Clearing the air about Brontomerus
February 25, 2011
Many people in the paleontological community have probably seen the comments about our work on Brontomerus by Jim Kirkland. Most of these comments have been posted on Facebook or sent around by email. We have held off until now in responding to them because we wanted to have everything–both the criticisms and our responses–publicly available to everyone, not in the walled garden of Facebook. Jim has now stated on Facebook that we have permission to post his messages and respond to them, and his longest critique has been posted as a comment on the initial Brontomerus post.
All three of us–Mike, Matt, and Rich, the authors of the new paper describing Brontomerus–have known Jim for some time. He and Rich collaborated in the Cedar Mountain Formation for most of the 1990s, and basically split the catch, with Jim getting most of the dinosaurs and Rich getting the mammals. Matt has known Jim since the late 1990s, and has had many productive conversations with him about sauropods and faunal change in the Early Cretaceous of North America. Mike’s interactions with Jim have been more limited, mainly because they live on different continents, but he has spoken to Jim at meetings and they have exchanged occasional correspondence–always friendly–for years.
Not only has Jim been a friend of ours for some time, he also assisted with the Brontomerus project. Jim first alerted Rich to the existence of the quarry in 1994. Following Rich’s visit to the quarry in September of that year, Jim went out with Scott Madsen and Randy Nydam to collect the fossils of what would become Brontomerus in 1995, and the fossils were prepared under his guidance at Dinamation before being transported to the Oklahoma Museum of Natural History for curation. Jim was also helpful in providing information about the quarry and allowing us to cite personal communications from him in the paper.
We’ve all had long and productive working relationships with Jim for years, and we’d like to see those relationships continue. However, some of his comments are not only factually incorrect but also call our veracity and scientific judgment into question. We feel that the record should publicly be set straight.
In the rest of the post, we have the full text of Jim’s long SV-POW! comment and some of his comments from Facebook, followed by a breakdown of his specific claims and our responses to them.
Jim’s self-described rant
On February 23, Jim sent around an email with the subject “Brontomerus pdf and rant”. ReBecca recently posted a slightly longer version here on Jim’s behalf.
While, it is possible, that Brontomerus is a new species based solely on the juvenile ilium, there is no way based on the minimal contextual information known of this site, that one can say that all the sauropod material we collected at Hotel Mesa pertains to the same species.
When, I was first taken to this site in 1994, it had been opened by guys hoping to develop a commercial Morrison dinosaur quarry. The Bureau of Land Management (BLM) clearly did not OK this! Another party, who told me he had only advised them to get a permit, subsequently took me out to the site.
Examining this site, it was obviously in the Cedar Mt. Fm. [LINK] and of great interest to me, but politics being what they were, I could not get a BLM permit in Utah and as I had recognized a fair number of teeth and claws (theropods and crocs) in the site, I thought perhaps it might be a potential microvertebrate site, so I asked Rich Cifelli at the OMNH if he might be interested in the site. Rich put me on his Utah BLM permit and sent out Randy Nydam and I corralled Scott Madsen (then at Dinosaur National Monument (DNM) and we went out to evaluate the site for microvertebrates and salvage the exposed bones. This took us about 1.5 days (camped for two nights). Unfortunately, the matrix would not break down and thus the site could not be screenwashed for microvertebrates, so Rich lost interest in the site. We prepared all the bones in our (Dinamation Intl. Soc.) lab in Fruita, Colorado before sending them on to the OMNH with his crew when they returned to Oklahoma from working their Utah sites at the end of the following summer.
After, I became Utah’s State Paleontologist in 1999, I expressed interest in reopening the Hotel Mesa Quarry, as this was the only Albian age site in all of eastern Utah, but BLM policy was that all specimens from a given site needed to be reposited at the same repository. Therefore, since Utah paid my salary, it was impossible to justify excavating and preparing a collection of vertebrate materials and sending them to Oklahoma.
A few years ago, Mike Taylor informed me that he and Matt Wedel felt that there was a new sauropod taxon in the collections from Hotel Mesa. I was excited to learn this, as I figured they would seek to open the site and collect more specimens and data concerning this important locality.
I was deeply saddened to learn they had described the new sauropod taxa with no regard to establishing a base of contextual data to support its hypodym.
