This famous Edmontosaurus skeleton was found with intricate traces of skin over much of its body. Image in Osborn, 1916, from Wikipedia.

Last week, I wrote about attempts by paleontologist Phil Bell and colleagues to extract biological secrets from fossilized traces of dinosaur skin. Among the questions the study might help answer is why so many hadrosaurs are found with remnants of their soft tissue intact. Specimens from almost every dinosaur subgroup have been found with some kind of soft tissue preservation, yet, out of all these, the shovel-beaked hadrosaurs of the Late Cretaceous are found with skin impressions and casts most often. Why?

Yale University graduate student Matt Davis has taken a stab at the mystery in an in-press Acta Paleontologica Polonica paper. Previously researchers have proposed that the abundance of hadrosaur skin remnants is attributable to large hadrosaur populations (the more hadrosaurs there were, the more likely their skin might be preserved), the habits of the dinosaurs (perhaps they lived in environments where fine-resolution fossilization was more likely) or some internal factor that made their skin more resilient after burial. to examine these ideas, Davis compiled a database of dinosaur skin traces to see if there was any pattern consistent with these ideas.

According to Davis, the large collection of hadrosaur skin fossils isn’t attributable to their population sizes or to death in a particular kind of environment. The horned ceratopsid dinosaurs–namely Triceratops–were even more numerous on the latest Cretaceous landscape, yet we don’t have as many skin fossils from them. And hadrosaur skin impressions have been found in several different kinds of rock, meaning that the intricate fossilization occurred in multiple types of settings and not just sandy river channels. While Davis doesn’t speculate about what made hadrosaurs so different, he proposes that their skin might have been thicker or otherwise more resistant than that of other dinosaurs. A sturdy hide might have offered the dinosaurs protection from injury in life and survived into the fossil record after death.

Still, I have to wonder if there was something about the behavior or ecology of hadrosaurs that drew them to environments where there was a greater chance of rapid burial (regardless of whether the sediment was sandy, silty or muddy). And the trouble with ceratopsids is that they have historically been head-hunted. Is it possible that we’ve missed a number of ceratopsid skin traces because paleontologists have often collected skulls rather than whole skeletons? The few ceratopsid skin fossils found so far indicate that they, too, had thick hides ornamented with large, scale-like structures. Were such tough-looking dinosaur hides really weaker than they appear, or is something else at play? Hadrosaurs may very well have had extra-sturdy skin, but the trick is testing whether that characteristic really accounts for the many hadrosaur skin patches resting in museum collections.

Reference:

Davis, M. 2012. Census of dinosaur skin reveals lithology may not be the most important factor in increased preservation of hadrosaurid skin. Acta Paleontologica Polonica http://dx.doi.org/10.4202/app.2012.0077

Osborn, H. 1916. Integument of the iguanodon dinosaur Trachodon. Memoirs of the American Museum of Natural History. 1, 2: 33-54

Sternberg, C.M. 1925. Integument of Chasmosaurus belli. The Canadian Field Naturalist. XXXIX, 5: 108-110

Dinosaur reconstructions often begin and end with bones. Dinosaur muscles and organs usually don’t survive the processes that turn bodies into fossils, with casts of the intestinal tract–called cololites–and other soft tissue clues being rarities. Restoration of those squishy bits relies on comparison with modern animals, muscle scars on bones and other lines of evidence. Yet paleontologists have found a great deal of dinosaur skin impressions, especially from the shovel-beaked hadrosaurs of the Cretaceous. We probably know more about the actual external appearance of hadrosaurs such as Edmontosaurus and Saurolophus than almost any other dinosaurs.

Hadrosaurs found with skin impressions are often called “mummies.” This isn’t quite right. Natural mummies–human and otherwise–preserve the organism’s actual skin due to any number of environmental conditions, from arid heat to extreme cold or preservation in a bog. What we know of hadrosaur skin isn’t the original organic material that made up the dinosaur’s flesh, but rock that has made a mold or cast of the dinosaur’s pebbly outer coating. Terminology aside, though, paleontologists have found enough dinosaur skin impressions that the fossils can be used to detect different ornamentation patterns and may even help distinguish one species from another. Earlier this year, paleontologist Phil Bell demonstrated that two Saurolophus species exhibited different patterns on their bumpy skins–an additional kind of ornamentation aside from their prominent head crests.

But how do skin impressions became preserved? And why are such traces so often found with hadrosaurs but not other dinosaurs? Is it because hadrosaurs frequented environments where such preservation was more likely, or are we just missing similar impressions associated with other fossils? There’s much about dinosaur skin impressions that we don’t yet understand. In the video above, Bell gives us a preview of new research on a recently collected hadrosaur that has skin traces, in the hope that some high-tech analysis will help him better understand how such fossils form.

The reconstructed skull of Eolambia–based on a partial adult skull and scaled juvenile elements–and a restoration by artist Lukas Panzarin. From McDonald et al., 2012.

Hadrosaurs were not the most charismatic dinosaurs. Some, such as Parasaurolophus and Lambeosaurus, had ornate, hollow crests jutting through their skulls, but, otherwise, these herbivorous dinosaurs seem rather drab next to their contemporaries. They lacked the garish displays of horns and armor seen among lineages such as the ceratopsians and ankylosaurs, and they cannot compete with the celebrity of the feathery carnivores that preyed upon them. Yet in the habitats where they lived, hadrosaurs were among the most common dinosaurs and essential parts of their ecosystems. What would tyrannosaurs do without ample hadrosaurian prey?

While many hadrosaurs might seem visually unremarkable next to their neighbors, the wealth of these dinosaurs that paleontologists have uncovered represent a huge database of paleobiological information waiting to be tapped for new insights into dino biology and evolution.

In order to draw out dinosaur secrets, though, paleontologists need to properly identify, describe and categorize the fossils they find. We need to know who’s who before their stories can come into focus. On that score, paleontologist Andrew McDonald and colleagues have just published a detailed catalog of Eolambia caroljonesa, an archaic hadrosaur that was once abundant in Cretaceous Utah.

Eolambia is not a new dinosaur. Discovered in the roughly 96-million-year-old rock of the Cedar Mountain Formation, this dinosaur was named by paleontologist James Kirkland–a coauthor on the new paper–in 1998. Now there are multiple skeletons from two different localities representing both sub-adult and adult animals, and those specimens form the basis of the full description.

While the new paper is primarily concerned with the details of the dinosaur’s skeleton, including a provisional skull reconstruction accompanied by an excellent restoration by artist Lukas Panzarin, McDonald and coauthors found a new place for Eolambia in the hadrosaur family tree. When Kirkland announced the dinosaur, he named it Eolambia because it seemed to be at the dawn (“eo”) of the crested lambeosaurine lineage of hadrosaurs. But in the new paper McDonald, Kirkland and collaborators found that Eolambia was actually a more archaic animal–a hadrosauroid that falls outside the hadrosaurid lineage containing the crested forms.

Much like its later relatives, Eolambia would have been a common sight on the mid-Cretaceous landscape. The descriptive paper lists eight isolated animals and two bonebeds containing a total of 16 additional individuals. They lived in an assemblage that was right at the transition between the early and late Cretaceous faunas–tyrannosaurs, deinonychosaurs and ceratopsians have been found in the same part of the formation, as well as Jurassic holdouts like sauropods. How this community fit into the grander scheme of dinosaur evolution in North America is still coming together, though. The Early and Middle parts of the Cretaceous are still poorly known, and paleontologists are just getting acquainted with Eolambia, its kin and contemporaries.

