Saturday, September 10, 2011

Trivial Mistakes and Taxonomic Super Glue

I’ve been in pursuit of trivial mistakes or, more accurately, they’ve been pursuing me.  Sure I dread big mistakes, but I reserve particular anger for my embarrassing little ones, the ones seemingly easy to avoid and which crop up everywhere, including in this blog.  I help edit a newsletter for a fossil club, and perhaps the most demanding aspect of each issue’s production is the final proofing, the checking of that last firewall between me and the ire of the members.  Just when I think no one is reading the rag, a trivial mistake in an issue sparks voices from the void.  Misspelling a club member’s name seems to be at the top of the list of cardinal sins of newsletter editing; for a fossil club, right up there is messing up a scientific name.

Although our latest issue proved unexceptional in this regard (having the usual complement of little errors), its production came in the midst of my protracted efforts to identify a fossil shell I found in material from the Lee Creek Mine in North Carolina.  I believe this fossil is from the Pungo River Formation, an early Miocene formation (laid down some 20 to 15 million years ago).  But given that the mining operation mixes up material, this shell may actually have originated in some other formation present at the site.

The juxtaposition of newsletter editing and fossil identification offered me a new perspective on the making of trivial mistakes – I've come to appreciate that at least the public airing of mine is fleeting.

Here are several views of the specimen whose identity still escapes me.  It’s 27 mm long (a bit more than 1 inch).  This shell is a rich dessert among the other gastropod shells that I’ve found in the same area.  The shell looks for all the world to me like a phyllo pastry, its varices (the raised ridges along its whorls) made of delicately stacked, wavy layers of pastry.

At this stage, I don’t remember the sequence of steps that led me to the general vicinity of an initial possible identification of this shell.  Perhaps I saw the imprecise drawing of Pterorhytis conradi that appears in the North Carolina Fossil Club’s Neogene Fossils of North Carolina:  A Field Guide (1997).  Regardless, the process took me once again to the descriptions and drawings of fossil shells in paleontologist William Healey Dall’s Tertiary Fauna of Florida, with Especial Reference to the Miocene Silex-Beds of Tampa and the Pliocene Beds of the Caloosahatchie River (Transactions of the Wagner Free Institute of Science of Philadelphia, Volume 3, August 1890)  (My initial encounter with Dall came while preparing a previous posting – A Boatload About Eupleura caudata (Say, 1822))  In this article, Dall described Murex (Pterorhytis) conradi Dall, and offered two fine drawings of the shell – a view of the aperture side of the shell and a "head-on" view of the apex (in the living organism, the apex points toward the rear).  (Buried in the opening text is his acknowledgement of the artist contributions of J.C. McConnell and J.H. Ridgway.  This seems like meager reward for an essential component of the work.)

There are at least a couple of key differences suggesting that what I have may not be P. conradi – in the drawings, the anterior canal of the P. conradi is covered or closed and its varices are more prominent than those of my shell.  With a careful look at the drawing of the aperture view in Dall’s work, one might pick up on another difference.  In the drawing, there appear to be little protrusions or “teeth” coming from the lip of the outer edge of the shell aperture.  Granted that my specimen may have been damaged over the years, uncovering the canal and breaking off the teeth, but, after careful examination of the shell, I really don't think so.

Though I like this artwork, others do not.  Their criticism is leveled at the purported untethering of the drawings from reality.  The authors of a chapter on mollusca that appears in the Lee Creek series published by the Smithsonian Contributions to Paleobiology asserted that the drawings in Dall’s work were “somewhat artistically tailored to a more regular, smooth-looking form, whereas in reality the sculpture is somewhat rougher and shaggier, and a good deal of the fine detail shown by Dall is obscure.”  (Lauck W.Ward and Blake W. Blackwelder, Late Pliocene and Early Pleistocene Mollusca From the James City and Chowan River Formations at the Lee Creek Mine, Geology and Paleontology of the Lee Creek Mine, North Carolina, Volume II, 1987, p. 174)

Here are the photographs these authors use to illustrate Pterorhytis conradi (numbers 7 and 8).

