Wednesday, October 22, 2014

Coelopleurus! The most gorgeous urchin you never heard of!

This week, I thought I'd share some gorgeous sea urchin love! Behold Coelopleurus

What's that? You've never HEARD of Coelopleurus??  Well, that's about right, I suppose. Its a distinctive looking enough species but it lives in slightly deeper water than is typical for most casual SCUBA divers or vacationing snorkelers..
Described by Louis Agassiz in 1840, Coelopleurus is a genus in the family Arbaciidae. There are about 14 known species. Eleven living species and four fossils.  

Coelopleurus is a deep-sea urchin, but on the shallow side, about 75 to 500 meters. They occur primarily in the tropics, but across the Atlantic, Pacific and Indian Oceans. 

Biology of these animals is poorly known. 


It is also kind of unusual because it is one of the few sea urchins that displays secondary sex characteristics.. i.e., you can tell the females from the males when the males are spawning. 

You see that structure that the red arrows are pointing to?? 

That is the male "papillae". And in "C" you can see sperm being ejected into the water column. Yow!! This image is from a paper by Dave Pawson and John E. Miller in the Bulletin of Marine Science, 1979. 29(4): 581-586.  
Coelopleurus is unusual because it has these big, long curved spines BUT they are brilliantly colored in red and white!
But even MORE than that?? The tests (i.e., the skeletons) are brightly colored with these very striking patterns that seem to be rather variable..

Here is the test of Coelopleurus floridanus... 
But here's one that is considered the SAME species but a LARGER specimen.... Honestly.. it wasn't clear to me how important the patterns were to identifying each species.

The colors and patterns are embedded in the skeleton. So, if you drop them in a preservative like alcohol, the reds and purples, and etc. don't go away. They remain after death.
Here's another species. This one is from Japan... Coelopleurus undulatus from M. Shigei. 1986. The sea urchins of Sagami Bay. Biological Laboratory, Imperial Household, Maruzen Co. Ltd, Japan.

Gorgeous and amazing. 
Image from the NHM Echinoid database
Here is the most recently described species, Coelopleurus exquisitus which had the distinction of being described, in part from specimens purchased from the online auction house Ebay in 2006. 



Here again, is the very distinctive and unusual color pattern observed in this species... 

But wait! Coelopleurus also occurs in the fossil record!!  Here's Coelopleurus coronaformis from the Cenozoic of Mexico (< 66 million years ago) so pretty recent..

Here's Coelopleurus coronalis from the Eocene of Barcelona, Spain... 

Wednesday, October 15, 2014

Five Points About The Fossil History of Echinoderms! Happy National Fossil Day!

Happy National Fossil Day!
Every few years I'm in a position to share some more love about echinoderms and fossils. I've done this on previous National Fossil Days and tried to shed some light on the often arcane world of fossil echinoderms...

Here's one on paleocology & fossil parasites..

A nice gallery of fossil crinoids..   and this classic piece on giant floating/pelagic crinoids! 

Paleozoic Echinoderms: The Ophiocystioids!  and the Helicoplacoids! 

A LOT of the REALLY weird stuff in echinoderms takes place in the days of the Paleozoic, some 245 to 541 MILLION YEARS Ago... There was a lot of crazy stuff (evolutionarily speaking) happening then. Echinoderms, as a lineage PREDATE Dinosaurs and they've been around since before vertebrates walked on land.

But here's a bunch of interesting facts I've cobbled together to better understand and appreciate fossil echinoderms and their history!!

5. Animal Body Type can bias preservation. This is really a dynamic of fossil preservation which is true for almost ANYTHING. In order for animals or any organism to undergo the fossilization process, it has to "survive" long enough to be buried and then kept together so that it undergoes the process.  MANY factors can affect which animals/organisms/whatever are preserved in the fossil record. The study of how different factors affect fossil preservation is called taphonomy and it affects our perception of the history of life on the planet.

One of those factors is the physical strength of the body itself. Is it delicate? Is it REALLY strong and tough?? Delicate, soft bodies tend NOT to preserve very well (although they can exceptionally) but some bodies with very heavy and strongly calcified bodies are MORE likely to preserve.

So for example, these starfish, in life would have a fairly chalky body. They hold together pretty well when all the tissue is removed.
Here's a whole bunch of crinoid stems preserved in limestone. These are pieces of the "stalk" in stalked crinoids. Hard parts that are pretty structurally solid. You're most likely to find this of all the pieces of a crinoid (aka a "stone lily").

4. Preservation Environment is important. So, here's the thing. The fossilization process requires pretty RAPID burial of the subject organism/animal, whatever for fossilization to eventually take place.  Which brings us to another "bias" of preservation: The environment!!

