Thursday, February 28, 2013

The Adventure of the Unobservant and Unseeing Collector and the Lion's Mane

You see, but you do not observe.  The distinction is clear.

~ Sherlock Holmes to Dr. Watson in the story
A Scandal in Bohemia

Fossil hunting is often a series of small mysteries and bits of deduction.  Apparently, for me, it may also be periods of failing to see or observe.

In the middle of February, I went down to the Chesapeake Bay in search of microfossils and a bit of winter.  I hoped I would find a blast of frosty air sweeping off the waters.  I’d had enough of the false winter that had settled on my part of the mid-Atlantic region with little snow and temperatures that were much too bearable.  The flocks of robins that stayed in my neighborhood these past few months have forsaken their role as the heralds of spring, they’re becoming just another of the usual local avian denizens during the winter.

I prowled the beach for just a couple of hours.  I thought I’d failed to find any real trace of winter, but I successfully discovered some middle Miocene fossil bivalves that had come out of the Calvert Cliffs with both valves intact and filled with matrix.  Such sandy clay is often rich in foraminifera and ostracode shells (very roughly 13 to 15 million years old).  Articulated shells of the mollusks Chesapecten and Glycymeris were bagged for the trip home.

Then I saw two long, narrow pieces of fossil bone lying neatly atop a block of gray clayey matrix at the edge of a large expanse of slump that had come off the cliff.  A mystery.  The beach was deserted and had been all morning, so I deduced that these slivers of bone had been placed here in the past day or so by someone who had been digging through the slump.  Had he or she considered them to be just random shards of whale or dolphin bone?  Had they been set out on this piece of matrix as a gift to the next collector with low enough standards to add them to his collection?  Or, better yet, as an offering to the fossil gods?

Actually, I have come to think that the unknown hunter who preceded me hadn’t closely observed these bone fragments which, it turns out, are pieces of jaw neatly lined with empty, relatively uniform tooth sockets.

I couldn’t resist.  I pocketed them (low standards?).  As far as I'm concerned, jaw sections with extant tooth sockets are relatively scarce along this part of the Bay because the bone tends to break along the socket line which marks a weakness in the fossil.  These fossils came from one or two Miocene homodonts (animals with homogeneous teeth), most likely dolphins.  To provide some context to my fossils (not necessarily to suggest an identity for the animal from which they came), here is a picture I took of the skeleton of Xiphiacetus sp., a middle Miocene dolphin apparently from the Calvert Cliffs, on display at the Smithsonian’s National Museum of Natural History.  I’ve attached a close-up of a portion of the jaw to the image of the full skeleton.

 Later that morning, in sand on the water’s edge, I came upon a worn fossil vertebra, also possibly from a dolphin.  This is evidently from a juvenile animal because I observed a distinctive pattern on the end (seen in the picture below) which is the signal that the epiphysis or growth plate is missing, that it never fused with the vertebra.  Such fusion occurs when animals reach maturity.  The vertebra is also missing most of its processes.

I think that it was only as I turned to work my way back up the beach, that I really paid attention to some patches of something faintly tinted red and pink drifting along in the wash.

Jellyfish!  Those harbingers of the dog days of summer along this coast, those scourges of bathers, those floating gelatinous globs of stingers and stomachs.

What, in heaven, were they doing here on the Bay in the middle of February?  Another signal of a climate gone haywire, seasons knocked out of whack?  That was certainly my conclusion.  I was fully convinced that I’d never encountered them in my past mid-winter treks to the Bay.  The jellies on the Bay in the winter joined the lingering robins as my new stories of the effects of climate change.  The jellyfish pictured below is perhaps 5 inches across.  

 But, in all likelihood, I was wrong about this.  In past years, I probably not only didn’t observe, I didn’t see all that was around me as I wandered these beaches in winter.

As Holmes explains to Watson in A Scandal in Bohemia, the foundation of his deductions is seeing and observing.  To illustrate the “clear distinction” between the two, Holmes continues, “For example, you have frequently seen the steps which lead up from the hall to this room.”  Watson says that, of course, he has.

