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YouTubeTo celebrate the site’s 25th birthday this year, Wikipedia is encouraging/challenging people to read one Wikipedia article a day for 25 consecutive days. I felt that I could do one better than that: not only reading an article but – where I found one that was particularly interesting – to write a blog post or record a podcast episode for each of those days, sharing what I learned. For each entry, I’ll hit “random article” a few times until something catches my interest, start reading, and then start writing! Everything I’ve written below came from Wikipedia… so you should check other sources before you use it to do your homework. Happy birthday, Wikipedia!
Today’s random article: Cirrothauma
Today’s topic: Cirrothauma murrayi
My random landing page today is a genus for which there’s only a single species, so I hopped over to that species’ page.
And what a species!
This is the blind cirrate octopus (cirrothauma murrayi), a species found beneath the oceans all around the world but at such a depth that they’re not well-understood. We’re not even sure whether the specimens we’ve studied represent a single species or two separate species!
The Latin name comes from oceanographer John Murray, best known for his Challenger Expedition from 1872–1876, but whose four month North Atlantic Oceanographic Expedition in 1910 – which he self-funded – was the first to find this unusual species. It was described by Carl Chun, whose previous claim to fame had been the discovery of the (also amazingly alien-looking) vampire squid, seven years earlier.
(The vampire squid is its own amazing thing: did you know that it turns itself inside out to evade predators, exposing the inner surface of its spiked tentacles? Also it can spit glow-in-the-dark mucus to dazzle an attacker.)
You can tell it’s a cirrate octopus by those fins on its head. Cirrates are one of the two major families of octopodes: they’re the ones that do have a pair of mini strands dangling off each sucker on each tentacle, but don’t have an ink sac. They’re also notoriously fragile, and when we’ve pulled them up for research purposes they’re often in poor condition by the time they’re on the surface… and that’s especially true for deep dwellers like the blind cirrate octopus.
As for blind: well – it’s got eyes… but those eyes don’t have lenses. As a result, they’re probably able to tell light from dark but probably can’t make out the particular shapes of objects. (This is a great example, contrary to claims of irreducible complexity in the eye by proponents of “intelligent design” of an eye with only some of the components that seem essential to a fully-functional organ that still provides value for its host!).
Speaking of which – do you know how cool the eyes of an octopus are?
- Like all cephalopods, they have no blind spot because their retina is in front of the nerve fibres instead of behind them.
- Like squid and possibly cuttlefish, they can differentiate the polarisation of light. (I believe that sheep and goats can, too!)
- Their pupils automatically rotate to stay horizontal, no matter which way up they are!
There’s some debate about whether or not octopodes and other cephalopods’ eyes evolved from a shared ancestor or are an example of convergent evolution, and the arguments for both are really interesting.
Of course, our friend the blind cirrate octopus is, umm… mostly blind. Very different from other octopodes.
As I said, we know so little about it! We don’t know what it eats (we think it probably eats whole shellfish). We don’t know how it breeds. We don’t know how commonplace it is or whether its environment is under threat.
But what we do know is that it’s a freaky-looking thing from way down deep. Thanks, Wikipedia, for telling me about this strange beast. Let’s see what you have to share with me tomorrow!
