A Different Way to See Fossil Skeleton Mounts

Memorandum
To:  Myself
Subject:  Fossil Skeleton Mounts

Next time you are in a natural history museum (one with its fossil halls not undergoing renovation, so, forget the Smithsonian’s National Museum of Natural History), approach a fossil skeleton mount (that sine qua non of natural history museums), and try your damnedest to get beyond that initial awe-inspiring view.  Move as close as you’re allowed and look for those telltale signs of how that skeleton is being held together, how it’s holding its pose.  Look for the armature, that construct of metal that keeps the bones in place.  Yes, some armatures are internal, but a glimpse of a bit of metal sneaking through joints, from inside one bone into another, might be had (unless the joints are filled in with plaster).  An external armature might be as obvious as that holding up the neck and torso of the Apatosaurus skeleton dominating the Peabody Museum of Natural History’s Great Hall,

or it might be mostly hidden on the backside of the bones.

Look carefully at the bones.  Try to identify which of the skeleton’s bones are real fossils and which are casts.  Museums seem to be doing a better job these days of ensuring that fossil bones and casts can be distinguished from each other.  On older mounts this may not be so easy given that fossils and casts were often painted the same color.

If fossil bones can be distinguished from casts, consider the fate of those real fossil bones in such a mount.


It’s not clear when I’ll be able to follow the guidance in this memo.  [Later edit:  I will be able to follow the memo a lot sooner than I thought.  In the original version of this post, I wrote that "there are no fossil skeleton mounts on display, at the moment, at the NMNH (my natural history museum home)."  That's wrong.  There's at least one on display in the Sant Ocean Hall, a Basilosaurus, which is an ancient whale.  See Addendum at end.]  “Hatcher,” the cast of a Triceratops, which had been the sole dinosaur standing publicly in the museum after the Fossil Halls shuttered their doors earlier this year, is now behind temporary walls on the third floor as a new Late Cretaceous display takes shape around it and “Stan,” the museum’s T. rex cast.  When it opens in late November, this display will be up for five years as the Fossil Halls undergo their total makeover.

It’s not a coincidence that my interest in the process and consequences of including real fossils in skeleton mounts has taken flight just when the NMNH Fossil Halls are off-limits.  Most folks would be interested in the construction of the new NMNH displays, but, in my contrarian (perhaps better read “perverse”) fashion, I have become focused on the flipside of that, that is, on the dismantling of the myriad mounts that graced the Fossil Halls for the past century.

Some wonderful pictures of aspects of this deconstruction can be found in various postings in the Smithsonian blog Digging the Fossil Record:  Paleobiology at the Smithsonian.  To date, primarily featured in these posts is the taking apart and moving of the casts of “Hatcher” and “Stan” (cast mounts really aren't my concern here).

Visitors to the NMNH can witness some of that fossil mount deconstruction if they visit the museum’s FossiLab on the second floor and look in through the windows and watch the volunteers at work.  A recent entry in the Digging the Fossil Record blog highlighted the reopening of the FossiLab (which had briefly been shielded from public view in its previous location down in the Fossil Halls) and noted that some volunteers in the lab will be engaged in taking mounts apart and creating storage containers for the disarticulated bones.  The blogger (sadly, anonymous) comments that:

Dismantling skeletons is challenging.   Some of the mounts were built a long time ago and, since mounting techniques have changed a lot over time, nearly every mount was constructed in a different way.  Add in the problem that some of the bones are extremely fragile, and it can take some puzzling to figure out how to tease the mounts apart safely.  Once the bones are free of the armature they are photographed, logged into our collections database, and placed in archival storage where they will be preserved for scientific study and, perhaps, remounting for a future exhibit.

What happens to fossil bones when they are included in such mounts, particularly those “built a long time ago”?  There is literature out there about that.  A particularly depressing account comes from Robert L. Evander, senior principal preparator at the American Museum of Natural History, in a 2009 piece titled Armature Damage to a Mounted Specimen (this full-text link is listed on the Society of Vertebrate Paleontology’s Preparator’s Resources site).