            “Then how many are there?”

            “How many?  I don’t know.”

“Quite so!  You have not observed.  And yet you have seen.  That is just my point.  Now, I know that there are seventeen steps, because I have both seen and observed.”

I don’t know what Holmes would make of a fossil hunter out on the beach who fails not only to observe, but apparently even fails to see.  Certainly not ask him to write up his cases as Holmes asks Watson immediately after telling him he is unobservant.

Upon returning home, I turned to Life in the Chesapeake Bay by Alice and Robert Lippson (3rd edition, 2006) and looked up jellyfish.  Not unexpectedly, topping the list was the “infamous stinging sea nettle,” Chrysaora quinquecirrha, which often plagues Bay beaches during the summer, but disappears in the fall after spawning, its fertilized eggs having developed into minute larvae which drift to the bottom, attach themselves, and develop into polyps.  These wait for the temperatures of spring to release the medusae that will then grow into the nettle form we know and love.

I was quite shocked to see that number two on this list was Cyanea capillata, known as lion’s mane or winter jellyfish.  These are the Bay’s jellyfish during the winter and they’re not just a marginal thing either.  According to the Lippsons, the lion’s mane jellyfish can be “as abundant in the Bay as sea nettles, but it occurs only during winter and spring months.”

It troubled me initially that pictures of lion’s mane jellyfish that appear on the web generally bear only a passing resemblance to the organisms I spotted on the beach a couple of week ago.  They differ often as to color (somewhat) and size (markedly).  So I consulted a professional marine naturalist who, based on the photo I provided, confirmed that what I’d encountered was indeed Cyanea capillata.  The Lippsons do note that the lion’s mane jellies can come in various sizes, and that further north in the Atlantic, they are larger, apparently living up to their names by sporting extremely long and dense tentacles, and becoming more like the model of a lion’s mane jellyfish which graces (terrorizes) the Smithsonian Natural History Museum’s Sant Ocean Hall (seen below in my picture).

According to the National Geographic, the lion’s mane jellyfish can reach a diameter of some 6.6 feet across with tentacles stretching out more than 49 feet.

I have to assume (with some reservation) that all of these past winters, the lion’s mane jellies have been decorating the beaches but they’ve never registered in my mind – apparently they were unobserved and unseen, and I was unobservant and unseeing.

This isn’t quite like stairs.  Unless he is singularly disconnected from reality, Watson couldn’t have replied to Holmes, “I assume there are stairs up to these rooms because I manage every day to get from the ground floor up to here.  I just don’t ever remember seeing them, so clearly I don’t have any idea how many there are.”

Have I been so disconnected?  Probably, but, I still wonder if perhaps this winter really is different.

Failure of sight, observation, and, indeed, memory.

It is appropriate at this juncture to turn to another Holmes mystery, one late in the canon, The Adventure of the Lion’s Mane.

This is only one of two stories narrated by the great detective himself.  He does a rather poor job of it, while revealing that, as he has aged, his memory has begun to fail.  The mystery is a singularly weak one, spotted with half-hearted red herrings that fail to suggest plausible alternatives to what has clearly happened.  (Belated spoiler alert:  Oh, yeah, I guess I’ve already given away the solution to this mystery.)

Holmes, now retired to a house in Sussex with a view of the Channel, solves the murder of Fitzroy McPherson, science instructor at a nearby educational institution.  One morning, McPherson, who despite a heart condition is a vigorous swimmer, staggers up the path from the beach and collapses in sight of Holmes.  On the verge of death, McPherson summons the strength to speak

. . . two or three words with an eager air of warning.  They were slurred and indistinct, but to my ear the last of them, which burst in a shriek from his lips, were ‘the Lion’s Mane.’  It was utterly irrelevant and unintelligible, and yet I could twist the sound into no other sense.  Then he half raised himself from the ground, threw his arms into the air, and fell forward on his side.  He was dead.

