Thursday, February 26, 2009

Mellow Oreasterid Video Day!

To follow up on the earlier post on Culcita, here are some mellow videos of oreasterid starfish to bookend your week!

Pentaster obtusatus (Oreasteridae) from ?

Protoreaster nodosus Turning over!

P. nodosus Close up!

Pentaceraster sp.? time lapse
(not the best quality-and looks bootlegged but pretty cool!)

and finally, here's Culctia novaeguineae..not doing much..but you can at least see it alive!

Tuesday, February 24, 2009

The Cushion star Culcita novaeguineae: An exercise in growth-related taxonomic confusion!

So, people have seen some of the high-profile accounts of how some weird deep-sea fish classified into three families, were actually shown to be the males, females, and larvae of one species!
Well, not to be outdone, we at the Echinoblog have a similar (if somewhat less extreme) version of that...

Ontogeny and growth of course can be quite a pickle of a problem when trying to understand the diversity within a species.

For example, here is the juvenile form of one individual.
And here is the adult!! They look NOTHING alike!!
Now, if we look at Culcita novaeguineae, a starfish which inhabits the tropical Indo-Pacific region where it feeds primarily on coral .
We have a parallel where the JUVENILE is VASTLY different from the ADULT!!

Can you possibly believe that THIS?
Is the juvenile form of THIS????
I actually get a whole bunch of images from curious aquarists, divers and even scientists who have seen the big cushion stars and the tinier, "cookie" stars but NEVER realized that they were the SAME!!

How does that happen?
As it turns out, this well as all species within the OREASTERIDAE have this particular developmental quirk.. That is there is what's called a "goniasterid" phase. the babies look like members of a different FAMILY!!
The small "cookies" were called "Goniodiscus sebae" (among about 12 other synonyms) and were members of the Goniasteridae until they were "raised out" to the adult forms.
(Goniasteridae: Peltaster placenta for comparison)
Whereas the adults were called Culcita novaeguineae and were members of the Oreasteridae.

and what happens? Quite simply, they just grow out, becoming more "inflated" as they reach an "adult" size, making cushions out of cookies!!

As it turns out, MANY members of the Oreasteridae have a "juvenile stage" and this complicates our understanding of just how many prominent oreasterids are the older, bigger stages of smaller cookie-or otherwise tiny starfish in other groups?

Thursday, February 19, 2009

South African Wonder! Calliaster baccatus & Other Rarely seen South African Starfish Species!

One of the genuine pleasures of my job is receiving photos from scientists, photographers, and SCUBA divers from around the world and identifying sometimes VERY rare species that have never been seen alive before!
This week, I received a series of photographs from the Curator of Marine Invertebrates at the National Museum of Northern Ireland, noted nature photographer and author Bernard Picton (bio here), who hosts this excellent website on the marine life of the UK and Ireland and an author, who has written "A Field Guide to the Shallow-water Echinoderms of the British Isles" and this guide to "Inshore Marine Life" as well as several other fine books on sponges, nudibranchs and other marine invertebrates!

Mr. Picton got ahold of me after the World Asteroidea Database went online and asked me if I could identify these species he photographed from South Africa.

After all these species were identified they were uploaded to the WAD and are available there in conjunction with the taxonomic information already in place!

South Africa has a really NEAT marine fauna. Why?
Because of all the ocean stuff that mix. Indian & Atlantic. Tropical & Cold/Temperate.

LIVING pictures of these animals are VERY difficult to come by-and in all liklihood, this is the FIRST time that some of these species have EVER been seen outside of South Africa!!

Calliaster baccatus (Goniasteridae)
Described by Walter Percy Sladen in the classic H.M.S. Challenger Expedition monograph and recorded only a few times after that. This is the probably one of the FIRST EVER pictures of this species alive!!
We know nothing about it. But this species is recorded ONLY from South Africa!
Austrofromia schultzei (Ophidiasteridae)
Another species we know very little about. Also known only from South Africa...
Marthasterias glacialis (forma-africans)
Marthasterias is widely distributed throughout the Atlantic on the European/African side but is still a very impressive looking animal. Anyone interested in a phylogeography/biogeography project? (thanks to Bernard for the tip!)
Patiriella dyscrita (Asterinidae)
Another African/South African species....
Callopatiria granifera (Asterinidae)
Same family, but different..
Henricia ornata (Echinasteridae)
One of the many places where one finds the cold/temperate water genus Henricia. If you live in the temperate North Atlantic or North can see them there as well...
Thanks again to Bernard Picton for allowing me the chance to share these animals with everyone!! Pics were taken on an expedition led by Cathi McFadden and supported by the Cnidarian Tree of Life Project! thanks to all!

Monday, February 16, 2009

Japanese Larval Echinoderm Videos!

