Deep-Sea Coral Starfish PREDATORS! New Genus! New Species! Deep-sea Corals shudder in FEAR!

So, today you guys get something a little special that I've been cooking up! After a few years of gathering specimens and working up data, I finally published this paper with Martha Nizinski of the National Marine Fisheries Service (NMFS) and Lonny Lundsten of the Monterey Bay Aquarium Research Institute (MBARI).

My paper describes THREE new species and one new genus in the subfamily Hippasterinae, which is a group within the family Goniasteridae. Goniasterids occur all over the world and and are probably the MOST diverse of all the starfish groups with some 64 genera and close to 260 species!

This one subfamily, the Hippasterinae, includes the familar Hippasteria (below) which live primarily in the deep-sea, but in some parts of the world, can be seen SCUBA diving depending on where you live (e.g., Washington, Oregon, British Columbia, etc.).
Hippasteria has been known to humanity for a LONG time. It was literally one of the first sea stars described by European scientists in 1840. But for the most part, its a deep-sea species and we didn't know much about it or its relatives up until recently.

So, it turns out that Hippasteria's got some pretty important eating habits. It and its relatives are voracious predators of cnidarians, specifically deep-sea CORAL. I've written about various sea star corallivores before (early on in the Echinoblog-here).

But as a quick reminder-Hippasteria (and its relatives) aren't the ONLY asteroids that feed on "corals" (which can be broadly defined as almost any cnidarian with a biogenic skeleton).
Shown above, is Acanthaster planci-the infamous Crown-of-Thorns starfish which attacks and devours primarily shallow-water tropical "hard" coral (i.e., scleractinian). While the above species has grown to plague proportions-it is an important member of the coral-reef ecosystem. As it is likely these deep-sea corallivores are ALSO likely to be... So, how did this whole process begin? As with many things...it started with me identifying a starfish...

Discovering New Deep-Sea Coral Eating Starfish!

My colleague, Dr. Martha Nizinski approached me several years ago with some pretty large-sized starfishes from the tropical Atlantic.

These were in the NMNH collections as part of the considerable "backlog" of unidentified material from her studies with the Johnson Sea Link. I had just arrived and was examining everything that I could...
It turns out that there were not one but TWO species among the specimens that Dr. Nizinski had collected!

One was a rare species called "Hippasteria" caribaea that turned out to be incorrectly classified and was more properly placed in a Pacific-only genus called Gilbertaster, making the full correct name Gilbertaster caribaea.

It turns out that Gilbertaster caribaea is rarely encountered. Only 6 specimens are known
Its a very neat looking animal with all of these very LARGE lip-shaped pedicellariae.

Pedicellariae are pincer or wrench-shaped structures that sea stars use to interact with the environment.

Perhaps they are used to fend off predators? or perhaps to keep their surfaces clear of settling debris? Its not clear what the function is in all taxa... but one thing IS clear? There's a LOT of pedicellariae on the body surface...(each lip-shaped pedicellariae is about 2-5 mm long each)
and there's a bunch of them on the oral surface around the mouth (again, each about 2-5 mm long each)
AND in addition to Gilbertaster caribaea above, there was ANOTHER SPECIES. One that had NOT been recognized by scientists before. Not only was it a new species...but a new GENUS.

The animal has a really stout, heavy body and so I called it Sthenaster from the Greek "sthenos" for strength and -aster for star. So, "Strong Star"
It too has the many, many large pedicellariae...
Finally, I named the species after my colleague Dr. Emma Bullock in the NMNH Mineral Science Department, with the name Sthenaster emmae !!

Dr. Bullock is shown here holding her namesake!
At about the same time, Lonny Lundsten, one of my colleagues from the West coast at the Monterey Bay Aquarium Research Institute had just returned from several cruises off the coast of California..
And he had discovered several NEW specimens of ANOTHER rarely encountered sea star in the genus Evoplosoma. At the time, Evoplosoma was known less than about a dozen specimens worldwide

Here's a pic of the Atlantic species to give you an idea of what they look like...
Lots of spines and pedicellariae...

Well, it turns out that Lonny had MORE than just the preserved specimens..he also had VIDEO and photos of these animals on the sea bottom (>2000 m depths!) doing stuff like this!
NO species of Evoplosoma was known from off the west coast of North America! After examining specimens, it turned out there were TWO distinct species of Evoplosoma present. Both were observed feeding on deep-sea corals.

