With all of this in mind, Dave, Yoshi, and I wrote our report about this new species of burrowing dinosaur, its young, and its burrow, and we gave it a simple title: A Burrowing, Denning Dinosaur. If you had asked us then, we would have told you that our paper was astonishing, a true masterpiece of paleontological literature that would surely earn the academic equivalent of an A++++++ (evoking Ralphie’s daydream from the movie A Christmas Story). With supreme confidence, in mid-2006 we submitted it to an elite scientific journal, one in which Dave had published papers before.
But then peer review struck. Remember in the preceding description where the editor can say “not worthy” and kick it back to you without further review? That happened to us not once but twice. An editor from the first journal sent a terse reply within just a few days of submission, informing us that it was “not appropriate for the journal at this time,” a response that made us wonder if the previous or following week would have been better. A little daunted and confused, we regrouped and revised the article, then submitted it to another elite scientific journal. This met a similar fate, with the rejection notice again coming only a couple of days after submission.
We were confounded. What had gone wrong? It was hard to say, considering that neither journal editor addressed anything about the content of our manuscript. Perhaps it was just a matter of bad timing, as both journals may have had too many other dinosaur-discovery articles in review or being published then and those other specimens were more attractive or from more exotic places. Or as one paleontologist acerbically commented to Dave afterwards, “Well, of course they didn’t accept it. It [the dinosaur] didn’t have feathers and it wasn’t from China.” Oh well. That’s the nature of science.
With egos properly deflated, we decided to try one more time, and with a journal that would be more receptive to the notion of a burrowing dinosaur from Montana. We had to hurry, though, as our concept of burrowing dinosaurs was starting to take on form through other people. For example, in a paper published in late 2006, its author (David Loope) proposed small dinosaurs as possible burrowmakers for large structures he found in Early Jurassic rocks of the western U.S. Although Loope did not have any bones in these burrows, his analysis of the burrows was very well done and perfectly credible. The secrecy we had kept around our discovery was also starting to unravel. In mid-2006, I stumbled onto an ostensibly innocent online discussion about burrowing dinosaurs, but one that had been prompted by someone associated with Dave’s original Montana field crew. It was only a matter of time before more information got out, and peer review might be compromised by any such rumors (or facts). Editors and reviewers tend to frown on papers in which authors seek pre-publication publicity, and we did not need to risk this study any further.
For the proverbial “third time’s the charm” attempt, toward the end of 2006 we sent our report to a venerable British journal, Proceedings of the Royal Society of London. This time, the editor kindly gave us a chance and sent the article to two reviewers, both of whom signed their names to their honest and in-depth assessments of the research. One agreed with nearly everything we said, but the other thought we had placed too much emphasis on biologically based arguments and needed to include more geological evidence. Oddly, the editor then told us the paper was “rejected,” but encouraged us to resubmit a revised article. It was like being told by a date that he or she thinks you’re ugly, smelly, and stupid, but would like to go out with you again, just as long as you lose some weight, take a shower, and start playing Sudoku. Nonetheless, we did as told, revised and resubmitted, and the paper was finally accepted.
In February 2007, the online version of the paper was finally released, which coincided with our sending out press releases, and a good amount of media attention followed. Granted, this was not a feathered dinosaur from China, nor was it a close relative of Tyrannosaurus rex. Nevertheless, after 95 million years, Oryctodromeus cubicularis, a dinosaur buried in a burrow of its making and with its offspring, was now known to the rest of the world. The words “denning,” “burrowing,” and “dinosaur” could be used in the same sentence, and thanks to a fortuitous combination of trace and body fossil evidence, dinosaurs had entered yet another dimension in our Mesozoic imaginations: underground.