First there is no evidence to suggest that all the sauropod bones in the site pertain to the same taxon. The Holotype ilium (cute as a bugs ear, I must say, particularly before the shim went through the middle of it, when we flipped the scapula jacket), comes from a much smaller animal that the rest of the reported “hypodym”.
The nearly equivalent and geographically much closer Price River 2 Quarry preserves more than one sauropod taxon among the many hundreds of sauropod bones collected there. Staff at CEUs Prehistoric Museum pointed out that they had long cervicals similar to Sauropossiden and short stouter cervicals. Their new director Ken Carpenter sent me this picture [LINK] showing two morphs of ilia (at top of figure), one with a short prepubic portion and a stout pubic peduncle and on with a long prepubis and slender pubic peduncle. Thus, the Upper Albian part of Cedar Mt preserves a wealth of sauropods and this taxon promises to add to the general confusion regarding North America’s Early Cretaceous sauropods.
Also in terms of stratigraphy (and these guys are not completely at fault here, but if asked I would have told them), the Ruby Ranch Member is Albian in age from all our dating. Abydosaurus mcintoshi from DNM is not from the younger Mussentichit Mbr. but the upper Albian (Chure et al.’s 2010, date of ~104 Ma says that) and as stated in … our abstract coming out at GSA this spring and to be submitted as a manuscript long before that, An unconformity (sequence boundary) separates the basal Cenomanian (98-96 Ma) Mussentuchit from the Albian strata below it. Two date, there are no over lapping parts between Brontomerus mcintoshi and Abydosaurus mcintoshi and these two sites may nearly be equivalent.
The much older upper Barremian to basal Aptian Dalton Wells Quarry low in the Cedar Mt has at least 3 sauropod taxa among the numerous individuals in Brigham Young University’s collection. Remember the Cedar Mountain represents about as much time as the entire Upper Cretaceous.
Basically, the statement that the juvenile holotype belongs to the same taxon as the handful of adult material in the site is a stretch without some supporting taphonomic documentation (more excavation, as the site keeps going. However, the statement is a falsifiable hypothesis so is a scientific statement that needs testing.
Now that we are beginning to excavate our own sauropods, which thank god are at the base of the Cedar Mt. Fm., I’m actually beginning to care about the general taxonomic mess that Albian sauropods are in with the number of taxa described without overlapping parts.
Another observation that I accidentally made was that the reconstruction of the ilium in the paper, differs from that we made in preparing the specimen fresh from the field. These two reconstructions are shown in at the bottom of the picture. We figure this reconstruction from 1995 in Kirkland and Madsen, 2007, Fig. 13E, p. 15). On line at: [LINK]
I’m certainly curious what happened between Rich’s OMNH crew’s picking the specimens up and Mike and Matt’s beginning their research on it. Regardless of whatever happened, it is clear the proportions on the Holotype ilium need to be reappraised.
PLEASE, someone open up this quarry and generate some real information (it is an 8hr drive from Salt Lake City, so I do not have the funds to undertake this). The site is in the Dolores Triangle so the Hotel Mesa Site can only be approached from Colorado, so the Museum of Western Colorado is by far the closest institution to it.
AND; finally, the site is actually in the Burro Canyon Formation not the Cedar Mountain Formation as the name changes as you cross the Colorado River going east. So the stratigraphic level would be, for the sake of accuracy by best referred to as high in the Ruby Ranch Member of the Burro Canyon Formation. This is how it is show on the recently published 1X100,000 geological map of the area. Geological jargon that is useless to argue with unless you are going to publish the justification of changing the convention.
Oh and there are many dozens of sauropods waiting to be excavated in the Ceadar Mountain Formation during the “Age of Ankylosaurs.”
Done spouting off for the minute.
Jim’s Facebook comments
Besides the email/SV-POW! comment, Jim has posted some serious criticisms of the paper on Facebook. These started back in January, when the accepted manuscript of the as-yet-unpublished paper was inadvertently posted on the Acta site. Jim kindly took them down following our request that he do so. However, the deleted criticisms had already been seen by hundreds of people (Jim has 898 Facebook friends) and received many comments, so we feel that it is appropriate to publicly respond to them.
[January 28] Since Abydosaurus mcintoshi and Brontomerus mcintoshi are essentially from the same stratigraphic horizon ~ 150 kilometers apart and have no overlapping parts yet. It is an interesting synonymy since the species name would not change. We have all these sauropod skeletons in the Cedar Mountain, lets not describe scrap.
