Posts Tagged ‘molluscs’

Because we know we can’t be found

12 October 2011

In case you missed it, today marks the end of Cephalopod Awareness Day 2011. I cannot decide if it is comedy or tragedy that the cephalopod who garnered the most awareness this week is one that probably never existed. “Triassic Kraken” has already entered the hyper-meta phase: here is a reaction to the reaction to the reaction to the early “reporting” on the story.

But amidst the orgy of credulity, incredulity, joy, anguish, laughter and rage (and whatever this is supposed to be), it struck me that something was missing. I have seen loads of skeptical remarks from vert paleo types, and certainly we are well suited to critique the work, but it seems nobody thought to ask the opinions of those that have studied the middens left behind by living octopodes.

So I did.

I fired off a list of questions to two midden experts, Dr. Richard Ambrose and Dr. Jennifer Mather, both of whom have published multiple papers on the topic of octopus middens. Both were incredibly gracious in providing detailed and thoughtful replies within hours.

My interest here was not whether McMenamin’s scenario is realistic. Clearly it is, at best, wild and highly imaginative speculation.

But I was interested whether it might be feasible to identify octopus middens in the fossil record. How we might identify vertebrate victims of cephalopod predation? And, leaving aside the whole “self-portrait” thing, is it really feasible that a giant bathypelagic squid would be exhibiting behavior associated with shallow water octopods.

In short the answers seem to be: 1) “Probably” 2) “Hard to say” and 3) “No.”

Both Dr. Ambrose and Dr. Mather were kind enough to allow me to share their comments:

Probable example of an octopus bite mark on fossil bivalve shell from Harper 2002.

me: What are the prospects of successfully identifying octopus middens in the fossil record (i.e. are they permanent enough features that they would be likely to be buried by sediment, and would they be readily distinguishable from storm deposits)?

Richard Ambrose: I think middens could be discovered in the fossil record.  Depending on the species, octopuses may den at the same location for a considerable time (“considerable” being relative, since octopuses are semelparous and most species live only a few years at most; even the giant Pacific octopus probably lives only 5 years or so) and they would continue to deposit midden items as long as they occupied the site.  Moreover, good denning sites are often limited, so even once on octopus vacated the den site another would be likely to take up residence, further building up the midden.  When we are looking for middens while diving, we focus only on the recent midden items because these are whiter and more conspicuous, but I would not be surprised to see an accumulation of midden items over many years.

Of course, many midden items are dispersed by currents.  For example, we rarely find many crab exoskeletons because they are easily swept away by currents.  Depending on the location, even heavier items like clam and snail shells can be dispersed.  So for the middens to enter the fossil record, you would need some event, like dramatic sedimentation associated with a storm or perhaps an undersea slide, to preserve the items in place.  But this is not inconceivable, especially after a storm.  I do think they likely could be distinguished from storm deposits.  Although storms might deposit a concentration of shells in one area because of local topography, most items would be widespread over the storm-affected area.

Jennifer Mather: Prospects would probably be good, some but not all fossil remains get buried in soft sediment.  Distinguished from storm deposits would be possible.  First they might have drill and chip marks on the shells–chips on clams, drills on clams, snails and sometimes crustacean claws.  Drill holes of cephs are tiny, too and specifically placed (Marion Nixon did a lot on that).  Not all shells are drilled or chipped, though.  Second, they WOULD NOT be broken.  Cephs have partial digestion externally, they scrape and digest out the soft parts leaving a disarticulated set of crab shell pieces or empty clean mollusc shells. Shell collectors prize octopus middens. So a midden would have a nice complete collection of crab parts, for instance, and if it was in soft sediment and got buried quite quickly, it might get well preserved. I remember watching the ‘fate’ of the eight blue shells of one octopuses chiton meal.  They slipped down the pile and slowly got buried, when I exhumed the whole thing much later, the blue winged shells emerged one by one, very well preserved and with a drill hole in one valve.

me: Assuming vertebrate remains would not show the drill holes characteristic of shelled prey, what signs could we look for to indicate cephalopod predation?