If the animal lives in an environment in which it is predisposed to be buried ANYWAY, that makes it THAT much MORE likely that it will be preserved. One good example are sand dollars (or really anything which lives buried).

Sand dollars have a pretty solid skeleton but ALSO live buried in sand. Sometimes, they can be killed by burial and pretty much just get preserved there in the sediment as it turns into rock.
                           

and voila! (yes, its not the same species but play along, its not easy finding matching videos and pictures of fossil sand dollars! )

3. There were MORE KINDS of Echinoderms in the Paleozoic!
One of the oldest questions from biologists unfamiliar with the fossil record is, "Why haven't you completely figured out the evolutionary history (i.e. phylogeny) of Echinoderms yet?? There's only FIVE of them!"

Yes. Only five LIVING groups (crinoids, sea stars, brittle stars, sea urchins & sea cucumbers) are around today. BUT when you get into the VERY earliest days of echinoderms in the Paleozoic (245-541 MILLION years ago), you have easily TRIPLE the number of groups! (i.e. classes) and a crazy diversity of body plans NOT seen today!

You got things that look like crinoids. Disc-shaped echinoderms. Accordian-shaped, asymmetrical echinoderms. Weird, crazy tentacle-balls. and all sorts of natural "experiments" in Echinoderm morphology.

A crazy panoply of things! Oh, to go back in a time machine to see when rock was young!
                           
2. The Roots of Recent Echinoderms were there...
Picking up on the crazy, diversity of echinoderms mentioned above its worth mentioning that the ancestors of MODERN echinoderms were seen among them.

Ophiocistioids for example are intermediate between sea urchins and sea cucumbers.

Also in the Paleozoic, we had the early ancestors to brittle stars and sea stars.  Today, the brittle stars and sea stars distinctive looking in appearance that we can easily tell them apart, but looking at those early forms was NOT so easy...

Can you imagine walking around in the Paleozoic seas and seeing something that was NOT quite a starfish but also NOT quite a brittle star!! Something in between....

That's kind of why some paleontologists get so twitchy about what you call a "sea star" versus a "brittle star". They have LITERALLY spent years arguing WHY that is the case..

1. The Permian/Triassic Extinction Changed everything
So, then at the END of the Paleozoic, in the Permian, you have one of the most devastating MASS EXTINCTIONS known to life on Earth at the Permian-Triassic Boundary. That is the end of the Paleozoic and the beginning of the Mesozoic (i..e time of the dinosaurs).

This extinction was huge. 96% of marine species were wiped out. Part of this? All those aforementioned echinoderm classes.. (about 15 of them)? GONE.

Only survivors from FIVE groups survived to live on today.   Here's a cartoon of this from Echinoblog Art Department!
Echinoblog Art Department Lives on!
Any one of these could be a whole blog post but this gives you a short summary of some dynamics involved with the rich fossil history of the Echinoderms! Happy National Fossil Day! 

Sunday, October 12, 2014

What is that WEIRD THING on FACEBOOK???


So by now, everyone and their 3 best friends have seen the critter above and the video on Facebook (below) which seems to have freaked everyone the frack out. Its been circulated and seen by over 5.6 million people!!

And everyone keeps on asking WHAT IS IT?? I've received this video now, what feels like a million, jillion times from people who want.. nay, DEMAND to know:  What IS IT???

Answer: A basket star. A distant relative of sea stars.

First thing: HARMLESS.  and out of its element. But we don't know much about them.

This was even given time by IFLS but not being echinoderm specialists, their answer was a bit over generalized... So, here's MORE. Its actually a pretty neat beast.

1. This is a BASKET STAR. These are specialized ophiuroids. Ophiuroids are members of the phylum Echinodermata. In other words, its related to Sea Stars, sea urchins, etc. Basket stars in particular have a highly branched system of arms which they use to feed. I've discussed the feeding biology of basket stars here They have hooks on those branches with which they feed on tiny bits of food.

There are actually several different groups (i.e., families) of ophiuroids which have these fleshy arms and highly branched arms.They occur widely and vary from habitat to habitat.

2. Euryale aspera?  I've consulted with one of the world's experts on basket stars and euryalinid brittle stars, my colleague Dr. Masanori Okanishi, currently at Kyoto University. Discussions with him and checking my own resources suggests that the animal above is a shallow-water tropical species, called Euryale aspera. Identification of the species is uncertain since there was only a picture and no specimen but based on my cross-check, this seems like a likely name.