Oh, yes, “utterly irrelevant and unintelligible.”  (“Pay no attention to that man behind the curtain.”)

That his body is covered with welts, as though he has been whipped, only serves to deepen the mystery (hmmm).  To stir the pot a bit, Conan Doyle drops in red herrings and clueless police:  McPherson’s dry beach towel; a fellow teacher at the school who seems to hate everyone and who has had a falling out with McPherson; the local constabulary which is, as usual, utterly befuddled; some love notes between the dead man and a woman in the nearby village; and the woman’s father and brother who seem totally capable of murder over her affair with McPherson.

As the story progresses and Holmes eliminates all of the prime suspects, he struggles with the sense that something vital to the mystery lies buried somewhere in his memory.  He asserts that his mind holds a “vast store of out-of-the-way knowledge without scientific system, but very available for the needs of my work.”  Well, perhaps not so available, because he also admits that his mind’s “like a crowded box-room with packets of all sorts stowed away therein – so many that I may well have but a vague perception of what was there.”

So much for seeing and observing.  This is the Trivial Pursuit method of crime detection.  Of course, the missing little fact comes to Holmes, sending him off in a desperate search of his library for a particular volume.  With that nature book finally in hand, he solves the mystery and the monstrous, villainous jellyfish, found in a pool along the beach, is summarily dispatched.

Certainly not an adventure about seeing and observing.  For some reason, I don’t feel so bad about missing (if I did) the Cyanea capillata all these years.

Wednesday, February 20, 2013

Another Voyage of Discovery ~ A Review of Richard Corfield's The Silent Landscape

In which the blogger reviews a very good book and ultimately wanders off to join the American Miscellaneous Society.

On February 21, 1873, the HMS Challenger could have been found dredging and taking soundings at 24º 20′ N, 24º 28′ W, about 538 miles southwest of the Canary Islands and some 604 miles from the west coast of Africa.  From the bottom, some 2,740 fathoms (3.1 miles) below the ship, the dredge brought up red clay.  The recorded water temperature on the seafloor was 2º C.

The Challenger was a small vessel, about 2,300 tons displacement and 200 feet long.

The illustration above is from Sir Charles Wyville Thomson’s published account of the ship’s time in the Atlantic Ocean during the voyage.  Wyville Thomson was the lead scientist aboard the ship, heading a staff of five other scientists.  (This and all other images in this blog post are taken from The Voyage of the “Challenger”:  The Atlantic, A Preliminary Account of the General Results of the Exploring Voyage of H.M.S. “Challenger” During the Year 1873 and the Early Part of the Year 1876, Volume I,  1878.)

On that day, 140 years ago tomorrow, the Challenger was in the first months of what scientist and writer Richard Corfield has described as
. . . the first great voyage of scientific exploration, sent out with no other purpose than the acquisition of knowledge.  It was a milestone in the history of humanity, when the importance of learning for its own sake was perceived, not just by a small intellectual elite, but by ordinary people as well.”  (The Silent Landscape:  The Scientific Voyage of HMS Challenger, 2003, p. 252 – 253.)

The voyage would take about three and a half years and, by the time it ended, on May 24, 1876, the vessel and (most of) its crew would have covered 68,900 miles circumnavigating the globe.  The results of that voyage of scientific discovery have echoed down these many years, helping to make and remake fundamental concepts in biology, geology, and oceanography.  Corfield avers that "its importance can hardly be exaggerated."

The Silent Landscape is Corfield’s fascinating, well told account of the voyage, but it is much more than that.  It’s also an accessible exploration of the scientific meaning of the voyage, covering an expansive range of scientific topics of fundamental importance for us today, including climate change, plate tectonics, and evolution.  (Though the book was published a decade ago, I've only just discovered it.)

The Challenger voyage, the product of a collaboration between the Royal Society (with Thomas Huxley at the helm) and the British Admiralty, was undertaken to explore the deep oceans worldwide.  To that end, the scientists on board systematically and regularly gathered such information as depth and temperature, analyzed the chemical composition of sea water at varying depths, determined the makeup of deep seafloor deposits, and examined the organic life found at different depths, including the ocean floor.  (The Silent Landscape, p. 4-5.)

