Archive for the 'Stomatopods (Mantis Shrimp)' Category



Aww, I hurt Squid-Man’s delicate feelings

PZ Myers, my original science blogging hero, was disturbed by the video I posted (gloatingly) of some Stomatopod on Cephalopod ass-whooping.

You know, the rotten little crunchy, jointed thing wouldn’t have stood a chance if he’d been fighting within his own weight-class. I found this video on a blog called Arthropoda — a clearly biased advocacy site for violence on molluscs by the world’s dominant, bullying metazoans. -PZ

OK, let’s give the squishy a size advantage over my favorite mantis shrimp, Hemisquilla californiensis.

Ha-Ha! Run for your life, softy!

Seriously though, I am very suspicious of that video. The octopus seems lethargic and completely uninterested in the mantis shrimp. I get the feeling that the filmmakers are constantly pushing the octopus back towards the burrow as it is trying to get away.

Regardless, the score is still:

Maybe this will make the Tentacled-One feel better though…

NOOOOOOOOOooooooooo......... Photo: Roy Caldwell

We don’t get to see for certain that the mantis shrimp in that photo gets eaten. Personally, I imagine a Rocky IV-style, final round recovery from the crustacean.

Unlucky Octopus

Check out this brutal video from Roy Caldwell’s Lab at UC Berkeley. It shows the ‘interaction’ between a mantis shrimp (Odotodactylus scyllarus) and a blue-ringed octopus (Hapalochlaena lunulata), when the latter is introduced into the mantis shrimp’s tank. Both of these animals occur amongst coral reef rubble in the Western Pacific, so it’s possible that they often meet in the wild. Take a look at what happens when they do…

Well, that didn’t go so well for the unfortunate octopus. Take that, squishies!

It’s unknown how the stomatopod copes with the venom of the blue-ring as it kills and devours the cephalopod.

You can learn more about keeping your own murderous mantis shrimp at Roy’s List.

Why Stomatopods are Awesome, I: Super Strength

Stomatopods, or mantis shrimp, are an exceptional order of marine crustaceans made up of over 500 species that live in a variety of benthic habitats around the world. They are aggressive predators that actively seek out their prey with an advanced suite visual and chemosensory organs. Stomatopods are immediately distinguished by a pair of enlarged raptorial appendages located ventrally, near their heads. Stomatopods use these appendages as their primary means of predation, as well as for digging in substrate, defense, and intraspecific sparring.

The appearance of the raptorial appendages varies from species to species as they are evolutionarily specialized for capturing or killing distinct prey animals. The raptorial appendages can be deployed at lightning speeds, and with tremendous force relative to the size of the stomatopods; which can range from under 2 cm to 40 cm body length. Depending on the species, these appendages can be employed to smash, spear, or grab their prey.

Here are video examples of “smasher” and “sprearer” stomatopods in action:

Odontodactylus scyllarus smashes the shells of mollusks and crustaceans.

Lysiosquillina maculata ambushes swimming fish and crustaceans, spearing them out of the water column. Click through to Youtube to see this one.

Since the 1960’s, a series of research has unraveled the speed, power, and mechanics of the stomatopod’s astonishing attack.

Continue reading ‘Why Stomatopods are Awesome, I: Super Strength’

Arthrophoto: Lysiosquillina maculata

This photograph is amazing for a litany of reasons beyond its aesthetic composition. The mantis shrimp in the shot is Lysiosquillina maculata. This is the largest species of mantis shrimp, reaching at least 16 inches, eyes to tail. The photographer, Laurent Ballesta, has caught the animal mid-strike, as it lunges out of its burrow at lightning speed, extending its raptorial appendages to spear a passing fish. You can purchase a book of underwater photography by Laurent Ballesta, here.

Here is an extreme slow motion video of this same species lunging for a piece of meat in a lab. Also, check out this excellent video of Sheila Patek discussing her work on the mantis shrimp’s strike.

Slalomopod

Every year, my biology department throws a holiday party that includes a ornament contest. The only rule is that the ornament must be constructed entirely out of lab materials. My lab-mate came up with this awesome skiing stomatopod (mantis shrimp).


Creationists love mantis shrimp

My graduate adviser and some of his collaborators recently published a paper in Nature Photonics, about the efficiency of the natural quarter-wave retarder used in the mantis shrimp’s circularly polarized light detection system. The paper got a lot of play in popular press (because mantis shrimp are awesome), including a write-up by the “prestigious” Institute of Creation Research (ICR).

