Tuesday, April 9, 2013

Starfish or Sea Star? Asteroid? 5th Anniversary Post!!

thanks to Paul G. for the photo!
Greetings! Today for the FIFTH ANNIVERSARY (began April 9th, 2008) of the Echinoblog a special topic!  One so controversial and so earth shattering that it will pit Friend vs. friend! Sibling vs. sibling! Spouse vs. spouse! Mentor vs. student! 

A topic that has found bitter and vicious debate at museums, aquariums, marine biology and even paleontology programs around the world!


Undoubtedly upon this post reaching public circulation, many of my colleagues will probably stop returning my email and spit upon me as I walk by them (although some of them do that anyway!)


I speak of course, of the dreaded "Starfish or Sea star (seastar)??" controversy!

Which common name should we use for these frequently encountered and familiar marine animals??? 

But where to start?  Let's define some terms, so this discussion doesn't get completely out of hand.

Let us make no mistake-when we talk of this debate that we speak of members of the ASTEROIDEA. 

  1. Starfish/Sea Star is a term that VERY SPECIFICALLY refers to the ASTEROIDEA-one of five living classes within the phylum Echinodermata (the others include sea urchins, sea cucumbers, crinoids, and ophiuroids). 
  2. It is incorrect to refer to OPHIUROIDS as "sea stars" or "starfish", per se.  Ophiuroids are an altogether DIFFERENT class of animals from asteroids. Go HERE to see some characters that tell them apart.  Common names of ophiuroids include: brittle stars, serpent stars, basket stars. I find it acceptable that certain echinoderms are referred to as "XXXX  stars" under certain circumstances. A separate class of echinoderm-the Crinoidea (lacking a stalk), for example are often called "Feather stars." I'm cool with that. The specific terms "sea stars" and "starfish" should only be applied to ASTEROIDS.
  3. Note that this is one of the few groups in which the common name DOES correspond to a 'real' classification. Terms such as "crab", "coral", or "jellyfish" actually do NOT refer to a single natural classification of animal-but rather several similar looking kinds of often distantly related animals. This video about "jellyfish" explains the issue nicely:
There is also one more caveat-that we restrict this discussion treats only MODERN animals. In the Paleozoic there are fossil animals that blur the line between asteroids and ophiuroids. This gets trickier and is a discussion left for another day... 

Here we go.. Asteroid vs. Starfish vs. Sea Star!!!
There are THREE, Latin-based, English terms- as outlined below: "asteroid" (from the scientific name Asteroidea), "starfish", and "sea star." This discussion comes up over and over..and seldom seems to find resolution...  Here then are a list and discussion of these terms and the back-and-forth over the terms..

Note that the terms "starfish" and "sea star" do not reflect different morphologies within the Asteroidea the way that say, common names for ophiuroids do (e.g., Basket stars = the name for Gorgonocephalidae). So there really has been quite a commotion over these two terms as they find standardized use...

These reflect various arguments I have heard/collected over the years. While I have my conclusions at the bottom...please feel free to take these different perspectives to your classrooms, aquarium education courses, and grad school discussion groups to discuss at your pleasure!  Yell at me in the comments if you wish! 

1. The term "asteroid" (from class Asteroidea)
We Should Use the Term Asteroid Because:
The latin name from the group, ASTEROIDEA was officially put to paper by the noted French zoologist Henri Marie Ducrotay de Blainville in 1830 from the Greek aster and eidos referring to "star (as in the sky)" and "form or likeness."  Nouns are derived from the scientific name.. so "asteroids" is technically the proper term for animals that we would refer to as "sea stars" or "starfish".

The Main Argument against: No, we can't use the term "asteroid" because it might be confused with a giant space rock hurtling through space! OH NOES!
From Nat Geo article about asteroid collision
2. The term "Starfyshe"(starfish)?
n415_w1150
Arguments FOR using the term starfish!
1. The word starfish is widely used and "I" like it. So why change what ain't broke?
          Google recovers 13, 200,000 hits relating to "starfish"including use in religion, politics, obscene rock lyrics, hitting the bed and splaying out on the surface, charity organizations, nuclear bombs, and yes, sometimes it even refers to animals!