RA: That’s true, only shells are likely to show indisputable evidence of octopus predation.  (Octopuses also “drill” crabs, but those would be quite perishable.)  For vertebrates, they would just eat the flesh.  There might be some dis-articulation, but the fish eaten by the octopuses I’ve kept in the lab were not pulled apart, so I don’t know how common that would be.  So it would be very hard to find marks or other characteristics that would indicate consumption by a cephalopod.  There might be scrapes from the beak on bones, but I’ve never looked at/for these and I would think they would not be very distinctive.

Octopus midden from Flickr user Steven Severinghaus - Creative Commons 2.0

me: How widely distributed is midden building behavior among octopus species? Has it evolved more than once? Is it known from deep sea or pelagic species?

RA: This is really the key issue, I think.  Midden building is very common among octopuses, but it seems to me that it is most likely a simple consequence of their denning behavior and the fact that they often (but not always) bring food back to their den for consumption.  Hence, they discard prey items outside of their dens.  There is some manipulation of discarded food items and other items – like rocks – by octopuses in their dens, most often to close or partially close the opening to the den.  But I’ve never noticed anything like a systematic arrangement of items as a means of communication (like some birds do, such as bower birds) or artistic expression – no self-portraits that I’ve ever noticed, despite the intelligence of the species I’ve studied!  Note: this is not to say that something like communication through prey discard items isn’t possible.  I could see how it could evolve (and maybe that would be something to look for!), I just don’t know of any examples of it occurring.

So, as far as I know midden formation is likely to occur anytime octopuses den in one place for any period of time.  This is restricted to relatively shallow water octopuses.  Even then, most octopuses living on soft bottom habitats would not produce dens under most circumstances.  Deep sea octopuses and pelagic species do not, as far as I know, take shelter in dens or produce middens.  This makes sense; there are no caves or holes in the deep sea, for the most part.  Especially any species that would forage widely, like up in the water column, would have little reason to return to a particular place to eat.

I know of no examples of non-octopus cephalopods (squids or cuttlefish) producing middens.  Cuttlefish closely associated with reefs might be a reasonable candidate for producing middens, but I have never heard of this. Any cuttlefish or squid living in the water column would be extremely unlikely to produce middens.

JM: Middens aren’t really built.  Octopuses do build ‘walls’ of rocks in front of the home.  But when they eat prey at home, they just push out or blow out with a jet of water, or leave shell remains in the home. It’s more like a garbage heap.  We don’t know a lot about octopus species, we’re particularly short of field work.  However, midden remains have been assessed in the Mediterranean, the Caribbean and Bermuda, off the coast of Brazil and up the Pacific coast of North America (these are published papers, there are probably other assessments). My guess is that it evolved fairly early in the ancestry of octopuses, it’s likely widespread because all you need is a sheltering home and the habit of tossing your trash out.  It is limited by topography, remains aren’t found where there is a strong current, they obviously get whisked away. Middens are NOT found in pelagic species because there is no place to put them, squid do not make middens and cuttlefish probably do not either.  Deep sea octopus species might, it depends on what they find to eat.

Images

Top – Illustration from Victor Hugo’s Toilers of the Sea (1888 Crowell Edition).

Middle – Figure from Elizabeth Harper (2002) “Plio-Pleistocene Octopod Drilling Behavior in Scallops from FloridaPalaios 17:3 292-296 DOI: 10.1669/0883-1351(2002)017<0292:PPODBI>2.0.CO;2

Bottom – Photograph from Flickr user Steven Severinghaus – Used under Creative Commons 2.0.

Flippant

14 September 2011

Deep in some dream last night, I flip a rock and reveal an isopod the size of a silver dollar. Excited I snatch her up to show somebody, I cannot say who, but as I walk the crustacean ebbs to standard lilliputian proportions. Or maybe it’s my hands that are growing.

This all sounds pretty Jungian, or maybe worse, and I suppose soil is the great collective unconscious of terrestrial ecosystems (huh?)

But I guess I’m just a little haunted for not making more of International Rock-Flipping Day 2011.

