobed fins! Coelacanths have two dorsal fins, one attached directly to the body as in other fish. All the others come at the end of fleshy stalks that contain the same kind of bone structure as found in tetrapod limbs. They are extremely manoeuvrable and allow Coelacanths to swim head down, searching for fish to eat from the seabed.
- A unique organ up their nose detects the electrical impulses given off by prey. No other creature has it, and along with their sensitive eyes, it allows them to find prey in their gloomy habitat.
- Now it's time to snatch their prey, and they have another feature unseen in any other living animal to help out. It's called an intracranial joint. It allows the front half of the head to lift up so the Coelacanth's mouth can open much more widely than it looks like it should.
- Then there are the tough, rough scales quite unlike those of most fish. They serve as a kind of armour so that the Coelacanth can spend lots of time relaxing in the nooks and niches of craggy rock formations without fear of injury.
Looking a little deeper at those interesting organs, we find more:
- A kind of swim bladder full of oil and fat. Most fish fill this thing with air, but that would be crushed in the pressure of the Coelacanth's deep abode.
- A notochord! Most vertebrates turn this into the backbone during embryonic development, but in common with some fish like the Sturgeon, Coelacanths retain the flexible notochord for life.
- A tiny brain! Coelacanths are fat-heads. Their brains takes up just 1.5% of their braincase, all the rest is fat. This is incredibly tiny for such a massive animal, but this fish of very little brain seems to be doing quite well on it!
- Oh, yeh... and they still have those hollow spines that got them their name in the first place. I'm almost sorry about that; it would be hilarious if they were named after the one thing they didn't have any more!
The Coelacanth is a nocturnal lurker (like some of you :P) who sits in the darkness, happy to drift slowly on the currents and use their fins primarily to point their face in whatever direction they want. When they see prey, a swish of the tail allows them to pounce with great speed.
The day is spent resting among the complicated architecture of volcanic rock. Coelacanths are quite gregarious, sometimes hanging out together in crowded caves. They don't like to physically touch, though. Sounds like the start of a gothic love story! Therefore they must eventually touch... quite a lot. You know...
After which the female will be pregnant for over a year! She produces up to 25 eggs but doesn't lay them. Instead, they hatch within her body and grow to about 30 cm (a foot) long before mother gives birth and the young pups see the
So the Coelacanrh is certainly a strange fish richly endowed with peculiarities and archaic characteristics, but is it really a living fossil? Certainly it's living (famously so!), but is it fossil?
Unfortunately, "living fossil" isn't a particularly well defined term. The two modern Coelacanths were not around hundreds of millions of years ago, unlike certain Tadpole Shrimp, for example. They aren't even placed in the same genus as any ancient Coelacanth. But their evolution does seem to be very slow, and they are the last living example of a once diverse slice of life that is now otherwise completely gone.
Today, Coelacanths are one of the three subclasses placed in the class Sarcopterygii, which means "flesh fin" because they are the lobe-finned fishes. The other two are the lungfish, which are yet more fishes with lobed fins, and the last one contains the tetrapods, like you and me!
The story of the Coelacanth is a fascinating one. It makes one wonder what other strange beasts may lurk in far flung locations, waiting to be discovered, only for it to turn out that the locals knew about it the whole time and labelled it "inedible".
But it also makes me wonder what ancient creatures are completely lost to us through the vagaries of the fossilisation process. Coelacanths were alive somewhere for 65 million years and we don't have a single fossil from that entire period! Where were they? What else was hanging around in this place so unforgiving to fossils?
At least it's nice to know that the Coelacanth would see me as an incredibly weird-looking fish. That's heartening.