2. So what if the word is a misnomer?  
Plenty of words in the English language are inaccurate. Greenland is icy and Iceland is green! Sea horses aren't horses! Why can't we just put up with one more? That's life! C'est la vie! 

3. Starfish is the oldest known western term.  (thanks to John Lawrence, at USF for the info)  According to the Oxford English Dictionary (OED) this dates back to 1538 referring to "Stella, a   sterre, also a sterrefyshe."(from Elvot, dic.) This usage corresponds to the first definitiion given for "fish" in the OED: "In popular language, any animal living exclusively in the water"

These days of course, our terminology has been much revised based on tons of evidence showing classifications among animals and we acknowledge that "fishe" had a much different meaning 475 years ago, but the term has stuck with us and its not likely to be going away anytime soon. 

I'll bet that scientists and students are probably not as big a majority user of the term "starfish" as they believe themselves to be. The term is widely used throughout the many aforementioned outside disciplines and probably won't find much change even if scientists begin to radically suppress the term...


Arguments against the term starfish!
Starfish are NOT fish!  The term is inaccurate since any MODERN definition of "fish" refers to proper vertebrates and NOT invertebrates! Inaccurate terms are SO confusing! People and students who have not had basic biology will not know that asteroids are NOT fish! Oh Noes!

3. The term "Sea Star (or Seastar)"? (yes there's even a controversy over whether "sea star" is one or two words!)
n52_w1150

Arguments for using the term sea star (or seastar)!
1. The term is more accurate. Asteroids aren't true fish so why call them that ?? (other than historical tradition, which is dumb!).

2. ALL the other western countries use "sea star" why don't we? We should do that too! Its consistent!  Get with the program! Don't you want to be doing what all the cool countries are doing?  (e.g., German=seesterne, Spanish=estrella de mar, French=étoile de mer and I believe even the Chinese word means "ocean star")

Arguments against the term Sea Star
1.  The term Sea Star gets less use than Starfish. "Seastar" (one word gets 2,660,000 hits) but note that "sea star" (two words gets 475,000,000 hits-but many of these may be random combinations of "sea" and "star"). Its dumb that we use such a wishy washy word that other countries use!

2.  Sea Stars are not stars.  Asteroids may not be "fish" but nor are they big burning balls of space gas! I once used the "sea stars are not stars" thing jokingly-but it turns out, the reference to stellar bodies has a real basis!

The FIRST definition for "sea star" in the OE dictionary (and indeed Websters as well) (date uncertain) is of a "star which guides mariners at sea", the Star of the Sea, with only the SECOND definition referring to proper asteroids.
Blue Star.
Blue Star. by negombo83 on Flickr
Earliest usage in reference to the animal I have record of:
1569... A kind of fishe called Stella or Sea starre, bycause it hath the figure of a painted starre (fr. Fenton-Secret Wond. Nature)
Curiously a subsequent definition reads
1594..The fishes called Sea-starres, that burne one another by excessive heat. (fr.Nashe, Unfort. Trav.) 
3.  Asteroids are not always star-shaped!  Sometimes they are pentagonal...almost to the point of being round..
 Other times flat and almost paper-like..
And still others can be almost ball-shaped

Dispelling a Myth about "sea star" as political correctness
In the 90s (or thereabouts) there was a huge revolution in educational programs across museums and aquariums throughout the US, and inevitably beyond. Many of the various common names ended up getting names that people felt were more accurate. So jellyfish were called sea jellies. Hagfish were called sea hags and so on.

At about the same time was the big "political correctness" revolution from the late 80s, early 90s which was intended at diffusing offense and infusing more respectful terminology among public and political dialog-with extensive changes to almost all terminology.
Here is a full workup of that scene at Wikipedia.