Certainly, a wilder architecture in this specimen than that presented by Dall.

But there are variations within species.  Might variations in P. conradi embrace my specimen?  In an entry in her blog (The Fossil Murex Blog), Greta Polites considered the variations among her many Pterorytis specimens from Florida and from North Carolina’s Lee Creek, and raised the question of whether and when those variations actually distinguish among valid species.  Amid the pictures of Pterorytis are two of the aperture of a single P. conradi specimen from Lee Creek; these clearly show several teeth extending from that outer lip.  They also show a closed anterior canal.  So, mine is probably not P. conradi.

No, Polites' spelling of the genus name is not one of my "trivial" mistakes - no "h" in the name.  More on that in a moment.

In a separate posting titled “Toothless Pterorytis – They’re Not All P. roxaneae!”, Polites offered a photograph of the apertures of three Pterorytis roxaneae shells – no teeth on any of them, and variation in the anterior canals, with one specimen sporting a canal fully uncovered as in my specimen.  Do I perhaps have P. roxaneae?  Sigh, probably not.  For what it’s worth, the Paleobiology Database entry for Pterorytis roxaneae suggests the shell may be known from Florida and the Late Pliocene.

Nevertheless, my operating assumption for the time being is that my shell is at least from the genus Pterorytis (and spelled this way).  I make this choice as to genus despite conchologist William K. Emerson’s review of the genus in the article titled The Gastropod Genus Pterorytis, appearing in American Museum Novitates, (Number 1974, November 14, 1959).  In a terse bit of description, he wrote:  “Siphonal [anterior] canal short, closed.”  (p. 2)  Though his description is of the type species of the genus, Pterorytis umbrifer, in none of the illustrations and photos of the other species he placed in this genus is the canal open.

Guess I’m left rooting for natural variation.

Amid this rummaging around in the taxonomic attic, I suddenly felt plagued by one of my usual trivial mistakes.  I initially wrote the genus name as Pterorhytis but I decided that was in error when I noticed that later I was finding the genus spelled Pterorytis.  I started changing the names of files and folders only to realize finally that the genus name was spelled two different ways in the literature.

Scientists take great pride in the self-correcting nature of science, grounded in the scientific method.  Errors or, indeed, outright lies and fabrications in research will eventually be discovered and corrected as other scientists attempt to reproduce findings, mount challenges to theories, and advance new hypotheses.  In an essay titled Falsity and Failure, writer and physician Lewis Thomas argued that, in the 1970s, a seeming rash of deliberate scientific malfeasance, such as data doctoring or plagiarizing, was less a rash than a single blemish, but it was significant because of its threat to public confidence in science.  As for discovering and correcting the mistakes, Thomas wrote
It is an impossibility for a scientist to fake his results and get away with it, unless he is lucky enough to have the faked data conform, in every fine detail, to a guessed-at truth about nature (the probability of this kind of luck is exceedingly small), or unless the work he describes is too trivial to be of interest to other investigators.  Either way, he cannot win.  If he reports something of genuine significance, he knows for a certainty that other workers will repeat his experiments, or try to, and if he has cooked his data the word will soon be out, to the ruin of his career.  (Late Night Thoughts on Listening to Mahler’s Ninth Symphony, 1983, p. 111)
That takes care of the big mistakes and probably most of the little ones.  Still I find it somewhat ironic that, in one area, the rules of science may end up enshrining mistakes, protecting them from subsequent efforts to correct them.  Pterorhytis and Pterorytis are an instance of just that.