3. Where and HOW does it live? Euryale aspera is a shallow water species which occurs widely across the Indo-Pacifc. This species is found throughout the Indo-Pacific, from Asia but as far west as Madagascar in the Indian Ocean.

As with other basket stars, feeding is accomplished via tiny hooks present on the MANY branching arms spread out into the water column when they feed.

Here are some videos of various Japanese basket stars which MIGHT be Euryale aspera. Its difficult to ID these from images, but these give you an idea of how they live. Arms up in the water during ideal water flow, but withdrawn when not feeding.



4. What does the name mean? So, as you may have noticed from one of my earlier posts, one of the better known genera of basket stars is called Gorgonocephalus. "Cephalus" means head while "Gorgon" refers to the head of Medusa and her sisters: The Gorgons of ancient Greek Myth. One of Medusa's sisters is named EURYALE. She was identical to Medusa in appearance with snakes for hair and transformed men into stone with her gaze. Thus, the genus of this other "basket star" follows the theme of a "medusa's head" type appearance. The species name "aspera" is Latin and a references a descriptor for "rough" which likely alludes to the spines and other tiny accessories on the body surface.
Euryale aspera was described in 1816 by the famous zoologist Jean Baptiste Lamarck himself!

5. What about OTHER BASKET STARS???
The term "basket stars" informally refers to several groups of ophiuroids within the order Euryalida, which all have thick, fleshy arms. Some are more serpentine (i.e. serpent stars) whereas others are branching and appear to form a "basket" (i.e., basket stars). But they are often similar in appearance leading once again to some "blurred lines" where common names are applied. There are about 177 species in five families.

Members of the Euryalida occur widely throughout the ocean depths. Many are shallow water, occurring in both cold and tropical habitats whereas others occur in the deep, deep sea (> 1000 m). Many of them occur at depths in between. But you can encounter basket stars at SCUBA depths on reefs or other shallow habitats, which is where the "creature" above was apparently collected from.

A "serpent star" (Asteroporpa annulata from the tropical Atlantic)
A "basket star"


And by the way, these have been caught on deck and seen before... 


The original video indicates that the one collected was returned to the ocean. These don't take exposure very well.. but perhaps more adverse to the animal was its ability to re-establish a perch to resume feeding. But, frankly our knowledge of their biology is very poor. We don't know much about them.

Wednesday, October 8, 2014

A panoply of Pycnogonid (sea spider) biology from the latest round of Okeanos Explorer

So, after a few days of bad weather, we finally finished this last round of the 2014 Okeanos Explorer's dives into the North Atlantic! 

BUT we were not left high and dry! There was an unusual abundance of GREAT observations! But wow! there were some SPECTACULAR SEA SPIDER aka Pycnogonid biology events seen! Especially on the last few dives.. 


I don't know a lot about pycnogonid biology, but its a pretty sure bet that a lot of what they do is poorly known, especially in deep-sea species. 

Most of the observations below took place below 1000 m, most were probably between 1000 and 2000 m.  Some pretty rarely seen (or maybe first time) sightings. 

Most of these were screen grabs I took.. but my thanks to the Facebook Underwater Screengrab group, Carina Tsottbauer (@CarinaDSLR) and Nicole Morgan (@coralnerd)! for their help! 

1. From Atlantis II Seamount. This Daddy Pycnogonid with a brood clutch of eggs!

2.  From Nantucket Canyon. This pycnogonid with an arcturid isopod on its proboscis (ID thanks to Tammy Horton). Not sure why its there. Possibly food or??


3. From Physalia Seamount! A big sea spider, possibly Colossendeis, caught in the act of extending its proboscis into this large solitary hydroid! Woo! An in situ feeding observation! 





4. From Physalia Seamount, a pycnogonid in this sediment depression! Possibly feeding on a burrowing anemone? 

5. This pycnogonid in Nantucket Canyon hanging out with some single cup corals.. 


6. From McMaster Canyon! A swimming pycnogonid! 
Wow! at first I thought this might be novel.. but thanks to Twitter (@tammy_horton) and quick communication with Tammy Horton, curator of the Discovery collection at Southampton, and deep-sea arthropod biologist extraordinaire! It turns out that there ARE some records of swimming sea spiders in the scientific literature from 1977!! 



Tuesday, September 30, 2014

Some Okeanos Explorer Dumbo Octopus Love!

Just a bit of off-topic this week. Saw this GREAT dumbo octopus during the Atlantis II seamount dive on the Okeanos Explorer cruise this weekend and thought it was too great not to share.

NMFS cephalopod expert Mike Vecchione has identified this one as Grimpoteuthis sp. Generally speaking though, "dumbo octopus" applies to one of two genera, Grimpoteuthis or Opisthoteuthis.

