Tuesday, December 27, 2011

Helping out our friends at National Geographic with some additional information...

(photo by Paul Nicklen, National Geographic)

GREETINGS!! and Happy Pre-Emptive End of the Year to all of you!

I have been sitting back after a good year of research and echinoblogging-and honestly, I was going to give you guys some videos and "best of" stuff for this holiday season, but I found something that I thought all of you might appreciate instead!

So, the good people over at National Geographic have a truly beautiful website with stunning images deserving of such a widely read and respected magazine.

I found that they had this delightful gallery of "sea stars" (click here).

Alas, there were some..inaccuracies and points that I thought a person with my particular eye might be able to contribute to their photo gallery (which regrettably lacks a comments section).

And so, what I present to you herein is a collection of THEIR pictures but with my added commentary and/or factoids/links that help to embellish their very fine figures!!

So, before I begin-I do recognize that a lot of these are just various starfish factoids applied liberally to give each picture a story...but y'know what? I can do these animals a bit more justice and so I will...

1. Pycnopodia helianthoides-the sunflower star (Asteriidae)
(photo by Paul Nicklen, National Geographic)

For the most part, the narrative for this image was correct, but I had to take some umbrage with the statement "only the five rayed species really resemble stars-others may boast as many as 40 appendages".

BUT, While most five rayed species are "stellate", not everything with five rays "resemble stars". Take for example:
This blog post featuring fossil Sphaeraster and LIVING Podosphaeraster (click).

This blog featuring the deep-sea asteroid-Tremaster mirabilis (click)

The tropical reef "cushion star" Culcita novaeguinae (click)

..and of course the holiday favorite-the cookie shaped Goniasteridae! (click)

and by the way...multi-rayed individuals can get up to 50 arms! (we'll see that below).

2. Fromia indica (Goniasteridae)
(photo by Tim Laman, National Geographic)
The original accompanying text calls this surface of this species "the backside".

hmm.

The bottom-also called- the oral surface- is where the mouth is located.
As a consequence, the opposite or upper side is called the aboral surface. In general, sea stars lack a "back" since there's no backbone.

Calling a starfish abactinal surface a "backside" is kind of like saying humans don't have enough ambulacral ossicles. It really doesn't make any sense.

The narrative also mentions this:
This star boasts a full complement of five arms but it may not always keep them. When grabbed by a predator, the sea star can simply lose a limb and later grow a replacement. In fact, some species can grow a new body from just a single severed limb and a small part of their central disk.
Parts of this are true for Fromia, which have a basic ability to regenerate arms.

But I'm not sure that cutting or damaging a starfish like Fromia to the extent that you have only an arm fragment+disk would result into a new animal.

Its true, that some species such as Linckia multifora or Asterias spp. can regrow a body from a chunk of the disk+arm. But from what I've seen, cutting something like this Fromia into two pieces-would most likely result in getting two halves of a dead Fromia!

3. OPHIUROIDS (aka Basket/Serpent/Brittle Stars) ARE NOT SEA STARS/STARFISH!!!

The following hits at two pictures described as "sea stars" in the National Geographic gallery...

So, as a person who studies and classifies animals for a living, I CAN assure you, this sort of thing is important! Asteroids and ophiuroids are two ENTIRELY separate animals that have been evolutionarily separated from one another LONGER than humans have EXISTED. So, please give them some respect!

What's the difference between asteroids (starfish or sea stars) Versus ophiuroids (basket stars and brittle stars)???

Take this post I wrote about structural differences for starters...

3a. Gorgonocephalus! okay? Now, THIS (original post here) ? is a member of the Class Ophiuroidea. It is a "basket star", a member of a whole family within the Ophiuroidea. Specifically, the genus Gorgonocephalus...
(photo by Emory Kristof, National Geographic)
AND by the way...do ya' wanna know more about these weird basket star things??
HERE is a post I wrote about them!

3b. Tiny Brittle Star & some stuff on Brittle Stars! Now, the pic on this tiny thing isn't enough to clearly tell even which family it is (looks like either a member of the Ophiothricidae or the Amphiuridae though..). Note that this tiny little brittle star? is itself sitting on a much larger starfish called Euretaster (not sure which species but you can see one example here in all of its glory!)
The narrative on this pic reads

Some 2,000 sea star species live throughout the world’s oceans. Some weigh as much as 11 pounds (5 kilograms) and stretch more than 2 feet (65 centimeters) across, but others are only half an inch (1 centimeter) in diameter. These animals reproduce prolifically, and some sea stars can release millions of eggs into the water for fertilization at the same time.
Now, if this were actually an asteroid (i.e. a sea star or starfish) this would be true. But the pic seems focused on the little tiny brittle star (ophiuroid).