References:

McDonald, A., Bird, J., Kirkland, J., Dodson, P. 2012. Osteology of the basal hadrosauroid Eolambia caroljonesa (Dinosauria: Ornithopoda) from the Cedar Mountain Formation of Utah. PLOS One 7, 10: e45712

Fossil teeth, found by Ferdinand Hayden in Montana, which Joseph Leidy attributed to the dinosaur “Trachodon.” From Leidy, 1860, image from Wikipedia.

More than 150 years ago, a young naturalist picked up a collection of isolated teeth and bones weathering out of the ground in what is now northern Montana. These weren’t the remains of any living animals but vestiges of Cretaceous life that naturalists had only just begun to recognize and categorize. Even the young explorer who picked them up, Ferdinand Hayden, didn’t know what they were, and so he sent them back east for identification. As the Philadelphia-based polymath Joseph Leidy later determined, some of Hayden’s scrappy finds were dinosaurs–among the earliest recorded dinosaur discoveries in the American West.

Hayden wasn’t the first person to discover fossils in North America. First Nations peoples were familiar enough with strange fossil bones that the prehistoric remnants inspired their legends, and naturalists such as Thomas Jefferson puzzled over what was left of Ice Age mammals such as mastodons and giant ground sloths. Dinosaurs got a relatively early start, too, although naturalists didn’t always realize what they had found. Even though he misidentified the fossil as part of a giant fish, explorer Meriwether Lewis found part of a dinosaur rib in the vicinity of what is now Billings, Montana, when he passed through the area in 1806 on his famous expedition with William Clark. And starting in the 1830s, the Amherst geologist Edward Hitchcok described scores of Early Jurassic dinosaur tracks, which he attributed to prehistoric birds.

All the same, the bits and pieces Hayden found showed that the wilds of the western territories harbored dinosaurs and were a portent of the “Bone Wars” that would later unfold among the badlands of Montana, Wyoming and Colorado. Now, the Great Falls Tribune reports, paleontologist Kristi Curry Rogers and her geologist husband Ray Rogers believe that they have located the place where Hayden stumbled across the Cretaceous tidbits.

Even though Hayden did not keep detailed field notes, a brief mention in a technical paper of the area in which he found the fossils helped the Rogers team narrow down their search area. From there, they followed game trails and looked for sites that would have produced the kinds of fossils Hayden picked up. They can’t be entirely certain that their site is the very same Hayden sampled, and they are wary of divulging the exact location given how often fossil sites are vandalized, but the Rogers have placed Hayden’s stop somewhere in Montana’s Missouri River Breaks north of Winifred. With assistance from the Bureau of Land Management, they want the area to be placed in the National Register of Historic Places–a testament to Hayden’s lasting contribution to American paleontology.

One of the vertebrae–as seen from the front (a) and back (b)–used to name the dinosaur Arkharavia heterocoelica. Although originally thought to come from a sauropod, it turns out that this bone belonged to a hadrosaur. From Alifanov and Bolotsky, 2010.

Dinosaurs come and go. Even though paleontologists are naming new dinosaurs at a fantastic rate–hardly a week seems to go by without the announcement of a previously-unknown species–researchers are also sinking and revising previously-discovered taxa as new finds are compared against what has already been found. The ever-growing ontogeny debate–which threatens the horned dinosaur Torosaurus and the hadrosaur Anatotitan, among others–is just one part of these paleontological growing pains. Sometimes dinosaur identity crises can be even more drastic.

Yesterday I wrote about a new paper by paleontologist Pascal Godefroit of the Royal Belgian Institute of Natural Sciences and co-authors that redescribes the charismatic hadrosaur Olorotitan. As I read through the paper, a brief, but significant, side note caught my eye. In the section describing the deposits in which the known Olorotitan skeletons were found, the paper mentions that paleontologists V.R. Alifanov and Yuri Bolotsky described a sauropod–one of the long-necked, heavy bodied dinosaurs–from the same locality. On the basis of a tooth and several isolated tail vertebrae, Alifanov and Bolotsky named the dinosaur Arkharavia in their 2010 description. Since the encasing rock was deposited during the latest Cretaceous, around 70 million years ago or so, this was apparently one of the last sauropods on earth.

Only Godefroit and colleagues, including Yuri Bolotsky, have now revised the identity of Arkharavia. In their paper on Olorotitan, the paleontologists make the passing comment that “those vertebrae [used to name the sauropod] likely belong to hadrosaurid dinosaurs.” Rather than being a previously-unknown kind of sauropod, then, the fossils used to name “Arkharavia” probably belonged to one of the two hadrosaurs that dominate the locality–Olorotitan or Kundurosaurus.

This isn’t the first time a hadrosaur has been confused for a sauropod. Two years ago, paleontologists Michael D’Emic and Jeffrey Wilson of the University of Michigan and Richard Thompson of the University of Arizona determined that so-called “sauropod” vertebrae found in the 75-million-year-old rock of Arizona’s Santa Rita Mountains should actually be attributed to a hadrosaur akin to Gryposaurus. Fragmentary dinosaurs can be extremely tricky to identify correctly.

These changes aren’t frivolous. Identifications of isolated bones affect our understanding of dinosaur evolution and history. In the case of the misidentified hadrosaur bones from Arizona, the revised diagnosis altered the picture of when sauropods returned to North America after an absence spanning tens of millions of years. (This is called the “sauropod hiatus” by specialists.)

In the case of Arkharavia, the fossils represented one of the last dinosaurs in eastern Russia before the end-Cretaceous mass extinction. Misunderstood as sauropod bones, the fossils appeared to be the scrappy evidence for an entire group of dinosaurs at the locality. Properly understood as hadrosaur tail bones, though, the fossils become isolated elements from a group already known to be numerous in the fossil beds. While these changes might sound small, they can certainly influence grand-scale analyses of when certain groups of dinosaurs appeared or went extinct. There’s a big difference between sauropods living alongside hadrosaurs just before the end-Cretaceous mass extinction and a habitat dominated by hadrosaurs and devoid of sauropods. Even isolated bones can make a big difference.

References:

Alifanov, V., Bolotsky, Y. (2010). Arkharavia heterocoelica gen. et sp. nov., a New Sauropod Dinosaur from the Upper Cretaceous of the Far East of Russia Paleontological Journal, 44 (1), 84-91 DOI: 10.1134/S0031030110010119

Godefroit, P., Bolotsky, Y.L., and Bolotsky, I.Y. (2012). Olorotitan arharensis, a hollow-crested hadrosaurid dinosaur from the latest Cretaceous of Far Eastern Russia. Acta Palaeontologica Polonica DOI: 10.4202/app.2011.0051

The reconstructed skeleton of Olorotitan, from Godefroit et al., 2012.

Olorotitan was one of the most elegant dinosaurs of all time. The 26-foot-long hadrosaur, found in the Late Cretaceous rocks of eastern Russia, had the typical deep tail, beefy legs and slender arms of its kin, but a fan-shaped crest jutting out of the back of the dinosaur’s skull gave it a striking profile. As with its North American cousins Corythosaurus and Lambeosaurus, the hollow head ornament is what makes this dinosaur stand out.