The two genera are quite diverse. Grimpoteuthis includes about 18 species (according to marinespecies.org) whereas Opisthoteuthis includes about 20. Although these two genera are separated into distinct families, my understanding is that there is some disagreement over the taxonomy of the group.

The video followed this guy around from the water column down to the rock, after which it eventually swam off..

This was kind of a neat moment, when it sort of inverted and we could see the webbing between the arms.. 


Close up on the head, eyes and flippers..

And from the 2014 Gulf of Mexico cruise, THIS Awesome video which showed some of that unusual tentacle folding during the swimming motion.  Based on the original account here, I believe Dr. Vecchione has also identified the one in the video as Grimpoteuthis.
and I suppose I'll cheat a bit and include the E/V Nautilus dumbo octopus video... I'm not sure if this one is the same genus as the one above however...

Tuesday, September 23, 2014

Let's Meet the Deep-Sea Stars of the North Atlantic Canyons! Your Guide to Starfishy Okeanos Exploring!


 This week a special OKEANOS Explorer Treat!              

Owing to a fantastic combination of various technologies: deep-sea subersibles, HD cameras, quick and efficient internet transmission and the wonder of social media, not only do we have LIVE streams of deep-sea biology and exploration via the R/V Okeanos Explorer, BUT we have for the ability for almost ANYONE to tune and watch discoveries as they happen! AND watching and observing the scientists making these discoveries as they happen!

Thanks to Twitter and even a special Facebook Group that takes screengrabs of things seen by the ROV we now have a unique circumstance:  Exploration of the deep-sea being seen by everyone!! and not just scientists!!

But, the starfish you encounter on these dives are not exactly common place. Starting to learn about them first entails knowing which ones are which! Not an easy task given how poorly known how some of these species are. Some of these have never been seen alive! And that's where I come in.

And so as my BIG GIFT to people (scientists AND non-scientists) who are following the Okeanos Explorer  2014 LIVE deep-sea feed, here is a gallery/field guide of deep-sea starfishes observed along the North Atlantic east coast!! 

To be clear, this list of starfish species that is known from the deep-sea Atlantic region (>1000 m in this case) is likely INCOMPLETE.. It is biased by what I've been able to identify and the limits of the known science of each species. So, yes we WILL still probably see things that are not on this post. And eventually, these things will see publication...as many are new records.

A caveat about use: This is mainly for use in the North Atlantic along the east coast of North America. Some of the genera (e.g., Novodinia, Hymenaster, Pteraster) occur world wide so you'll see them in deep-sea pictures in many places. Some, such as Porania pulvillus may also occur in very shallow water, which is unusual. But you can' t necessarily expect to find all of these species in say, Hawaii or even the nearby Gulf of Mexico.  Where species occur is often a funny thing in biology, likely dependent on a number of factors that make those places suitable for a specific species.

My thanks in advance to Dr. Chris Kellogg (@DrChrisKellogg ), Carina M. Gsottbauer (@CarinaDSLR) AND the members of the Facebook Underwater Screengrab Group for their diligence!

1. Tremaster mirabilis (Asterinidae)
Here's an animal we don't know much about. Go here to see more of what this species looks like. It occurs widely in the Atlantic, the South Pacific, the Indian Ocean, the Antarctic in fairly deep water. Video images from OE were the first time that I'd ever seen this species alive. Its been imaged alive in tropical Pacific but never quite this nicely...
                            
2. Chondraster grandis (I think). (Poraniidae)
We don't know much about this. Someone collected it and named in back in 1878 but we really don't have any info about its biology. Its living color wasn't even really known until recently.

The body form in these is very unusual. Very soft and has kind of the texture of a mango.

Which brings us to this mystery. Same animal... I think?  But TWO colors?? Is one a new species? Or could the body color simply be variation??  This is where collected specimens permit us to examine the body and perhaps extract DNA to study the possibility that there could be separate species being seen...

3. Porania pulvillus (Poraniidae)
I have previously written about this species from shallower water, feeding on various cnidarians based on crowd-sourced images!   Whereas once thought of as a fairly passively feeding species, new observations now suggest its a bit more of a predator than had previously been thought. 

The white patterns show the papulae (or gills) as well as folds in the skin of the body. The entire body is overlain by a kind of thick tissue which makes it soft. So, like Chondraster grandis, this species also feels kind of like a mango if you touch it. 
Interestingly, here is a shallow-water individual (from Norway) of what I think is the SAME species for comparison. Similar pattern but different color!  Based on the museum specimens, morphologically, these are nearly indistinguishable. but does this indicate a separate species??
               

