Thursday, July 28, 2016

The Crown of Thorns Starfish in Macro! Acanthaster planci? or alien landscape?

Acanthaster plancii détail

Today as I was scrolling through the many years of posts I realized that I have NEVER written about the Crown of Thorns starfish, Acanthaster planci!  If you don't live in the Indo-Pacific you might not realize that this is actually one of the most heavily studied starfish in the world!  There are whole BOOKS written just about the biology and ecology of this single starfish species! 

Why? What makes this species so important?
This starfish is a voracious coral predator!  It just extends its stomach onto the fleshy tissue of a "hard coral" (i.e. scleractinian) and a little while later, only the "cleaned" skeleton of the coral remains! 
If it was a reasonable number of these animals feeding on coral, it would actually be healthy for the ecosystem. Predators control community structure and are important to ecosystem function..

The thing is though that this species, for reasons which have been studied since the 1960s, have undergone sporadic and localized HUGE population explosions! Their incredible abundance results in the wholesale LOSS of complete coral reefs! 
 Crown-of-thorns starfish

They have become especially infamous in the Great Barrier Reef and to many Australians who have become accustomed to physically destroying them on contact. They actually have developed ROBOTS to seek them out and destroy them.. 

So, unlike most starfish, they aren't very popular....

The Beauty of the Beast...


Image from Wikipedia, taken by Jon Hanson, in Thailand: https://en.wikipedia.org/wiki/Crown-of-thorns_starfish#/media/File:Crown_of_Thorns-jonhanson.jpg
Here's the thing though. In spite of all the hate that gets laid on these animals.. I STILL think they are kind of freakin' AMAZING! 

So, today, I thought I would exploit the wonderous world of Flickr and show off some of these spectacular macro shots displaying the surreal surface of these animals...

The crown of thorns occurs across a WIDE range. From Baja California to Hawaii and Japan and then down to the east coast of Africa in the Indian Ocean. The range of colors is similarly vast! Its not entirely clear if these might represent separate species or perhaps represent some other kind of variation based on the environment. Perhaps food? growth? Difficult to say...

But genetics DOES indicate that there are multiple "cryptic species" across this animal's wide range in the Indo-Pacific..

The big thorny bits are of course, the spines.. the dark dots on the surface are the papulae  (or gills) and if you see little white or dark beak like structures, those are called pedicellariae whose function in these animals is not entirely clear... But likely some kind of "in close" defense against parasites or what have you.... 
Crown of Thorns Sea Star

Crown-of-Thorns Sea Star
Crown of thorns closeup - Okinawa
tunguska
Crown-of-Thorns Sea Star (Acanthaster planci) from Aliha Giri.
Close-Up Thorns
crown-of-thorns star: Acanthaster planci
Close up picture of a Crown of Thorns Starfish (Acanthaster planci)

and the ANUS of course! That's the dark spot, probably surrounded by spines...  this shot is nice because it not only shows off the papulae (the gills) but also the pedicellariae (the red tweezer like structures)
Crown of Thorns Sea Star Center Close
Crown-of-Thorns Starfish - Kailua-Kona, Hawaii

As one finds often time in nature.. you have some big animal with lots of complex surface textures.. so are there animals to take advantage of it! Shrimps often live closely and among the spines on the animals' surface...

here are tiny shrimps.. some in the genus Periclimenes...
Sea Star Shrimp
Periclimenes soror on Acanthaster ellisii

And the ORAL surface!
Strangely enough, the top surface of Acanthaster is remarkably well known but how many people have actually seen the ORAL surface where the mouth is???


In addition to the tube feet all converging at the mouth, you also see the oral spines projecting into the mouth itself! 
Side B
and in this one, you can actually see some of the cardiac stomach below the purple spines...
upside-down crown-of-thorns
Crown of Thorns sea star (Acanthaster planci)
Crown Of Thorns Sea Star

And a video to top it all off!


At some point, there will be much, much MORE about the Crown of Thorns! 

Wednesday, July 13, 2016

Astropyga The Radial, Fiery Star Butt Urchin! Observed insights from Flickr & YouTube!

A happy July week to all of you! So, as we enter into the lull of the summer I present to you some choice Echinoblog image and video picks from various image streams that show off one the internet's most frequently photographed sea urchins! The diadematid ASTROPYGA

Common names of these urchins include "radial urchins" and "fire urchins." But many refer to echinothuriids in the genus Asthenosoma as "proper" Fire Urchins, for obvious reasons.. but mainly because they are VERY painful to get stung by..

Astropyga also appears to have a rather painful array of spines but I'm unsure if these pack quite the toxic wallop that Asthenosoma does..