Naturally, it was widely assumed that common names in science had befallen the same fate. But as indicated above.. the term "sea star" has been around since the 1700s.  And across different languages. And since, ultimately, asteroids DON'T really care WHAT you call them, it does seem unecessary to apply political correctness to echinoderms.

Are European terms the only one we should consider?

At a certain point in this discussion it becomes readily apparent that the "common name" argument for asteroids emphasizes the western/English terms. Do terms for starfish in other languages offer more attractive options?  Let's look at a few!

*hitode (ヒトデ). This word means "palm" in Japanese. Here is a post I wrote about Japanese starfish names!  Records of the term hitode date back to 1712!
*tapak sulaiman.In Malay, this word literally translates to "Solomon's Footprint"! Snazzy, eh?
*불가사리  In Korean, the word for starfish refers to "Immortality"!!!

(my thanks to Yoichi Kogure, Marcus, Tai-Lin and Taekjun for their helpful insights!)
These are all awesome. and hmm.. Solomon's Footprint is a pretty cool name for an asteroid!

Ultimately, though these terms seem to work out best in their homelands where the cultural context makes the terms more useful (and perhaps less confusing in English). Although I dunno... I'm still kinda  fond of Solomon's footprint..


What was the oldest name again? 
1538: sterrefyshe
1569: sea starre
1712: hitode
Yup. Its "starfish" and not technically "sea star"..so if you're a big taxonomic synonymy fan but not a big fan of "starfish"..uh.. sorry... 

Within the international rules that dictate proper scientific names for animal species, it is generally accepted that the OLDEST term has seniority over the others. But these rules generally only apply to the proper Latin species names and not the "common" or popular names. So, they don't necessarily apply. But as far as established 'legal' criteria goes this is one of the few which exists, so it should be considered.  "Starfish" is the senior name..

Finish it up! I ain't got all day!
These are things that are not negotiable

1. Asteroids are starfish/sea stars. NOT ophiuroids (aka brittle stars). I often see a wide variety of individuals in the popular arena apply the terms mistakenly. That is improper use and thus, is disapproved of. Hrrumph!! Double Hrrmumph! PLEASE STOP IT! 


2.  The term "asteroid" is technically correct. As indicated above, this is a NOUN based on the actual scientific name of the animal?  HERE YOU GO. But of course, we could still confuse a big space rock with a giant interstellar starfish. 

I prefer to use "asteroid" as a scientist of course, but barring that?  

WHY NOT USE ALL THE TERMS?  
Many languages have different words for the same thing. I accept that there are different words with the same meaning.  I trust context to decide usage.  I tend to use "sea star" around students and/or an audience that might not be familiar with asteroidsI use "starfish" around people who know better.. and I use "asteroid" among my colleagues..but obviously there is interchange.

But yes, please know that a "starfish" is NOT a fish before you begin using it. :-)


Over the years, the whole argument has started to sound kind of silly...


person 1: We can't use "asteroid" because we could confuse it with a space rock! Oh NOES!
person 2: Okay. Let's use starfish instead.
person 1: We CAN'T use starfish because people would confuse it with a FISH! 
We MUST use sea star.
person 2: Sea star! Pfah! weak. Why be conformist? Plus they are not burning balls of hydrogen! Bark! Bark! We shall use starfish!!! Its traditional! And sounds better! 
person 1:  NO! SEA STAR! IT LESS CONFUSING!
person 2: STARFISH! 
person 1: SEA STAR! 
person 2: STARFISH! 
person 3: SEASTAR!  BUT WITH NO SPACE BETWEEN THE WORDS! 
BARK! BARK! 
Me: Asteroid?
everyone: Oh NOES! TOO CONFUSING WITH Space Rock!
*sigh*

HAPPY 5th ANNIVERSARY from the Echinoblog! 