Paleontologist Pascal Godefroit of the Royal Belgian Institute of Natural Sciences and colleagues initially described Olorotitan in 2003. Now, in Acta Palaeontologica Polonica, Godefroit joins co-authors Yuri Bolotsky of the Russian Academy of Sciences and Ivan Bolotsky of Jilin University in China in a thorough assessment of the hadrosaur’s osteology and relationships. The study is based on a mostly complete skull and skeleton–the dinosaur is primarily missing its hands and feet, perhaps because scavengers consumed them before the Olorotitan was buried, but much of the rest of the skeleton was found in articulation.

The hadrosaur’s crest is the most distinct part of its skeleton. As the researchers write, “The large crest dominates the skull.” While crushed and not entirely complete, the preserved part of the crest nevertheless shows that the ornament curved up high over the skull. According to the paper’s reconstruction of the missing skull parts, the front spire of the crest supported a backwards-pointing fan of bone.

This crest was hollow, just as in North American lambeosaurine hadrosaurs such as Parasaurolophus. Indeed, these ornaments were not just for show, but probably allowed adorned dinosaurs to allow them to bellow low-frequency calls over long distances. Each species had their own call based on the shape of the nasal passage inside their skull. Frustratingly, though, the relevant portions of the crest in the Olorotitan skull are either fragmentary or crushed, so no one knows the route its nasal passage took. We need another skull to find out.

There are a few other curious things about Olorotitan. The dinosaur’s skeleton has 18 neck vertebrae–several more than other hadrosaurs. While certainly not in the sauropod class of magnificent necks, Olorotitan had a relatively elongated neck compared with its closest relatives, which is fitting for a creature’s whose name translates to “gigantic swan.”

Further along the spine, the dinosaur’s skeleton seemed to have 15 sacral vertebrae (the fused vertebrae that run through the upper blades of the hips). But, as Godefroit and collaborators point out, the actual number of sacral vertebrae is probably slightly lower. The principal, mostly-complete Olorotitan skeleton used in the study was apparently an old individual in which extra bones of the lower back and tail fused to those at the sacrum.

But, in comparison with another specimen, the estimated age of the mostly-complete Olorotitan shows how size can be a deceiving factor in determining how old a dinosaur was. Godefroit and colleagues point out that various aspects of the old animal’s skeleton were fused, and that the dinosaur shows evidence of many repaired fractures. But there’s another partial Olorotitan skeleton–principally a portion of the lower back, hip and part of the tail–that appears to be of “equivalent size” that doesn’t show these age-related characteristics. If this is accurate, it’s a reminder that dinosaurs varied in terms of size at any particular age–just like us. That’s a simple fact, but something worth keeping in mind as researchers continue to debate how dinosaurs grew up. Skeletal indicators of age, such as bone fusion and the microstructure of skeletal elements, are more important than size alone.

Reference:

Godefroit, P., Bolotsky, Y., Alifanov, V. (2003). A remarkable hollow-crested hadrosaur from Russia: an Asian origin for lambeosaurines Comptes Rendus Palevol, 2, 143-151 DOI: 10.1016/S1631-0683(03)00017-4

Godefroit, P., Bolotsky, Y.L., and Bolotsky, I.Y. (2012). Olorotitan arharensis, a hollow-crested hadrosaurid dinosaur from the latest Cretaceous of Far Eastern Russia. Acta Palaeontologica Polonica DOI: 10.4202/app.2011.0051

A sculpture of Pentaceratops outside the New Mexico Museum of Natural History and Science. Could sexual selection account for the prominent ornaments of this dinosaur? Photo by the author.

Non-avian dinosaurs were weird. That’s one of the reasons we love them so much. There’s nothing quite like a slender-necked Barosaurus, a beautifully-crested Dilophosaurus or lavishly-ornamented Pentaceratops alive today. If such dinosaurs were anything, they were bizarre, but why were they so strange? Each case demands its own explanation, and paleontologists have continuously tussled over whether particular ornaments were weapons, sexual displays or something else.

According to an in-press paper at Trends in Ecology & Evolution, at least some weird dinosaur features may best be understood in the context of mate competition, mate choice and sexual signalling. The paper, by entomologist Robert Knell and colleagues, is the latest in a long-running debate over whether sexual selection had any influence on dinosaur lives and how to detect the hallmark of such pressures.

The debate has been going on for years but only recently increased in intensity. In a 2010 study, paleontologists Kevin Padian and Jack Horner rightly noted that sexual dimorphism–or a significant anatomical difference between the sexes–has never been conclusively demonstrated among non-avian dinosaurs. The idea had been proposed for a variety of dinosaurs using a number of skeletal landmarks, but none of the hypotheses have stuck. Even if sexual dimorphism existed among dinosaurs, we lack the sample size to identify the phenomenon. More than that, Padian and Horner cited the lack of sexual dimorphism as a sign that sexual selection probably wasn’t an important facet in the origin and modification of bizarre dinosaur features. Instead, the researchers hypothesized, the various horns, crests, plates and other ornaments evolved because of species recognition–the ability for dinosaurs to quickly and easily identify members of their own species.

Other researchers disagreed. Knell and Scott Sampson had a brief exchange in the journal pages with Padian and Horner. This was followed by a paper by Dave Hone and co-authors that suggested that mutual sexual selection might explain the mystery of why dinosaurs had bizarre ornaments but don’t seem to exhibit sexual dimorphism. Under this hypothesis, both males and females may prefer mates with elaborate visual signals, and therefore the same prominent structures would be expressed in both sexes. This kind of sexual selection has been documented in modern avian dinosaurs, but, until now, hasn’t been considered as an explanation for the ornamentation of non-avian dinosaurs. Even though mutual sexual selection has not been proven as an evolutionary driver among extinct dinosaurs, it’s a possibility worth considering.

The new paper by Knell and co-authors also draws on modern examples to investigate how we might identify examples of sexual selection among prehistoric species. The paper covers a wide variety of creatures, from ammonites to birds, but, since this is the “Dinosaur Tracking” blog, I’ll focus on how the argument applies to the ever-controversial adornments of non-avian dinosaurs.

As the researchers state, there’s no simple, tell-tale way to identify sexual selection. This is partly because many strange structures are multifunctional, and structures may be co-opted for different functions during the course of their evolution. Think of sauropods. The elongated necks of these dinosaurs allowed them to feed over a wide swath of greenery, but they could have also been used as visual displays. A big fleshy neck is prime advertising space. In this case, a feeding advantage appears to have preceded any signalling function, but the mosaic nature of evolution hinders our efforts to tease apart the influence of different, interacting pressures.

All the same, there are a few clues that can help paleontologists identify possible cases where sexual selection was at play in the deep past. One possible line of investigation is sexual dimorphism, although, as I said above, this has yet to be conclusively demonstrated in dinosaurs. (And, as Knell and co-authors argue, sometimes the sexes might differ for reasons other than sexual selection.) The way prominent displays grew is another phenomenon worth looking into. We would expect that features that make a difference in mating would only appear as the dinosaur approached sexual maturity. Juvenile, and presumably sexually-immature, Lambeosaurus don’t have the full-blown crests of older individuals. Perhaps this is because the crests are sexual signals that only grow as the dinosaurs approach mating age, although it’s possible that the development of crests are related to the overall growth of the dinosaur’s skeleton.