4. Neomorphaster forcipatus (Stichasteridae)
This is by FAR one of the most commonly encountered species during the Okeanos Explorer expeditions.

We don't know much about the actual biology of this species. We don't know anything about how/what it eats or what/how it reproduces or even anything about its ecology.  The genus Neomorphaster also occurs in the eastern Atlantic in the deeps off Europe.

These are deep-sea members of what is mostly a Southern Hemisphere group, the Stichasteridae.
Stichasterids are a basal group within the  Forcipulatacea (i.e., an early branching within the evolutionary history of the group), a large group of starfishes which also includes the common starfish Asterias as well as the brisingids and 6 rayed starfish below. A post about their family tree is here
                             
5. 6-armed starfish? Ampheraster? or Unknown Asteriid/pedicellasterid?
This one is kind of a mystery. It could be several possible genera or species. The names probably mean nothing to most people. But basically, this is likely a distant relative of Asterias. But we've not collected one. So uncertainty remains. It could be new! Or it could be known. I briefly discussed this in an earlier Okeanos post here. 
                             
6. Novodinia americana? (Brisingidae)
BRISINGIDS!  My favorite critters! These are actually starfish which use tiny little wrench-like structures called pedicellariae to capture food as water currents  carry it through their arms. Sort of like velcro. See my full article on brisingids here

Brisingids are notoriously difficult, if not impossible, to identify from pictures. Usually, you can't because the features used to identify it need to be studied under a microscope.

Fortunately,  Novodinia has a large swollen arm region around the disk with very thick spines as you can see below..

7. "Brisingid" Not sure which...
BUT after you get past Novodinia, the identifications of different brisingid sea stars becomes pretty difficult since none of the diagnostic features are visible from pictures..There are MANY encountered in these deep-sea habitats and probably several species which are not easily registered from pictures.

But they remain striking members of the deep-sea community.. Go here to see more of this
8. Evoplosoma sp. (Goniasteridae)
Evoplosoma!  A deep-sea octocoral predator! Often seen feeding on various bamboo "corals" (i.e. members of the Isididae). I wrote at some length about these here.  There's several species of this genus in this region and its difficult to make the call on these from pictures.
                            
From one of the recent dives:  you see all those bare branches on this bamboo coral?? That's Evoplosoma chowing down on the "meat" of the coral... Its not unusual to see them climbing high up into the branches of such a colony..

9. Ceramaster granularis? (Goniasteridae)
A so-called "cookie star" This species might be the shallower-water C. granularis or maybe something else?  Likely, feeding on encrusing organisms or the "goo" on the substrate but we really don't know.
                             
10. Pythonaster, probably  P. atlantidis
This was a RARE one. Barely known from 2 or 3 specimens, this is probably one of the FIRST living pictures of this species ever taken! We know NOTHING about its biology.

I wrote about it in more detail here.  Let's hope we see another one in the next few weeks!
11. Peribolaster or ??
Another rarely encountered species. Haven't even quite figured out what this one is yet. But it has what looks to be an osculum, i.e., an opening on the central disk to allow water onto the body surface.

What is an osculum?? Look to the links on pterasterids below....
12. Hymenaster? (probably)
This genus of sea star, is widespread around the world's oceans. Another poorly known group of animals..but with a very distinctive appearance and the ability to produce mucus as a defense mechanism! Go here to see more on this..
13. Pteraster sp. 
The other genus of "slime star" with shallow and deep-water members. The link about slime stars is here.. Note the osculum.. the opening that allows water in and shoots mucus out

14. Lophaster
Wasn't sure what this one was for certain. But it has spines along the surface that suggests a widespread cold-water group. We'll have to keep our eyes open for more of these...

If this IS Lophaster, then it would be the 5-rayed relative to Solaster, the sun star (below... )
15. Solaster sp. 

16. Henricia sp. 1
I have not written much about this group because the genus Henricia is a huge mess for taxonomists (i.e., people who describe new species and new diversity)..  Why?  Because these starfishes are all VERY similar in appearance to one another on a widespread scale! There are at least 2 species in this region. 

Yes, species in this group occur all around the world. VERY widespread. But even in a very specific area, they can be nearly identical in appearance.  So, unfortunately, unless the species is highly unusual (has > 5 arms, etc.) these are quite difficult to tell apart...

So, is that it?? Have I revealed ALL the STARFISH SECRETS???   Nope.  But knowing the names is the START of knowledge! I encourage everyone to let me know if you see any on these dives that is NOT on this post. Or if you see ANY of these species doing something, eating, spawning etc.