Tuesday, April 2, 2013

Happy Spring! Here's some bright pink and orange sea cucumbers (sea apples)! WOO!

Tentacles of the warty pink sea cucumber (Colochirus quadrangularis)
Fantastic image by Arthur Anker-Colochirus quadrangularis 
Today, we welcome spring with these awesome brightly colored sea cucumbers from the tropical Indo-Pacific!

My thanks again to Arthur Anker, WildSingapore and other photographers who have put their images up to enjoy!

Warty pink sea cucumber (Colochirus quadrangularis)
Fantastic image by Arthur Anker-Colochirus quadrangularis

Pink-orange sea cucumber (Cercodemas anceps)
Cercodemas anceps by Arthur Anker
Another Cercodemas from Wildsingapore!
Pink warty sea cucumber (Cercodemas anceps)


Pink warty sea cucumber (Cercodemas anceps)

A nice one of Cercodemas with the feeding arms extended
Pink warty sea cucumber (Cercodemas anceps)

And here's BOTH Cercodemaas AND Colochirus! 
20061108 d6668

Sea apple - the most colourful sea cucumber in the world
Sea apple - the most colourful sea cucumber in the world



Pseudocolochirus olivaceus. Images below by Arthur Anker, Singapore Marine Biodiversity Survey.

Another nice Pseudocolochirus shot by Jeff Mullins (underwater komodo)
Sea Apple - Cannibal Rock - Komodo

The feeding end of Pseudocolochirus. Image by Arne Kuilman
Power feeder (Pseudocolochirus violaceus)

A nice close up of the tentacles in a sea apple. Image by Pat M. Williams
Sea Apple


and finally, here's  a video of one in its habitat (this one from Hong Kong)


Wednesday, March 27, 2013

Off-topic! Fire Worms! Chloeia Video & Picture round up!

Chloeia flava
Image by Ben Naden
Chloeia is a fairly conspicuous polychaete worm in the family Amphinomidae which apparently occurs widely throughout the Indo-Pacific. About 27 species..and honestly I'm not sure if everything that is labelled C. flava in the videos and pics IS correctly identified but here's a round up of videos and pics while I am distracted by a job interview!

 
This one shows some burrowing action at the end...


More


Here's one eating...


This one is a stunning iridescent green! Image by friscodive
Chloeia sp.

Chloeia fusca.  Image by Ben Naden
Chloeia fusca

Another similar one. Image by divemecressi
Peacock bristle worm - Chloeia flava

And yet another by friscodive
Chloeia flava 01 - Nudi Pixel

An awesome one from the Panama Canal. Image by Arthur Anker
Fireworm (Chloeia sp) from Panama Canal

Back atcha next week with more echinoderm blog love!

Wednesday, March 20, 2013

Antarctic Echinoderms:Canary in a Coal Mine for Ocean Acidification?

This week a 2011 vol. 119(5): 457-466 paper  from the Journal of Geology by Antarctic biologist James McClintock, my colleagues at the University of Alabama (M. Amsler, R. Angus, R.C. Challener, J.B. Schram, C.D. Amsler), myself and colleagues at the University of South Florida (J. Cuce and B. Baker).

Our paper addresses how Antarctic echinoderms but specifically sea stars (=starfish) and brittle stars are likely to be vulnerable as the climate changes, creating a more acidic ocean environment.

Here is a quick video that nicely summarizes the broader phenomena of Ocean Acidification (abbreviated OA)

But here is where we add further details-the acidification? affects different kinds of calcium carbonate (the material which composes shells, coral skeletons, etc.) differently...

Most of the shells and skeletons that you read about in the news are usually made either out of different forms of calcium carbonate-either aragonite (wikipedia has a nice summary here) or calcite. Aragonite is usually what's seen as associated with shells, skeletons, etc..

But, of course, echinoderms being echinoderms have something a little different going on... Echinoderms have skeletons with a high concentration of magnesium (Mg).

