Friday, March 22, 2013

A Fine Cast of Characters



A very frugal man . . . .
~   Description of paleobotanist Roland W. Brown in the Smithsonian Institution Archives

He was a little man with inexhaustible powers of life.
~ Description of paleobotanist Leo Lesquereux by J.P. Lesley in Memoir of Leo Lesquereux (1890)

He was regarded by some of his contemporaries as an extreme “splitter”.
~ Description of naturalist T.D. A. Cockerell by Robert L. Zuparko in The Published Names of TDA Cockerell (March 31, 2008)


I use the scientific names of fossils as an entrée to biography.  The resulting exploration of the people behind fossils’ scientific names is akin to hunting fossils in the first place, you never know what (or whom) you might find.

I recently purchased (so much for “hunting”) a small fossil that had been found in the Green River Formation in Wyoming.  This carbonized compression (I think that's what it is) of a samara, or winged seed, from the tree Ailanthus lesquereuxi Cockerell, dates from a portion of the Eocene epoch (about 55 to 38 million years ago) and is approximately 22 millimeters in length.  Though at first glance it looks rather like a little fusiform leaflet, this is actually the seed.  On a fossil of A. lesquereuxi of a higher quality than mine, an obvious dark circle (evidence of the seed proper) sits in roughly the center with the two wings extending to either side.  My specimen shows little evidence of the seed itself.  Perhaps part of the seed was located where the empty circular space appears.

[Later edit:  I've been imprecise with my terminology and continue to struggle with the precise structural nature of this fossil.  It appears that a thin carbon layer is preserved which, if I read Christopher J. Cleal and Barry A. Thomas's An Introduction to Plant Fossils (2009, p. 3-4) correctly, makes this a compression.  But, to be honest, I really don't know.  I changed "impression" to "compression" in this paragraph.]



The Ailanthus genus of trees (member of the Simaroubaceae family) is extant and includes, among its various species, one considered a particularly vile invasive species in the United States, the A. altissima, native to Asia and known as the “Tree of Heaven” as well as the “stinking sumac.”  (See Trees by Allen J. Coombes, 2002, Smithsonian Handbooks, p. 296.)

The samara from the Eocene A. lesquereuxi is apparently very characteristic of the fruit from extant Ailanthus species, including the Tree of Heaven.  That is evident in the photo below of A. altissima leaves and samara.  (This picture is reproduced with permission of its photographer Kurt Stüber under a GNU Free Documentation License.  It can be found on Wikipedia.)


The name Ailanthus lesquereuxi Cockerell simply demanded some poking around in its taxonomic history and related biographical histories.  The fine cast of characters discovered in this particular exploration included Roland Brown, Leo Lesquereux, and T.D.A. Cockerell.

Roland Brown (1893 - 1961)

My hope, early on in one of these searches, is that I’ll find some published record that includes not only a list of the synonyms to the present name and where they were published, but which also offers some narrative about that taxonomic history.

In 1934, paleobotanist Roland W. Brown, who spent his career with the U.S. Geological Survey (retiring in 1958), and who, for the last decade of his life, was also a research associate at the Smithsonian's National Museum of Natural History, published the perfect introduction to my fossil and the people associated with it.  I expected Brown simply to open the door; I didn’t realize that he, himself, might be the best find of this search.

In The Recognizable Species of the Green River Flora (U.S. Geological Survey, Professional Paper 185-C, 1934, p. 59), Brown described the A. lesquereuxi, providing two synonym citations.  The first was to Ailanthus longepetiolata Lesquereux, first described in the U.S. Geological Survey’s “Terr. Rept.” (volume 8, p. 197, and shown in plate 40, figure 7).  The second  was to Ailanthus lesquereuxi Cockerell, as described by Cockerell in Torreya (volume 27, 1927, p. 95).  Brown went further than just listing these sources, he discussed the taxonomic history of the fossil.
Lesquereux in 1883 described a leaf and a fruit under the common designation Ailanthus longepetiolata.  Cockerell in 1927 segregated these objects, called the fruit by a new name, A. lesquereuxi, but passing the leaf with the suggestion that it might be a species of Quercus [oak].  The fruit is a characteristic Ailanthus fruit that is little if at all different from A. americana Cockerell, from the Florissant lake beds. (p. 59)
Brown agreed that the leaf Lesquereux described in 1883 was not Ailanthus, but, in a wonderfully hopeful and inspiring conclusion to his description (one that resonates with all fossil hunters), he observed:
No fossil showing the distinctive characters of an Ailanthus leaflet has yet been identified from the Green River formation.  The presence of undoubted fruits, however, encourages the belief that some day the search for the leaves will be rewarded with success.  (p. 59)
Has there been any success in this search?  I don’t know.