So, this week is kinda busy...but truth be told, awhile back I found these REALLY cool videos on Japanese YouTube and have just been ITCHING to show them to everyone!

They show various echinoderms going through their Larval stages in pretty nice photoquality accompanied by a pretty cool-as-hell jazzy/folksy music ensemble.

Here is a link to Google Translate for general translation-but I make no claims as to the reliability or the accuracy of the results. I find it useful mainly to get the general idea of what the descriptions say..

1 Spatangoid Sea Urchin of some kind.

2."Regular" Sea Urchin larval growth

3. Ophothrix exigua Brittle Star larval growth

4. Starfish Larval growth


Wednesday, February 11, 2009

Echinoderm Sex pt. 2! More ALL-Star PSEUDOCOPULATION!

Whew!, where were we? OH yes... PSEUDOCOPULATION!!
I was surprised how many different starfish and brittle stars will "do it" And when and where does it occur?
One of the curious things I noticed was that all the papers out there note how it "optimizes fertilization success" or somesuch thing.. But the begs the question, if that's the case, then why don't all of them do it?

A mystery.

Almost all of the other taxa I was able to learn about were either temperate-cold water or lived in the deep-sea with Archaster being one of the only tropical species I was able to find info on as exhibiting pseudocopulation

Interestingly, in these other colder water taxa, pseudocopulation is triggered by a change (either an increase or decrease) in tempeature and the time to spawn is much shorter relative to the pseudopulation to spawn ratio in the tropical Archaster.

What else pseudocopulates?? Let's look at some hot starfish on starfish, brittle star on brittle star ACTION!! Bwucka Wow wow! indeed!

1. Leptasterias polaris
From a study by Jean-Francois Hamel and Annie Mercier at the University of Quebec at Rimouski is an account of the large six rayed Leptasterias polaris.
Leptasterias polaris is a typically solitary species UNTIL the early winter, around November-December, when they start to aggregate and become more...intimate..

Pseudocopulation became more frequent in early December and peaked just before the main spawning period in late December as the water temps reached a range of 3-4 degrees.

Unlike Archaster..there is no sex-specific order..just big clumps of Teh pseudopsex!

Then in stops and the stars go back to ignoring each other.

2. Neosmilaster georgianus
From the Antarctic we have the asteriid starfish Neosmilaster georgianus as reported by Marc Slattery and Sid Bosch!

N. georgianus was reported to reproduce throughout the year but the pseudocopulatory behavior was observed in the austral spring/summer in September/October.

Before the action starts, there is "exploratory contact behavior" as the animals touch each other up with males initiating contact with females.

This is followed by the males mounting the females (so in this species the female is on the bottom). Sometimes 3 or more males will be involved... But in all cases only the bottom one is female!

Because the attraction of males to females is thought to be rooted in pheromones or some other chemotactic stimulus, its possible that one male pairing might actually attract other males to a reproductively active female!

This whole thing takes place over the course of minutes to hours. Interestingly, pairing events were observed to be relatively rare throughout the population studied.

Spawning happens a few hours later (as opposed to 2 months in the tropical Archaster)

On the whole, this suggested that at least for the study area, reproduction occurred at low rates throughout the year.

3. Ophiura robusta

Finally, a neat article on Arctic/subArctic pseudocopulation and other "aggregative" reproductive behavior from the Gulf of St. Lawrence by John Himmelman and others!

Their paper not only observed mass spawning in ophiuroids but also the asteriid, Asterias vulgaris (=Asterias rubens). Perhaps something like this?
Among these ophiuroids, including Ophiura robusta and Ophiopholis aculeata, some would wrap its arms around the central disk or engage in a seething orgy of reproductive optimization!! in which 3 to 5 of individuals would wrap their arms around each other!!
The first individual to spawn was observed to be male, followed by the females, suggesting that there is some pheromonal or chemical cue.

Interestingly, animals in this region began their spawn in the summer (as opposed to Leptasterias polaris which lives in a similar kind of environment) in reaction to increasing (vs. decreasing in L. polaris) temperature!

Ultimately, these would spawn, with animals crawling up to high platforms or elevated surfaces with the disk raised to "optimize fertilization success".

This gallery has some AWESOME pictures of ophiuroid spawning with this posture..

Unknown Deep-Sea Bahamian ophiuroid.
sorry. I got nothing on this.. But pretty cool, eh? I'm not even sure what species? Maybe Ophiomusium?
So..on that note...have a great pseudocopulating weekend!

The World Asteroidea Database is OPEN!!

So, ya remember how I said I was working on something? Here it is!!!


Currently over 1800 names and counting!!!

My gift to the world! Yeeeha!

Still under development in some places...but has all of the taxonomic fundamentals!

Enjoy! (back to starfish sex tomorrow!)

Saturday, February 7, 2009

The Sex Life of Archaster! Pseudocopulation in Sand Stars!