To understand that, I turn to Timothy Abbot Conrad (1803 – 1887) who named this particular genus.  Conrad, though apparently lacking any college education, did important work in paleontology and geology.  He was employed as a paleontologist and geologist for the New York Geological Survey from the late 1830s to 1841, for several years in the 1850s he had a part time position at the Smithsonian, and later in life he worked for the North Carolina Geological Survey.  At age 28, he was elected to the Academy of Natural Sciences of Philadelphia.  Over the course of his working life, Conrad identified and named myriad fossils.

What kind of standing in the scientific community does Conrad have?  According to paleontologist Ellen James Moore,
Conrad was a perceptive paleontologist who was the first to attempt to describe and date, on the basis of fossils, the Tertiary formations of North America. . . .   His discrimination of genera was outstanding, and by far the majority of generic names he proposed still stand as valid today.  (Conrad’s Cenozoic Fossil Marine Mollusk Type Specimens at the Academy of Natural Sciences of Philadelphia, Proceedings of the Academy of Natural Sciences of Philadelphia, volume 114, 1962, p. 26)
There was another, somewhat darker side to the man.  It's a more complex portrait we need to paint, one colored by years of ill health, apparently both mental and physical, financial insecurity, deep shyness, and, surprisingly, given Moore’s assessment of his prowess as a paleontologist, a degree of carelessness.  Moore wrote:
Conrad was an absent-minded, moody, somewhat careless man whose life was fraught with pecuniary difficulties and poor health. . . .  Conrad was prone to introduce the same specific name as new more than once within one genus, because of absent-mindedness, and his descriptions are sometimes very brief and occasionally illustrated by unclear drawings. . . . Conrad’s desk was usually piled high with fossils, shells, books, papers, etc., and had to be periodically sorted to save collections not already hopelessly mixed or separated from labels.  (p. 26-27)
Ah, therein lies the source of my struggle with Pterorhytis/Pterorytis.  In 1862, Conrad introduced the genus name, Pterorytis, in Catalogue of the Miocene Shells of the Atlantic Slope which appeared in the Proceedings of the Academy of Natural Sciences of Philadelphia (volume 14, p. 560).  Then, in 1868, he wrote about the same fauna and this time used the genus name Pterorhytis (Descriptions of Miocene Shells of the Atlantic Slope, American Journal of Conchology, 1868, volume IV, p. 64).

In his 1959 article, Emerson explained that Conrad was attempting in this second publication to correct a mistake he’d made in constructing the genus name he published in 1862.  But the effort was doomed to fail (or should have been).
Although Conrad (1868) eventually emended Pterorytis to the etymologically more correct Pterorhytis, the rules of the International Commission on Zoological Nomenclature require that the original spelling be retained.  (p. 3)
The etymological mistake?  Conrad nailed the Ptero part of the name which is Greek for “wing,” “feather,” or “fin.”  But in his initial effort he misspelled the Greek root for "wrinkled."  It's rhytis.  (Donald J. Borror, Dictionary of Word Roots and Combining Forms (1988))  Given the early history of taxonomy when names were changed on the merest whim, thereby undermining the naming enterprise, rules that serve to lock in a name make sense.  Though etymologically flawed, Pterorytis violates no ICZN naming rules and so is a valid name.  The taxonomic super glue takes hold.

Yet . . . as the previous discussion of relatively recent literature on Pterorytis shows, scientists who probably should know better have breathed life, knowingly or unknowingly, into Conrad's attempted correction.

Evolutionary biologist Richard Dawkins recently commented in a footnote about a different scientific naming gaffe that “the rules of zoological nomenclature are strict, and even obvious mistakes can’t be changed, once they are enshrined in a naming publication.”  (The Greatest Show on Earth:  The Evidence for Evolution, note on p. 177)  He added (proving, once again, that Dawkins’ notes should never be skipped),
The taxonomy is littered with such fossilized mistakes.  My favourite is Khaya, African mahogany.  Legend (which I long to believe) has it that in a local language it means "I don’t know", with the presumed subtext, "And I don’t care and why don’t you stop asking stupid questions about plant names."

1 comment:

    Link above has a similar looking specimen from Lee Creek.


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