Brown (or “Brownie” as he was known) was certainly, as the Smithsonian Institution Archives describes him, “a very frugal man.”  Pam Henson has a marvelous post on the Smithsonian National Museum of Natural History’s Unearthed blog (July 27, 2010), about Brownie’s thriftiness during his decade at the NMNH as a research associate.  He had been granted an office at the Museum, of which he took full advantage.  When he went into the field in pursuit of fossil plants, he saw no point in continuing to pay rent on the rooms where he had been living.  So, he stored his belongings in his Museum office.  Henson added,
When he returned, he sometimes did not rent a room again, sleeping in a sleeping bag in a park at night and otherwise living in the Museum. He would boil a potato or egg in a hot pot on his desk for dinner.
Sears, Roebuck & Co. catalogs served as his notebooks.  Brownie would paste papers of interest and notes onto the pages of the catalogs.  In the photo below, taken in 1958, he is seen seated at his desk in his Museum office; the catalogs are shelved above his desk.


(This photograph is reproduced with permission from the Smithsonian Institution Archives, and carries the identification number SIA2010-1592.  It can be found here.)

Ultimately, Brownie’s parsimony paid off for the Museum in the form of an endowment “of considerable size” from his estate.  (Sergius H. Mamay, Memorial to Roland W. Brown (1893 – 1961), Geological Society of America Bulletin, volume 74, no. 6, 1963, p.81.)  Nevertheless, living in one’s office did become a thing of the past.
By mid-century, the Museum director, Alexander Wetmore, decided that perhaps it was time to end this practice, and all staff were required to leave by midnight, ending an era when the Museum was literally a home to its staff.  (Blog post by Pam Henson.)
Leo Lesquereux (1806 - 1889)

Paleobotanist Charles Léo Lesquereux was the first to describe this Ailanthus seed from the Green River Formation; it was among the material brought back by geologist Ferdinand Vandeveer Hayden from surveying expeditions to the West.  In The Cretaceous and Tertiary Floras (Volume VIII of the Report of the United States Geological Survey of The Territories, 1883, p. 197), Lesquereux described Green River leaflets and winged fruit found in Wyoming and named their source Ailanthus longe-petiolata, sp. nov.  The bulk of his description centered on the leaflets.  A drawing of the samara included in the publication is shown below – figure 7:



That Lesquereux had some doubts about how he was linking the leaflets and winged seeds is obvious.
Fig. 7 may not represent the fruit of the same species, though I have not seen any other leaf from the same locality which could be referred to this genus.  The samara is equally winged on both sides of the seed, oblong, obtuse at both ends, slightly constricted in the middle.  The fruit has a close affinity to that of Ailanthus recognita . . . .
It’s not clear to me why, if the samara were so obviously related to, if not actually, Ailanthus, that Lesquereux didn’t take the next step and assume that leaves from the same tree would also be likely to resemble those from Ailanthus.  So be it.

Lesquereux was a member of a small, but influential, cadre of Swiss scientists that emigrated to the United States in the 1840s; all of these men had been members of the Society of the Natural Sciences at Neuchâtel, Switzerland.  Perhaps foremost among them was the paleontologist Louis Agassiz (1807 – 1873) who helped reshape the practice and teaching of science in America.  (A brief biographical piece on Agassiz was posted previously on this blog.)  The others included geologist and geographer Arnold Henry Guyot (1807 – 1884) who went on to teach at Princeton University.

When Lesquereux left Europe in 1848 with his wife and five children, he was already highly regarded for his work on mosses and peat bogs.  After coming to America, he worked briefly for Agassiz in Boston, before relocating to Columbus, Ohio.  There he established a reputation as a highly skilled paleobotanist and, throughout the rest of his life, was often employed by federal and state geological surveys to study and identify fossil plants.  He also wrote a number of seminal studies on ancient plants.  In 1864, Lesquereux was elected to the National Academy of Sciences, just a year after its establishment.  (Agassiz and Guyot were charter members.)  Throughout, to make ends meet, Lesquereux reportedly worked as a watchmaker.