I did get the chance to turn a few stones. As it happened, some of the same stones as when I first observed the holiday four years ago. Not surprisingly, more or less the same crowd turned up. Minus a weevil, plus a planarian.

Here I count representatives of no fewer than six independent invasions of land, not even counting the plants or fungi — nor the vertebrates which, apart from myself largely didn’t show. Hunkered beneath the twenty million-year-old fossilized shell of a bivalve, one clade that never made it out of the water in any respectable way. Sort of crazy.

Totally forgot the most important part:

Permanent Ink

24 January 2010

squidink_1464882c
Which reminds me…

I meant to write about this when it was news.  Now it’s olds, which suits me fine.

Copy of Pearce's restoration of Belemnotheutis, re-drawn by Colin Stuart from Donovan and Crane (1992).

I.  The drawing above is of the extinct Jurassic cephalopod Belemnotheutis antiquus. In fact, it’s a fairly exact replica of a drawing made by Joseph Chaning Pearce who first named the genus in 1842 (shown at left).  Pearce may have intended to name the fossil Belemnoteuthis (teuthis=Gr. squid as in teuthology study of cephalopods), or he may have intentionally used a variant spelling.  Either way, Donovan and Crane 1992[pdf] argue that the original published spelling should stand according to the rules of taxonomic nomenclature.  Historically, Belemnoteuthis(sic) has been widely used and Richard Cowen has described Pearce’s original spelling as “barbarism.” Nevertheless there it stands: a possible typo enshrined into taxonomic priority.

II.  Engineering icon Isambard Kingdom Brunel, was the vision behind the construction of the Great Western Railway which linked London by rail to south west England (including the Jurassic Coast) and Wales during the 1830s and 40s.  Around 1840, rail workers constructing a line near the village of Christian Malford stumbled across incredibly well preserved fossils some of which were collected and studied by Pearce.  The site was eventually flooded and forgotten for more than a century and a half before it was rediscovered by British scientists just a few years ago.

III.  Which, the focus on all those new reports about that featured this drawing wasn’t mainly on the historical quirks surrounding the image or name at all but concerned instead the historical quirks surrounding the origin of the ink which is: FREAKING BELEMNITE INK!

Ink from a well-preserved Belemnotheutis, dead for 165 million years or so, was reconstituted and used to draw a copy of one of Pearce’s original drawings.

IV.  Which is really cool, but not nearly as unique as you might expect.

Joel Segal Books Blog does a nice job of putting fossil cephalopod ink into proper historical context, borrowing an image from my sidebar, a painting of Ichthyosaurus made by Henry De la Beche in 1834 using FREAKING BELEMNITE INK!

From Clary (2003)

Credit where it’s due: I nicked the picture from the doctoral dissertation of Renee M. Clary (2003) which explores the pioneering role De la Beche played in using imaginative visual aids to convey geological and paleobiological information.  Mandatory reading for anyone interested in the history of geology, the use of illustration in the earth sciences or the development “paleoart.”

Preserved ink sacs of fossil cephalopods - from William Buckland's Geology and Mineralogy with respect to Natural Theology (1836).

In fact, De la Beche was just one of a number of 19th century scholars and artists that messed around with reconstituted fossil ink.  In his “Bridgewater Treatise” Geology and Mineralogy with respect to Natural Theology (1836) William Buckland illustrated (so far as I know, with conventional ink),  the well-preserved ink sacs from several fossil cephalopods.  In that same work, Buckland gives an account of one of the earliest artistic experiments using fossil cephalopod ink:

Elizabeth Philpot, the often forgotten friend and associate of Mary Anning who is a central character in Tracy Cevalier’s recently published novel Remarkable Creatures, is also said to have painted with “fossil sepia” and sometimes credited with being the first to do so.  Other enterprising residents of Lyme are said to have followed suit painting  in an effort to cater to the burgeoning tourist industry fueled by Victorian fossil fever and the construction of the Great Western Railway.