The diversity–or disparity–of ornament shapes among closely-related species may also be important. Even closely-related species of ceratopsid dinosaurs, Knell and collaborators note, had very different horn shapes and arrangements. This could be a sign of sexual selection by way of competition and mate choice, but, as Padian and Horner pointed out, the same evolutionary pattern could be the result of selection for distinct-looking species. Finally, Knell and co-authors cite “costliness” as another potential indicator–if a trait is flashy, requires a good deal of energy to grow and comes at a cost to the organism’s survival potential, then it may be a sexually-selected trait.

Obviously, each line of evidence comes with caveats. Sexual selection can be difficult to identify even among living species, much less extinct ones. It would be strange if sexual selection played no role in dinosaur evolution, but we’re left with the question of how to detect and test the hypothesis of sexual selection. Paleontologists will have to very carefully test hypotheses about bizarre structures, paying careful attention to distinguish between competing alternatives. Ultimately, paleontologists may only be able to identify possible scenarios for the origin and evolution of bizarre features, but studies of modern species can at least provide guidelines for what researchers should look out for.

If we’re truly going to understand the visual signals of dinosaurs, though, we need better sample sizes. We need to know how individuals of the same species varied from one life stage to the next. Without this anatomical foundation, researchers will be left to argue from a typological standpoint that may misconstrue how certain features changed with age and evolved over time. Recall the “Toroceratops” debate–if Triceratops changed into a Torosaurus-form late in life, most likely beyond the onset of sexual maturity, that is certainly going to influence how paleontologists investigate and discuss dinosaur visual signals.

The influence of sexual selection, or lack thereof, will undoubtedly be debated for some time to come. But, as Knell and colleagues conclude, investigating the possible influence of sexual selection in prehistory “is neither a forlorn nor impossible task.” We may yet find out what’s sexy to a dinosaur.

For more on this study, see this post by Dave Hone, one of the paper’s authors.

[My thanks to Darren Naish, another of the paper's authors, for sending me the new study.]

Reference:

Knell, R., Naish, D., Tomkins, J., Hone, D. (2012) Sexual selection in prehistoric animals: detection and implications, Trends in Ecology & Evolution DOI: 10.1016/j.tree.2012.07.015.

The AMNH skeleton of Styracosaurus, one of the dinosaurs from the upper zone of the Dinosaur Park Formation. Image from Brown and Schlaikjer, 1937 via Wikipedia.

Dinosaurs didn’t all live at the same time. Not counting the avian species that have thrived during the last 65 million years, dinosaurs proliferated throughout the world during a span of over 160 million years. As I’ve pointed out before, it’s amazing to think that less time separates us from Tyrannosaurus than separated Tyrannosaurus from Stegosaurus.

Even within specific geologic formations, not all the dinosaurs found in those layers lived side by side. Dinosaur-bearing strata accumulated over millions and millions of years and record both ecological and evolutionary changes. Look closely enough, and you can even see particular communities of dinosaurs give way to different assemblages. In an in-press Palaeogeography, Palaeoclimatology, Palaeoecology paper, Jordan Mallon and colleagues have done just that.

Canada’s Dinosaur Park Formation is one of the most spectacular slices of Late Cretaceous time found anywhere in the world. Spanning approximately 76.5 to 74.8 million years ago, the formation has yielded lovely specimens of dinosaurs such as the crested hadrosaur Corythosaurus, the spiky ceratopsid Styracosaurus, the lithe tyrannosaur Gorgosaurus, the heavy-armored ankylosaur Euplocephalus and many others. Not all of these dinosaurs were neighbors, though. Since 1950, at least, paleontologists have recognized that some kinds of dinosaurs are restricted to certain slices of the formation, and the dinosaur community changed over time. Mallon and co-authors decided to have another look at the dinosaur turnover, focusing on the large herbivores and investigating what might have shook up the dinosaur populations during the time the Dinosaur Park Formation was being laid down.

The paleontologists identified two broad divisions in the Dinosaur Park Formation, which they call “megaherbivore assemblage zones.” Each zone lasted roughly 600,000 years each. There are a lot of names here, so bear with me. In the lower zone, the horned dinosaur Centrosaurus and the crested hadrosaur Corythosaurus are found throughout; other dinosaurs restricted to this half of the formation include the ceratopsid Chasmosaurus russelli, the hadrosaurs Gryposaurus and Parasaurolophus, and the ankylosaur Dyoplosaurus.

Yet there are some dinosaurs that first appear in the lower zone and persist into next one. The ceratopsid Chasmosaurus belli, the ankylosaur Euoplocephalus and the hadrosaurs Lambeosaurus clavinitialis and Lambeosaurus lambei show up in the lower zone but pass through into the second zone as well. And, as with the lower swath, there were dinosaurs that were only found in the second zone. The hadrosaurs Prosaurolophus and Lambeosaurus magnicristatus, as well as the horned dinosaurs Styracosaurus, Vagaceratops and a pachyrhinosaur, are only found in the upper zone.

So the big picture is that the lower zone is characterized by Centrosaurus and Corythosaurus, the upper zone is distinguished by Styracosaurus and Prosaurolophus, and there are some dinosaurs–such as Lambeosaurus and Chasmosaurus–that are smeared across the two. As the researchers note, it’s even possible to break down the two halves into even smaller subsets, although the picture gets a little muddier at these levels.

What does all this evolutionary dinosaur shuffling mean? Other researchers have proposed that the Dinosaur Park Formation represents a series of turnover pulses–after a period of stability, rapid ecological change wiped out some dinosaurs while creating opportunities for a new community. The now-vanished Western Interior Seaway has been invoked as a possible mechanism for this. As this shallow sea, which once split North America in two, expanded and encroached further inland, the area of the Dinosaur Park Formation became a mostly coastal, muddy, swampy habitat. This may have put pressure on some forms of dinosaur while providing opportunities for others. As the seaway fluctuated, the attendant changes would have altered the environment and therefore affected dinosaur populations.

According to Mallon and collaborators, though, there’s no strong evidence for the turnover pulse hypothesis. We simply don’t have the resolution to tell how closely certain dinosaurs were tied to particular habitats or niches, and shifts in ecology would have influenced dinosaur evolution. Other possible influences–such as dinosaurs migrating to the area from elsewhere, or the evolution of one species into another within the formation–are also frustratingly unclear. As the researchers state, “Whether the appearance and disappearance of the megaherbivorous taxa of the [Dinosaur Park Formation] was due to evolution, migration, or to a combination of these factors, is difficult to determine.” We don’t yet know what drove the alterations in the formation’s dinosaur communities.

Aside from the ongoing mystery about what caused the changes between the two zones, the revised look at the Dinosaur Park Formation also raises a few questions about dinosaur ecology. Despite the shifts in dinosaur communities, the paleontologists note, there were about six to eight different megaherbivorous dinosaur species living alongside each other. That’s a lot of big herbivores on the landscape, especially since the hadrosaurs and ceratopsids may have formed huge herds. Such vast, hefty dinosaur communities would have required a large amount of vegetation, and the disparate megaherbivores were in competition with each other for food. In order to live alongside one another, then, we can assume that there was some kind of niche partitioning–the dinosaurs were adapted to have restricted diets or live in particular habitats as a result of their competition for resources. How exactly this happened, though, requires further study into the ecology and evolution of these dinosaurs.