Thus, dredging, such as that undertaken on February 21, 1873, was a crucial activity on the mission, and it occurred often.  The map below shows where and how often the bottom was dredged and soundings taken (perhaps some trawling as well) during the Atlantic crossing in 1873.

Each time muck from the bottom was brought to the surface, it was pounced upon by the Scientifics (as the team of scientists was called by the crew).  Each "catch" from the dredge was analyzed in the labs and work areas that had replaced nearly all of the Challenger's guns (testament to the scientific focus of the voyage).  Depicted below is the ship’s natural history workroom.

As the ship moved across the Atlantic in early 1873, the Scientifics noticed dramatic changes in the material coming from the ocean floor.

Corfield’s discussion of this phenomenon follows his overall approach to the Challenger’s scientific discoveries throughout the book.  First, he sets the scene – where the vessel is located, what events might have punctuated the life of the men on board, and what the scientists were up to and finding.  Then he explores the understanding today of the science behind the discoveries, and often describes how that understanding was achieved.  It’s an eminently workable and successful framework for his book.

Immediately after departing the Canary Islands, the dredges had brought up the expected white mud from the seafloor, identified by the Scientifics as Pteropod and Globigerina ooze.  The former consisted largely of small mollusk shells; the latter was made up of tiny foraminifera shells.  Two views of a shell from the foraminifera Pulvinulina menardii are shown in the illustration below.  Wyville Thomson noted that this specimen was found at 1,900 fathoms.

But as the water’s depth increased, the nature of what came to the surface in the dredges changed, from white ooze, to gray, until a red clay appeared.  According to Corfield, the Scientifics observed that, during this crossing, Pteropod ooze marked shallow bottoms down to some 400 fathoms, and was succeeded by Globigerina ooze to a depth of about 1,500 fathoms.  At that depth, grey mud showed up, which was ultimately replaced by red clay when the depth reached 2,200 fathoms or more.

Corfield recounts that the Scientifics took a large step toward explaining this red clay phenomenon when they added a weak acid to the Globigerina ooze, revealing the presence of red clay as the shells dissolved.  As a result, they knew that the red clay marked the absence of the mollusk and foraminifera shells, not a new precipitation of red clay.  That was as far as they got.

At this point in his account, Corfield explains what we now know to be behind this phenomenon.  As ocean depth increases, the acidity of the water also increases until it reaches a point where the water is sufficiently acidic to dissolve the calcium carbonate shells of mollusks and foraminifera.  This is the calcite compensation depth “where the rate of calcium carbonate supply from the surface is balanced by the rate of dissolution so that there is no net accumulation of carbonate.”  (p. 63)  Corfield then describes the process accounting for the increase in acidity with greater depth.  [Later edit:  As the climate changes, this relationship between calcium carbonate shells and ocean acidity is playing out in a threatening way.  The increasing levels of carbon dioxide in the atmosphere contribute to greater acidification of the oceans which, in turn, directly affects shell-producing organisms such as foraminifera.  A recent study found foraminifera shells to be a third thinner than they were in the immediate past.  (Sean B. Carroll, "Nature's Masons" Do Double Duty as Storytellers, New York Times, June 25, 2012.)]

As he moves back and forth between the Challenger voyage to an explication of our current scientific knowledge, Corfield provides vignettes of the efforts of later scientists to whom we owe our contemporary understanding.  As a result, we readers learn of many “voyages” of discovery, from the work of Bruce Heezen and Marie Tharp whose creation of detailed maps of the ocean floor were crucial to showing that the seafloor was spreading outward from mid-ocean rifts, to the creation of the bathysphere by William Beebee and Otis Barton which took humans to ocean depths never before achieved and which sparked invention of mobile, powered deep sea exploration vehicles such as the bathyscaphe of August and Jacques Piccard.  Even when the Challenger bypassed the Mediterranean, it’s an occasion for Corfield to comment on a missed opportunity and explain what the Scientifics might have learned (in this case, that the Mediterranean floor reveals that some 5 to 6 million years ago, the Mediterranean, drained of all its water, was a salt encrusted desert).