Again- ophiuroids (including brittle stars and basket stars) is a member of a separate CLASS. A completely DIFFERENT group of animals that not only is VERY structurally different (again see here).. But one that has been evolutionarily separated from sea stars since the Paleozoic (for at LEAST 250 million years ago if not older). Ophiuroids are quite diverse on their own..and are probably the MOST numerous of all the living echinoderms! Asteroids number about 1800 maybe 1900 species. The number of ophiuroid species STARTS at about 2000 with MORE being discovered regularly!

Bottom line: Asteroids and Ophiuroids are NOT THE SAME THING. And should not be "lumped together" under the same common name.

Please make a note of it!

4. Pisaster giganteus (Asteriidae).What's going on Here? Probably SEX!
(photo by David Doubilet, National Geographic)

I think this is an unobserved reproductive stance! Go HERE to read about other species and their sexy starfish love positions!!

I honestly, don't know if this position has been recorded from Pisaster giganteus before! See what you miss if you don't know what you're looking at???

5. Labidiaster annulatus (Heliasteridae)

This is actually a pretty cool and novel image! I don't know that ANYONE has ever observed Labidiaster feeding on a BIRD before!

Ha! take that vertebrates!
Personally, I'm not sure calling these "sun stars" as a common name is either accurate or particularly original. Especially given that at least 3 other species in different families have been called "sun stars".

Labidiaster in the Antarctic are VERY specialized benthopelagic predators! Go here to read the full account!

6. Tosia neossia (Goniasteridae)
(photo by Jason Edwards, National Geographic)
Based on the colors and some of the other characters, this looked more to me like the brooding than the non-brooding species...

There is a GREAT story about cryptic species surrounding these Australian "biscuit stars"-Tosia australis and a new species Tosia neossia!! Go HERE to see it!


7. Oreaster reticulatus (Oreasteridae)
(photo by Tim Laman, National Geographic)

The narrative that goes along with this picture is correct in many general ways-asteroids are important in marine ecosystems, and they note "....including keeping populatinos of shellfish in check.."

Now, they may have simply been speaking in generalities again-but just to be clear-this species-Oreaster reticulatus? Does not feed on shellfish!

The known diet for most oreasterids-including Protoreaster nodosus (the so-called chocolate chip star known to the pet and tourist trade) and Oreaster reticulatus suggests that they feed on encrusting animals, such as sponges in addition to microalgal film and fine organic particles from the surrounding sediment and nearby bottoms.

Don't believe me? Go here and see this. This. And this.

8. Acanthaster planci (Acanthasteridae)
(photo by Brian J. Skerry, National Geographic)

The original story with this pic had a line that read "Scientists aren't sure exactly what causes such outbreaks, or what their ultimate impacts may be on coral reef health".

Hm. I think I can do a little better than that...

New research suggests that the plague-level outbreaks of this species are tied to a surge in nutrients. Read a blog about this here.

To be sure, there are always uncertainties around "big ideas" that explain natural phenomena such as huge population outbreaks..so who knows? Perhaps new explanations will present themselves in the years to come...

Tuesday, December 20, 2011

Astropecten for the Holidays!

Happy Holidays from the Echinoblog!

I am en transit today (heading home for the holidays) but here are some Astropecten (sand stars) videos to keep all of you preoccupied!

A nice Astropecten spp. from Singapore digging itself out of harm's way! They are surprisingly quick..


And here's a new one (Astropecten) from the Enoshima Aquarium..


More after I've settled out....

Tuesday, December 13, 2011

A farewell to (crinoid) arms! Last week in Paris!


The last month has passed quickly for the Echinoblog's trip to Paris!

It has been a great trip in one of the most beautiful and vivacious cities in the world..
filled with some of the most delicious food in the world....(which is strangely made with the simplest ingredients). Below.. some Breton cakes (a regional desert made in the Brittany region of France). (click here for a recipe!)
And with barely a day left, I thought I would just end with a brief spotlight on some of the most remarkable of echinoderms studied at the Paris Museum..the crinoids!

Here is a specimen of yet another unearthly animal that doesn't even look real! Yes. This is ALIVE!!! A seldom seen crinoid-a modified feather star from New Caledonia (in the South Pacific) called Gymnocrinus richeri!

Some background on these critters can be found here from a blog I wrote about another related species called Holopus.

