Calcareous Stuff, Part 2.
Richard L. Howey, Wyoming, USA
I warned you at the end of my last essay/gallery on calcareous bits that there would likely be a follow up because there’s just so much to cover. This time we’ll focus on echinoderms and then see if we have any space left over or if we need to go on to a third part.
Let’s begin with a couple of examples of types that people often think of as “typical” sea urchins (echinoids). The first sample is one which is covered with hundreds of small spines which gives the misleading impression that it might be fuzzy to touch. Pseudoboletia maculata.
However, another common type is one which has relatively few, but much larger, spines and is definitely not something you would have the remotest interest in trying to stroke. This Prionocidaris baculosa (australis?) Which as you can see has rotary stripes on the spines which are quite intriguing.
These are more interesting in closeup.
And more interesting yet is a closeup where they are still attached to the urchin.
Over and over again, we need to remind ourselves that all of these structures are essentially modified chalk.
Bizarre as this may sound, I’ll now, in typical P.T. Barnum style, show you chalk symbiotic on chalk. In food rich tropical oceans, virtually every space is one that can serve as a potential home. And, as startling as it may seem, sea urchin spines of certain species can come to serve as “homes” for a surprising number of organisms; just look at the barnacles on this tropical cidaroid urchin.
In addition to barnacles, I have found tiny mussels, tiny brachiopods and even a couple of tiny brittle stars with their “arms” tightly wrapped around the spine.
However, some spines are hard to wrap around as evidenced by those of Psychocidaris ohshimai.
Nonetheless, one might think that there are so many bumpy bits that these would be ideal places to attach, yet of the dozen specimens I have examined, I have found no hitch hikers.
That wondrous trickster, Mother Nature, is constantly reminding us of how much we don’t know.
In this view, they look a bit scruffy, but overall relatively clean. But let’s examine a closeup.
Oh what a difference bit of magnification makes! There’s stuff (to use the strict scientific parlance, crud,) all over these spines. As a matter of fact, they’re loaded with micro-algae, diatoms, forams, and sponges. If we don’t probe deeply enough and ask ourselves the right questions, we can end up missing entire micro-worlds.
An important thing to remember is that not all infestations are created equal and sometimes you’ll find quite different invaders. Here’s a specimen of the same species, which is relatively “clean” apart from 3 intriguing little brachiopods.
As one progresses, one begins to get the feeling that the oceans are giant seas of chalk. Let’s look at some more progressively heavy-duty examples. Any naturalist who has spent time around tidepools is certainly familiar with barnacles and from the cuts and scrapes one may have acquired, one may not be as enthusiastic as Darwin was, who wrote extensively about them. He spent 8 years studying them and wrote 2 volumes about living forms and another 2 volumes on fossil forms.
Mollusks are repositories of significant amounts of calcium carbonate from lovely, delicate examples up to the giant clam (Tridacna) which can weigh up to 450 pounds.
A splendidly beautiful little shell is the Epitomium (?) Or Wentletrap which is a Dutch word meaning spiral staircase. Every naturalist should have one in his or her collection. I bought several and gave them to special friends.
Another “must have”, from my eccentric point of view, is a specimen of Tibia fusus with it’s long spike. I guess it’s sort of a molluscan narwhal.
Perhaps one of Nature’s little jokes; I can’t imagine 2 of these dueling or “chasing” after prey to impale it .
Now, some might chastize me for encouraging naturalists to seek out lovely and exotic specimens and give me a stern lecture on endangered species and imperiling the planet. First of all, I NEVER advocate collecting any endangered species. If a few hundred people, and especially young people, can be dragged away from their not-so-smart phones, iPads, and game consoles to collect, examine and perhaps even study such minor miracles of nature, then they should be strongly encouraged. Their discovery of the beauty of nature might end up contributing to saving the planet. Furthermore, none of the organisms I recommend are endangered. Also, there is the consideration that we have already thrown things out of balance in such a way that some organisms have become invasive as is now the case with the purple sea urchin along the Northwest Coast of the United States where they are systematically stripping and destroying the underwater kelp forests which provide a habitat for many species of organisms. Because of short-sighted regulations, they can only be removed by hand by divers and this can make only a tiny dent in the urchin overpopulation. So here is a case where educational and research institutions should be volunteering to collect these organisms to use for instruction and experimentation and, at the same time, benefit the kelp forests.