The fossil mount in question is the skeleton of a glyptodont, a large (some were car-sized), armored, armadillo-like mammal, that dates back to at least the Miocene (23 to 5 million years ago) and which went extinct about 10,000 years ago.  Evander basically reverse-engineered the mount because the American Museum of Natural History’s Adam Hermann, who prepared the mount from the fossil bones in 1916 – 1917, left no detailed account of how that particular mount was constructed.  This was the final fossil skeleton he mounted, so, it may reflect the best of Hermann’s work.  Writes Evander,

Adam Hermann’s free mounts are deceptive.  The bones appear to be gently mounted upon cleverly-hidden external armatures closely shaped to the bones.  The few visible drill holes seem to be attaching individual bones to this external armature.

How did he achieve this deception?  Well, he drilled some 100 holes lengthwise into articulated fossil bones in order to run wires through them as part of the internal armature.  Spaces in joints were filled with plaster.  The external armature was shaped on the basis of plaster casts of the bones and was then attached to the fossil bones by more drilling through the bones, and the insertion of many more nuts and bolts.  Here’s an illustration of parts of this method from a piece Hermann wrote explaining his fossil preparation and mounting techniques; the caption tells the story (Modern Laboratory Methods in Vertebrate Palæontology, Bulletin of the American Museum of Natural History, Volume XXVI, 1909, p. 318):

Evander discovered that, because the armatures are harder than the bones, the points at which the armatures are screwed or bolted to the fossil bones are places where cracks and breaks have developed.

Conclusion?  Disaster.  Writes Evander of this fossil skeleton and others mounted by Hermann a century ago,

In some measure, Hermann’s mounting has adversely affected scientific access to these specimens, which will never be freely available to study in the disarticulated state.  Individual postcranial elements cannot be extracted easily.  Realistically, these mounts are permanent.

It is ironic (from our perspective a century later) that in the same 1909 piece of his, Hermann cautioned,

I therefore say, that a beginner in a palæontological laboratory never ought to be trusted with a delicate and rare specimen.  In my experience, I have seen irremediable damage done on account of poor judgment.  (p. 331)

Because Hermann-like treatment of fossil bones in mounted skeletons continued well into the 20th century, Evander finishes with a word for us frequenters of natural history museums:

Thus the mounted specimens seen in the museums of the world may be more fragile than they appear.

Though the doors to the NMNH’s Fossil Halls are shut, I wondered whether photographs I’d taken previously of its fossil skeleton mounts might show something about the mounting process employed.  One entry in Digging the Fossil Record includes a couple of pictures of the work on dismantling the museum’s Irish Elk with its massive antlers.  This particular mount, which went on display in 1872, was the Smithsonian’s first mount utilizing real fossil bones.  (A post on the superb blog Dinosours! [sic] discusses this skeleton mount.)  That prompted me to look at pictures I’d taken of the Irish Elk for a previous post on my blog.  The picture below (looking head on) shows the animal’s left antler and the wiring that holds up.  A couple of seemingly benign metal supports appear to cradle the antler from its ventral side.

But, the following picture (taken from behind the animal) suggests that all is not so benign.  The “cradling” arms are apparently bolted through the antler to a metal plate on the backside of the antler.  Further, part of a metal armature can be seen coming from the skeleton up onto the antler.  This too is apparently bolted to the antler.  I have marked several of these bolt heads.

I found a bit more in my collection of photos.  A set of photos of the NMNH’s Brontotherium hatcheri (taken for a blog posting about this rhinoceros-like herbivore related to horses that lived some 40 million years ago) may also be revealing.  Unfortunately, I cannot be certain when this mount was created (the fossil bones were discovered by John Bell Hatcher in 1887) nor exactly which of the bones in this skeleton are real.  But, the Smithsonian’s Collections Search Center describes this specimen as including the following fossil bones:  “skull elements, lower jaw, Axial element, thoracic vertebra, Appendicular elements, pelvic girdle, phalange.”  Here’s a picture of the rump of the specimen.  I’ve marked two places that particularly drew my attention.

The lower arrow points to part of the external armature, where it is bolted onto the skeleton.

