Monday, April 26, 2010

Predators and Prey – Seeing Out of the Corner of Your Eye

This is a posting about predators and prey, and the ingenuity of scientists in picturing the unobservable.

One prompt for this posting came the other day when, as I sat at my desk, dogs outside began an insistent barking. This was one of those moments when I am reminded that, even in this paved over, abused urban landscape, we are part of the ebb and flow of nature. My little schnauzer, German-bred to hunt rats and other vermin, was wonderfully excited, throwing sharp barks up past the back gate. My neighbor’s basset hound, bred by the French (French-bred?) to track down small game such as rabbits, stood in her yard baying loudly.

Cause of the commotion? Nestled in the grass in front of a stack of firewood on a slope overlooking the backyards sat a red fox, a member of the Canidae family which includes those domesticated, yammering canines.

The appearance of this demure creature explains those sudden bursts of barking that had punctuated the quiet of the neighborhood in the evenings and early mornings for several weeks. The interloper, probably pushed out of a more secure environment, was leading a life uncomfortably near to humans, houses, and those dogs. The fox retained her cool. Bemused by the racket she was causing, she yawned a couple of times, exposing her long white canine teeth, sat back and stared for awhile. Then, tiring of this and having the somewhat more important job of survival to attend to, she briefly scratched under her chin and faded away. The dogs continued their noise.

Three relatively closely related predators in close proximity for a moment – reminder that it’s a dog eat dog world, or, as William Buckland (grand subject of my previous posting) put it, “The stomach, sir, rules the world. The great ones eat the less, and the less the lesser still.”


Several weeks ago, I commented about the demise of a fossil collection as an intact collection and the spread of its specimens to other collections, including mine. A couple of microfossils that came my way puzzled me. Embedded in a piece of shale were conodont fossils, something unknown to me. That’s embarrassing to admit because conodonts are incredibly common. They are nearly ubiquitous in marine sedimentary beds from the Cambrian to the Triassic, and have a “fossil record . . . generally held to be among the best of any group of organisms.” (Mark A. Purnell and Philip C.J. Donoghue, Between Death and Data: Biases in Interpretation of the Fossil Record of Conodonts, Special Papers in Palaeontology, Volume 73, 2005, p. 7. Available among the publications posted at Purnell’s website) Yes, conodont fossils are nearly everywhere. Here’s one of those new to my collection (their small size makes them a photographic challenge particularly with a modest digital camera).

They come in many different shapes as shown in the picture below taken by the late Charles Drewes, biologist at Iowa State University and included on his website.

Following their discovery in 1856 by the Russian biologist and embryologist Heinz Christian Pander (or, as it is sometimes recorded, Christian Heinrich Pander), conodonts were the focus of a prolonged debate – what were they? animal or plant? the whole organism or part of it?

With the later discovery of a few fossils including the soft parts of the conodont organism, it became clear that the hard parts we almost always see in isolation are fossilized mouthparts. The conodont is now known to have been a primitive vertebrate, one of the Agnatha (jawless fish) whose only extant representatives are hagfish and lampreys.

But, how did those mouthparts work? Of course, for these long gone creatures, as Mark Purnell of the University of Leicester observed, “direct observation of feeding is not possible.” As a result, saying something conclusive about the behavior of conodonts and how they used their body parts is difficult, as it is for other extinct organisms.

The advice in science for these situations appears to be: “If you cannot see it directly, try some indirection.”

In one of those nifty bits of cleverness that attracts me to the study of science and scientists at work, Purnell theorized that, if they were teeth used for crushing and shearing, there would be evidence of that, in the form of microscopic wear patterns on the fossils, similar to those well known from the teeth of mammals and certain reptiles. Absent those signs of wear, these mouthparts would likely have been a filtering device for bits of food. He looked closely and found wear patterns, ergo, teeth. And, from this, he concluded that the first vertebrates were predators . . . ah, Conodont the Predator, though what they preyed on remains an open question. (Mark A. Purnell, Microwear on conodont elements and macrophagy in the first vertebrates, Nature, Volume 374, April 27, 1995; and M.A. Purnell, Feeding in Conodonts and other Early Vertebrates, from Palaeobiology II, 2001, available at Purnell’s website.)