Well, before you got me off on a tangent, I was commenting on How Tibia’s ornamentation is puzzling in terms of benefit. An even more expreme case is to be found in the Venus Comb or Murex pecten. Just look at this magnificent domicile and tell me that you don’t want one in your collection.
It does certainly have the advantage of creative advertising–Hey, you, try to eat me and you’re going to get a very painful mouthful to remember.
Another very elegant mollusk which is quite pleasant on the outside, hides most of its elegant and extraordinary mathematical beauty internally. This is the chambered Nautilus and I’ll show you a specimen where the shell has been sawn in half. This is something you’ll want to try at home only if you have exceptional high-tech equipment for sawing or a set of hand saws and the patience of Job.
Next I’m going to show you a lovely white abalone shell, 2 views, outer and inner.
Rather elegant objects, aren’t they? But, do you know that there are barbarians who use them as ashtrays? Vile creatures who fill their lungs with filthy smoke and then extinguish their butts in these lovely objects. Can you believe it? Such decadence! Such aesthetic depravity! I only smoked for 30 years but, in that short time, I never once used an abalone shell as an ashtray.
Then there are the true giants, Tridacna, which can weigh up to 450 pounds. Now, obviously, there are quite a few pounds of meat in that calculation and apparently some species have been used as food, but it is apparently not al all common and not something you can order at your local Fish-Filet Café. The accounts that Tridacna are man-eaters are complete mythology. Occasionally a hapless or stupid diver may have become trapped in one, but that’s something altogether different. However, getting back to the calcium carbonate, with creatures like these, it’s a wonder that there’s any chalk left over for blackboards.
So, let’s move on to some other more modest examples of creatures with chalky parts. Those of you who like poking around seashores have very likely come across chitons which have 8 dorsal calcareous plates. There is the large “gum boot” or Cryptochiton which has its plates embedded in tissue, so, if you want to see them, you have to dissect them out. Fortunately, however, there are species of a more manageable size disposed to display their calcareous wares without requiring us to undertake the tedious task of dissection. I shall present you with an image of what I like to call the “pink fingernail” chiton.
Now, can you believe, I offered to extract, isolate, and clean 2 such chitons for the pink plates and then glue them onto my wife’s fingernails for her but she was NOT pleased! I just don’t understand. I’ve also thought up another idea. I don’t know whether some people eat chitons or not but, I’ve thought up this idea for a terrific franchise and, if you want in on the ground floor, just let me know. I’m going to call it–The Crunchy Chiton Café –now, that’s got to be a winner.
As it turns out, there are lots and lots of other creatures out there that have varying degrees of crunchy bits, so let’s take a quick glance at a few more. Here’s a closeup of the oral aspect of a brittle star. Just look closely at all of those little spines along the arms.
Now , that already suggests a fairly heavy calcium carbonate load in a single specimen, but there’s much more. A highly instructive exercise is to take a good-sized specimen, place it in a jar of Clorox and dissolve out the tissue. This may take several replenishings of fresh Clorox solution and then a number of rinses in distilled water using a very fine-meshed sieve to keep from losing any of the calcareous bits. The distilled water rinses are essential to avoid crystals from forming on the specimens you want to observe. When I first did this experiment, I was stunned by the number of pieces I extracted–hundreds and hundreds. My sister and her husband are jigsaw puzzle fans, so I boxed the pieces from my experiment up and sent them to them for Christmas along with a magnifier and a note that read “The Ultimate Jigsaw Puzzle”. No, I didn’t; I’m not that cruel and besides, I didn’t want to give away my hard-earned specimens.
We haven’t even begun to exhaust the calcium in echinoids, so I”ll show you one more that you will certainly have to admit is an eccentric configuration of chalk.
This is Goniocidaris and these little cups or “inverted umbrellas” can be habitats for other creatures. I have found small sponges, wee tube worms, clusters of forams and even a tiny clam.
All of this calcareous stuff and we haven’t even gotten to starfish yet, so perhaps there will be yet another part concerning them and some other chalky denizens of the sea.
All comments to the author Richard Howey are welcomed.
Editor's note: Visit Richard Howey's new website at http://rhowey.googlepages.com/home where he plans to share aspects of his wide interests.
Published in the June 2020 edition of Micscape Magazine.
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