Do these go into fossil bone?  I don’t know.  I’d love to be able to see this skeleton again.

The upper arrow points to part of the pelvic girdle (which is listed as fossilized bone but perhaps not all of it is) where a bolt head is obvious.

I assume this bolt attaches to the external armature which runs behind the bone, and I believe that this bolt runs through fossil bone, not plaster.  Of interest is the crack that radiates from the bolt head.  Evander would probably not be surprised.

Despite all of this, I’m not prepared to let the other shoe drop, the one that signals opposition to inclusion of any actual fossils in free standing skeleton mounts.  That’s a major bone (pun intended) of contention in paleontological circles where there is concern, not just for the damage done in the mounting process, but the potential damage incurred by being in such a mount for the long term, subject to changes in temperature and humidity, vibrations, and other harmful stresses.  Though mounting techniques have changed for the better, I may still be heading in the direction of advocating for nothing real in free-standing mounts (I would not be alone in holding that position).

For the time being, memo writer, I will consider such mounts from that different perspective and with a great deal of concern.

ADDENDUM

Ben, author of the blog Dinosours!, commented on this posting (see below) and asked my reaction to more "gentle" mounting techniques.  In my response, I referred to Digging the Fossil Record and a post there by Matt Carrano, Smithsonian Curator of Dinosauria, in which he stated that mounts in which fossil bones were drilled into were a thing of the past.  He included a photo of some of the sternum bones of an ancient whale currently on display at the NMNH; these bones were cradled in metal supports.  When I went back to his post, I was dismayed on two counts:  first, I should have quoted Carrano in my original post (I do in my response to Ben), and, second, I had completely overlooked the fossil skeleton mount of the ancient whale in the Sant Ocean Hall (which allowed me to make the erroneous assertion that, with the closing of the Fossil Halls, there weren't any still on display - indeed, there may still be others, my search continues).  I've had a chance to take a look at that whale skeleton (which includes real bones) and, though I tried, I found it difficult to really observe how all of it was mounted (sorry, memo writer) because the whole thing floats high overhead, suspended from the ceiling (and accompanied by two cast mounts).  Clearly, the sternum bones are being supported without drilling, as apparently are the vertebrae.  Also, real bone and cast are easily distinguishable, a good practice.  But, I cannot be so sure that some bolts aren't still penetrating real bone.  Unfortunately, I cannot get close enough to be sure.  Here is a picture of a few of the ribs and a flipper (real bone is darker and rougher).  Perhaps I'm just inclined to see it, but it does look to me as though some real bone may have been drilled into.

Waiting in the Wings for a Long Time

The block of rock sits on a table in the lab that the Smithsonian’s National Museum of Natural History has positioned in the public exhibit area.  This lab (the so-called FossiLab), with its glass windows on two sides, offers visitors a view of trained volunteers preparing some of the museum’s fossils for study and display.  From the block of rock in the lab, two converging rows of broad, glistening grey teeth have partially emerged, exposed by the rapid, targeted blows of an air scribe (think little jackhammer capable of being controlled with precision).

According to the small sign that has been propped up against it, this is the upper jaw of a Brontotherium, a rhinoceros-like herbivore related to horses that lived some 40 million years ago.  On display elsewhere in the museum is the full skeleton of a Brontotherium hatcheri, showing the massive jaws of the animal and the distinctive horn ornamentation on its snout.  The fossil in the lab seems to be missing its horns.

A small drawing accompanying the display shows how the head might have appeared in life.

But that information on the sign isn’t what really registered with me; rather, what caught my attention was the name of the collector – John Bell Hatcher, a man who occupies a special place in my clutch of paleontological heroes.  This ungainly block of matrix seems to connect more vividly to the man himself than do any of his other finds on display in the museum.  (The image below appeared in the American Geologist (March 1905), accompanying Hatcher's obituary.)

Hatcher was a risk-taking adventurer in the classic mode, and, above all, a consummate fossil hunter.  He was one of the country’s greatest fossil hunters during the last two decades of the 19th century, and was coming into his own as a professional paleontologist in the academic science world when his life was cut short by typhoid fever in 1904 at age 42.  Perhaps it is surprising that he lived so long given how often he seemed to take his life into his own hands out in the field.