The voyage was a dangerous experience.  Lives were lost, including one of the Scientifics.  But, it was also mind numbingly tedious.  Much of the time at sea was marked by days of boredom for the crew as the ship sailed a short distance and then engaged in the time consuming process of dredging, trawling, and taking sounds.  Over and over this process was repeated as the vessel circled the globe.

To get a flavor of what it was like to serve on the Challenger, I am currently reading the collected letters of one of the Challenger seamen, Joseph Matkin, the ship's steward's assistant.  (At Sea with the Scientifics:  The Challenger Letters of Joseph Matkin, edited by Philip R. Rehbock, 1992.).  It's a rare glimpse below decks.  Matkin makes clear the impact that the scientific nature of the voyage had on life at sea.  In a letter dated March 16, 1873, describing the crossing of the Atlantic, Matkin wrote, "We are 17 days from Teneriffe [Tenerife in the Canary Islands] today & expect to be there [St. Thomas in the Virgin Islands] in about 12 more days for we furl sails every day for 8 or 9 hours, & dredge, & take soundings &c which of course makes the journey much longer, & tedious."

Small ship, years at sea, not sailing to reach port, little sense of the big picture, no wonder fully a fourth of the crew deserted the Challenger during this voyage.  No one said doing science had to be comfortable or endlessly exciting.

Finally, I have to thank Corfield for introducing me to the wonderful, though short-lived, American Miscellaneous Society (AMSOC).  In his discussion of deep sea drilling efforts (the Deep Sea Drilling Project and its successor the Ocean Drilling Program) and their contribution to our understanding of plate tectonics and climate change, Corfield notes the crucial role played by AMSOC.  It organized Project Mohole (to explore the boundary between the earth’s crust and mantle) which was funded by the National Science Foundation, helping to foster subsequent deep sea drilling.

Although it has a clear connection to scientific work prompted by the Challenger exploration, AMSOC is a definite diversion for this review.  In some ways, it's a counterpoint to the dreary nature of much of the back breaking work that went on during that scientific voyage of discovery.  AMSOC is clever men of science having serious fun.  I love it.

AMSOC was the brainchild, in 1952, of Gordon Lill and Carl Alexis, two geologists working in the Geophysics Branch of the Office of Naval Research (ONR).  They founded AMSOC to deal with the many “miscellaneous” proposals coming to the ONR, proposals that didn’t seem to fit in any general category.  One author has described AMSOC as follows:
Any scientist who has business with ONR’s Geophysics Branch is likely to claim membership in the American Miscellaneous Society since there are no official membership rolls.  In fact, there are no bylaws, officers, publications or formal meetings.  Nor are there any dues, for funds are a source of controversy.  The membership is largely composed of university professors or scientific researchers but the rumor that only persons can be admitted whose research proposals to ONR have been turned down because they are too far-fetched is completely false – it is merely a coincidence.  (Willard Bascom, as quoted in Albatross Award of the American Miscellaneous Society, Scripps Institution Of Oceanography Archives.)
Indeed, it was summed up by one of its intimates as having been created "to see the lighter side of heavier problems."  (John Knauss, Gordon Lill, and Arthur Maxwell, Recounting the History of the Albatross Award, Eos, January 20, 1998.)  Its “members” took a non-bureaucratic, cut-the-crap approach to ONR proposals.  Corfield notes, AMSOC “existed solely to get things done.”  (p. 238).  That AMSOC created a “Committee for Co-operation with Visitors from Outer Space” and the “Society for Informing Animals of their Taxonomic Positions,” should certainly be viewed in its favor.