Crinoids and Echinoids

Another example of scientific resourcefulness in visualizing behavior in the distant past came my way recently in the form of a new article about crinoids. This also involved predators and their prey.

Crinoids can make beautiful fossils, sometimes appearing to be flowers fixed for an instant in the middle of a breeze. They are marine invertebrates commonly known as sea lilies (those with stems) or feather stars (stemless). Crinoids were nearly done in during the massive End-Permian extinction (about 251 million years ago, touched on in a previous posting), but recovered rapidly beginning in the Triassic, diversifying greatly, expanding into new territory, and developing new behaviors and physical attributes. Perhaps most dramatically, following the End-Permian extinction, many types of crinoids became mobile, “a trait not found among Paelozoic crinoids.” (Tomasz K. Baumiller, et al., Post-Paleozoic crinoid radiation in response to benthic predation preceded the Mesozoic marine revolution, Proceedings of the National Academy of Sciences, early edition, March 30, 2010, volume 107 (13).)

These changes in crinoids have been attributed by some scientists to the impact of predation, particularly by fish, which, it is argued, prompted crinoids to seek out safer environments, developing direct methods of escaping predators. Geologist and paleontologist Tomasz Baumiller and his colleagues theorized that, in addition to attacks by fish, predation by dwellers of the sea bottom might have also contributed significantly to these evolutionary developments in crinoids. They focused specifically on echinoids (sea urchins), animals that also were almost wiped out in the End-Permian extinction. Echinoids, like crinoids, bounced back, undergoing diversification in habitat and physical changes, including the strengthening of mouthparts.

To answer the question of whether predation by echinoids played a role in the evolution of the crinoid, particularly, the development of motility, Baumiller et al. were faced with that ever present problem of determining what happened in the very distant past. Once again, the ingenuity that scientists being to bear on addressing this challenge impressed me.

Baumiller et al. had living types of crinoids and echinoids to work with. Using live specimens in aquaria, they established that, indeed, echinoids do prey on crinoids, but, of course, that didn’t prove a predator-prey interaction between them in the Triassic. It did suggest it was possible, and, beyond that, offered a clever way to test whether that interaction had occurred. Baumiller et al. discovered that crinoid pieces that had been ingested by echinoids were scratched and pitted in very specific ways. They then looked for those characteristic marks in crinoid fossils from the Triassic, and they found them, in spades – 20% of 2,500 crinoid fossil fragments studied had those same pits and scratches. The research offered support of the proposition that bottom dwelling predators, such as echinoids, preyed on crinoids during the Triassic, spurring the development of mobility.

Concluding Thought

Scientists are powerfully creative in dealing with problems, or visualizing events, that cannot be approached directly. Evolutionary biologist Geerat Vermeij identified three ways to determine predation from the fossil record, the last two decidedly indirect – (1) luck out and find fossils showing the predation occurring, if not freezing the capture in time, at least showing the remains of the prey in the predator’s gut; (2) find evidence on prey fossils of predator action; or (3) infer the behavior from predator morphology. (As described by E.M. Harper in Dissecting post-Paleozoic arms races, Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 232, 2006, p. 324.)

The two examples described in this posting reflect Vermeij’s indirect methods, exhibiting a degree of artistry I find impressive, and, in my mind, adding an extra dimension to the effort. I may particularly appreciate them because I prefer the indirect or oblique approach to almost everything. Approaching your prey from an unanticipated direction means sometimes succeeding unexpectedly or capturing something unexpected.

I am fond of the poem Bach, Winter by Jane Mead, which suggests something hidden (in this case, music) may be lost if you come at it head on. Here are the poem’s opening verses.

Bach must have known – how
something flutters away when you turn
to face the face you caught sideways
in a mirror, in a hall, at dusk –

Monday, April 19, 2010

Not My Geological Hero . . . Better Than That

I fully intended to respond to geologist Callen Bentley’s posting on his blog, Mountain Beltway, which called for other geobloggers (like him) and readers of geoblogs (like me) to post stories of their geological heroes. Callen raised the bar pretty high when he identified heroes as “extraordinary individuals who helped make your life, your science, and your planet better than they would otherwise have been.”