Dinosaurs Down Under
We were lost. As a result, this otherwise fine fall day of May 10, 2006 had turned into an unexpectedly long one for our group of eight while we hiked atop the high cliffs of Cretaceous rocks along coastal Victoria, Australia. We were looking for an auspiciously named locality—Knowledge Creek—that continued to elude us despite our maps, GPS units, and field-savvy participants, including a few Australians who knew the surrounding area. Having already taken two wrong turns down toward the shore, only to double back and climb up, we were all becoming a bit tired and frustrated. Below us, ocean waves burst onto the rocks, a dull, rhythmic booming carried to us by a strong, cool sea breeze, imploring us to try again.
In the early afternoon, we finally found the proper route, a grassy path that cut through the scrubby coastal forest parallel to a ravine cut by Knowledge Creek. Two of our group went back to fetch our vehicles, a sacrifice that would shorten the travel time for the rest of us at the end of the day and supply our field lunches, which we had dumbly left behind. The steep incline down to the coastal outcrops promised a long, slow fight against gravity that would coincide with diminishing light, as the sun began arcing toward the horizon. Underestimating the length and difficulty of the hike in, some of our group had not brought enough water, and those of us who did shared what little we had left. On the off chance that any dinosaur bones would be found at the site, one of our party was hauling a portable rock saw on his back, and another was carrying fuel for it. I did not envy their journey back up the slope we were now descending for a third time. None of us had ever been to Knowledge Creek, and two paleontologists who had visited before us had only gone once, firmly vowing to never come back. We were starting to understand why.
Australians have a long tradition of ill-fated expeditions, and I felt like I had unwittingly instigated one of these. Yet our motivations were paleontological, and with good reason. First of all, I was in Victoria on a semester-long sabbatical from my university to work on a science-education project with Patricia (Pat) Vickers-Rich. In 1980, she and her husband Tom Rich trekked to Knowledge Creek; yes, they were the two aforementioned paleontologists who had been there before us. They were prospecting for dinosaur bones in the Early Cretaceous (~105 mya) rocks there, which had been found at other coastal outcrops just east of Knowledge Creek. While there, they failed to find any bones, but they did manage to discover what was then the only clear example of a dinosaur track in all of southern Australia. Only about 10 cm (4 in) wide and long, with three stout and well-defined toes, the track was attributed to a small ornithopod dinosaur, probably a hypsilophodont.
By the time I arrived in Australia—more than 25 years later—it was still the only undisputed dinosaur track in all of southern Australia. I had found some not-so-clear dinosaur tracks only a few months before at another spot, but it was time to find more. Thus, the purpose of our troublesome foray that day was to revisit the source of that track and look for more dinosaur tracks. Pat and Tom, still filled with the wisdom imparted by Knowledge Creek the day they went there in 1980, had declined our invitation to come along.
Dinosaur bones were relatively rare in this part of the world and, most interesting, represented a polar dinosaur assemblage. Based on plate-tectonic reconstructions, the rocks in this part of Australia were originally formed near the South Pole, when southern Australia was connected to Antarctica during the Early Cretaceous (130–100 mya) before drifting north to its present location. Nearly all of the dinosaur bones and teeth in strata there were from small dinosaurs, and most of these were hypsilophodonts. Only a few pieces were from theropods, such as one bone that came from a dinosaur similar to the Late Jurassic Allosaurus of North America.
Hence, Pat and Tom often
asked themselves, “Why hypsilophodonts?” and wondered how these ornithopods, which were probably too small to migrate, had adapted to long, cold, dark winters of polar environments during the Cretaceous. In a paper they and other co-authors published in the journal Science in 1988, they proposed that hypsilophodonts and other dinosaurs in the region were likely endothermic, or “warm-blooded,” generating their own body heat. At that time, warm-blooded dinosaurs were still being hotly debated (no pun intended), and recall that Robert Bakker’s The Dinosaur Heresies had only been published two years before then. Not all paleontologists were so accepting of the idea that dinosaurs were less like reptiles and more like birds, and others thought that maybe dinosaurs represented something entirely different from either group of modern animals.