I named one, Evoplosoma voratus. "Voratus" means to "greedily devour" and the second, Evoplosoma claguei I named for Dr. David Clague an MBARI Geologist who headed the mission and collected several of the specimens!
I proceeded to engage in a phylogenetic analysis of these and other related sea stars in the Hippasterinae/Goniasteridae, including Hippasteriaand the closely related Cryptopeltasterusing computer software to analyze the external characters to group similar taxa together...
To get a tree that looks like this!

The tree shows some interesting stuff... the genus Evoplsoma is found ONLY in the deep-sea and is probably a derived (i.e., highly specialized) member of the Hippasterinae. And so, its ancestors probably hail from a shallow-water ancestor.

I also realized that there were observations of coral predation from nearly EVERY member of the Hippasterinae. There was no evidence for Gilbertaster feeding on coral-but there was for all the rest.

As you can see here, the starfish is actually climbing UP the stalk and leaving the skeleton of the animal devoid of living flesh as it devours the animal like delicious deep-sea cnidarian lollipop!
I checked the gut contents of our new genus and species, Sthenaster emmae which had been collected in close proximity to deep-sea corals! Examining the food left in the stomach of these animals resulted in our discovering ...SCLERITES
Sclerites are skeletal bits from certain kinds of deep-sea corals. They are also distinctive enough for some species that they can be used to identify species!! Later examination of the collection video of these animals did in fact show that these WERE feeding on deep-sea corals!

I've also gotten to looking for these animals on the internet. Its actually seen on quite a few oceanographic expeditions in the Atlantic and the Pacific!
Here is an image from a 2004 Alaskan Seamount expedition. Probably Hippasteria...Here's another image of what is probably Evoplosoma from the same 2004 ExpeditionAnd from a 2003 HURL mission to Hawaii...Although I'm not sure which species this is..and I observed Evoplosoma on the 2009 Pacific Northwest Expedition!
And this 2004 account of what turns out to be a new species of Evoplosoma from Bear Seamount in the Atlantic!Potentially, we are seeing the discovery of a pretty widespread ecological interaction...and an important part of understanding deep-sea corals! A conservation priority in the deep-sea as outlined by NOAA and others...

Hopefully the paper will find good use as discovery of these sea stars becomes increasingly more common...

Okeanos Explorer,Evoplosoma and the North Atlantic Starfish Coral Predators!!

This week, a bit of a break from my work in Japan to blog about my NEW paper!! Its a little something I've published in Marine Biodiversity Records focusing primarily on the deep-sea coral devouring starfish Evoplosoma and some of its relatives in the family Goniasteridae!  

The paper is noteworthy because it uses actual images and data from the Okeanos Explorer research and outreach cruises operated by NOAA.  I've made a point to mention how I've data mined the OE photo archives for some great deep-sea biology (here).   And many of the images below are no exception. 

I've certainly been present as an eyewitness to feeding by Evoplosoma on Okeanos Explorer dives in the last two years, such as the one above from the September mission....

but there were several that occurred well before I became more deeply involved. It often takes a taxonomist (or any scientist) who has become SO familiar with the subject animals that you can recognize when something is new and something is old and rare.. sometimes from plates and figures that are over 100 years old!

via Twitter! https://twitter.com/search?q=evoplosoma&src=typd

Ya see how the stalk with starfish is barren?  and the "healthy" branch to the right still has tissue and polyps (i.e feeding structures) on it??  We're seeing feeding by the sea star which digests that tissue off the white center stalk.. 

I have written about other related deep-sea starfish predators here...

These types of observations have only recently been more frequent in the last few years..

So, everyone "sees" these observations on the expeditions. But what most folks don't realize is that this is SCIENCE IN ACTION. Observations and data being recorded while they are watching the live stream!

This blog post and the paper are the FORMAL RESULT of these pictures and video!!! The science entered into the formal record.

Lets see what we've got!! 

1. Some deep-sea seastars will feed on deep-sea "corals" for at least a YEAR! or more!

So, one cool thing I came upon during my providing "scientist on shore" input for the Okeanos Explorer live streamed expeditions was an anecdote by Dr. Scott France, who mentioned seeing a piece of "bubblegum coral" (not a true coral, but an octocoral called Paragorgia) on Manning Seamount in the North Atlantic, which had been knocked over at some point and was being fed upon by some sea stars, which at the time were unidentified..