Astropyga includes four known species, one in the tropical East Pacific and another in the Indo-Pacific and two in the tropical Atlantic. All are known to occur primarily from relatively shallow to mesophotic depths as we saw recently on a Bishop Museum expedition to the "Twilight Zone" (here

But even within the widely occurring Indo-Pacific species. A. radiata there appears to be quite a bit of color variation from the dark colors seen below to the lighter ones like this
Blue-spotted Sea Urchin (Astropyga radiata)

The genus name can be broken down to "Astro" meaning star and "pyga" which refers to rump or buttocks.. so the name literally translates to "Star Butt"!!.

Why? Well, you see this giant bulb on the surface? That's an extension of the intestine called the anal sac. That's where the POOP comes out! I've talked about that here.  So, basically some wry taxonomist looked at the anal sac and the pentagonal symmetry and decided "yes. The STAR ASS!"
Fire urchin
Flickr and Youtube are GREAT for picking up on natural history observations. Yes, there's always the lack of scientific rigor but sometimes divers just make simple observations. And THAT can be the start of knowledge.

All the images below are probably A. radiata from the Indo-Pacific.

Astropyga scavenging on dead fish! (Lembeh)
Based on a round up of papers I could locate, A. radiata has been reported primarily as a scavengers, feeding on algal debris and other stuff from sediments, etc. But if this image is accurate (and not posed) they occasionally much on dead fish as well. This is actually consistent with other sea urchin feeding habits, so I feel comfortable in presenting it here..
Radial Sea Urchin feeding on dead fish - Lembeh

Blue Iridescent Spots! Its been speculated that these are photoreceptors but they've not been tested and its unclear exactly what their function is.. But they immediately stick out when observed on an otherwise bright red sea urchin! 
Astropyga radiata, Red sea urchin
Fire Urchin
75
magnificent urchin

Spawning!
This speaks for itself. As with other echinoderms I've shown here (such as the sea cucumbers) just because you see white fluid being emitted its not actually clear what sexes of the species are present. The fluids likely represent BOTH sperm AND eggs. 
Sometimes this species form large aggregations, which are most likely to help facilitate their reproduction and sexy time!
Urchins unite!Magnificent Urchin family
Astropyga moves surprisingly quickly!
While I haven't actually seen one of these alive and close up, its pretty clear that even for sea urchins they are capable of a surprisingly brisk sprints! and across some unusual terrains to boot! 

That's quite a lot of coordination of spines and tube feet at play.. 

here's a bunch of them in what looks like a mating aggregation, moving en masse!

Better yet! here's Astropyga moving in TIME LAPSE!

my first underwater timelapse from prodtv on Vimeo.

Crustacean Relationships! 
Sea urchins are basically big spiny balls that seldom move and surprise! surprise! There never seems to be a shortage of OTHER, smaller animals that can take advantage of this as "habitat."

 Crab Commensals!  These don't seem to be as bad as the crabs on Asthenosoma, (the proper fire urchins) simply because these don't seem to "dig" themselves into the urchin surface. Spines on Astropyga seem long enough to provide adequate protection as-is...
Walking on fire!
ZEBRA CRAB ON FIRE URCHIN, LEMBEH STRAIT

and vice versa?? Probably one of the most unusual things I've seen imaged by divers since Flickr and YouTube became a thing has been this.. Crabs in the family Dorippidae that PICK UP urchins, sea anemones and carry them on their carapace in order to use them as sort of a defense as they walk along the sea bottom.
IMG_1077
But why explain? When you can just watch...

...and of course.. POOPING!
And finally, one of the things that we LOVE to watch urchins doing? POOPING! Something that is arguably part of their namesake!  Here's the time I corrected New Scientist on their mistaken urchin pooping picture! 

Here's a whole post on echinoderm anuses for your reading pleasure! 
Here's a lovely shot entitled "Radiant Crap" by Eunice Khoo!
Radiant crap!
And of course there's pooping AND commensal crabs! TOGETHER.
Urchin crab - Zebrida adamsii - T Tebal

Friday, July 8, 2016

Pycnopodia Watch! Cautious Optimism about Sunflower Stars!

The Starfish Wasting Disease was first documented on the west coast of North America in 2009 and began to hit really hard in 2013 as I blogged about here and it became suddenly noticeable by MANY scientists on the west coast from Canada to California.  Due to a massive population explosion there followed a catastrophic die off in British Columbia which I documented here, with pictures courtesy of Jonathan Martin. 

In the intervening years, the Starfish Wasting Disease "event" had taken on a HUGE stage. UC Santa Cruz now monitors the health of west coast asteroids on their website (here). 