It didn’t seem so far fetched for me to have such a hero. After all, paleontology and geology are science handmaidens and I’ve touched on geology in a number of posting on this blog. I considered the question – Was there a geologist, about whom I knew enough and felt strongly enough, that I’d be willing to crown with the title of my geological hero?

After musing on the question, I did come up with a likely candidate. I took the further step of doing some more reading about his life and his scientific work, and I outlined a posting. But, as I started to write, I realized I couldn’t pull it off. Heck, who was I fooling? The fact that I’d had to think about the hero question for any length of time showed that I didn’t have a geological hero. It’s a label to confer instantly and viscerally, without thought or the building of a case to convince oneself.

With more thought, I realized that fondness had been my touchstone for geologist William Buckland, not hero worship. Over the past couple of years, I developed affection for him, a feeling having little to do with his geological endeavors (a fatal flaw in a search for a geological hero) and only a bit for his paleontological work (which was prodigious). Rather, I am attracted to him by his genial eccentricities, and I am not alone.

Let me explain.

His career was certainly illustrious. William Buckland was a prominent figure in geology and paleontology during the first half of the 19th Century, one of the worthies of early English geology, as he was characterized by paleontologist Stephen Jay Gould. Buckland was born in 1784 and died in 1856. Educated at the University of Oxford (Corpus Christi College), he taught there, simultaneously holding appointments as Reader in Mineralogy and the university’s first Reader in Geology. He was also an ordained Anglican priest. In his early 60s, he was appointed Dean of Westminster Abbey. His final years were a sad chapter in an otherwise vigorous, productive life; he descended deeply into mental and physical illness.

Throughout his career, he was among the noteworthy scientists practicing and teaching in England. He twice served as President of the Geological Society, and was a member of the Royal Society and the British Association.

A dominant focus of his professional energy was, as he put it, to show the “consistency of geological discoveries with sacred [religious] history,” (Geology and Mineralogy Considered, p. 8) an effort reflected in the titles of some of his major works:

Vindiciae Geologiae; or the Connexion of Geology with Religion explained (1820);
Reliquiae Diluvianae; or, Observations of the Organic Remains Contained in Caves, Fissures, and Diluvial Gravel, and on Other Geological Phenomena, attesting the Action of an Universal Deluge (1823); and
Geology and Mineralogy Considered With Reference to Natural Theology (1836).

Arguably, these efforts reflected an astute reading of the political and religious environment at Anglican-dominated Oxford where, early in his career, upon Buckland leaving for a European tour, one Oxford “elder” reportedly observed, “Well, Buckland is gone to Italy; so, thank God, we shall hear no more of this geology.” (Life and Correspondence of William Buckland, p. 10) Buckland worked, through his books, papers, talks, and teaching, to infuse geology into the curriculum, while concurrently trying to assuage the fears of those who viewed the science as a threat to religious beliefs. One does, though, have to acknowledge that his heart was in these dense tomes.

Yet, he was not a biblical fundamentalist. He argued for an old Earth, asserted that a “day” in the Genesis story did not refer to a 24 hour day, and that the “beginning” in Genesis described a period of unknown length that preceded creation of the present inhabitants of the Earth. He acknowledged that many species had gone extinct, a position reflecting his scientific work. For instance, Buckland had excavated Kirkdale Cave, an ancient hyenas’ den abounding with fossils he concluded were from extinct animal species. In his inaugural talk as president of the Geological Society, he made the formal announcement, based on huge fossil bones recovered at Stonesfield, of an extinct reptile he named Megalosaurus. The formal paper published from that talk would be the first on animals that would later be called dinosaurs.

