Friday 5 February 2016

Strange monstrosa

We got ourselves a new monstrosa! Or at least one of their socks.

Also a whole bunch of new Xenoturbella! Do you remember Xenoturbella? They were the Strange Worms found at the bottom of the North Sea near Sweden and named Xeno (strange or alien) turbella (a name referring to the free-living flatworms of the class Turbellaria) because they looked like flatworms with even fewer body parts than usual.

Scientists spent decades trying to figure out what the thing was. Genetic tests indicated they were some kind of bizarre, bivalve who'd lost its shell (among other things). But then it turned out the samples were contaminated by actual bivalve tissue the Strange Worm had apparently eaten. Later tests suggested they might actually be more closely related to echinoderms like starfish and sea urchins.

The basic question was this: are Xenoturbella related to complex animals blessed with numerous body parts? If that's the case it would mean they must have lost their brain, gut, anus and other body parts along the way, much like some kind of intestinal parasite who has no need for such organs.

Or are they instead some incredibly ancient lineage of creatures who arose some time after the jellyfish and never acquired all those juicy body parts in the first place?

Well, it's taken a whole bunch of time, but they've finally found no less than FOUR new species of Xenoturbella! The Scripps Institution of Oceanography must have thought they were late to the party after seeing all those deflated balloons strewn across the Pacific Ocean floor!

The new species range in size from 2.5 cm (an inch) long in X. hollandorum to a whopping 20 cm (8 in) in the wonderfully named X. monstrosa. They're all found near interesting, lively, deep sea habitats like hydrothermal vents, cold seeps and whale carcasses. These are all places with enough food to support a community of creatures, including the bivalves which seem to make up Xenoturbella's diet.

And, after yet more genetic analysis, it looks like they're archaically simple. They're not like snakes who lost their legs. cave fish who lost their eyes or tapeworms who lost almost everything. Instead, they're Strange Worms who never had those things in the first place.

Now all they have to do is find out how they mange to eat bivalves despite having no teeth in their tiny mouths!


TexWisGirl said...

yuck! looks like a tongue!

Esther said...

They look like the leftovers from someone's elses body parts... you keep being weird, Xenos!

elfinelvin said...

Fascinating! I can't help thinking of Alice's comment "Curiouser and curiouser." Your question is a good one, it will be interesting to see what they learn about this creature.

Joseph JG said...

@TexWisGirl: It does!

@Esther: Yeah, a deflated body part!

@elfinelvin: I can't wait! They're soooo slow it looks like they'll have to catch in the act of... something.

Lear's Fool said...

I still can't wait to figure out how they eat

Joseph JG said...

Me too! I wonder how strange it'll turn out to be?