I’m not sure whether any of the illustrations made by Chantrey, Philpot or their followers have survived, I haven’t been able to turn any up aside from De la Beche’s ichthyosaur.  Unlike the De la Beche drawing, other vintage fossil ink works might not be clearly labeled as such and could easily be sitting in a private collection or a museum forgotten and unrecognized.  Philpot’s or Chantrey’s original works, most likely long gone, would be priceless historical gems of the finest order.

V. Fossil ink makes literary cameos in the work of Jules Verne and the poet Martin Farquhar Tupper.  It also turns up in one of my favorite essays of all time, Thomas Henry Huxley’s “On the Method of Zadig”:

“No amount of physiological reasoning could enable any one to say whether the animal which fabricated the Belemnite was more like Nautilus, or more like Spirula. But the accidental discovery of Belemnites in due connection with black elongated masses which were: certainly fossilised ink-bags, inasmuch as the ink could be ground up and used for painting as well as if it were recent sepia, settled the question; and it became perfectly safe to prophesy that the creature which fabricated the Belemnite was a two-gilled cephalopod with suckers on its arms, and with all the other essential features of our living squids, cuttle-fishes, and Spirulæ. The palæontologist was, by this time, able to speak as confidently about the animal of the Belemnite, as Zadig was respecting the queen’s spaniel. He could give a very fair description of its external appearance, and even enter pretty fully into the details of its internal organisation, and yet could declare that neither he, nor any one else, had ever seen one.”  Thomas Henry Huxley “On the Method of Zadig” (1880)

VI.  Pigments, paints, dyes and inks come either from dead organisms or minerals, and so all have some biological or geological story to tell.  The case at hand straddles both categories, which seems unique until you remember the ubiquity of “synthetic” inks distilled from petroleum that is the remnants of marine organisms, dead and buried for millions of years.  That might include some of the ink used to run the Belemnotheutis newspaper stories, unless British newspaper printers have all switched to soy-based inks like their U.S. counterparts.  Your keyboard and mouse are probably made from sea animals.  If you print this post out (which I can’t imagine why but just go with me here) the ink you use, and perhaps the energy to do it, are quite possibly the byproducts of long dead phytoplankton.

VII.  And as long as we’re talking autochthonous/authigenic art, I have to mention Matt Celeskey’s work with 200+ million year old Triassic charcoal.  Matt, in turn, turned me on to Alexis Rockman whose “field drawings” use site-specific pigments themed around of both living and fossil ecosystems ranging from the Burgess Shale and La Brea Tar Pits to Fresh Kills landfill.

VIII.  Here then for almost no reason except that I like the picture is Brunel, posed beside the launching chains of the SS Great Eastern, whom Brunel affectionately called the “Great Babe.”  The ship will experience a steam explosion, killing 5, before being repaired, sent across the Atlantic as a passenger vessel half-a-dozen times nearly sinking once before being converted to cable laying ship and laying the first Trans-Atlantic telegraph cable, later converted into a floating music hall and promotional gimmick and eventually broken up and sold for scrap.  Which has nothing to do with anything.  Like I said, I just like the picture.

And if you made it this far without being tempted by at least one of those hyperlinks, I can’t help you.

PZ Myers Signed My Squid

22 January 2010

Loligo opalescens (click for hi-res version)

“I just need one whole squid.” To his credit, the fishmonger did not bat an eye.  Even better, he gave it to me free of charge.

Later, before the talk, I confessed, “I have a mollusc in my pocket.” “Me too!  I have a limpet that’s been in there for 2 years.”  “Neil’s is a bit fresher than that.”

Later, “Oh no. What have you done?” saith PZ Myers,  “This almost feels wrong.” (I’d like to report he said ‘sacrilegious,’ but he didn’t.)

“What are you going to do with it?” asketh PZ, “Are you going to eat it?”

“Well, it’s been sitting in my pocket for a few hours”

“I wouldn’t recommend eating it then…”

Wise words from a wise man.  Likewise when he compared Ray Comfort to an incompetent sphincter.

The squid is in the freezer with Spike the water monitor.  I think I’ll name it PZ Jr.