Their skeletons are composed of Mg-calcite (magnesium calcite)

One can see many recent stories about how aragonite in shells is easily dissolved by ocean acidification.

Mg-calcite is even MORE soluble (and more vulnerable) than aragonite!

Looking at Mg-calcite in Antarctic Echinoderms
McClintock and his team sampled some 26 species of echinoderms, representing all 5 living classes (sea stars, brittle stars, crinoids, sea urchins, sea cucumbers) and analyzed them for % composition of Mg calcite. 

The sampled specimens showed that skeletal components in Anatarctic echinoderms met the defined standards for "high-Mg-calcite species" (MORE than 4% Mg-calcite by mol%)
Sea stars

Of all the echinoderms? Which had the HIGHEST amount of Mg-calcite by % weight??
Several species of Starfish!

I would note that ophiuroids were not heavily sampled-below but in all liklihood they are just as if not more important here..

Specfically, this very widespread species, Porania antarctica  dsplayed among the HIGHEST % weight of Mg-Calcite
Photo by Dirk Shories at this site.
In the above image-the animal looks quite fleshy but in a dried one below..you can see there's actually quite a bit going on...
And here are some rather large Macroptychaster in a pic seen around the world..but you can see how big they get. The % of Mg-calcite is quite high in this and many other Antarctic asteroid species...
                                      
One major conclusion: Antarctic echinoderms-especially sea stars (starfish) have high amounts (in terms of % of total weight) of Mg-calcite in their skeletons.  

Mg-calcite is more inclined to dissolve as a result from OA and therefore makes them highly vulnerable to dissolution!
This total amount of Mg-calcite was compared relative to OTHER %of Wt. values across different latitudes (0=equator, higher = closer to Antarctica)


Note the datapoints indicated by the RED ARROW. Those are the data from Antarctic taxa.

There's a global pattern that shows that those echinoderms close to the tropics have, by weight, the greatest % of Mg-calcite.  This makes sense when you think about how heavily calcified tropical starfish are (such as this Protoreaster nodosus)
Protoreaster nodosus

So, if tropical echinoderms have the greatest % of Mg-calcite by weight, why are we worried the MOST about POLAR species???

An excellent question.  Here are some answers.

1.  Temperature is an important part of the "calcium carbonate in sea water" ocean chemistry dynamic. Cold water settings, such as the Arctic and the Antarctic have shown the most dramatic decreases in the amount of calcium carbonate available for shell/skeleton building as ocean acidification increases.  This has been shown most recently in pteropod mollusks (click here for ref)

2. Mg-calcite is most vulnerable to dissolution. A study on coralline algae (that's algae which builds a skeleton for itself using the mineral Mg-calcite) showed that when 8-12% by wt. of a calcite skeleton is composed of Mg-calcite it becomes HIGHLY soluble.. Look above at the Table 2 from the paper most sea stars have 9 to 10% by wt. Mg-calcite skeletons!

3. Echinoderms are a dominant force in the Antarctic. They have HUGE biomass. In other words there's a LOT of them and they're important to the global carbon cycle.  Notice the large numbers of sea stars in the video below...That is a lot of Mg-calcite...
Thus, Antarctic species may not have the highest % of Mg-calcite across the full "band" of possibilities but they are among the MOST vulnerable.

So-all this leads to an important realization:  

Echinoderms, probably sea stars, will probably be an important, I daresay, critical indicator of  which faunas will be affected as climate change continues and  ocean acidification creates a more acidic ocean environment.  

This could affect the larval development, the physiology or the ecology of these species. Its also important to realize that echinoderms have an endoskeleton as opposed to a shell which is what you see in other studied taxa...  MUCH more remains to be studied. 

Its also interesting to note the prior extinctions of echinoderms and other echinoderms from Antarctica as I've mentioned here , possibly during the Eocene glaciation event.

Tuesday, March 12, 2013

A spotlight on Echinoderm Art

Things got a bit busy this week  and I've been discovering the wonders of the natural history side of DeviantArt!