The first Sea Star Wasting Symposium was held earlier this year in Seattle. A meeting which I attended and reported on here

Perhaps one of the most significant losses following the massive starfish wasting disease epidemic that hit the west coast of North America (and possibly parts of the east coast) was the apocalyptic loss of the iconic sunflower sea star, Pycnopodia helianthoides.
When I was growing up on the west coast, there were sunflower stars that were HUGE!!  Tall tales would  report them reaching two and a half, then THREE feet across! But most were a good dinner plate size.

These animals were voracious predators and for starfish, moved quickly across the intertidal and subtidal...

Sunflower Stars are an ecologically important species. 

Unfortunately, populations of this species were DEVASTATED by the starfish wasting disease epidemic. More so than almost any of the other species, the sunflower stars were more often than not, completely removed from local areas along the coast.

Ecologically this has had VERY significant ramifications. Recent ecological studies, such as this 2016 paper in PeerJ by Schultz et al   have indicated that green sea urchin abundance in British Columbia has increased FOUR FOLD!

This has agreed somewhat with anecdotal observations by naturalists on Twitter observing sea urchin abundance in California...
The exact reason is not clear. Possibly because the sunflower stars are not around? and the animals have just come out of hiding? Or have the stars been controlling the population structure of the urchins?  But it DOES seem to be related to the absence of the once abundant and mighty sunflower stars.

But Sunflower stars are also an ICONIC species..
In addition to be an ecologically important part of the intertidal and subtidal ecosystem, there's a lot to be said for how they really represented the North Pacific. Pycnopodia is an endemic, found nowhere else in the world.. and was often used as an example of the special and diverse fauna on the west coast of North America..

Some of the individuals which had been on display in public aquaria died within days. Some of these individuals had been around for over 20 years. Suddenly? Gone.

Those of us who are most familiar with the West coast fauna.. divers, naturalists, scientists, citizen scientists, beach goers, students, fishermen, anyone with an intertidal or subtidal ID guide was suddenly NOT seeing this species. It was and still is a significant and sad loss.

And so.. observations of THIS species have had a SPECIAL significance..

BUT today, a colleague of mine, Ms. Brenna Green observed THIS. A juvenile Pycnopodia helianthoides in Northern California!! According to her, one of the first she's seen in a good long while!!
A small individual. Only a few inches across. But still...

I was directed to iNaturalist which has been monitoring observations of ALL asteroids on the west coast.. There were only 60 observations of Pycnopodia since 2014!!- so only about 20 per year that are reported  Note also-some of those observations were from areas that are distant from the primary Sea Star Wasting Disease areas (such as Alaska).

Make no mistake, that's a very low number... but surprising considering that they were considered completely gone from some areas..

But they ARE still out there. And are still popping up..

An anecdotal skim of Flickr and Twitter shows that small sunflower stars have been popping up over the last year or so...
From Titlow, Tacoma, Washington from February 29, 2016
Sunflower Sea Star
Weir's Beach, British Columbia by Laura Verhegge (taken April 21, 2015)
Pycnopodia helianthoides

Recent accounts (such as this one) have documented a resurgence in populations of sea stars hit by starfish wasting disease (based on this paper).

But I would like to think that is SOME good news, even if this doesn't mean a full and immediate recovery..

Another significant issue? SIZE of the observed individuals
Here's one of the most critical parts of these observations: Most are consistently SMALL. Many of the "adult" individuals we were used to encountering were easily dinner plate size or larger have not really been encountered.. or if so, not regularly. 

Are the small sized ones a sign that they simply grow very slowly?  Or more ominously,  do they die as they reach a certain size??

On the upside, I have heard SOME anecdotal observations of adult (~40 cm) sized individuals being seen in Washington and in other localites...

Stay tuned! Research continues. 

In the meantime, for further news check out:


Thursday, June 30, 2016

Five GREAT Polychaete Names! for #PolychaeteDay

Beautiful polychaete worm (Syllidae)
July 1st, every year is now recognized as INTERNATIONAL POLYCHAETE DAY in honor of long-time and widely loved polychaete worm expert, Dr. Kristian Fauchald's birthday!  Dr. Fauchald passed away in April 2015

Here is a great post on Dr. Fauchald's academic legacy at the museum and beyond...

But the Invertebrate Zoology Department at the National Museum of Natural History honors his life's work with an INTERNATIONAL and MUSEUM wide education celebration of his favorite animals: POLYCHAETES!   If you are in the DC area feel free to visit Ocean Hall or the Q?rius Center to see specimens and displays about polychaete worms!!

Meanwhile, I honor International Polychaete Day with a polychaete worm-themed post!!  Here's the one I wrote up last year that revealed polychaete facts you may not have known!