And there was something else that caught my eye. The new study focused on the megaherbivores, but what about the large carnivores? The large tyrannosaur Gorgosaurus was also present in the Dinosaur Park Formation and was rejected by the researchers as a zone marker because this theropod ranges throughout the formation. Think about that for a moment. We can see a significant amount of change and turnover among the big herbivores, but one of the large carnivores stays the same throughout the entirety of the formation. Why should this be so? Perhaps it has something to do with the fact that the ornamentation and headgear of hadrosaurs and ceratopsids changed quite a bit, but their general body plans were conservative–a Gorgosaurus could take down a Corythosaurus just as well as a Lambeosaurus.

Likewise, I wonder if the same pattern might hold true elsewhere. The Kaiparowits formation of southern Utah, laid down around the time of the Dinosaur Park Formation further north, also hosts an array of hadrosaurs, ceratopsids and ankylosaurs, but there seems to be just one large dinosaurian predator, the tyrannosaur Teratophoneus. (The giant alligator cousin Deinosuchus was another megacarnivore in the Kaiparowits.) We need more fossils to be sure, but perhaps, like Gorgosaurus, the short-snouted Teratophoneus remained the same as different large herbivores came and went. If this turns out to be the case, the lack of an arms race between predator and prey would be further evidence that the ornamentation of ceratopsids and other dinosaurs had more to do with decoration and combat among each other than defense.

Indeed, the new study of the Dinosaur Park Formation lays some important groundwork for future studies. Paleontologists are currently investigating and debating why the roughly 75-million-year-old dinosaurs from Alberta are different from the roughly 75-million-year-old dinosaurs from southern Utah. What factors drove the diversity and disparity of these dinosaurs across the latitudes, and who really lived alongside whom? So far, the Dinosaur Park Formation is the best-sampled slice we have, and there is much work to be done. With any luck, and a few more decades of careful sampling, we’ll be able to put together an intricate picture of how dinosaurs lived and evolved during this brief span of Late Cretaceous time.

Reference:

Mallon, Jordan C., Evans, David C., Ryan, Michael J., Anderson,, & Jason S. (2012). Megaherbivorous dinosaur turnover in the Dinosaur Park Formation
(upper Campanian) of Alberta, Canada Palaeogeography, Palaeoclimatology, Palaeoecology DOI: 10.1016/j.palaeo.2012.06.024

The skull of Edmontosaurus, a Cretaceous hadrosaur from North America. The vandalized dinosaur wasn’t an Edmontosaurus, but belonged to the same evolutionary group. Photo from Ballista, image from Wikipedia.

When paleontologists uncover a dinosaur, they have plenty of reason to worry. In some parts of the world, such as Mongolia, black market thieves often steal and smuggle dinosaurs that wind up bringing in hefty sums at auction houses. Sometimes, paleontologists have returned to field sites to find skeletons stolen right out from under their noses. But, even closer to home, vandals regularly damage and destroy dinosaurs. Earlier this month, an “irreplaceable” dinosaur skeleton discovered near Grande Prairie, Canada was destroyed by persons unknown.

According t0 the CBC, the destroyed skeleton was a hadrosaur being excavated by paleontologist Phil Bell and a University of Alberta field team. The dinosaur was discovered on June 15th, and was complete enough that Bell intended the dinosaur to eventually go up on exhibit. When Bell returned to the site this month, however, the dinosaur was turned into a cascade of broken bone fragments. Even worse, this isn’t the first time dinosaurs at this site have been vandalized. Since May, the report says, three other fossils have been stolen or damaged.

There’s no clear motive for why the criminals smashed the site. But they vandals left a clue behind. At a campsite near the dinosaur excavation, the CBC reports, investigators found a liquor store receipt that may help track down the people who so callously pulverized the hadrosaur.

I’m completely baffled as to why anyone would want to destroy a dinosaur. The fantastic animal beat the odds against preservation and remained locked in stone for tens of millions of years, and can tell us about a world that we can never see ourselves. What sort of stupid, selfish person would even think of turning a wonderful fossil into a pile of rubble? It is truly sad that paleontologists have to worry about this kind of destruction. Dinosaurs belong to everyone, and it’s heartbreaking to see one stolen from us by ignorant despoilers.

A reconstruction of the Edmontosaurus skull LACM 23502, with a beak based on a natural mold. From Morris, 1970.

I’ve never liked the term “duck-billed dinosaur.” I know it’s part of the accepted dinosaur lexicon, just like “raptor” is, but every time I hear the phrase I think of a sluggish, swamp-bound Edmontosaurus dabbling in the water for soft water plants and algae. Paleontologists tossed out this imagery decades ago—hadrosaurs were terrestrial creatures with jaws specially adapted to grinding down tough vegetation.

I admit that the skull of Edmontosaurus looks superficially duck-like. Much like a mallard’s, the Late Cretaceous hadrosaur’s mouth is long, low and generally bill-shaped. The resemblance between these very, very distant relatives helped inspire images of wading hadrosaurs. But most Edmontosaurus skulls you see in museums present only the bony framework of the skull. The tough keratinous beak that tipped the skull typically decayed during the fossilization process, but in 1970, paleontologist William Morris described a rare Edmontosaurus skull with a beak trace.

You can see the specimen on display at the Natural History Museum of Los Angeles today. Designated LACM 23502, this Edmontosaurus skull was collected by Harley Garbani near Montana’s Ft. Peck Reservoir. Other Edmontosaurus have been found here, but this fossil included a natural mold of the dinosaur’s beak. (While the beak itself was not preserved, the mold showed what the internal surface looked like. In life, the actual beak sat on top of the fossilized mold.) The structure was not shaped just like a duck’s bill. On the bottom jaw, the beak surface curved slightly upward, and the upper half of the beak created a vertical, fluted surface that hung over the tip of the lower jaw. Maybe the term isn’t the most apt—and I’m open to suggestions—but Edmontosaurus seemed to be a shovel-beaked dinosaur rather than a duck-billed one.

At the time Morris described the skull, though, hadrosaurs were still thought to be semi-aquatic dinosaurs. Morris believed that the bill traces he described supported this idea and imagined that ridges on the interior part of the mold helped the dinosaurs strain plants and small invertebrates from the water. “A filtering device would be very important in assuring that these large animals could ingest large amounts of concentrated food relatively free of water in a manner similar to that of the dabbler ducks,” Morris wrote, which made the term “duck-bill” seem all the more apt for these dinosaurs.

Despite Morris’ insistence that hadrosaurs nourished themselves by slurping plant-heavy Cretaceous soup, though, we now know that Edmontosaurus and kin were terrestrial animals capable of breaking down tougher plant materials. Exactly how the beak of Edmontosaurus contributed to feeding is not entirely clear—perhaps the beak cropped vegetation that was broken down by the rows of small teeth lining the jaws. One thing is for sure, though. The duck-bills weren’t really so duck-like after all.

Reference:

Morris, William J. (1970). “Hadrosaurian dinosaur bills — morphology and function“. Contributions in Science (Los Angeles County Museum of Natural History) 193: 1–14.

A reconstruction of Corythosaurus at the Royal Ontario Museum. Image from Wikipedia.

