Archive for August, 2011

More Scaphopod Information – Including Some Ancient Scaphopod Jewelry

Friday, August 26th, 2011

 Scaphopod Connections

Over the past few days, I have finished scanning my images of Native American scaphopod jewelry and decorated clothing, all of which were photographed in 1987 in the Burke Museum on the University of Washington campus in Seattle.  Some of the Native American dentalium jewelry/clothing images that I have are REALLY impressive, not only for the wealth they contained, but also for the tremendous skill of the remarkable women who made them.  Somehow, I wish I could find something like the shawl in the image below in an old trunk in my garage, and take it to the appraisers on The Antiques Roadshow.  It would get the attention it really deserved.  Ah… well.  All I am likely to find in old trunks in my garage is old trash covered in old dust.

 A shawl, made by a seamstress and master craftswomen from one of the Plains Tribes, in the mid-to-late 19th century.

This is a shoulder wrap or some sort of vestment, I neglected to photograph both sides in 1987, when I took the image.  I would estimate that there may be close to a 1000 Antalis pretiosum shells in this item.

Not surprisingly considering their shapes and durability,  scaphopod shells were widely used in ornamentation elsewhere and elsewhen throughout history.   The following image was taken by Don Hitchcock in from the Dolní Věstonice Museum in the Czech Republic, which has some wonderful artifacts recoverd from an ice age mammoth hunter’s site.  

dolniimg_2014b

A reconstructed necklace made from fossilized Dentalium badense shell fragment artifacts recovered at the Dolní Věstonice site in the Czech Republic.  The artifacts at this site have been dated with Carbon-14 to about 29,000 years ago.  Photo: Don Hitchcock donsmaps.com

In one of the more bizarre coincidences I have had recently, I found the above image and information with the assistance of Mr. Google and associates.  I hadn’t seen it prior to findinig on the web, but I knew that there should be ancient European, Asian or African dentalium work illustrated somewhere on the web, and charged ahead to find something I might use.  I found this image, and it fit the bill of what I wanted, and I went to track down some information about it, including where the Dolní Věstonice site (which, from reading the information at the site, I realized I must have read about it sometime ago, I recollected nothing at all about it ) is located. 

This Google Earth image shows where the Dolní Věstonice site is located.  The other site indicated, the Frydek-Mistek region, is  where my ancestors, at least back to before the mid-1700’s, lived. !!!  My great-great-grandfather was one of four brothers that migrated together from this area to the US (Texas) just after the Civil War.

Nobody knows, of course, what happened to the descendents of the people who made and used the scaphopod shell necklace, or even if they left descendents at all.   But I think it could be possible -stretching possibilities very thinly- if those descendents remained in that area, that maybe some of the genes of the person who made the scaphopod necklace may have decended to be in the genome – some 28,000 years later – that directed the growth of my scaphopod-studying body.

In closing this entry, I must thank Don Hitchcock for his gracious permission to use his fine image of the scaphopod necklace.  Don has an immense array of web information about the paleolithic period throughout the world, and I have linked to his site in my blogroll.  It is well worth a visit.

Until later,

Cheers,

Scaphopods

Thursday, August 18th, 2011

Where

Recently I started scanning my images of scaphopods, an animal group from which very few people have seen living animals.  I did a lot of research on them actually starting about 1975, and becoming intensely active in 1983 and finally winding down about 1997.  I still have a paper or two to write but I haven’t done any field work in a long time.  I described two deep-sea species (1, 2) from specimens sent to me, but most of my work has been done on the scaphopods found in the shallow waters of the Northeastern Pacific.  Scaphopods are particularly common in many of the fjord environments north of the Strait of Juan de Fuca.  I spent some small amount of time examining their distribution in the waters of Northern Puget Sound, particularly in the northern American San Juan Islands.  In this area, two species of scaphopods, Rhabdus rectius and Pulsellum salishorum are found, and may be reasonably common in a few areas.   There a couple of marine research laboratories/field stations in that region, but as far as I know, I am the only person in the last half century who has worked at one of those labs and done any kind of research on scaphopods.

During the period from 1981 until 2003, I taught at various times at a Canadian marine station located in Bamfield, British Columbia, situated on a small inlet on the southeast side of Barkley Sound, a large fjord system on the west side of Vancouver Island.  This marine laboratory, known as the Bamfield Marine Station from its beginning in the 1970s until it morphed into the Bamfield Marine Sciences Centre in the early 2003, offers easy access to some of the scaphopod habitats of the Barkley Sound region.  For the two-year period from September of 1983 until September of 1985, I was the Assistant Director of the marine station, and actively carried out an intensive project on scaphopod ecology and natural history.  Subsequent to that time, I worked up data collected during that period, as well as initiating other scaphopod work, mostly with specimens sent to me by various researchers.   As a result, I have published about a half dozen research papers on scaphopods, and have a couple of more in the works… if I can only get my act together enough to finish them.