Even as he sought to bridge the growing chasm between religion and natural history, Buckland exhibited an admirable receptivity to new ideas and a surprising degree of intellectual flexibility. For instance, he posited initially that the geological surface of Britain reflected the impact of a “universal deluge,” which at times he associated with the Biblical flood. Later, he abandoned that position, taking a different stance, one that rings quite contemporary with its embrace of deep time and species that, the further back one goes, seem increasingly different from those extant. In Geology and Mineralogy, he wrote,

Some have attempted to ascribe the formation of all the stratified rocks to the effects of the Mosaic Deluge; an opinion which is irreconcilable with the enormous thickness and almost infinite subdivisions of these strata, with the numerous and regular successions which they contain of the remains of animals and vegetables, differing more and more widely from existing species, as the strata in which we find them are placed at greater depths. (p. 16)

These “successions” of animal and plant remains in the different strata convinced Buckland that “the strata in which they occur were deposited slowly and gradually, during long periods of time, and at widely distant intervals.”

But, lest one think he was on to evolution, Buckland concluded that one succession did not change into another, and, “[t]hese extinct animals and vegetables could therefore have formed no part of the creation with which we are immediately connected.”

Four years later, in 1840, he toured Scotland, examining its geological features under the guiding hand of the Swiss naturalist Louis Agassiz, a good friend. To Buckland, the evidence of glaciers at work was everywhere, and he fully embraced Agassiz’s glacier theory. The action of glaciers explained so much of the landscape that he’d previously attributed to the work of floods.

I'm afraid it’s easy for me to set Buckland’s scientific efforts aside because what really attracts me to him is his humanity, and, yes, those over-the-top eccentricities. Some of his behavior was undoubtedly more shocking to early 19th Century sensibilities than it would be to ours, while other activities, perhaps meriting little more than a tolerant smile among his contemporaries, would prompt a bit of aversion today.

People liked Buckland and were drawn to his conversation, sense of humor, and generous nature. In reminiscing about him, Oxford professor Storey Makelyne, who had been one of his students, wrote, “Dr. Buckland’s wonderful conversational powers were as incommunicable as the bouquet of a bottle of champagne, but no one who remembers them as I do, can ever forget them. It was indeed at the feast of reason and the flow of social and intellectual intercourse that Buckland shone.” (Life and Correspondence, p. 35) In the account of his Oxford days, the artist and writer John Ruskin said that Buckland and his family “were all sensible and good-natured, with originality enough in the sense of them to give sap and savour to the whole college.” (Works of John Ruskin, Volume 35, p. 204)

Examples of Buckland’s humor abound. Ruskin observed, “The Doctor had too much humour ever to follow far enough the dull side of a subject.” (p. 205) Reportedly, Buckland referred to geology as “undergroundology.” Once, warned by an observer that he might be in danger as he scaled the sheer wall in a quarry, the good doctor responded, “Never mind, . . . the stones know me.” (Life and Correspondence, p. 22) (Buckland was probably wearing his black academic gowns at the time, standard garb for the academic out in the field.) Then there was his burial plot, selected personally by this geologist, which was discovered, after his death, to be atop hard Jurassic period limestone that had to be blown apart before his grave could be dug . . . a last laugh, perhaps.

In many different ways, Buckland crossed boundaries. His generous spirit led him to befriend fossil collector Mary Anning, a poor, single woman. In this friendship and in the effort he made to generate financial support for her, Buckland ignored several social and economic class barriers that were rigidly in place in 19th Century Britain.

To Buckland, gastronomical boundaries were meaningless. His appetite for new and different foods was prodigious. Writer Augustus John Cuthbert Hare wrote, “Dr. Buckland used to say that he had eaten his way straight through the whole animal creation, and that the worst thing was a mole – that was utterly horrible.” One can only imagine a grinning Buckland “afterwards [telling] Lady Lyndhurst that there was one thing even worse than a mole, and that was a blue-bottle fly.” (As quoted in a note in Works of John Ruskin, p. 205) Others clearly joined in this exotic feast enthusiastically. Ruskin claimed that he “always regretted a day of unlucky engagement on which I missed a delicate toast of mice.” (p. 205)

Ah, a natural segue. Mary Anning had been finding curious fossilized lumps in the remains of her ichthyosaurs. She theorized that these lumps, which contained bone and shell, were fossilized excrement. Buckland became quite taken with these objects which he named coprolites – from the Greek kopros for dung and lithos for stone. A useful field of study was launched. Of course, his enthusiasm got the better of him and he had a dining room table inlaid with polished coprolites.