Out of all the parts of a dinosaur’s skeleton, nothing is as prized as the skull. While an entire Tyrannosaurus is a frightening visage, the jaws are what we fear the most. Triceratops is a stout herbivore, but the highly decorated skull is what makes the dinosaur a fan favorite. And the entire character of Apatosaurus, née “Brontosaurus,” changed when paleontologists recognized that they had mounted the wrong head on the dinosaur’s body. No surprise, then, that many paleontologists have been dinosaur head-hunters.

Royal Tyrrell Museum paleontologists Darren Tanke and Rhian Russell recently solved one case of a decapitated dinosaur, they explained at the 16th annual symposium of the Alberta Palaeontological Society. In 1992, paleontologists prospecting in Alberta’s Dinosaur Provincial Park came across an abandoned dinosaur quarry. The site was one of many unrecorded quarries scattered throughout the park—remnants of early 20th century expeditions that did not necessary excavate or record data to modern scientific standards. But the early fossil hunters hadn’t collected everything in the rock. The 75-million-year-old site still contained the parts of the hips legs, and tail of a large hadrosaur, while the front half of the skeleton seemed to have eroded away. For whatever reason, the fossil collectors decided to abandon the quarry without collecting the whole dinosaur.

Paleontologist Phil Currie found a hadrosaur lower jaw at the site in 1992, but this did not seem remarkable since the site was part of a bonebed with many fossils. The site was recorded and sometimes visited, but who dug the quarry and when remained a mystery. Then, last year, someone found a hadrosaur toe bone and a scrap of newspaper at the quarry. The newspaper carried a 1920 date, and there was only one person working in the area at that time: George F. Sternberg.

With a little historical detective work, Tanke and Russell found that Sternberg, accompanied by his wife and young son, collected a single hadrosaur specimen in 1920. The fossil was a skull of Corythosaurus, although the specimen was missing the lower jaws. The skull is on display at the University of Alberta in Edmonton, while the jaw and toe bone are at the Royal Tyrrell Museum and the remainder of the skeleton is in the field.

But why did Sternberg leave so much of the fossil in the ground? Maybe, Tanke and Russell propose, he thought that the skull was the only part worth collecting. The dinosaur’s body between the skull and the hips—including the neck, chest and arms—was disarticulated, and lacking a trained field crew to excavate what remained, maybe Sternberg decided to pick up the skull and leave the body. We may never know for sure.

Still, the fact remains that a single dinosaur is now split among several places—two museums and a field site. This is not an isolated case. Other headless dinosaur bodies undoubtedly exist in the field, and these fossils might be collected and stored in different museums. And even sites that have been carefully excavated may yield additional bones as erosion scrapes away at the rock, and different paleontologists may eventually find parts of skeletons that have already been mostly collected. This is why detailed records are so important in paleontology. Even if a skeleton is scattered hither and yon, there is at least the hope that the parts can be reunited someday.

References:

Tanke, D., Russell, R. 2012. Headless wonder: Possible evidence of a head-hunted dinosaur skeleton in Dinosaur Provincial Park, Alberta. Alberta Palaeontological Society Sixteenth Annual Symposium Abstracts. 14-17

A restoration of Saurolophus angustirostris based upon skeletal and soft-tissue fossils. Art by L. Xing and Y. Liu, from Bell, 2012.

We love to bring dinosaurs back to life. From museum displays and academic papers to big-budget movies, we have an obsession with putting flesh on old bones. How much anatomical conjecture and artistic license is required to do so varies from dinosaur to dinosaur.

Some dinosaurs are known from a paltry collection of fragments and require a considerable among of reconstruction and restoration on the basis of better-known specimens of related species. Other dinosaurs are known from complete skeletons and require less osteological wrangling, but they still present the challenge of filling in the soft tissue anatomy that the skeleton supported in life. Every now and then, though, paleontologists discover skin impressions associated with the bones of dinosaurs. These rare fossils can give us a better idea of what the outside of some dinosaurs looked like.

Skin impressions are found most often with hadrosaurs. These herbivores, such as Edmontosaurus and the crested Corythosaurus, were plentiful and seemed to dwell in habitats where deceased dinosaurs could be buried rapidly by sediment, a key to the preservation of soft-tissue anatomy. In the roughly 68-million-year-old strata of Canada and Mongolia, for example, skeletons of two different species of the hadrosaur Saurolophus have been found associated with skin impressions. But these fossils can do more than help use restore the outer appearance. According to a new paper by University of Alberta paleontologist Phil Bell, subtle differences in Saurolophus skin traces can help paleontologists distinguish one species of dinosaur from on another on the basis of soft tissue anatomy alone.

In 1912, professional dinosaur hunter Barnum Brown named the hadrosaur Saurolophus osborni from skeletons found in Alberta’s Horseshoe Canyon Formation. Although not mentioned at the time, three skeletons of this species were associated with skin impressions from various parts of the body, including the jaw, hips, foot and tail. Forty years later, from skeletons found in a huge bonebed called the “Dragon’s Tomb” in Mongolia’s Nemegt Formation, paleontologist Anatoly Konstantinovich Rozhdestvensky named a second species, Saurolophus angustirostris. Numerous skin impressions were found with skeletons of this species, too. The fact that two Saurolophus species had been found with intact skin impressions provided Bell with a unique opportunity to compare the outer anatomy of two closely related dinosaurs.

Both Saurolophus species had pebbly skin. Like other hadrosaurs, the skin of these dinosaurs was primarily composed of non-overlapping scales or tubercles of varying shape. In detail, though, Bell ascertained that the skin of the two species differed enough that one species can be readily distinguished from the other.

Along the base of the tail, the North American species (S. osborni) had mosaic-like clusters of scales, while the species from Mongolia (S. angustirostris) seemed to have vertical bands of specialized scales interspersed with larger, rounded scales Bell terms “feature scales.” This pattern in S. angustirostris remained consistent in young and old individuals—evidence that this was a real pattern peculiar to this species and not just a matter of variation among individuals.

Frustratingly, the skin impressions from the North American species cover less of the body and come from fewer specimens than those from the Dragon’s Tomb. That limits the possible comparisons between the species. Still, based on the consistent differences between the Saurolophus species in the skin at the base of the tail, it appears that paleontologists might be able to use soft-tissue anatomy to identify and diagnose particular dinosaur species. This could be especially useful for the study of hadrosaurs. These dinosaurs are notoriously difficult to tell apart on the basis of their post-cranial skeleton, but Bell’s study hints that skin impressions might show prominent differences. Judging a dinosaur by its cover might not be such a bad idea.

References:

Bell, P. (2012). Standardized Terminology and Potential Taxonomic Utility for Hadrosaurid Skin Impressions: A Case Study for Saurolophus from Canada and Mongolia PLoS ONE, 7 (2) DOI: 10.1371/journal.pone.0031295

A restoration of the island hadrosauroid Tethyshadros by Nobu Tamura. Image from Wikipedia.

Everyone knows what a “duck-billed” dinosaur was. This bit of shorthand has been permanently grafted onto the hadrosaurs—the widespread group of herbivorous dinosaurs with elongated skulls and what appear to be duck-like beaks.