MANY creative and wonderful artists out there and I thought it would be cool to showcase some of the notable ones, especially the ones that can be compared against the "originals"

Frankly, I'm pretty impressed. At one time, a LOT of these animals were known only to a handful of specialists in the world. And NOW?People make them into art!! That's amazing!

Here's a few...
Enypniastes! The deep-sea Swimming Sea cucumber! I blogged about these HERE.
Here are some video of the original inspiration!


SEA PIGS! The sea cucumber called Scotoplanes! I wrote a bit on this HERE.
OINK!
and holiday classics!
An interesting one with a Chinese art theme

A digital sea pig

Here's a link to a neat one called "Sea Pig Nouveau" that sadly, was not embeddable..but click here.

and of course, here's the original..

What follows here are some PALEOZOIC fossils, with added colors and "reconstructed" onto a Paleozoic sea bottom as if they were alive...
I try to compare some of these with actual fossils...

Ophiocistioids! Strange Paleozoic forms! I wrote about these only awhile ago HERE.
Here is an actual fossil of the ophiocistioid Eucladia from Yale's collection

Cystoid echinoderms from the Paleozoic!  I'll blog more about the various Paleozoic echinoderms some day, but there's easily as many extinct echinoderm fossil groups (most of them with stems) as living groups.   This image has a nice assortment of them from the Ordovician of New York..
Here are the three primary critters for comparison! The light olive one in the upper right corner, wrapped around the bryozoans is called Cupulocrinus jewetti
Image by Paleoportal. Photo by Joe Koniecki
The artist indicates the blue individual as the cystoid Pleurocystites squamosus 
Image from Paleoportal. Photo by Joe Koniecki
Here's another.. the brown one with all the unusual spines? tentacles along the sides? Is identified as Glyptocystites multiporus. Here's a fossil from the Ordovician in Ontario for comparison
Image from Paleoportal. Photo by Joe Koniecki

Tuesday, March 5, 2013

Off topic: Stunning Crab Photos from Arthur Anker!

Today, a little diversion from echinoderm as we feature, once again, the stunning invertebrate zoology photography of Arthur Anker featuring some of his favorite animals!

A "strawberry crab" (Pelia mutica) from the Honduras
Strawberry crab (Pelia mutica), Honduras


wow! A festive decorator spider crab called Cyclax suborbicularis (Majidae) from Moorea, French Polynesia
Carnival time !


A "christmas lights crab (Paractaea rufopunctata)
Christmas lights crab (Paractaea rufopunctata)


The spectacular deep-water crab Rochinia crassa
The spectacular deep-water crab Rochinia crassa


An awesome looking leucosiid crab, Heteronucia venusta from Guam
Heteronucia venusta (Leucosiidae), Guam


A stunning Chilean hermit crab (Pagurus edwardsi) infested by a parasitic barnacle (=a rhizocephalan called Peltogasterella gracilis)
A Chilean hermit crab (Pagurus edwardsi) infested by a rhizocephalan (Peltogasterella gracilis)


A striking striped crab, Liopetrolisthes mitra
Liopetrolisthes mitra, striped colour morph


An interesting grapsid crab, from French Polynesia
Metopograpsus thukuhar (Grapsidae), French Polynesia


A gorgeous polka dot xanthid crab, Cycloxanthops vittatus from Panama
Cycloxanthops vittatus, Panama


Stunning red xanthid crab, Liomera rubra from Guam
Liomera rubra (Xanthidae), Guam


Fire crab! (Hirsutodynomene sp.)
Fire crab (Hirsutodynomene sp)


More polka dots! (Trapezia tigrina)
Coral crab (Trapezia tigrina), Guam


A flat-rock elbow crab, Cryptopodia fornicata
Flat-rock elbow crab (Cryptopodia fornicata)


and wow..there's more which I will add in another post some day!