The Critters

Scaphopods, or “tusk” or “tooth” shells are mollusks that live as subsurface predators in the marine sandy or muddy sea bottom.  Covering an estimated 60% of the planetary surface, this is THE largest habitat in on the planet’s surface.  As the scaphopods are either abundant or dominant predators in this habitat, that makes them some of the most ecologically important animals. 

By last count there are about 8 to 10 people living today who have published papers on scaphopods, which may make them the most understudied of all important marine animals.  Given that a number of those people are museum workers whose entire conception of the Molluscan Class Scaphopoda is that it is a collection of oddly shaped shells, it is evident that the world-wide scientific interest in the group is probably so close to nil as to be statistically indistinguishable from it.

This means that to a very real extent, that anybody who works on scaphopods as a full, or even part-, time venture is on their way to committing, or has committed, scientific/academic suicide.  While it is true, to paraphrase one of my old profs, “If only five people work on your group, you can’t be ranked any lower than the fifth most prestigious worker on the group.” 

However, if only five people work on your group of interest, it means nobody will care what you write.  So, the good side is that everybody working on the group knows who you are. On the other hand, nobody else in the world – or known universe – cares who you are or anything about the animals…  If there is so little interest in group worldwide, no matter how good your publications are, they will simply disappear into the large black cesspool of unread papers as nobody will care about you write.  

Well, who am I to argue?  I will state, however, in my defense, after that statement that I am the senior author of the definitive reference about the animals published to date:  Shimek, R. L., and G. Steiner.  1997.  Scaphopoda.  In:  Harrison F., and A. J. Kohn, Eds. Mollusca IIMicroscopic Anatomy of the Invertebrates. Volume 6B: 719-781.  Wiley-Liss Inc. New York, NY.  ISBN 0-471-15441-5.   Whooopty-doooo…

 

Five species of Scaphopods found in the Barkley Sound region of Vancouver Island, British Columbia, Canada.  The scale bar is in millimeter.

From top to bottom, Pulsellum salishorum, upper two rows, females on the left, males on the right, next single row, Cadulus tolmiei, female left, male right, below that species is a single row of two Gadila aberrans, female left, males right, The next two individuals are Rhabdus rectius, female on the top, male on the bottom, and the lower-most individual is a single specimen of Antalis pretiosum (formerly Dentalium pretiosum), the “Indian Money Shell.”  These individuals were alive at the time, and in the high definition of the moment, the top four species have shells that are thin enough to be translucent, and the gonads from each gender are differently colored, so I could discrimate the sexes.  It is hard to see in the low res image here, but if you look at the top animals on the left, you can see a hint of pink in the shell, and that is the color of the ovaries of Pulsellum salishorum.

Heretofore…

Scaphopods were very economically important animals in the North American native cultures.  Given the common name of the “Indian Money Shell,” one species, at one time called “Dentalium pretiosum,” was collected and traded throughout large parts of Northern North America.  Here is an image from a National Geographic Magazine article about the trade; I was a technical advisor to the NGM for that article.  The scaphopods were harvested in by some of the tribes from the Pacific Northwest, both in what would become Canada and the U.S.  There are numerous “tales” about how the shells were collected, and at least two different and likely ways of collecting them.  Knowing what I found out about the habits of that species (now called Antalis pretiosum), it appears that very few of the actual living animals were collected, but rather shells containing small hermit crabs the primary source of “scaphopods.”  There is a hermit crab in the region were the scaphopods are found that is not coiled to fit into a snail shell as are most hermit crabs, rather this one, Orthopagurus mimumus, has a straight body and lives preferentially in the large “dentalium” shells.  The crabs crawl around on the surface of the habitat, while the living animals are generally deeply under the surface, at least a foot (30 cm) below the water/sediment interface.  In fact, the living scaphopods all have a rapid burrowing response – an exposed scaph is a dead scaph – as crabs and fish eat them.  In text books and references, they are often illustrated as having their pointed ends exposed from the sediments, and some are found this way,  between1 in 60, to 1 in about 10,000 depending on the species I have looked are exposed at any one time.   So much for the standard references…  More about why this should be so in my next issue of this blog.

Anyway, one of the more recent “proofs” of the hypothesis that it was mostly dead scaphopod shells inhabitated by hermit crabs that were collected actually comes from one of the National Geographic Magazine sites.  They have a series of images purported to be Antalis pretiosum, all of dead scaphopod shells taken by David Doubilet, and  all showing hermit crabs showing hermit crabs in the shells.  Doubilet was apparently in search of the wily dentalium and, by golly, he got some pictures of it… or at least of its shell.   Interestingly enough, there is an image also on their site showing Antalis pretiosum feeding below the sediment surface.  This wonderful image is a painting by Gregory A. Harlin, and it clearly shows that scaphopods don’t have legs…  Of course, Doubilet didn’t look at the painted image.   One further note that adds even more humor to this bit of fubardom (fubar = fucked up beyond all recognition) is that Harlin’s painting was done for the previously mentioned earlier article in NGM about the dentalium trade for which I was a technical advisor.  Harlin based his painting on my drawing of Rhabdus rectius feeding below the sediment surface that was used in Shimek and Steiner, 1997. 