The title made perfect sense during the early 20th century when these dinosaurs, such as Edmontosaurus and Parasaurolophus, were thought to be amphibious creatures that dabbled in the water for soft plants and escaped into Cretaceous lakes when predators came near. If the dinosaurs looked like monstrous ducks, then they must have acted like ducks. But that vision of paddling hadrosaurs was discarded decades ago. These dinosaurs were terrestrial animals, and discoveries of well-preserved hadrosaur beaks have indicated that the mouths of these dinosaurs were not so duck-like, after all. One beautifully preserved Edmontosaurus skull on display at the Natural History Museum of Los Angeles shows that the tough beak of this dinosaur ended in squared-off, almost vertical croppers and not a duck-like, spoon-shaped bill. The so-called duck-billed dinosaurs didn’t look like mallards at all. And one of the strangest variations in beak shape was found in a small, island-dwelling hadrosauroid described in 2009.

On the basis of a nearly complete and articulated skeleton, paleontologist Fabio Dalla Vecchia named the dinosaur Tethyshadros insularis. The name is a testament to where the dinosaur lived. During the time of Tethyshadros, around 71 million years ago, an ancient sea called Tethys covered most of southern Europe. This oceanic incursion created chains of islands, and it was on one of these islands—where Italy sits today—that Tethyshadros lived. More than that, the isolation of the dinosaur on the island might have been responsible for the dinosaur’s relatively small size (about 13 feet long) compared to its distant, North American cousins such as Edmontosaurus—it’s an example of a phenomenon called insular dwarfism that has been documented for other prehistoric herbivores, including dinosaurs.

But one of the most peculiar aspects of Tethyshadros was its beak. Instead of a long, low duck bill, the upper beak of this dinosaur was a ridged structure jutting out in a shape roughly reminiscent of a snowplow. And rather than being smooth, the margin of the upper beak was pointed, with the middle point being the largest. This general type of serrated beak has been seen before in iguanodontian dinosaurs—the stock from which hadrosaurs evolved, with Tethyshadros being closer to hadrosaurs than to the iguanodontians—but never before in such an extreme shape. Why Tethyshadros had such a strange beak is a mystery. As paleontologist Darren Naish wrote in his detailed summary of this new dinosaur, “Did [the beak spikes] help Tethyshadros to bite at specific food items? Were they for grooming? For display? The mind boggles.”

References:

Dalla Vecchia, F. (2009). Tethyshadros insularis, a new hadrosauroid dinosaur (Ornithischia) from the Upper Cretaceous of Italy Journal of Vertebrate Paleontology, 29 (4), 1100-1116 DOI: 10.1671/039.029.0428

A Parasaurolophus at the Natural History Museum of Utah. Photo by the author.

Of all the crested hadrosaurs, Parasaurolophus is one of my favorites. The long, slightly-curved tube that projects from the back of the dinosaur’s head is a wonderful ornament. But why did this peculiar dinosaur decoration evolve?

Parasaurolophus was initially described by paleontologist William Parks  in 1922 on the basis of a skeleton found in the vicinity of Alberta’s Red Deer River. This dinosaur was clearly different from other ornamented hadrosaurs–such as Corythosaurus and Saurolophus–that had been found before, and especially perplexing was the makeup of the dinosaur’s crest. The structure was not solid–a break in this part of the skull revealed a series of internal tubes separated by thin walls of bone.

No one was exactly sure why Parasaurolophus had a hollow crest, but the supposed hadrosaur lifestyle generated a number of speculative answers. Hadrosaurs were supposed to be amphibious dinosaurs who acted like giant, dabbling ducks. After all, their broadened snouts gave them the popular moniker “duckbill dinosaurs.” Paleontologists therefore considered the dinosaur’s crest in reference to a life spent foraging for soft plants in Cretaceous swamps.

Paleontologist James Hopson reviewed these ideas in a 1975 Paleobiology paper about the role hadrosaur crests may have played in display. In 1933 Alfred Sherwood Romer speculated that the crest might have been used as a snorkel or an air storage chamber. While there was no hole in the crest to allow air to come in–the snorkel idea was scuttled–the air tank hypothesis was popular. As a young dinosaur fan, I remember encountering an image of a submerged Parasaurolophus in Edwin Colbert’s The Dinosaur Book with a solid black line running through the crest to indicate the amount of stored air. Another book, Rudolph Zallinger’s Dinosaurs and Other Prehistoric Reptiles, featured an even more detailed vision of Corythosaurus and Parasaurolophus paddling around beneath the surface of a prehistoric lake. But this notion didn’t last either. The anatomy of hadrosaurs has undeniably cast them as terrestrial animals, not expert swimmers, and the amount of air these dinosaurs were able to store in their crests would have been miniscule compared to their lung volume–the supposed air tanks would not have done them much good.

Charles Mortram Sternberg, son of the celebrated dinosaur collector Charles H. Sternberg, proposed a different variation of the aquatic feeding theme. In 1935 Sternberg wrote a paper on the “hooded” hadrosaurs from the Late Cretaceous of Canada and proposed that a U-shaped bend in the tubular crest passage prevented water from entering the respiratory system while the dinosaur was feeding underwater. Again, this idea is based on the notion that hadrosaurs frequently dipped their heads underwater to feed, and paleontologist John Ostrom later pointed out that, in such a scenario, the water pressure would have overcome the air pressure inside the crest and flooded the passage. Whatever the function of the Parasaurolophus crest, the structure was certainly ill-suited to underwater feeding.

Paleontologists kicked around a few other ideas. In a series of papers published in the late 30s and 40s, Martin Wilfarth suggested that elaborate hadrosaur crests were attachment areas for long, fleshy snouts. No evidence was found to support this. Likewise, Ostrom’s later suggestion that the nasal passages were extended to give the dinosaurs a better sense of smell was refuted–there was no indication that  the convoluted passageways had anything to do with a better sense of smell.

Hopson himself considered the crests to primarily be visual display structures, and hadrosaurs with hollow crests, such as Parasaurolophus, may have also used their crests as resonating chambers to send low-frequency sounds over long distances. This is the view generally taken now, but settling on particular functions for the crests does not necessarily illustrate how those structures evolved. Perhaps the origin of the various hadrosaur crest shapes was driven by pressures associated with species recognition–the need to identify members of one’s own kind, be they parents, rivals, mates, etc. Then again, perhaps some aspect of sexual selection was at play. Exactly what evolutionary factors led to the origin of such strange skull shapes is difficult to ascertain. Much remains unknown about the evolution and social significance of fantastic ornaments in dinosaurs.

References:

Hopson, J. 1975. The Evolution of Cranial Display Structures in Hadrosaurian Dinosaurs. Paleobiology, 1 (1). pp. 21-43

Naish, D. 2009. The Great Dinosaur Discoveries. Berkeley: University of California Press. pp. 72-73

A Corythosaurus with skin impressions--similar to this one on display at the American Museum of Natural History--was lost when a German military vessel sank the SS Mount Temple on December 6, 1916. Image from Brown, 1916, via Wikipedia.

Last month, paleontologist Andrew Farke and colleagues described the previously-unknown, multi-horned dinosaur Spinops sternbergorum. The centrosaurine was a gnarly-looking creature and worthy of headlines by itself, but the real hook of the story was that this dinosaur had been hiding in the collections of London’s Natural History Museum for nearly a century. The fossils–collected by veteran dinosaur hunter Charles H. Sternberg and his sons from the Cretaceous badlands of Alberta, Canada in 1916–had been regarded as “rubbish” by the museum’s staff, and it wasn’t until Farke took a second look at the specimen that the unique nature of this dinosaur was realized. But Spinops wasn’t the only creature found by the Sternbergs and ultimately lost. The same year that the bones of Spinops were first uncovered, an entire shipment of dinosaurs vanished into the cold waters of the Atlantic ocean.