This account and this picture were taken in 2004...

ONE YEAR LATER! the Okeanos Explorer again was on Manning Seamount and had returned to the same spot and BEHOLD the sea stars were STILL there feeding on the bubblegum coral...

The colony was still "alive" but being slowly fed upon by the sea stars!! Almost 15 MONTHS later! The feeding rate was incredibly slow compared to those measured in shallow water coral predators such as the Crown of Thorns (Acanthaster planci).

Lots of thoughts and comments have probably jumped into my head and probably yours as well. "Are you sure those are the same four (three) sea stars?"   "Couldn't they have moved on and come back?"

"Did they REALLY stay there, eating a coral for a year?"

Apparently yes. 

This feeding events gives us a rare look into how important nutrients and FOOD are to animals in the deep-sea... and the the time scale involved...

2. A new species of Evoplosoma, a coral devouring sea-star is named after its discoverer, Dr. Les Watling (University of Hawaii & University of Maine) !! 

During an expedition to Bear Seamount in the North Atlantic in 2004, Dr. Les Watling spied this sea star, apparently feeding on the deep-sea corals he works on.

                              

Not being an expert on sea stars, he tentatively identified it, and put the specimen into storage following its collection.  LOTS of different animals feed or live in or around deep-sea corals and sometimes there's just not enough time to work up every single, new piece of data...or new specimen that comes up...

                              

That's where I come in!  A few years later, I'm working on this group and examine the specimen he collected now over a decade ago! and voila it turns out to be a new species! 

This lag in discover to description is not unusual. As I've mentioned in a prior blog post, it can take OVER 20 YEARS for a new species to be described following its discovery in the field!!

                              

And..thus behold the new species Evoplosoma watlingi! Named for its discoverer!! 

3. Evoplosoma feeds on coral in a very particular way... what are all those spines and pedicellariae for anyway?

Everyone seems confident in assuming that sea stars feed in the same way.. that is, hump over the shell of a clam and extrude stomach into the crack and feed away, right??

Well, in coral-feeding sea stars we see a fine bit of acrobatic action involved!!!  And thanks to the high definition videos of Okeanos Explorer, we can see them in VERY fine detail!

Basically, what's interesting about this and OTHER pics of these animals is how such a big, bulky animal seems able to effortlessly CLIMB up into the branches of these deep-sea coral colonies in apparent defiance of gravity!

Well, bear in mind, this is all underwater and these sea stars are mostly water inside those calcium carbonate skeletons...

They can use those fancy, adhesive tube feet to climb up any surface!! 

Other surprisingly common features on these animals? Spines... and little claw-like structures known as pedicellariae.  Are these used to help feed and climb???

The Lessons of Okeanos Explorer

1. Specimens are still necessary for the "nitty-gritty" biology. New species, etc. 
2. You CAN observe behavior and with a lot of sophisticated high-def video, you can even identify some of the critters you are watching! 
3. There's a LOT of video nobody has been watching with a TON of good stuff in it!! 
4. You can make a paper out of it! 

Thanks to 
The crews & team members of the Okeanos Explorer and at NOAA for the support and help!
Kate Neill, from the National Institute of Water & Atmosphere (NIWA) in Wellington, New Zealand! Marc Eléaume from the Museum national d'Historie naturelle in Paris, France and Scott France at the University of Louisiana!

As many of you know, I am a big fan of the Okeanos Explorer Program and have summarized highlights from many of their dives!   Here are some of them again!

What if the Okeanos Explorer went back to Indonesia? (here)
Xenophyophoreans! Giant deep-sea amoebas! (kind of) (here)
The rarely seen swimming sea cucumber Pelagothuria! (here)
Dumbo Octopus Love! (here)
Sea spiders aka Pycnogonid LOVE! (here)

and here's more Evoplosoma love from the Pacific via the Monterey Bay Aquarium Research Institute from work I did back in 2010!!

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. UPDATE: Likely a smaller individual or different species of Pythonaster 

Work on these is ongoing..

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. Peribolaster (Updated!)

I initially thought this was Lophaster, but it turns out, something else.. probably a new species! A member of the Korethrasteridae

15. Solaster sp. 

Solaster aka the "sun star" are multi-armed predators. Mostly known to feed on sea cucumbers and other fleshy prey, they are also documented as "cannibals" that feed on other starfishes.  More on this behavior here.

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.