A diagram of Rhabdus rectius shown in its feeding posture below the sediment surface, drawn in life from animals in aquaria. Compare with the painting by Gregory A. Harlin,

The dentalium shells collected on the coast were traded through out North America, at least as far east as the Great Lakes and were quite valuable.  They were used in the construction of jewelry and as ornamentation on clothing.  I have read, with no real estimate of the validity of the statement, that one or two of them could be exchanged for a tanned buffalo hide.  Consider that when you look at the image I have imbedded below.

 

Plains Indian neck ring jewelry in the collection of the Burke Museum,University of Washington, Seattle, Washington.

It has been reported, that given that the shells of the animals were quite valuable, it stands to reason that the one of the first things the Europeans did (in the guise of the Hudson’s Bay Company) was to “devalue the currency” by flooding the market with “counterfeit” shells.  When the HBC traders began to realize how valuable the shells were, they sent word back up the communications chain, and European shells were harvested in some relatively great numbers.  The European species, Dentalium entale, is/was essentially identical to Dentalium pretiosum and easily collected (and remember, both are now in the genus Antalis).  These were sent to HBC traders throughoutNorth America and used to purchase all sorts of trade goods.  So many shells became available that this sufficiently brought the value of the shells down so low as to make them worthless as trade goods for the coastal tribes as they could not harvest enough to get the traditional materials (such as buffalo robes, and they became dependent upon the HBC to sell them blankets).  If this is true, it is a great (?) lesson in market economics…

More on scaphs later….

Until then…

Cheers, Ron

 

Gastropteron

Monday, August 8th, 2011

Although they look like they are nudibranchs, the two snail species featured in today’s posting are surely not nudibranchs, even if one is kind of sluggish in form and fashion.  The larger of the two, Gastropteron pacificum, is a bubble shell, meaning it has a shell that looks quite like a soap bubble and it is about as durable.  When sitting on the bottom, the animal is about the size of a grape.  The sides of the animal’s foot are expanded into two long lateral lobes that are normally folded up over the animal, but virtually nothing of the animal is normally visible as it is generally covered in a mucous sheet which, in turn, is covered by sediment particles.  The animal looks like a lump of mud on a bottom that is covered in lumps of mud, and so this is pretty good camouflage.  

Gastropteron pacificum, a stationary lump of pseudo-mud. The pink structure is a fleshy, tubular, siphon that brings in breathing water. 

Gastopteron pacificum individuals are found frequently in the spring in waters of the North American “Pacific Northwest” and if a diver ventures into its gorpy, mucky, muddy habitat – otherwise known when I was working in these areas, as a “Shimek study site” –  one can often see the trails left by these little guys as they move around, presumably in search of food or a mate. 

Gastropteron pacificum, leaving a trail in the mud as it crawls from there to here.

They are probably detritivores, as they are reported to eat detritus and diatoms in the laboratory, but I am not sure what they eat in nature, and neither, to the best of my knowledge, is anybody else.  I don’t think they have been studied in any detail which, if true, is quite a pity as they are neat little critters.  When something startles them – a diver (me) in my case for the photograph, or the presence of a bottom-feeding fish, such as the ratfish, Hydrolagus colliei, the little snail unfolds its foot flaps and flaps away.  They are quite strong swimmers and this appears to often be an effective escape response.  

Hydrolagus colliei

This “rat fish,” or “chimerid,” is a cartilaginous-skeletoned fish but obviously not a shark.  Individuals in this particular species can reach about 70 cm (28 inches) in length. Rat fishes are some of the most common predators in the soft-sediment ecosystems of the NE Pacific, and some of my unpublished data indicate they feed on mollusks, annelids, and echinoderms. 

A Gastropteron pacificum individual.

This little animal is swimming away from the most fearsome and horrific predator of all, a diver – in this case, of course, me.  I was sensed, probably by my water disturbances, and it then took off, and stayed waterborne for about 2 minutes.  Although Gastropteron swimming appears to be undirected, given the currents in the region, it will likely cover some distance before it quits swimming and falls back to the bottom.

If the Gastropteron is successful in its life, it find a good friend and they will do the snaily version of the “wild thing” resulting some time later in the deposition of some jelly-like “egg masses” attached to the bottom.  These are filled with small fertilized eggs (zygotes) that develop within the misnamed egg mass, which eventually dissolves releasing the larvae into the plankton. 

A group of Gastropteron “egg,” actually embryo, masses. I don’t know if all of these are deposited by one individual or if they aggregate during spawning to deposit the jelly-like masses (many snails in this region do form spawning aggregatations).

However, they don’t get a break!  There is a small sacoglossan slug, Olea hansinensis, in the area that searches out and eats the eggs of Gastropteron and its relatives.    

Olea hansinensis.

This is a small sacoglossan slug that eats eggs of cephalaspidean snails, such as Gastropteron.  This one was about 3 mm (1/8th inch) long, but larger individuals are said to reach about 13 mm, or half an inch in length.

More later,

Until then,

Cheers,