Wednesday, 22 February 2012

Polynoid Scale Worm

Image: Barcroft Media
Oh, dear... not for the first time we find that our nightmares were a reality long before they were our nightmares. Take a deep breath, hold onto your teddy bear and prepare yourself. It's going to get better before it gets a lot worse...

Image: National Museums Northern Ireland and its licensors
Scale Worms are marine annelids. They are usually quite small and can be found all over the place, from tide pools to the deep sea and hydrothermal vents. A lot of them appear utterly nondescript...

Image: A. Glover
others are actually quite pretty.

Image: Moorea Biocode
They get the name "Scale Worm" from the scales on their back. And also from being a worm, I suppose.

Image: Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology
They're polychaetes, or bristle worms, so they have parapods on their sides with bristles sticking out.

They use their parapods to crawl along the sea floor in search of food. The ones that aren't too long, thin and wormy look quite a lot like friendly, neighbourhood roly-polies.

But then they find food.

This is when the trouble starts.

The terrible, horrifying trouble.

Image: Ifremer
OH.

Image: Ifremer
MY.

Image: Ifremer
GOD.

You see, the problem with these things is that they are largely predatory. There are some that live around echinoderms, others that live inside the mantle of snails or mussels and steal their food, still more eat bacteria or scavenge... but a lot of them feed on worms.

As you can see, they have just the kind of murderous jaws required to destroy their prey. Also, even though they look like plasticine in the microscope shots, some Scale Worms can give us humans a nasty nip.

It gets worse, though...

Image: Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology
As we noticed in our worm round-up a while back, a lot of worms have a proboscis. This is a long appendage sticking out of the head, the kind of thing that butterflies are allowed to get away with.

Image: Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology
But worms don't have a cute and curly proboscis. They have an eversible pharynx. This means it's a throat that is turned inside out.

Image: Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology
So the Scale Worm looks quite unremarkable until it finds something to eat. That's when it opens its mouth and shoots its jaws out at the end of its own muscular throat.

Image: Ifremer
Some of them have jaws that aren't so obviously threatening. They're still scary, it's just that they follow a different tradition.

Image: Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology 
Then there's just crazy stuff. I mean... what is this? What's that for? It looks like half a human skull!

You know what's most obscene of all? These worms are in the family Polynoidae, which is in the superfamily Aphroditoidea, itself in the suborder Aphroditiformia. That's 2 mentions of Aphrodite, Greek goddess of love, beauty, pleasure, and procreation. I don't know who decided to use that name, but that person was a strange person.

Image: Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology 
There's one thing I DO know, though... this is a worm that should definitely keep its mouth shut and its jaws hidden.

.....

Thanks to Katie and Clair who I met at that meetup for suggesting this madness! It's always nice when good things happen after you go off meeting people, and the most disgusting worm I've ever laid eyes on is definitely a good thing!

10 comments:

Unknown said...

While he gives no rationale for having done so, it seems that the person responsible for using the name of Aphrodite in vain (as it were) was one Ralph V Chamberlin of the Museum of Comparative Zoology at Harvard. He was also known for causing a real controversy over Evolution at BYU in 1911. More proof that the anti-evolutionarists have been at it for a very long time ;D

Unknown said...

Also, for what ever reason, Blogger has decided I don't exist.

- Jim @ thatcaptjim.livejournal.com

TexWisGirl said...

squiggy, creepy, eek!

Comment1 said...

@Jim: It's so cool you could find that out! Thanks a lot!

Unfortunately there was one thing I couldn't find: I once saw a pdf or something of a book from the early 20th century rebutting a load of anti-evolution arguments. It was quite amazing because they were all arguments still used and misused today!

@TexWisGirl: I just can't believe how abominable these things look! I'm glad I'm the size I am and they're the size they are.

Chloƫ Langley said...

Lots of... interesting... pictures.

The first picture is definitely the most scary one!

And the most disgusting one is where the worm shows off its extendible jaw.

Comment1 said...

I was really happy to see so many pictures! Seeing that maw in context was definitely a shock!

msmith2 said...

Excellent photos for my student who are currently studying annelids.

Thanks,
M

Comment1 said...

Glad I could help!

Drhoz said...

One possible reason that the Sea Mouse was called Aphrodite is because of its shape... an oval, fur-covered mound.... Um.

Comment1 said...

Ha! Oh dear... hopefully they don't all sprout little legs and crawl away.

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