Pat and Tom, along with many other contributors to their paper, fed this debate further by documenting the best-known polar dinosaur assemblage in the Southern Hemisphere. This added support to the then-remarkable idea that dinosaurs lived in frigid places, a hypothesis later backed up by discoveries of thousands of dinosaur bones and tracks in Cretaceous rocks of Alaska that were also in formerly polar environments.
However, a single sentence in this 1988 paper later shouted at me, showing some remarkable prescience by the authors. It was a simple sentence, and one that very easily could have been cut by the authors, peer reviewers, or editor for being too speculative. Here is what they said:
With the possible exception of the Allosaurus sp., all of the animals were small enough to have found shelter readily by burrowing.
That particular day, while winding down into the valley carved by Knowledge Creek, I was not aware of that sentence, nor would I have cared. We were doggedly trying to get to the shoreline to look at the exposed rocks along the marine platform to see whether any more dinosaur tracks were there. Once the path exited the forest, we crossed the trickle of fresh water that was Knowledge Creek, and most of us successfully avoided the leeches there, wriggling excitedly at our warm-blooded presence. Our boots met Cretaceous rock surfaces, which extended out as a platform and met the sea. Successful in reaching our goal, we paused to catch our breath but also found ourselves gasping in another way at the spectacular cliffs of bedded sandstones and conglomerates looming above us. Because this part of the world was entering winter, the waves at the shore were noticeably higher and more vigorous than usual, encouraged by offshore winds that had just blown over and around Tasmania.
With little time left before we had to meet our two vehicle-driving companions, we started looking for dinosaur tracks, bones, or anything else paleontological that caught our attention. One of our party, Mike Cleeland, was a long-time volunteer with Pat and Tom in their Victoria-dinosaur endeavors, and despite his great height, he was legendary for his uncanny ability to spot tiny scraps of bone. Hence, he and most others there had their “osteo-eyes” switched on, looking for bones and teeth. Alternatively, my wife Ruth (who had enthusiastically persevered with us through the day) and I were using our “ichno-eyes” to search for trace fossils ranging from small invertebrate burrows to dinosaur tracks.
What I was not expecting to see there was a dinosaur burrow. Even less likely, it matched the form and dimensions of the fossil burrow that Dave Varricchio and I had unearthed in the Cretaceous rocks of Montana only eight months before. Yet there it was in the outcrop, a gently dipping structure with a sediment-filled tunnel that twisted right, then left, and connected with an expanded chamber. It was naturally cast with sandstone toward its top and conglomerate at its bottom, but clearly cut across the bedding surrounding it. I stood transfixed, barely breathing, and gaped at it long enough to prompt Ruth to come over to stare with me.
“What is it?” she asked.
“I think it’s a dinosaur burrow,” I whispered.
At the time, she was one of only a few people in the world who knew about the fossil burrow in Montana. In fact, Dave, Yoshi, and I had not yet named Oryctodromeus, whose remains, along with the two juveniles, were still encased in plaster and rock. So we were still doing all we could to keep its discovery quiet until it had gone through a scientifically proper vetting process. Consequently, I had not yet told any of my new Australian friends about it and was not about to start now.
Nonetheless, the problem with outwardly expressing curiosity and wonder is that it attracts other people who then want to join in with you. As a result, only a few minutes elapsed before one of several geology graduate students with us, Chris Consoli, saw us standing there and wandered over to ask the same question as Ruth: “What’s that?” I answered truthfully but evasively, “I’m not sure, but it’s an interesting structure.” I then asked him if he would mind being the scale in my photographs, and quickly snapped three shots in succession. He soon strolled away once I supplied no other information about what was there. Ruth then helped me to take a few quick and surreptitious measurements of the enigmatic structure. Mike Cleeland also stopped by and asked about it, and I was similarly nonchalant with him.