Since this week leads up to Valentine's Day, I thought this would make a great time to talk about something that's been much on my mind.....

Yes! That's right! Pseudocopulation!!!

Wikipedia defines as:
Pseudocopulation describes behaviors similar to copulation that serve a reproductive function for one or both participants but do not involve actual sexual union between the individuals.
I mean, who doesn't think about pseudocopulating every so often?? it turns, out a bunch of echinoderms..particularly starfish and brittle stars do all the time!

But today, let's look at one of the best known of those asteroids which engage in this farce of faux fornication!
Archaster typicus!
Archaster is the single member of the Archasteridae, a group of starfish that live in the tropical Indo-Pacific, occurring from the east coast of Africa to New Caledonia, Australia, and the tropical regions of Asia, including Japan in shallow-water environments.

Archaster is a frequently encountered species, which closely resembles the other sand-star Astropecten. But both live in sandy, unconsolidated sediments..and are often called "sand stars" or "sand-sifting stars."

One of the more remarkable behavior aspects about these animals is that they are often found in pairs.

The Sex Life of Archaster typicus!

Since, their earliest discovery in 19th Century, this has been a point of interest in this species. Its since been documented as a case of pseudocopulation. Behavior that optimizes fertiliziation of the species.

A classic study by Run et al. (1988) in Marine Biology based on one species, A. typicus from a Taiwanese population revealed many SEXY starfish dynamics!

1. The pairing behavior occurs during a separate season from spawning season. Pairing occurs in early May, peaks in May-June and decreases in July, ending in August.

Gonads are REALLY swollen during this period! (just before spawning!).

Pairing leads to fertilization...the whole pairing/fertilization process takes about 2 minutes.

2. The actual SPAWNING occurs about two months after the pairing!
3. Density and movement of populations in Archaster both increase during "pairing season".

show a higher tendency for movement under these circumstances.

4. Archaster shows immediate sex recognition when individuals are side by side. Probably
owing to chemotactic recognition.

5. During the PAIRING: When a male FINDS a female..there is a behavior pattern that looks like this (aka the Archaster Kama Sutra!!):

6. The female is ALWAYS on the bottom! Males are always on top!

Oddly enough, the "male on top" urge is SO strong that male on male pairings, including male-on-male-on female "piles" of Archaster are encountered!

One of the interesting points is the measure of something called the Gonad Index, which is a measure of the ratio of the weight of the gonad to the body shows that the male GI is LOWER for males then for females!

There is thus the suggestion that a great deal of energy is used by the male relative to the female.. Possible uses of that energy?
  • The movement and "mounting and pairing" behavior itself is more energetically expensive
  • The females on the bottom can eat and store energy from the food. Males on top are isolated from their bottom food sources and can only feed on whatever happens to be on the aboral surface of the female.
  • While females are covered (i.e., protected) by males, being on top, males are exposed to air, sun, and the low tide (i.e., dessication) which is more stressful.
Whew! I'm all sweaty!

Go here for MORE Pseudocopulation! Ophiuroids! Asteroids!

Tuesday, February 3, 2009

Japanese Science Fiction: Monstrous Asterozoan Kaiju!

Today I present to you:
The Japanese Monster-Starfish Collision!!
Perhaps one of my favoritest things in the world is giant monsters: Godzilla!, Ultraman!, giant robots, big massive things that destroy stuff! Threaten the world! etc.

Japan, as one of the most creative countries in the world, has created a whole GENRE of films, TV and media that feature big monsters (called kaiju for 'mythical beast' in Japanese) and aliens (called seijin in Japanese) (and did I mention the guys in rubber foam suits??) as both antagonists and protagonists. Japan is also a country that is creatively inspired by the animal life living around it. Two of their emperors were marine biologists (and taxonomists to boot!).

So, it should come as no surprise that the two paths should cross....Here are some of the most prominent echinoderm-(mostly starfish) inspired creatures from Japanese science fiction!
1. The Starfish Aliens from "Warning From Space"

Oddly enough, I have never seen this movie the whole way through..but basically its about a bunch of starfish-seijin who try to warn the Earth about an impending disaster.

Starfish as the saviors of Earth.

I like it!

2. The Monstrous Pestar from Ultraman
From the 1960s classic Japanese show Ultraman (about a giant Silver giant alien who comes to Earth and fights monsters) is Pestar! The kaiju from the episode "Oil SOS" !!!
Pestar was two parts starfish, along with a BAT head stuck to it in the middle. It breathed fire and destroyed oil refineries!

Plus, it gets turned into a BUNCH of action figures:
(taken from someone's completely random collection! really!)
Some of which, glow in the dark!!

3. The Bizarre Brittle Star
Deimos from Ultraman Leo!
Now, WHERE will you ever find someone who can make a monster out of an ophiuroid?