An integral part of Lesquereux’s story is that illness, when he was a young man, had damaged his hearing, and a botched medical intervention left him almost completely deaf.  Though his deafness presumably made the transition to life in America rather challenging, particularly because he knew no English, he regarded his hearing loss as a boon to his scientific pursuits.
My deafness cut me off from everything that lay outside of science.  I have lived with Nature, the rocks, the trees, the flowers.  They know [me], I know them.  All outside are dead to me.
(L.R. McCabe, Sketch of Leo Lesquereux, The Popular Science Monthly, April 1887,  p. 839.)
(Besides McCabe’s piece, other sources for information on Lesquereux include Paleontology of the Upper Eocene Florissant Formation, Colorado, by Herbert William Meyer and Dena M. Smith, 2008, which includes a brief biographical sketch of Lesquereux on page 4; and J.P. Lesley’s Memoir of Leo Lesquereux, 1806-1889, National Academy of Sciences, 1890.)

T.D.A. Cockerell (1866 - 1948)

And, finally, there is T.D.A. Cockerell who, even as he supplanted Lesquereux as the namer of this fossil, paid homage to the man in the species name he gave it.  When I tracked down the publication in which Cockerell revised the taxonomic record of Ailanthus lesquereuxi, I was quite surprised how little was there.  In 1927, Torreya was the organ of The Torrey Botanical Club.  Cockerell’s piece, titled A New Oak from the Green River Eocene, which appeared in the September-October, 1927, issue was a brief two-page description of a fossil leaf he’d found in Colorado which he named Quercus utensis.  In passing, he observed that the leaf Lesquereux had identified as Ailanthus longepetiolata from the Green River Formation could quite possibly have been from an oak, but clearly was not Ailanthus.

As for the winged seed, Cockerell stated,
The samara, doubtfully referred here by Lesquereux, . . . , may be named Ailanthus lesquereuxi, n. n.  (p. 95)
That’s it.  That single sentence is the entirety of Cockerell’s contribution to the taxonomic debate on the seed!  Standards have certainly changed.

Born in England, Theodore Dru Alison Cockerell came to America as a young man, in search of a climate that might help him recover from tuberculosis.  Though he specialized in bees for much of his life, Cockerell’s scientific interests were wide, straying well beyond the confines of bees.  For a major portion of his career, he taught at the University of Colorado at Boulder.  During his time at UC-B, Cockerell failed to rise very high in the esteem of his academic colleagues, perhaps because he refused to adhere to much of an organized curriculum, and dared to think the doing of science was better for students than the reading of science.  As the UC Board of Regent’s reprimand in 1920 put it, he allowed “immature and unprepared undergraduates” to “attempt research.”  (Simply amazing.)

(Sources on Cockerell include the following:  Jefferson Dodge, Biologist T.D.A. Cockerell Holds Place in CU History, August 24, 2000; Barton Melissa, Study Nature, Not Books:  Cockerell and the Amateur Naturalists, Journal of Young Investigators, November, 2005, which quotes the Regent’s reprimand; and Sue Ann Gardner, Theodore Dru Alison Cockerell, Faculty Publications, UNL Libraries, Paper 109, 1999.)

As if his approach to education weren’t enough to endear him to me, his sowing of thousands of scientific names during his career makes him a welcome addition to this post’s cast of characters.  Robert Zuparko, who studied the myriad scientific names for which Cockerell was responsible, estimated that he bestowed over 9,000 scientific names, more than three-fourths of which were at the species level.  The vast majority of all names he penned were assigned to bee taxa.

His contribution to our story of Ailanthus lesquereuxi is, apparently, quite typical of his taxonomic work.  Zuparko recounted one episode that, whether true or not, was in keeping with Cockerell’s approach to naming and publication:
Dr. P.H. Timberlake reputedly reported that when traveling by train across the western United States, Cockerell would get out and collect bees at a watering station, and by the time the train made its next stop, he’d telegraphed a new description to a publisher.  Many of his descriptions are short and many of his taxa are distinguished largely by color differences.  (p. 1)
Certainly explains much about his minimalist contribution to Ailanthus lesquereuxi in Torreya.

Yes, a fine cast of characters assembled here.

Monday, March 11, 2013

A Fossil As TARDIS


Doctor Who, the long running BBC science fiction series, features a marvelous creation at its core – a time traveling vehicle designed to blend in with the time and place to which it moves.  Two aspects of this time machine, known as the TARDIS (time and relative dimension in space), raise it to the level of sheer genius.  First, it suffers from a malfunction, regardless of where and when it arrives, it’s stuck in the form of an English police call box (think phone booth, if you’re old enough to remember phone booths) from 1963.  But, for me, the most powerful aspect of this conceit is that the TARDIS is much larger (indeed, approaching infinite) on the inside than it is on the outside.  Apparently, the bounded exterior dimensions are belied by different interior dimensions.  Thus, this call box offers the time traveler myriad rooms, a cricket pavilion, swimming pools, . . . .  (A quick guide to the TARDIS can be found on the Doctor Who homepage on the BBC website.  Despite loving the concept of the TARDIS, I must admit that I am not a Doctor Who devotee.)