These were the only photos I took of the suspected burrow that day, as I really did not want to call much attention to it and we had other work to do in our short time there. All of us wandered about, looking down on bedding planes, glancing above us on the outcrops, and in between at nearby sections of the strata. This perusal was mildly successful, as during our short time there Mike and I found a few faint and incompletely expressed dinosaur tracks, including one that was likely from a large theropod. This meant that it would be worth coming back to look for more and better tracks. I also noted many fossil invertebrate burrows that were about the right sizes for ones made by insect larvae. These were valuable indicators of the original environments there, such as river floodplains that formed from the run-off of spring thaws following polar winters. Yet we saw no bones.
All told, we were at the site for only a little more than an hour before slogging back up the hill to meet our two friends, who wondered how things had gone. Amazingly, we still had enough time that afternoon to stop at nearby Dinosaur Cove, a world-famous locality for polar dinosaur bones that many of these same Australians accompanying me had quarried in the 1980s and 1990s. We departed just as the sun set over Dinosaur Cove, a long and satisfying day of field work completed.
Later, I studied the three photographs I had taken of the odd structure at Knowledge Creek and could not get over the eerie sameness it held compared to what I had seen in the Cretaceous rocks of Montana. Not knowing what else to do, I sent a photo to Dave Varricchio for him to assess. As expected, he was non-committal about what it meant, but it felt good to share this coincidence with someone else in the know. Nevertheless, one thing was for sure: I had to go back to Knowledge Creek.
So I returned the next year, in July 2007, only a few months after the publication of the paper on Oryctodromeus and its burrow. The day that paper came out, I wrote to Pat Vickers-Rich and Tom Rich to finally disclose my secret that they had a possible dinosaur burrow there in the Cretaceous rocks of Victoria. Of course, they were excited about this prospect (albeit understandably skeptical) and encouraged me to come back to Victoria. During this second trip, Mike Cleeland was along for the ride again, but joining us was Lesley Kool and five others. Lesley was a long-time dig-site manager for Pat and Tom, and like Mike is an extraordinarily keen-eyed finder of vertebrate bones.
Mike and Lesley looked at the possible burrow with me and confirmed what I had surmised initially, which was that it contained no skeletal debris. Thus this was going to be pure ichnology, dinosaur burrows without bones. However, it was on this foray that I noticed a second twisting, sandstone-filled structure above the one that had originally grabbed my attention. It was not as completely expressed as the other, with only a former tunnel and lacking a chamber at the end, but was the same width and filled with the same type of sandstone. This time, with much less urgency than the previous time, I carefully sketched, measured, and photographed both structures, documenting them enough so they could be summarized in a
paper and evaluated by my peers.
Because nearly everyone in our group was exhausted by the hike down but still faced a climb up, they took off as I did this tedious but necessary work. Roger Close, a young geology graduate student, stayed with me and assisted where needed before we also walked out. At the top, Lesley, her husband Gerry, and several others who had made the round trip greeted us with big grins and happily announced that they never needed to visit Knowledge Creek again.
Life got in the way throughout most of 2008 for me to do anything with these hard-earned data, until a burst of writing during the 2008–2009 holiday break from teaching duties between semesters resulted in a manuscript. I decided to author the paper by myself, because if it turned out to be totally wrong, I would own all of the failure. My interpretations of the field observations were risky because, unlike the Montana burrow, the structures did not hold any accompanying dinosaur bones.
However, in the paper I made sure to thoroughly explain the reasons why some polar dinosaurs should have burrowed as a behavior that would have allowed them to overwinter during cold, dark, harsh times in polar environments. For one, the Cretaceous rocks of Victoria abounded with evidence for hypsilophodonts, small ornithopods morphologically similar to Oryctodromeus and Orodromeus in North America. For another, such dinosaurs were too small to have migrated long distances between seasons. Thirdly, many modern polar vertebrates, from puffins to polar bears, burrow into dirt or snow to take refuge in those harsh environments. Consequently, in January 2009, I sent the paper to the journal Cretaceous Research and kept fingers, toes, and thumbs crossed that it would be received favorably.
Dinosaurs Without Bones Page 17