Ultraman Leo was a later incarnation of the successful Ultraman show
, which ran from 1974 to 1975. He fights a host of monsterous beasts, many of which take after marine life!

The six rays are perhaps inspired by the tropical six-rayed brittle stars Ophiactis savignyi or Ophiothela which would be found in the tropical regions of Japan??

Here for comparison is the giant tropical ophiuroid Ophiarachna incrassata! Which I wrote about awhile back...

4. Hitode murasaki (purple starfish) from the show "Kikaider" Kikaider=good guy with cool half blue/half red costume who fought evil monsters every week. These monsters typically had an animal theme and acted as the "boss" to a bunch of evil minions.. having some gimmick or power that made him the special menace of the week...

The sinister "Purple starfish" could apparently fly and leap over walls! Not a common adaptation seen in your garden variety echinoderm...

5. And of course......

Starfish Hitler!!!
(I'm not kidding-that's what he's called!) from Kamen Rider X -a popular Japanese franchise about motorcylce-high kickin' cyborgs!!! In Japanese the name is more alliterative: Hitode Hiteru

I really don't know how to top Starfish Hitler.

Monday, February 2, 2009

When Starfish Eat TOO MUCH!!

Perhaps one of the unique qualities one sees in starfish is their propensity to devour things that are actually BIGGER then their own mouth and disk....

If one thinks about it, these are the ONLY echinoderms that are known to uh..."overeat"
(from Monty Python's Meaning of Life..."would you like a wafer-thin mint?")

Here's a few..
The Paxillosida. A group of starfish that live in unconsolidated substrate (i.e., mud or sand) with an according suite of morphological characteristic adaptations to match, for example:
  • pointed tube feet and spines for digging
  • papulae (gills) protected by spiny, dumbell-shaped plates
  • and so on...
One of the peculiar aspects of the paxillosidan lifestyle is that they either lack or have a reduced, whereas most eat by extending that stomach over something?

Many paxillosidans SWALLOW their prey whole!

This is like saying "That food never touched my lips-I just tossed it right in!" that's the joke a paxillosidan would be telling at the water cooler with the other starfish.

1. Luidia superba.
One such animal is a widespread "sand star" called Luidia, which inhabits shallow water tropical to temperate habitats all around the world. We've briefly discussed other Luidia species on the Echinoblog in videos (and videos here also)and etymologically....

Here's one really cool species from the East Pacific..specifically, the Galapagos-
Luidia superba. L. superba is one of the world's LARGEST starfish
and apparently, is caught en flagrante delicto with a big Encope grandis sand dollar in its gut!
Maybe they suck on them the way we chew on gum, lollipops or ice cream bars?
2. Proserpinaster neozelanicus
In 1999, Helen Clark and Geoffrey Read described the presence of polychaete "quill worms" in the gut of P. neozelanicus, a frequently encountered astropectinid (also a Paxillosidan starfish).
These worms (Hyalinocecia spp.-fam. Onuphidae) have realy distinctive rigid, tubes. The stars eat the juicy worms inside but the tubes stay in the body...

That's kind of like eating christmas candy with the candy boxes STILL ON THEM and keeping them inside your GUTS and BODY spaces and stuff!!

They would totally stick out of you at weird angles. And sometimes they do...
The Forcipulatida

This is a very different group that includes familiar species such as Asterias (the common Atlantic starfish) or Pisaster (the common purple or ochre starfish).
In contrast to the paxillosida, forcipulatidans have cardiac stomachs but some species EAT a lot....

1. Rathbunaster californicus
A multi-armed starfish which lives off the west coast of North America in relatively deep-water.
Prey? Lots.. They can feed on crustaceans swimming by and are voracious predators that eat just about anything that they can get their arms and mouth around (yes that sounds dirty..just deal with it)....

One such prey item?? The irregular spatangoid sea urchin, Brisaster latifrons:
Shown here as the COMPLETE prey item of a very hungry Rathbunaster!! The test has been completely swallowed and sits in the mouth (i.e., the disk)!!

So, in this pic? We are looking at the oral side of the mouth.

The hairy/spiny stuff at the center is the sea urchin.

The rows around the edge are where the arms would connect to the disk. Here's a side view for persepctive...
2. Pycnopodia helianthoides
Finally..a story from 1973 by Don Wobber, (Veliger 16(2): 203-204) who did his work at my alma mater-San Francisco State University!
He reports a peculiar phenomenom wherein the sunflower star, P. helianthoides, were fed common market squid-Loligo opalescens.

We see the "pens" of squids (i.e., the leftover hard parts in the squid body) sticking up through the body wall (shown in the pic above) and eventually were thought to be ejected OUT of the aboral body wall!!
(pic shows "pens" sticking out through body wall)
He even reports that some other species of starfish might actually push the "inorganics" from their meals out through the TOP of their body THROUGH the "top" (i.e., aboral" surface)!!!