The description of the TARDIS is necessary context for the fossil shell from the gastropod Ampullella parisiensis (d’Orbigny, 1850) shown below.  This gift from a friend dates from the Bartonian Age (40 to 37 million years ago) in the Eocene Epoch and was found in the Guepelle Formation, near Survilliers, northeast of Paris.  (It is just a little less than an inch in height (apex to aperture).)


Without question, this shell was a TARDIS.  Yes, it had traveled in time.  But that’s a prosaic claim in the face of what I discovered on the inside, where clearly other dimensions held sway.

As the picture below of the aperture shows, this fossil as I received it was filled with yellowish sand (and so much more).


After delicately extracting this matrix (roughly a 1/4th teaspoon’s worth), I began to explore this fill and an ever expanding Eocene world opened up before me.  Infinite?  Hardly, but, without question, the riches in these few pinches of material made the shell’s inside seem so much larger, so much deeper, than its outside.  (I would like to think that the material that, over the years, came to rest inside the shell is all Eocene in age, but I recognize that more recent or, perhaps even older, bits of stuff might have intruded, as well.)

It was evident from the outset that, amid the quartz fragments of the matrix, would be several “large” shells.  I separated these from the sandy matrix.  A few appear in the picture below.


Among the several gastropod shells is another, smaller Ampullella parisiensis (upper right in the picture above).  The glistening white, curved tube is, I believe, from some species of the gastropod Dentalium.  There are two shells from bivalves shown in the picture, one with a hole drilled into it by some miniature predator.  (My initial efforts to identify these shells has taken me to Cyril Baudouin’s fine website, which features fossil shells from France by geological period.  Unfortunately, most of mine don’t appear to be reflected in the Bartonian specimens he features.)

One of the two crab claw fragments in the mix is quite striking.



At the microscopic level, my horizons within this Ampullella parisiensis stretched and twisted.  There amid the bits of quartz I found my favorite microfossils – minute shells from foraminifera (protists) and ostracodes (crustaceans).  Though I’ve only just begun to work through this fill, several dozen forams have made an appearance, along with twenty or so ostracodes.  The adjective “fossiliferous” legitimately applies to this material.

By far, the most common of the forams in this material look like vertical, nested bits of braided twine.


This shape comes in several subtle variations (e.g., some have vertical striations, others are relatively smooth).  This broad group of forams, which dominates numerically among the forams I’ve found here, may be from the genus Massilina which dates back to the Eocene, though there are Massilina of much more recent vintage than that.

I haven’t made any headway identifying the ostracodes that tumbled out of the Ampullella.  A group of small, kidney bean-shaped specimens predominates.


I suspect I have more than one ostracode species or genus among those shown above, and, in all likelihood, have positioned some of them upside down.  (A method for conclusively determining the dorsal/ventral orientation of an ostracode shell is to examine the hinges on the interior of the shells because these animals’ shells are only hinged along the dorsal margin.  Unfortunately, I’ve pushed my microscope to its limits and the hinges remain out of visual reach.)

Finally, there was a moment as I worked through the material that filled the Ampullella parisiensis when I felt as though I’d been dropped into a fractal shape.  Perhaps this was not surprising, since fractals and the TARDIS both play with spatial dimensions.  Because it sets aside all of the complex mathematics that delineates a fractal, I like the definition offered at one point by the father of fractal geometry, Benoit Mandelbrot,

A fractal is a shape made of parts similar to the whole in some way.  (As quoted in Fractals by Jens Feder, 1988, p. 11.)

Self-similarity, a defining characteristic of fractals, is one of their most enticing, visual features.  As you examine a fractal shape at ever greater levels of magnification, patterns and forms repeat themselves.  You can literally get lost in a fractal shape, though familiar worlds reappear endlessly.  (There are many fractal generators available on the web that allow you to peer into ever small parts of this geometric space to find those repeating worlds.)

There was self-similarity in the Ampullella parisiensis shell.  When I began to empty the matrix from this shell, the tiny A. parisiensis shell emerged (seen in a photo above).  More to the point, this shell was filled with the yellow sandy matrix.  Wonderful repetition, one level in.  Unfortunately, I let the small shell’s contents mix with everything else on the sorting tray.  Perhaps even smaller shells had been hidden inside, perhaps ostracodes and forams fell out.  Certainly not an endless succession of ever smaller A. parisiensis shells with matrix, still, it was a wonderful hint of the fractal.
 
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