While a student at Yale University’s Sheffield Scientific School, Hatcher fell under the sway of Yale paleontologist Othniel Charles Marsh and immediately upon graduation in 1884 began collecting at a torrid pace.  (At this juncture, it appeared Marsh had vanquished Edward Drinker Cope in the so-called dinosaur wars, a subject covered in a previous posting.)  During the summer of 1884, Hatcher apprenticed with commercial fossil collector Charles H. Sternberg in Kansas, but whether his preternatural skill at finding fossils was so obvious or he grew frustrated with what he considered Sternberg’s carelessness, after a month Hatcher was collecting on his own.

Over the next decade, he collected for Marsh throughout the west.  Spectacular find followed spectacular find, and trains carried boxcars filled with his fossils east to New Haven.  Hatcher’s success only fueled Marsh’s insistence that he stay in the field.  Particularly noteworthy were the Brontotherium fossils that Hatcher sent Marsh in 1886 and 1887 from the Western Nebraska Badlands, and the Ceratopsidae (“horned dinosaurs”) he subsequently found in Wyoming.  In fact, Hatcher’s name may be most often associated with the latter, particularly the Triceratops.  He found the first of these dinosaurs in 1889, and many more followed over the course of the next four years.  A brief foray, at Marsh’s instigation, in the winter of 1887 – 1888 to the Cretaceous formations in Maryland set the foundation for all future work on dinosaurs in this area.  (This was touched on in a recent posting on dinosaurs in Maryland.)

In 1893, Hatcher severed his ties with Yale, frustrated by Marsh’s unwillingness to let his assistants publish in their own names and aware that Marsh’s financial resources were drying up after Cope’s counterattack deprived Marsh of the position of chief paleontologist of the U.S. Geological Survey.  (As part of the fallout, many of the fossils collected by Hatcher for Marsh were claimed by the U.S. Government for the Smithsonian.  Presumably the Brontotherium jaw being prepped in the FossiLab was one of those fossils that worked their way from New Haven to Washington, D.C.)

Hatcher became curator of vertebrate paleontology at Princeton University.  While at Princeton, between 1896 and 1899, he undertook three fossil collecting expeditions to Patagonia (southern Chile and Argentina).  At the turn of the century, Hatcher assumed the position of curator of paleontology and osteology in the Carnegie Museum in Pittsburgh.

To capture the full flavor of the man, one need only read Hatcher’s account of his three Patagonian expeditions.  His Narrative of the Expeditions often reads as a Victorian era adventure novel, one still waiting to be made into a movie.  I can hear and see him laugh when told what he proposes to do is foolhardy.  He mounts his horse and rides out, right into disaster, perhaps the one about which he was forewarned or something else.  He comes through it, often much the worse for wear, but alive and eager to do it all again.  (John Bell Hatcher, Narrative of the Expeditions, Geography of Southern Patagonia, Volume I of the Reports of the Princeton University Expeditions to Patagonia, 1896 – 1899 (1903))

On the first expedition, Hatcher arrived in Buenos Aires, Argentina, in March, the start of the winter in the southern hemisphere.  Advised to put off his quest for fossils until spring, with some counseling him that no man could survive being out in the field during the winter, he shrugged it all off.

[W]e had tented it for many years on the wind-swept plains of Wyoming, Montana, and the Dakotas, often with the thermometer far below zero, and had no uneasiness as to our ability to survive successfully whatever blizzard Patagonia might have in store for us.

Apparently not until the second expedition, which began at the end of 1897 and lasted until the middle of September, 1898, did Hatcher feel the full force of a Patagonian winter, but then it unleashed its full fury.  His misery was compounded by a sustained attack of “rheumatism” which laid him up in the field for some six weeks.  (It’s not clear to me what he was actually suffering from, but often over the years his joints would swell and become extremely painful.)  At the end of June, when he was finally able to stand again, he and his sole companion began the 500 mile ride to Gallegos.  For over a month, “we dragged slowly through fields of snow and ice, shovelling away the snow each night over an area sufficient to accommodate our beds.  We were frequently hard pressed to find grass sufficient for our horses, . . . .”