Buckland’s teaching was dramatic and flamboyant. Physician Henry Acland’s described one lecture he attended as a student.

[Buckland] paced like a Franciscan preacher up and down behind a long showcase, . . . . He had in his hand a huge hyena's skull. He suddenly dashed down the steps — rushed, skull in hand, at the first undergraduate on the front bench — and shouted, “What rules the world?” The youth, terrified, threw himself against the next back seat and answered not a word. He rushed then on me, pointing the hyena full in my face — “What rules the world?” “Haven't an idea,” I said. “The stomach, sir,” he cried (again mounting his rostrum) “rules the world. The great ones eat the less, and the less the lesser still.” (Sir Henry Wentworth Acland . . . A Memoir, p. 35)

And, then, there were his rooms. The stuff of fiction.

Geologist Roderick Murchison described a visit to Buckland’s rooms at Corpus Christi.

I can never forget the scene which awaited me. Having, by direction of the janitor, climbed up a narrow staircase, I entered a long, corridor-like room, which was filled with rocks, shells and bones in dire confusion, and in a sort of sanctum at the end was my friend in his black gown, looking like a necromancer, sitting on one rickety chair covered with some fossils, and clearing out a fossil bone from the matrix. (as quoted in Life and Correspondence, p. 10)

In the life she wrote of her father, Elizabeth Oke Gordon quoted this description (without attribution it seems) of Buckland’s lodging while at Lyme Regis –

his breakfast-table . . . [was] loaded with beefsteaks and belemnites, tea and terebratula, muffins and madrepores, toast and trilobites, every table and chair as well as the floor occupied with fossils, whole and fragmentary, large and small, with rocks, earths, clays, and heaps of books and papers . . . . (Life and Correspondence, p. 8)

Deborah Cadbury, in Terrible Lizard: The First Dinosaur Hunters and the Birth of a New Science, noted that the Dean “was a keen naturalist and kept a number of unusual pets. There were cages full of snakes and green frogs in the dining-room, where candles were placed in Ichthyosauri’s vertebrae. Guinea-pigs roamed freely throughout his office.” (p. 60) The night Buckland had a jackal loose in his quarters, his guinea pigs suffered significant attrition.

These descriptions brought to mind one of my favorite books, T.H. White’s The Sword in the Stone (1939). Buckland was truly a Merlin, tumbling straight out of the book, and clearly he would have felt at home in Merlin’s fantastic and chaotic room.

It was the most marvelous room that the Wart [the young Arthur] had ever been in.

There was a real corkindrill hanging from the rafters, very lifelike and horrible with glass eyes and scaly tail stretched out behind it. When its master came into the room it winked one eye in salutation, although it was stuffed. There were hundreds of thousands of brown books in leather bindings, some chained to the book-shelves and others propped up against each other as if they had had too much spirits to drink and did not really trust themselves. . . . Then there were stuffed birds, popinjays, and maggot-pies and kingfishers, and peacocks with all their feathers but two, and tiny birds like beetles, and a reputed phoenix which smelt of incense and cinnamon. . . . There were several boar’s tusks and the claws of tigers and libbards mounted in symmetrical patterns . . . a guncase with all sorts of weapons which would not be invented for half a thousand years, . . . a gold medal for being the best scholar at Eton, four or five recorders, a nest of field mice all alive-o, two skulls, . . . three globes of the known geographical world, a few fossils, . . . . (p. 31-32)

Well, Buckland would have wanted more fossils (and perhaps a bit more to eat, please).


I’m following myriad footsteps. So many writers have been captured by Buckland, finding his personality warm and attractive, enhanced by his myriad quirks and foibles. Among the works I’ve drawn from are the following:

The Life and Correspondence of William Buckland by his daughter Mrs. Gordon (1894)– the picture of Buckland was copied from the frontispiece of this volume;

The Works of John Ruskin, Volume 35, 1908;

Learning More . . . William Buckland, Oxford University Museum of Natural History (no date);

Terrible Lizard by Deborah Cadbury (2000);

The Fossil Hunter: Dinosaurs, Evolution, and the Woman Whose Discoveries Changed the World, by Shelley Emling (2009);

Sir Henry Wentworth Acland, bart., K.C.B., F.R.S., regius professor of medicine in the University of Oxford, A Memoir, by J.B. Atlay (1903);

Geology and Mineralogy Considered with Reference to Natural Theology, by William Buckland Volume 1, (1836);

Reliquiae Diluvianae, by William Buckland, second edition (1824);

The Ice Finders: How a Poet, a Professor, and a Politician Discovered the Ice Age, by Edmund Blair Bolles (1999).