Research Publication Figure of the Week (1 week late)

21 April 2009
Figure 3. from Hagadorn and Seilacher 2009 - original caption: <i>Figure 3. Cartoon model of hermit arthropod with a crustacean versus chelicerate mode of abdominal bending. Model is not intended to represent details of track maker's anatomy.</i>

Figure 3. from Hagadorn and Seilacher 2009

What an interrogative week, huh?  National Geographic mused, koanically, “First Tool Users Were Sea Scorpions?” Discover’s online news mashup engine 80 Beats pondered, prosaically, “Did ‘Hermit’ Sea Creature Hide Under Borrowed Shells in First Forays Onto Land?”  Neither of which really even approach the telegraphic glory of Hagadorn and Seilacher’s rhetorical paper title “Hermit Arthropods 500 million years ago?” which appears in this month’s issue of Geology.

All of which would seem to beg the same answer, because the only thing more badass than a sea scorpion is a sea scorpion with a van!

Ref.
Hagadorn, JW and A Seilacher 2009. “Hermit arthropods 500 millon years ago?” Geology 37(4):295-298

Mmm…protoconch…

15 September 2008

Molluscs: let’s face it they’re delicious.  If there wasn’t a local folk tradition in Anhui that eating a gravid snail is an auspicious event it would be necessary to invent one.  Uh, such tradition that is.

Which reminds me: UCMP scholar Jan Vendetti has a blog about food in Japan, and studying snails in Japan, though not necessarily about studying gravid food snails in Japan.

Also, Os Mutantes are hawking Happy Meals, forty years later !?!? WTF!!!

When Animal Memes Attack!

29 September 2007

The last time I got tagged with a meme…well Decimating Birds: Episode V is coming any day now. I swear.

Now Brian has tagged me with the “Cool Animal Meme” that’s been racing around the interwebs like a Chinchilla on crystal meth. So…here it goes (I’ve broken things down by vert and invert so I could squeeze a bit more in):

An Interesting Animal I Had
vertebrate:

Tex

Interesting is certainly one way to describe Clyde. He has acres of personality and makes some of the strangest noises I’ve ever heard come from a dog. Here are three videos of Clyde interacting with a log in Tomales Bay (which he liked), a hawk feather, and a snake skin shed (both of which he did not like).

invertebrate:

A couple of springs ago I brought in a mantis egg case from the garden and put in on our window sill. I watched it carefully for a couple of weeks then promptly forgot about it. A couple of months later, while enjoying a cup of coffee, I glanced over at the sill and saw this:

I set most of the hatchlings free, but kept one which survived until about Christmas. My manticulture experiments this year didn’t fare so well, I accidentally left the container open and the mantis fled. Oh, well there’s always next year…

An Interesting Animal I Ate
vertebrate:

Okay, this is going to sound weird. Bobcat.  Let me explain (not that it will help)…

When I was a kid my dad hit a bobcat on the way home. Always one to seize an opportunity, my father threw the cat in in the back of the pickup with the idea of salvaging the pelt (which is still around some place). We also got a fair amount of venison this way. My dad also cooked up some of the bobcat meat because, you know, why not?

I don’t remember what it tasted like, but my dad sent me to my mom’s house with a little tupperware of cooked bobcat meat. This of course, totally freaked out my mother (which was surely my father’s intention) but my mom’s pot dealing/gourmet chef landlord raved “It tastes like filet mignon!”

invertebrate:

I’m a bit ashamed to admit that I’ve never intentionally eaten a terrestrial arthropod. We did have an “invertabrate dinner” at the end of my invertebrate biology course but all of the goodies were of the marine and/or molluscan persuasion. I can’t say I’m terribly fond of land snail, but fried conch is delicious.

Probably the tastiest invertebrate eats I’ve had was in El Rocío, Andalucía. After rolling into the dusty Spanish town we parked next to a hitching post and walked down the dirt roads till we found a little tapas bar, complete with horses hitched outside. We ordered up a round chipirones: whole baby squid with garlic and lemon. You had to pick the tiny beaks out of your teeth. Washed down with a cold bottle of Alhambra..yum!