[Later edit:  Rereading the few sources out there about AMSOC and the confused passages I've written about it, I realize that I really don't know what it was - a joke that, for a moment (Project Mohole), became serious; an effort by a group of research scientists to actually "get things done" that was able to fly under the bureaucratic radar because of its cover of humor; or something else entirely.]

Sunday, February 10, 2013

Brachycythere ~ Learning the Lexicon

            King.  Let’s further think of this,
Weigh what convenience both of time and means
May fit us to our shape.  If this should fail,
And that our drift look through our bad performance,
‘Twere better not assayed.  Therefore this project
Should have a back or second, that might hold
If this did blast in proof. . . . .
Hamlet, Act IV, Scene VII

At present, I am struggling with two kinds of texts.  The first is Hamlet.  In the passage given above, the King plots with Laertes to fashion a fencing match, replete with a sharp rapier and poison, sure to lead to Hamlet’s death.  Though I know the context, I wasn’t quite sure of what the King is advising.  Fortunately, in my Folger Library edition of the play, each page of dialogue has a facing page with annotations, explaining obscure words or passages.

May fit us to our shape means “may suit our design.”
Drift is “intention” (ah, as in “catch my drift”).
Blast in proof, a great phrase, means to “fail in the trial.”

And, so, I draw from this passage (which in the final analysis really wasn’t so obscure) the following – Claudius, the King, almost thinking aloud, advises that they should seize the opportunity to carry out their plot when it presents itself, but should it not and their plan go bust, they need a backup.  [Later edit:  The King, I think, worries that they wont be able to carry off their ruse convincingly - "our drift look through our bad performance."]

In reading Hamlet once again, I am amazed, as always, at how the play speaks to me some four centuries after it was written.  Hamlet’s struggle to deal with his grief and to act decisively, to do what he believe he must (or is expected to do), given the dire knowledge he has discovered, still resonates all these years later.  Admittedly, reading Shakespeare requires some acclimating.  I have to slow down, pay closer attention to the words, and use the annotations.  At times, I think, “Yes, that certainly looks and sounds like English, but I’ll be damned if I can make any sense of it.”  The work to draw out the meaning is a small price to pay for admission to this great play.

Coincidentally, I have also recently immersed myself in the paleontological literature on Brachycythere ostracodes.  Species from this genus of minute crustacean can be found as far back as the Cenomanian Stage (99.6 to 93.6 million years ago) of the Upper Cretaceous Period.  The genus went extinct early in the Oligocene Epoch (33.9 to 23.03 million years ago).  (Terry Markham Puckett, Systematics and Paleobiogeography of Brachycytherine Ostracoda, Micropaleontology, Volume 48, Supplement 2, 2002.)

I am trying to develop some ability to distinguish among the shells of late Cretaceous Brachycythere species.  As modest a goal as that may sound, it’s really quite a daunting challenge because the differences among Brachycythere species are, at least to my eyes, deucedly subtle.  Still, those distinctions aren’t the focus of this post.  Rather, it’s the learning of the language used by paleontologists to describe the general features of these ostracodes, a language replete with words that are obscure (to this layperson), even as they sometimes turn out to be singularly efficient, and, once in awhile, resoundingly poetic.

Reading Shakespeare and reading descriptions of ostracode fossil species are curiously analogous activities.  Certainly, these paleontologists aren’t Shakespeare and the importance of their writing pales beside that of the Bard, but the process of reading them is similar – I have to recognize that, for all of the strangeness of some passages (“sure looks like English”), I can unpack the words, grasp some meaning, and make sense of it.  But I wish the ostracode literature had the facing pages of annotations explaining the really obscure stuff.

Here’s an example of the opaque paleontological texts through which I’ve been working.  What follows is an excerpt of a description of the Brachycythere nausiformis by Frederick M. Swain (Ostracoda From Wells in North Carolina:  Part 2.  Mesozoic Ostracoda, U.S. Geological Survey Professional Paper 234-B, 1952).  This is a new species which Swain was naming and describing here.