Long story short- they are very "living fossil" crinoids..that is a living form that, at least superficially, resemble a species from the fossil record. Sort of like the coelocanth or horseshoe crabs.

here's a pic from the other side... they use those arms to grab prey as it swims by (or so its thought..)
Here's another specimen more spread out..
Among the other kinds of better known crinoids are of course, the stalked crinoids (Metacrinus interruptus). aka the "sea lillies"... Stalked crinoids are deep-sea forms that are seldom seen in modern waters (unless you are a deep-sea biologist)..BUT are abundant in Paleozoic fossils..(this is a story for another day.)
Here's a closeup of the cup that includes the feeding tentacles...
Stalked crinoids typically remain in one place most of the time..but every so often they get moving and become internet superstars! As we saw in this video...


Finally, the 3rd kind of crinoid-the unstalked or comatulid crinoids...also known as a feather star.. This Antarctic Promachocrinus shown here doing some fancy swimming...


I wanted to thank my hosts to Paris.. here is Dr. Marc Eleaume, one of the scientists-Curator of Echinoderms for the museum..
and DOCTOR Lenaig Hemery.. who just defended her PhD dissertation next week on Antarctic crinoids and a big-ass phylogeny (aka "family tree") for the ENTIRE living members of the Class Crinoidea.

I wish her the very best and look forward to her future accomplishments! She is shown here with one of "her" animals... the Antarctic feather star Promachocrinus kerguelenensis!
And finally..the ever-busy Dr. Nadia Ameziane-Chief Scientist of the lab who is always a blur of activity! Even taking a picture of her was difficult!
My thanks to all for a great research trip with many new species discovered an many exciting projects underway!!

Tuesday, December 6, 2011

Food & Starfish in Paris-Some of my Favorite Things!

My trip to the Museum national d'Histoire naturelle in Paris has been amazing!

This week-Some of my favorite things...

I'lle flottante-my favorite French desert. Basically, its egg whites made into a merangue and then placed on top of egg yellows mixed up with sugar.
Its rich beyond imagining-and the only reason I can handle it-is because I only have it when I visit Paris! Believe it or not, I've had larger and more sophisticated versions of this creamy wonder.. mmmmm....

*Ahem*But as far as echinoderms go..let's go look at some STARFISH (asteroids, sea stars, whatever...)
and other critters..

Here's a pic of me holding one of the world's LARGEST starfish-

1. Thromidia gigas from Madagascar!
You may remember this beast as one of the species listed in my "what are the largest starfish" post (click here to see!).

2. Sphaeriodiscus bourgeti! A funny looking beast that looks more like a cookie or a rubix cube type puzzle than an animal... This species lives in deep-sea habitats off the west coast of Africa in the tropical Atlantic. Sometimes, I honestly wonder how something with this shape can be alive at all.. (you will hear me re-iterate this question again below...)
Here is a jar with a few more smaller specimens..Colors and etc. are gone but that's their shape when alive. Ya' gotta wonder how they live shaped like modern art that you would find in an artsy French garden somewhere...
3. Luidia! A beautiful multi-armed species of the sand-star Luidia! This specimen is from Madagascar-but generally, these starfish live on sandy bottoms where they prey on mollusks and other smaller, slower sand-dwelling critters.

Interestingly-the patterns are part of the animal's body structure and don't fade in preservation. They are big animals and easily reach 1.5 feet in diamter..
We've seen something closely related to this species in some spectacular video...


4 Asterodiscides tessellatus aka the "Firebrick" or "ToeNail" star!
Each armtip has the signature smooth armored plates.
This video shows a similar species


5. Anseropoda spp. Among the most bizarre is the FLATTEST of the sea stars. Most of these live in the deep-sea. I've shown you pictures of them alive from Hawaii..
The genus of these animals hails form "Anseros" and "podia" which translates from the Latin to "goose-foot" which is what the body of these things resemble...

But its hard to convey from submersible camera shots, just HOW THIN and FLAT these starfish are...
For example, here's a dried specimen of another Pacific species.. the top.
the bottom...
and now, here's the SIDE...
Here's yet another species, but this one with multiple arms! (about 7). The top.
The bottom surface.. (note the mouth at center and the tube foot grooves radiating out from it) The arms and body are somewhat damaged..but hopefully you can make out the general shape..
Here's what the animal looks like if you pick it up. It so thin that light actually shines THROUGH it.
Seriously. How is something like that even ALIVE??? Amazing. and wonderful...

Annnnd..let's not forget our friends-the closely related ophiuroids (brittle stars)...(this one is Amphiophiura liberata)
And where would be if we didn't end with some kind of deep-sea sea cucumber? Not QUITE sea pigs..but close.... Here's some Oneirophanta mutabilis!
For some reason..I am always around places that have giant deep-sea crabs.

How many people can say that keeps happening to them??

More next week!