Charles H. Sternberg began working for the Natural History Museum–then still part of the British Museum–in the field season of 1916. This was a lucky break. The Geological Survey of Canada–which employed Sternberg and his sons to collect Late Cretaceous dinosaurs in Alberta in a bit of friendly competition with the American Museum of Natural History’s own excavator Barnum Brown–decided to stop field work and focus on the preparation of dinosaurs already stored at the National Museum of Canada in Ottawa. But Sternberg was a field man, through and through. While his sons George and Charles Mortram stayed with the survey, his other son Levi joined Charles the elder in looking for other fieldwork opportunities.

Finding funding seemed to be a daunting task. World War I limited the amount of money available for paleontology–armored dinosaurs could not compete with armored tanks for attention–but the Natural History Museum was able to wrangle enough to underwrite Sternberg’s expenses through the Percy Sladen Memorial Fund. According to a proposal letter written by a member of the museum staff, and reprinted via a paper about the expedition by David Spalding in Mesozoic Vertebrate Life, Sternberg was to receive $2,000 for two months of initial work, with an opportunity to earn another $2,000 during the following two months if the museum was pleased with what was collected.  The museum would also undertake the expense of shipping the specimens across the Atlantic so that they could be examined, prepared and stored. With any luck, the investment would yield a collection that would rival the collections the American Museum of Natural History had built up. “The Cretaceous Dinosaurs of Alberta comprise a great variety of the strangest armoured forms related to Triceratops besides other most astonishing developments of the Iguanodont and Megalosaurian groups,” the proposal promised, and it noted that the new specimens would complement an earlier collection made for the museum by William Cutler.

The challenge for Sternberg and his crew wasn’t finding dinosaurs. That part was easy. The trick was obtaining the high-quality, mountable skeletons the Natural History Museum was after. Since the area had already been explored so intensely, only the best dinosaurs available would do. Early finds–including what we now call Spinops–were scrappy and not especially wonderful, but Charles and his son Levi had better luck as the summer wore on.

In a letter sent to the museum’s paleontology curator Arthur Smith Woodward near the very end of the field season, Sternberg promised that “We have had the most wonderful success[;] three skeletons that can be mounted.” Even better, the last skeleton found that season was a nearly-complete hadrosaur, including numerous skin impressions. Sternberg regarded it as the second best specimen of its kind found in the strata–if only the dinosaur had a neck and skull! Still, the haul was good and additional specimens could certainly be obtained. While Sternberg felt that no one could ever exceed the collection Barnum Brown had built, he believed that the Natural History Museum “can however be equal or even superior to [the museum at] Ottawa if you please.”

But we’ll never know how good these specimens actually were. While an earlier shipment of fossils reached the British museum without incident about the SS Milwaukee, the second shipment was sunk along with the SS Mount Temple on December 6, 1916. The German military vessel the SMS Möwe stopped the ship, took the passengers prisoner, and then blew the Mount Temple to bits. (Coincidentally, the 95th anniversary of this event was the day when Spinops sternbergorum made its public debut.)

What had seemed like an excellent opportunity for the British museum became a frustrating tangle of paperwork. Half the dinosaurs were lost, those which had been received were not as impressive as hoped, and Sternberg sent multiple letters stressing his dire need for adequate compensation. And even the two crested hadrosaurs might not have been exactly as spectacular as the museum expected–each of the three hadrosaur skeletons was incomplete, and the dinosaur had already been named Corythosaurus by Barnum Brown. At least the fossil shipment had been insured, although this significantly complicated and delayed the payment to Sternberg.

Sternberg did not find out about what happened to the second shipment until a month after the event. “This is bitter news for me as well as for you,” he wrote to Woodward in a letter dated January 22, 1917, “As I considered the two skeletons in that shipment worth two or three times what the first shipment was, because it contained two skeletons that could be mounted.” All that work for nothing, and Sternberg urged Woodward to hurry up and send the insurance money to cover the field expenses of the previous year. In a way of mending wounds–and also securing employment–Sternberg also suggested that the museum sponsor him at the rate of $500 a month for a full year. This would allow Sternberg to make a new collection and fully prepare the specimens during the winter (while also meaning that he would have steady employment).

The museum does not seem to have shown any interest in supporting Sternberg, and the fossil hunter’s letters became more desperate as months went by. Confusion over shipping documents delayed the process of the insurance claim, and the Percy Sladen Memorial Fund was so unimpressed with the material that had been sent that they did not want to shell out additional funds for specimens sitting on the ocean bottom.

The letters sent from Sternberg to Woodward vacillated between sweet and sour–Sternberg was more polite and seemed hopeful each time he removed an additional bureaucratic obstacle to getting paid, but he would then write a cranky follow-up letter when the money still failed to arrive. In a letter to Woodward dated April 3, 1917, Sternberg wrote “Day after day I am waiting for the money I earned, and you promised to pay me, in your letter of June 3rd, 1916.” Sternberg felt betrayed. He had mortgaged his home and used all the credit available to him to excavate and ship the dinosaurs and was left to his own devices to pay down his debts while waiting for the monetary reward that had been promised. Worst of all, Sternberg lamented, there was virtually no money to launch an expedition for the summer of 1917. What had seemed to be an excellent opportunity to supply one of the world’s greatest museums with dinosaurs had turned into a financial mire that threatened to keep Sternberg out of the field. “It was awful enough to have a German Raider sink the two best specimens of Corythosaurus my party have found in 5 years … It will be still worse to completely ruin me, so I cannot keep at work.”

Just in time, the money came through. The various complications regarding paperwork were resolved and the full $2,500 estimate for the value of the fossils was awarded. Sternberg would have a 1917 season after all. He thanked Woodward for settling the matter, and in a May 5th letter advertised various fossil finds–and finds he hoped to make–that were for sale to museums. But the Natural History Museum seemingly did not want anything more to do with Sternberg. In a note Spalding turned up in the museum’s files from 1931, W.D. Lang wrote “Mr Charles Sternberg is constantly approaching the museum with offers of specimens for purchase. There is no need to take any notice of this appeal.”

Despite all the hurt feelings and frustration, however, very little was actually lost in this episode. Presuming that Sternberg had collected skeletons of Corythosaurus, the dinosaurs were not exactly rare specimens. Other, more complete individuals had been found and have been found since. As Spalding noted, their disappearance beneath the waves was primarily a loss to the British museum-going public. Beyond that, the damage was mostly restricted to Sternberg’s pride. The episode had ruined his relationship with the Natural History Museum and limited his pool of clients for the fossils he wanted to sell. Nevertheless, he kept on collecting for at least another two decades. For all the headaches the sinking of the Mount Temple created, the event is a strange wrinkle in the history of paleontology rather than a true tragedy.

References:

Spalding, D. 2001. Bones of Contention: Charles H. Sternberg’s Lost Dinosaurs. In: Mesozioc Vertebrate Life. Ed.s Tanke, D. H., Carpenter, K., Skrepnick, M. W. Indiana University Press. pp. 481-503