Saturday, April 10, 2010

A Tale of Two Whales – I Won’t Know It When I See It

Because you have seen something doesn’t mean you can explain it. Differing interpretations will always abound, even when good minds come to bear. The kernel of indisputable information is a dot in space; interpretations grow out of the desire to make this point a line, to give it a direction.
~ Barry Lopez, Arctic Dreams: Imagination and Desire in a Northern Landscape (1986)

This posting is about the tension between the observed and the explained, particularly for the paleontology amateur.

On April 16, 1982, writer Barry Lopez was aboard a plane flying over the Bering Sea when he and the others on board the plane sighted two narwhals in the ice filled waters. These whales are literally fantastic, so striking in their appearance and so shrouded in the mythology of unicorns because males typically grow long, single lance-like tusks that stick out from their heads. According to Lopez, to witness living specimens of this specific species in the Bering Sea was a stunning biological event, unprecedented in the annals of science. (The narwhals pictured below are off West Greenland, not in the Bering Sea. This photo is from the National Oceanic and Atmospheric Administration, courtesy of Mads Peter Heide-Jørgensen, link here.)

The narwhals’ presence at that place was the “something” that Lopez wrote one might see but not necessarily explain. Explanations, he asserted, involve interpretations, and, ultimately, interpretations invoke agendas, either held by the interpreter or someone acting on the interpretation. As a result, the myriad possible uses to which an explanation might be put “make good scientists chary.” At the time he wrote, oil exploration was on the horizon for the area and the presence of narwhals might constitute a “complicating environmental nuisance” to those companies holding oil leases, seriously raising the stakes for any scientist choosing to give meaning to the sighting of the whales. As Lopez posited, good scientists “are sometimes reluctant to elaborate on what they saw, because they cannot say what it means, and they are suspicious of those who say they know.”

I am bound up in that tension. For many years, I worked for an organization whose primary asset was a reputation for impartiality – all of our written work went through the “Joe Friday filter” (“All we want are the facts, ma’am.”). I chafed at suppressing my natural inclination to interpret, to ascribe meaning. That’s what human beings do . . . no, not chafe, . . . look for meaning. Besides, the goal was a chimera, even the very selection of which “facts” to report and in what order moves the writer across the line. To take it to its logical conclusion, even the selection of the topic itself is laden with meaning. Lopez’s scientists knew that; “[s]ome even distrust the motives behind the questions.”

But, my dilemma in the realm of amateur paleontology is even more fundamental than challenging the asking of the question. Honestly, I would love to get into the mess of explaining or interpreting, but I often get stuck on the observation. It’s not because there is anything at all at stake in an explanation that I might attach, it’s because I literally don’t know the what of what I see. Lopez wrote about the “kernel of indisputable information,” but what is that? I suppose it’s where we reach common agreement, a starting point – I saw that happen or I saw that object. Not so easy when I rely on my untrained eye.

Here is a for instance.

On a raw March afternoon on the western Chesapeake Bay, I knew I had company on the beach though no one was in sight. It required no sixth sense to realize I was not alone, footprints marred the shoreline and the faint, pungent smell of cigarette smoke corrupted the air. In disgust, I dropped to my knees and began to crawl along the furthest reach of the murky waves, looking for what little might have escaped detection so far today, looking for what would take some work to discover. I turned over small stones. I reached under and behind smallish chunks of gray, clayey slump from the cliffs. The cliffs abutting the shore were composed of the fossil-rich Calvert Formation, deposited during the lower and lower-middle Miocene. (Slump is a nicely expressive geological term used to describe the movement downhill of a fairly unified mass of rock debris and soil, as well as to describe the material itself that moved en masse.)