Shell subtriangular to subovate-acuminate in lateral view; greatest height a little more than one-third from anterior end; dorsal margin strongly arched, long posterior slope truncated and slightly concave; ventral margin gently to moderately convex; anterior margin broadly rounded, bearing tiny denticulations on each valve in well preserved specimens; posterior margin acuminate, strongly extended medially, truncate and slightly concave above.

. . .  Median surface of valves strongly convex with ventrum swollen to produce short alate expansions, and projecting beyond ventral contact of valves; crest of each ala bears a low longitudinal ridge with a broad furrow about it; a second weak longitudinal ridge lies dorsal of furrow.  A prominent elongate eye tubercle lies at anterodorsal angle; ventrad of tubercle in right valve is a short oblique sulcus, corresponding feature in left valve is deeper, wider and more pit-like. . . .

Best to have a specimen at hand to have the slightest chance of making any sense of this description.  Here’s my rough line drawing of a B. nausiformis (based on an actual specimen) in which I’ve tried to accentuate a few of the key features Swain described.  Each ostracode lives within two shells that are hinged at the top; the shell depicted below is a right valve.  The scale line is 200 microns (equal to 0.2 millimeters) which means this specimen is about 0.8 millimeters long.

And here’s my rough translation of Swain’s description:

Seen from the side, the shell is somewhat triangular to nearly egg shaped with tapering ends.  Its tallest point is a third of the way from the front where the top margin is strongly convex.  From that highest point, the top margin slopes to the rear end where it stops abruptly with a slight dip and a tapered end.  The bottom margin is somewhat convex.  The front end of the shell is broadly rounded, sometimes showing fine notches or teeth.

. . . The middle expanse of each shell is swollen, bowing out strongly, particularly toward the bottom.  Each swelling drops below the bottom margin where the two valves meet.  A ridge tops each of these swellings and is set off by a wide furrow (a faint second ridge parallels the first).  This creates wing-like projections from these ridges.  A prominent eye spot appears at the top peak toward the front of the shell.  In a right valve, a short groove runs below the eye spot; in a left valve, this groove is deeper, more pit-like. . . .

Some sense emerges from my version, I think.  I have arrayed this detailed description against several others that I’ve gathered which identify key characteristics of this and other Brachycythere species.  Slowly, I am coming to learn about a few of the key differences that others have posited distinguish among these species.  (Fortunately, I have an expert to whom I can turn when things gets problematic.)

In this process, I’m compiling a list of new words (well, nearly all new to me).  Given the general shape of the Brachycythere ostracodes – all of the species bear some close resemblance to the outline depicted above – several of these words are wonderfully apt.  Here’s the list at this juncture (these definitions are somewhat massaged versions of those given in The New Oxford American Dictionary, ebook, 2008):

  • acuminate = tapering to a slender point
  • alate = having wings or wing-like projections
  • carina = structure shaped like a keel (carinae, plural)
  • fusiform = tapering at both ends
  • punctate = having small holes or pits
  • subtriangular, subovoid = honestly, I didn’t know that the prefix sub in these instances means that the object being described by these adjectives is not precisely or perfectly triangular or egg-shaped
  • sulcus = groove or furrow
  • tubercle = nodule or projection
  • umbo = rounded elevation, like the boss of a shield (in shells, the umbo is the area above the hinge as described in a previous post).
In the midst of all of the often long winded descriptions I’ve been reading, a few stand out for their conciseness and their brevity (perhaps limiting their paleontological utility).  A couple even offer, dare I say it, a touch of poetry.  The following description of Cytheropteron sp. A (now known as Brachycythere ovata) was written by Merle C. Israelsky, and was originally published as a continuous paragraph (Upper Cretaceous Ostracoda of Arkansas, Arkansas Geological Survey, 1929):

Viewed from the side, subovoid;
higher before than behind.
Viewed from above or below,
outline is broadly fusiform,
slightly attenuated
before and behind;
valve contact
sinuous dorsally,
but slightly
sinuous ventrally.

Okay, I’ll concede that perhaps I’ve read too many of these.
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