Too be fair, their article actually starts off better than most of the popular science writing about these animals. However, after the fifth paragraph it takes a nose-dive into a mire of fairly typical creationist misconceptions and misdirections. The downward spiral begins with heaping helping of “living-fossil” nonsense.

“The mantis shrimp is also one of many examples of “living fossils”―creatures that have not changed over supposedly vast evolutionary time spans. Some modern mantis shrimps are exactly the same as their ancestors that were fossilized in Devonian strata, which have been assigned an astounding age of 400 million years. The odds of this creature remaining unchanged for that length of time are fantastically remote.”

*Facepalm*

No biologist claims that mantis shrimp have remained unchanged since the Devonian. Mantis shrimp diverged from other crustaceans around the Devonian. Here is a comparison between a fossil and modern mantis shrimp.

Sure they share some superficial similarities; similarities also shared with thousands of other malacostracan crustaceans. However, these are different animals, with different morphologies and ecologies.

Take, for example, the raptorial appendages (red arrow). The raptorial appendages in modern mantis shrimp are massively enlarged maxillipeds (mouth-parts). They are highly specialized and used for predation (I will post in depth about this at some point). You can see that the fossil proto-mantis shrimp does not have an enlarged set of maxillipeds. It took hundreds of millions of years for them to evolve to their modern glory. This evolutionary modification of the first maxillipeds is obvious in the fossil record.

The ICR continues,

“And the odds of nature having constructed the world’s most complicated eyes so soon after the “Cambrian Explosion” of life, only to have left them perfectly alone ever since, seems counter-evolutionary.”

The eyes, like the raptorial appendages, obviously did not reach their full complexity when the mantis shrimp diverged in the Devonian. They also took hundreds of millions of years of evolution to develop from their proto-typical form into their elaborate modern design. There is nothing “counter-evolutionary” about the mantis shrimp eye.

“This research had little to say about the origin of the mantis shrimp eye, but it is clear that such high design demands a high designer.”

*Double-Facepalm*

Argument from incredulity? Check!

Evolution builds complexity, the currently unknown is not unknowable, and just because we haven’t figured a particular detail out yet doesn’t mean we are going throw our arms in the air and give up. “Vision is complicated and science is hard, therefore God did it,” is a pitiful capitulation.

“While the source of mantis shrimps’ rarefied level of vision is unclear to evolutionists, other researchers, who are not convinced that nature is the only explanatory option for ultimate origins, suspect that the exquisite level of specificity, elegance, and effectiveness in the mantis shrimp vision system testifies to the unsurpassed level of the Creator’s genius.”

*Barf*

The source of stomatopod vision is not unclear to evolutionists. It is obviously the modified product of a suite of evolutionarily conserved visual pigments and optical components. These components are closely related to those in other crustaceans, slightly less related in other arthropods, and present (in some form) in all animals.

Also, I would like to know who these “other researchers” are. I am fairly well immersed in the mantis shrimp literature; it is not a huge research community. Nowhere have I heard a researcher present evidence or submit speculation that mantis shrimp are anything but the product of evolutionary processes. These “other researchers” are not studying the mantis shrimp visual system. They cherry-pick research from real scientists, and throw a creationist spin on it. Actual researchers do not doubt the evolutionary ancestry of the mantis shrimp visual system.

Creationists love mantis shrimp for one of the same reasons that I love them: because they are complicated. Creationists see this complexity, reported to them by actual researchers, and having done no work of their own, declare victory. Scientists also love mantis shrimp for their complexity. They offer unique and exciting opportunities for further research. Research in genetics, evolution, biomechanics, visual ecology, and neurobiology.

Tomorrow, countless scientists will go into their offices, labs, observatories, and field stations. They will work to better understand our world, and communicate that understanding with others. Scientists are driven by the ecstasy that comes with discovery, and they need not doubt that, “somewhere, something incredible is waiting to be known.” -Carl Sagan

Arthrophoto: Pullosquilla thomassini

Photo: Michael Bok

Here we see the female (pink) and male of the stomatopod species Pullosquilla thomassini. These tiny mantis shrimp live as monogamous pairs within burrows on marine sand flats. The males “spear” prey from the water column and share it with the females who tend the eggs below.
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I have moved.
Arthropoda can now be found here.

Michael Bok is a graduate student studying the visual system of mantis shrimp.

Flickr Photos

Fire in the Eye

View from atop South Island

Turtle and remora

Lizard Island lagoon panorama

Coral

Wind surfer over the reef, taken from atop South Island

Another Lizard Island Sunset

Odontodactylus latirostris

Mandarin

Lowest tide I have seen at Lizard Island  (-0.11 m)

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