Some 125 miles from Gallegos, Argentina, Hatcher struck out alone with five horses, the other member of this expedition having decided that he’d had enough.  The heavy rain that marked the early part of the day of his departure changed to driving snow as the temperature fell.  By ten o’clock that night when he finally reached a ranch, the area was in the grip of a full-throated blizzard.  For two days he waited it out.  Then, despite pleas that he stay put, Hatcher went on.  Though his rheumatism caused him great agony mounting and dismounting, the only way to traverse some of the sheer ice sheets he came upon was to lead the horses himself on foot.  At the end of five days he finally reached a ranch in North Gallegos with but a single horse, the other four fatigued animals having been abandoned in the ice and snow.

The single event that reveals to me the courage of the man occurred during his first expedition.  Hatcher could be counted on to find prodigious quantities of fossils and this expedition was no exception.  In October, 1896, he and his sole assistant arranged for the shipment of over four tons of fossils to Punta Arenas, Chile.  (This was the second shipment to go out and would be dwarfed by the third shipment that came a bit later.)  From Punta Arenas, this shipment would be transferred to a ship heading to New York; Hatcher decided that he needed to oversee the transfer in person, so he began the 225 mile ride to Punta Arenas on horseback alone.

The family at the ranch he reached his first night out in Killik Aike (part of the Welsh community in this part of Patagonia) pleaded with him to take more than a single horse for the rest of his trip.  He dismissed this advice, observing that he often made trips of 500 to 1,000 miles in the U.S. on just one horse.  Though the family was right to be worried and Hatcher ultimately did have to purchase a new horse to complete the trip, the lack of a second horse was not what nearly cost him his life.

During the afternoon of the third day on the trail, Hatcher dismounted to stretch his legs and allow his horse to eat and drink.  When he came to saddle up again, he saw that the horse had looped one hoof through the reins.  Hatcher stooped and released the hoof, but as he did so, something startled the animal who jerked his head down just as Hatcher started to rise.  A broken shank on the bit sliced into his scalp “in such a manner as to loosen the latter over a considerable area, at the same time rupturing some of the blood vessels and causing the wound to bleed very profusely.”  Hatcher’s efforts failed to stem the bleeding and so he continued on his way, blood pouring down his chest and saturating his clothes.  He traveled  for awhile in that condition but feeling faint (finally . . . I felt faint just reading the account) he dismounted, unsaddled and picketed his horse, and lay down, but not before wrapping the wound with two handkerchiefs and ramming his hat down over his head to hold the cloth in place.  Only late that night did the bleeding stop.  The next day he started out again, arriving at a ranch by mid morning, only to be told to move on by a cook, the only man not out working the ranch.  Hatcher tried to reason with him but, failing that, simply pushed his way past and commandeered food and coffee, and washed his wound and dressed it.  He then mounted up and was back on his way.

Still on the trail, his head wound became infected and he came down with a heavy, lingering cold.  On reaching Punta Arenas, he consulted with one of the two doctors in town who recommended that he be “bled.”  “I was not long in deciding that I would be my own physician and surgeon, well knowing that since the first night on the pampa after my accident I had been in no way suffering form an excess of blood.”

Hatcher engaged fully in the hunt for fossils whatever the physical cost, a reflection of his attitude about the best way to study and understand natural history.  In his account of the Patagonian expeditions, he spelled this out in a single, nearly stream of consciousness, run-on sentence:

The study of nature is always instructive and interesting, even inspiring and impressive, if the student be a real lover of nature seeking for truth at first hand and for truth’s sake, and not merely a fireside naturalist, who seldom, goes beyond his private study or dooryard, and either contents himself, like other parasites, with what is brought to him, like a bird of prey forcibly seizes upon the choicest morsels of his confreres, with little or no consideration for the rights of wishes of those who have brought together the material at so great expense of time and labor.