And don't forget this is a TWITTER thing also!! Hashtag #InternationalPolychaeteDay

Here is the Storify Of International Polychaete Day from Last year!  

Among the points I made? that many polychaetes are actually named for greek nymphs, goddesses and other mythological characters!! Today.. I focus on that topic and share the etymology of some awesome looking polychaete worms!!

5. Aphrodite
Probably one of the first polychaete worms I was able to recognize on sight was this gorgeous animal! Also known as the "sea mouse" the genus Aphrodite described by Linnaeus in 1758 is arguably one of the most distinctive of marine invertebrates.

It is of course named for the famous Greek Goddess of Love, Beauty and Sex. But I suspect what made her name particularly apt, was that she was born from the foam of the sea (aphros).. the complete name Aphrodite means "Risen from the Foam"
Image via Wikipedia: https://en.wikipedia.org/wiki/Aphrodite#/media/File:Sandro_Botticelli_-_La_nascita_di_Venere_-_Google_Art_Project_-_edited.jpg

Its many iridescent bristles and unusual shape have made it one of the more memorable animals to encounter in an Invertebrate Zoology laboratory or field trip. These and the various members of this family (the Aphroditidae) occur primarily in cold-water habitats and can be encountered in a wide range of habitats, from SCUBA diving to bottom trawls in the Antarctic!

And is any animal more deserving of the name? Stunning.
Sea Mouse

4. Chloeia
Perhaps one of the most strikingly beautiful fire worms (a type of polychaete with very inflamatory setae) is named for the female name Chloe. Given that the name was assigned by none other than the famous French naturalist Lamarck in 1818, the name may be in reference to Chloe from the Greek story Daphnis and Chloe

Chloeia is a worm with large, colorful bristles and occurs throughout the tropical Atlantic and Indo-Pacific, certainly the beauty of its namesake!
Chloeia sp.
Chloeia flava
Images of  "Chloeia flava" are seen commonly on various image and video websites. Its not clear if these are all correctly identified, but they DO show a wide range of colors and patterns!! 


3. Swima  & Flota
The "truth in advertising" award for polychaetes (in the Accrociridae) goes to these two pelagic worms with names that essentially DESCRIBES their life style! So, for Swima, was named for that species ability to SWIM.

The genus name Flota would seem to similarly suggest "float" in Latin..


There is of course a GREAT story surrounding Swima that you can watch in the MBARI video below but essentially Swima, with one particularly appropriate species, Swima bombaviridis can actually relelase GLOWING BOMB of BIOLUMINESCENCE as a defensive mechanism!(read more here

 You can read MORE about both of them aMBARI's feature story! 
           
We've been seeing SIMILAR types of worms on the Okeanos Explorer dives off Hawaii! I'm honestly not sure which genus we are seeing (or if there's a third? I am simply ignorant of)
Here is one of those swimming Swima worms with some... creative embellishment! THANK YOU Amber Cobley on TWITTER! 
2. Syllis & the Syllidae
Another bunch of polychaete worms whose name was apparently inspired by a classical mythological nymph is Syllis! Who was a naiad nymph from Greek mythology! (here
Disclaimer: Statue of a generalized classical nymph intended to represent concept and NOT a statue of Syllis! 
Syllis and all of the members of the Syllidae are quite gorgeous polychaete worms and its not hard to see how Marie Savigny and Lamarck saw fit to naming them after a Greek naiad! 
Freek worm
Pterosyllis
Syllis garciae
1. All the Worms named for Kristian Fauchald! 
International Polychaete Day honors Dr. Kristian Fauchald, but EVEN IF the event were to pass, his name has been immortalized into the polychaete literature!! 

Based on a search of the WoRMS database (World Registry of Marine Species), as of this writing, there are approximately FORTY polychaete worms which carry the name "Fauchald"!!

Most are species epithets but there are at least TWO genera, Fauchaldius and Fauchaldonuphis

Sadly, I could not locate any living images, but here are diagnostic diagrams of species named for Dr. Fauchald!!

Here for example is Amphisamytha fauchaldi which was a new species of ampharetid (Annelida: Polychaeta) from the hydrothermal vents at Guaymas Basin, Mexico. Over 2000 meter depths! (as one would expect for a hydrothermal vent species). 
Image from page 42 of "Bulletin" (1971-)
Image from page 294 of "Bulletin" (1971-)
Image from page 15 of "Bulletin" (1971-)

and here's actually ONE of a LIVING specimen!! Sphaerodorium fauchaldi!
Image from the Bergen Museum: From their page on the First International Polychaete Day: http://invertebrate.b.uib.no/2015/06/30/the-1st-international-polychaete-day/