With the prospect of doing field work in Southern China, I imagine my interesting animals I have eaten list is set to grow considerably.

An Interesting Animal In The Museum
vertebrate:

whale.jpg

Photo by Sam and/or Sophie from here.

This one’s easy. This juvenile blue whale from the Göteburg Naturhistoriska Museum is surely the most pimped out whale mount on the planet. I tweaked the photo a bit to try to expose the interior a little better, here is how the museum website describes it:

The great blue whale which was preparated in 1865, is exhibited beside its own skeleton and other whales and seals in “Valsalen”. This 15 meter long baby whale is the only stuffed blue whale in the world! Its jaws can be opened, and once a year you can inspect its inside with its wooden floor, flowered tapestry and mahogany benches.

I guess we had good timing because when we visited the whale was open and we climbed on inside, Jonah-style. Being inside a large animal is rather surreal, but I have to say, with the handsome wooden benches and the upholstered walls, the inside of a whale is far cozier than either the Bible or Pinocchio would have you believe.

invertebrate:

Explorit’s giant cave cockroaches (Blaberus giganteus) are pretty fun to share with kids and especially parents. They are much more lively than the hissing cockroaches (though I like them too). They secrete a mild vinegary chemical predator deterrent and are freaking huge.

An Interesting Thing I Did With Or To An Animal
vertebrate:

My first ever field biology project at eight or nine, was to tie colored thread to the wrists of toads to try and track their movement and figure out how many individuals were living in our yard. I have no recollection of the results although I do remember recapturing several.

invertebrate:

I’ve done some interesting things to the cave roaches. They have wings but they can’t really fly. However, they can flutter their wings to glide to the ground when tossed in the air. They can also use them to flip back over when they are put on their back. I know, it seems mean, but think about what most people do to cockroaches.

An Interesting Animal In Its Natural Habitat
vertebrate:

Well, I don’t really remember this, but when my parents were first bringing me home from the hospital it was a rainy, bleak day. On the way home they spotted a sodden Golden Eagle walking alongside the road. In true hippie fashion they promptly gave me an ‘indian name’: ‘Walking Eagle.’ Here’s the tattoo I have that commemorates that moment:

 

Eagle

 

A few years ago, when I was working as an intern at Fossil Butte National Monument in Wyoming I had my most memorable Eagle encounter. I was prospecting for Eocene mammal fossils in the Wasatch Formation. As I came over the crest of Cundick Ridge I came face to beak with an Eagle roosting on a rock. I was probably several meters away but it felt like I could have reached out and touched it.

My heart skipped a beat as I stood there awestruck and paralyzed in the presence of this gigantic bird.  After what felt like minutes, but must have been a split second, the eagle casually leapt off the rock into empty space, unfurled its wings, beat them twice and sailed off. It was out of sight in a few moments, replaced by a few stray fluffs of down slowly tumbling down the cliff.

invertebrate:

Again, it’s tough to pick just one.  Finding adult ant lions with kids this spring was pretty awesome.  And lately I’ve become obsessed with scorpion hunting.  Most recently I got a big kick out of seeing an octopus while exploring tidepools in Cambria.  None of the photos turned out really well but this was the best of the lot (its the brownish thing center left).

In that eerie way that often happens with exciting animal encounters, I somehow anticipated the whole thing.  As I watched hermit crabs and bat stars I had this ‘octopodial’ feeling. But I certainly didn’t expect to see one of these cryptic masters of disguise, even though I knew that they were probably around.

I was leaning over to examine a chunk of blueschist or something, when I heard a  sudden squirt and turned to see a fist-sized cephalopod inching away.  It morphed from a deep red, to brown, to almost black then back to brown.  I got a short video, you can hear the excitement in my annoying nasal drone:

I still wish I had picked it up, damn it.

Okay, I spent waay too much time on this.  It seems like everyone and their mom has already picked up this meme.  But I’d be nice to see what Carel has to say after he gets back from his blogging vacation.

Oh yeah and Jessica of the brand new blog Inorganics should give it a shot, although I’m predicting some overlap!