Like other parasites!!  What a caustic comment.  Though I read this passage as a bitter thrust at O.C. Marsh (who died in 1899), that reflects only part of Hatcher's complicated relationship with Marsh.  Regardless of how his relationship with Marsh ended, Hatcher acknowledged the pivotal role his late mentor had played in his life.  He dedicated the Narrative of the Expeditions to “The Memory of Othniel Charles Marsh:  Student and Lover of Nature.”

Beyond the fact that J.B. Hatcher was the collector of the Brontotherium jaw being prepped at the National Museum of Natural History, something else struck me about this fossil.  Assuming it was found and sent to Marsh in 1886 or 1887 from the Nebraska Badlands, only now, some 125 years later is this specimen being prepared for study and perhaps display.

This century and a quarter is insignificant in terms of the millions of years that span the time from the death of the animal to its discovery by Hatcher, but its significance cannot be gainsaid on the human scale of time.  Perhaps it’s not a great tragedy that Hatcher never saw this particular fossil cleared of its matrix; clearly, there are tons of fossils he never saw prepped.  Indeed, of the material Hatcher shipped to Marsh from the Brontotherium Beds, Yale paleontologist Charles Schuchert commented in 1905 on the sheer volume collected, writing, “It will be many years before all these collections are worked out.”  ([Obituary of] John Bell Hatcher, The American Geologist, March, 1905.)

Waiting in the wings.  That’s the image I have of myriad unprepped and unidentified fossils sitting in storage in museums around the world.  This is no criticism of the museums because I know this work takes money, time, and skilled people, and I can only imagine how short museums must be on all three.

While working on Hatcher’s background for this posting this past week, I happened to come across a fascinating posting  (December 6, 2011) in Science 2.0 on the identification of a new Ceratopsidae dinosaur species.  Given the long wait I’d discovered for Hatcher’s Brontotherium fossil, the title of the Science 2.0 article was an effective hook:  Spinops Sternbergorum - Horned Dinosaur Discovery 100 Years in the Making.  The scientific article formally identifying the new species appears in the current issue (Volume 56, Issue 4, 2011) of Acta Palaeontologica Polonica and is titled A New Centrosaurine from the Late Cretaceous of Alberta, Canada, and the Evolution of Parietal Ornamentation in Horned Dinosaurs (Andrew A. Farke, et al.).

This is another story of a long wait in the wings, in this case of nearly a century.  These fossils upon which the new species identification is based were found in 1916 by two collectors working in Alberta, Canada, on behalf of the British Museum (the Natural History Museum, London).  Though the collectors believed this to be important material, the Keeper of Geology at the Museum thought otherwise, using the word “rubbish” in one description of it.  “Consequently, most of the material remained overlooked and unprepared for over 90 years.”  (Farke, p. 693)  Though I’m not sure what prompted a shifting of the spotlight to this material, it apparently was worth it.  S. sternbergorum, a not too distant relative of Triceratops, potentially offers new insight into the evolution of the spikes on animal’s neck frill.

The collectors of these fossils?  The new species name tells the story – a couple of members of the so-called Sternberg dynasty of collectors.  In this case, Charles H. Sternberg and one of his sons, Levi.  Yes, the same Charles H. Sternberg who briefly oversaw the field work in Kansas of the young John Bell Hatcher.


Additional Sources

Other materials on Hatcher that were useful in the preparation of this posting include:

George F. Eaton, Obituary [of John Bell Hatcher], The American Journal of Science (August 1904).

Tom Rea, Bone Wars:  The Excavation and Celebrity of Andrew Carnegie’s Dinosaur  (2001).

O.C. Marsh and E.D. Cope:  A Rivalry, American Experience.

Two generations of the Sternberg family commercially collected fossils, establishing a most productive fossil hunting dynasty.  Interesting material on Charles H. Sternberg and others in his family appear in:

John Acorn, Deep Alberta:  Fossil Facts and Dinosaur Digs (2007).

Detailed profiles appear on Mike Everhart’s website Oceans of Kansas, including one of Charles H. Sternberg.

Mike Everhart, Sea Monsters:  Prehistorical Creatures of the Deep (2007).

Charles H. Sternberg, The Life of a Fossil Hunter (1909).