Bone. There was lots of fossil bone on the beach. Clearly, some slab of cliffside replete with bone had fallen at some point in the last several days and been broken apart in the surf. My fingers found a long, tapered object nestled against the base of a rounded piece of the slump. What was it? A piece of bone? A tooth? I slipped it into a pouch for safe keeping. Once home, I soaked it clean and photographed it. (The composite photo shows either end of the specimen.)

At what point could this event of mine become a kernel of indisputable information? For Lopez, there was no doubt that what he and the scientists observed were narwhals in a place they were completely unexpected. As simple as it was, there was a high level of specificity and knowledge built into the statement he could immediately make that day above the Bering Sea.

In contrast, here’s what I could say that day on the Chesapeake Bay shoreline – “I found this long pointy thing among the float material.”

Frustrating. The difference? Education, training, experience, and the company of experts.

So, I worked hard at generating a kernel of indisputable information about my find. It was a challenge because, once you get beyond the sharks and shark relatives among marine vertebrates, you’ve left the world of good, comprehensive, accessible guides, printed or online. I found a lead in the material I had in my small library which suggested I had a tooth from a whale. I turned to the primary literature that might be available online, aided, in part, by the very useful Biodiversity Heritage Library (where digital versions of some of the old literature reside), as well as the Paleobiology Database (where taxonomic information can be found on fossil specimens of plants and animals). Nevertheless, without access to the resources of a large research university library, you have to be very lucky to find copies of all of the most relevant material. Further, when that literature lacks pictures or drawings clearly resembling what you have in hand, even finding that literature doesn’t solve the basic dilemma.

That’s when other eyes need to be brought into the effort. So, I showed the specimen to other amateur paleontologists who didn’t hesitate in their identification (ah, there’s the experience at work). And, finally, I sent pictures to a professional paleontologist along with my tentative identification, one that he promptly and graciously confirmed (he was bringing to bear extensive experience coupled with education and training).

What I found is a tooth from an extinct sperm whale, an Orycterocetus crocodilinus. According to Michael D. Gottfried et al. (Miocene Cetaceans of the Chesapeake Group, Proceedings of the San Diego Society of Natural History, 1994, Volume 29, pages 229-238 – available in the Biodiversity Heritage Library), the O. crocodilinus was the largest toothed whale or, for that matter, the largest cetacean found in the Calvert Formation, but only one of many different genera and species of cetaceans found in this formation. (I’m easily distracted by the little things – this whale had teeth in both its lower and upper jaws. In contrast, extant sperm whales apparently only have teeth in their lower jaws which fit into empty sockets in the upper jaws. Amazing.)

Okay, here then is my kernel of indisputable information – “I found the tooth of an extinct sperm whale, an Orycterocetus crocodilinus, on a beach on the western side of the Chesapeake Bay at the foot of a cliff composed of Calvert Formation material.”


I guess there’s nothing to explain about that, no interpretation to apply, because the larger meaning – that the O. crocodilinus inhabited the waters of the Salisbury Embayment when it covered this area during the early portion of the Miocene – is accepted. The still larger question of why it and the rest of the rich assemblage of odontoceti (toothed whales) lived in waters there when the Calvert Formation was being laid down is another story for which there is no consensus explanation (and, to which, I suppose, this fossil has nothing to offer).

End of story. Well, I also found this piece of bone on the beach the same afternoon (see picture below). On the left is the exterior of the specimen, on the right, the interior.

Note the two deep slash marks on what is apparently the outside of this bone fragment. Perhaps, because there is nothing at stake and this fossil begs for an explanation, I can be excused for moving from seeing to explaining, even if I cannot create that kernel of indisputable information, because I cannot identify with any certainty the origin of the bone or the source of those marks. It clearly helps to be able to involve someone else in an explanation, well, more than just involve. I’ll put it in someone else’s words while I’m at it. Gottfried et al. wrote:

One well-substantiated aspect of Chesapeake Group cetacean paleobiology is that both mysticetes [baleen whales] and odontocetes were preyed upon and/or scavenged by sharks. Cetacean bones regularly show linear grooves and gouges caused by shark bites during attacks and/or scavenging on carcasses.
Nature Blog Network