Wednesday, April 15, 2015

Five Cool Things we have already seen on the Okeanos Oceano Profundo Expedition!

This week: Some echinoderm highlights from the 2015 Okeanos Oceano Profundo cruise! 

I've made the point in the past about how AWESOME it is to be able to see so many deep-sea animals alive!

As a scientist who works mostly with preserved specimens, our typical perception of these species from dead material is something like this:
The above specimen is a species of Freyastera, a deep-sea brisingid asteroid. Brisingids have special suspension feeding arms with very delicate arms covered by needle-like spines. I've discussed them at length here.

In stark contrast, here is one alive: 
Dang. THAT's a world of difference!! And the living observation gives us basic info like color and basic posture. Surprisingly important information when you consider how badly deformed and damaged specimens collected by trawl net can be....

But on the other hand, it is FROM these specimens that we are able to have records of these rare species from past expeditions.  

Case in point: 

1. Laetmaster spectabilis 
We saw this Tuesday. At a depth of 3915 meters from the east wall of Mona Canyon. This is a member of the Solasteridae, which are the "sun stars", which I have written up briefly here. 
This is one of the rarest known sea stars, which was known previously from one or two specimens in the late 19th Century on which the descriptions were based. Collected in 1878 by the Blake, a famous oceanographic vessel!

That pretty much means that no one has collected this species for over 130 years! It gave a hard pass to the 20th Century. yow.

2. Plinthaster dentatus feeding!
Another cool thing that we often encounter on these dives is basic aspects of biology which, for deep-sea species, are unknown. 

This "cookie star" is in the family Goniasteridae. These get collected quite a bit but we know very little about them. I wrote about some Hawaiian ones here.

Now, we know this one fees on sponges (or hydroids)!

3. Holopus sp. Bizarre stalked crinoid! 
This was a great pleasure to see... These are unusual types of stalked crinoids which I have written about before.
This sequence nicely shows the arms extended and withdrawn...

4. Oneirophanta mutabilis! A different kind of "sea pig"!! This one is in the family Deimatidae, so it is different from the classic sea pig Scotoplanes globosa.. So what is a "sea pig" anyway? A discussion for a different day...

5. Big Unknown Spiny Cidaroid Urchin!
with ophiuroid (Asteroporpa annulata? I think?) living on the spines!

But who is it? Not sure..
Note that there's some striped ophiuroids living on the spines...
They could be this species? Asteroporpa annulata?

Other noteworthy observations!!
Swimming sea cucumbers (Elasiopoda mostly) were everywhere...

A Enypniastes like species (possibly Amperima or Peniagone?) with transparent body.... That's the gut you are seeing THROUGH the body wall.
And a Benthodytes also with clear body wall showing the gut! 
And a white one.. but again.. transparent body wall...

And finally... one pic full of intrigue! my "phantom" wood starfish?? Did I see it or not? A revisitation to the HD is in the stars....

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