[January 28] I have wanted to see the Hotel Mesa site (turned over to OMNH) excavated for more than a decade. To describe a dinosaur from scrap salvaged from site and to leave rest rotting in the ground is irresponsible!
[January 28] Jim Kirkland: WTF I oversaw the collection of it all, as salvage over a couple of daysl None of these guys have been to site (more there). No way, you can say anything, but the type illium goes to this species.
Darren Naish: Are you sure that none of the guys have been to the site? Err…Rich Cifelli?
Jim Kirkland: I guarantee it, they would never find it.
[February 23] I just realized that they reconstructed the ilium of Brontomeris wrong! See my Hotel Mesa album. It is not thunder thighs, but at most quivering thighs! I would say it throws a big hook into the entire thing.
[February 23] There is no evidence that anything was stolen from the site or smashed for that matter. They simply uncovered it and inquired about a commercial permit.[speaking here of the alleged vandalism of the site by commercial collectors]
Specific claims, and our responses
We’re rather baffled by some of Jim’s statements. Rather than go through the email and Facebook comments line by line or in chronological order, we’ve distilled his criticisms into a number of specific claims, which appear here with our responses.
Claim 1: None of the authors ever visited the quarry.
Source: Facebook, “None of these guys have been to site…I guarantee it, they would never find it.”
Response: This not just incorrect, but insulting. From the paper (Taylor et al. 2011: 76):
One of us (RLC), who had already been working in Lower Cretaceous rocks of the region, was notified about the site through the courtesy of James I. Kirkland, and was guided to it by Bill Hawes of Grand Junction, Colorado, in September 1994. Additional collecting at the site for OMNH was conducted by Randall L. Nydam and James I. Kirkland in March 1995.
In an email to Matt and Mike with permission to cite, Rich wrote:
I took the information directly from my field notes and I remember the place pretty well. Of course I was there!
Claim 2: We erred in describing the site as being part of the Cedar Mountain Formation rather than the Burro Canyon Formation.
Source: SV-POW! comment, “the site is actually in the Burro Canyon Formation not the Cedar Mountain Formation as the name changes as you cross the Colorado River going east. So basically the proper description of the site would say, it is in the upper part of the Ruby Ranch Mbr. of the Burro Canyon Formation.”
Response: We acknowledge this in the paper, and clearly state that our discussion of the site as part of the CMF is one of convenience (Taylor et al. 2011: 76):
Stratigraphically, OMNH V857 lies in a sequence of Lower Cretaceous rocks interposed between the Morrison Formation (Kimmeridgian) below and the Dakota Formation (Cenomanian) above. Westward, these rocks are recognized as the Cedar Mountain Formation; eastward, the Burro Canyon Formation. The arbitrary dividing line between these entities is generally placed at the Colorado River (Stokes 1952; Tschudy et al. 1984) which technically places OMNH V857 within the Burro Canyon Formation. However, we will refer to the locality as belonging to the more widely recognized Cedar Mountain Formation, as it is in this formation that comparable specimens are known, and the stratigraphy and sedimentology do not change across the arbitrary border.
It is also worth noting that in his long comment, Jim himself discusses the quarry as part of the Cedar Mountain Formation, presumably out of convenience: “Examining this site, it was obviously in the Cedar Mt. Fm.” (from the third paragraph of his SV-POW! comment).
Claim 3: The quarry probably has more than one sauropod taxon, because other CMF quarries sometimes have more than one sauropod taxon. (conflicts with Claim 8)
Source: SV-POW! comment, “First there is no evidence to suggest that all the sauropod bones in the site pertain to the same taxon. The Holotype ilium (cute as a bugs ear, I must say, particularly before the shim went through the middle of it, when we flipped the scapula jacket), comes from a much smaller animal that the rest of the reported “hypodym”.
“The nearly equivalent and geographically much closer Price River 2 Quarry preserves more than one sauropod taxon among the many hundreds of sauropod bones collected there.”
Response: This is a possibility we discuss extensively in the paper (Taylor et al 2011: 79), but so far there is no evidence to support it. All of the material is consistent with a single taxon, most likely a basal somphospondyl, but conservatively a camarasauromorph. (We plan to talk much more in a subsequent article about this tentative assignment of all the material to a single taxon.)
There is a more general point to be made here. Any time someone erects a new taxon, the idea that the taxon is actually distinct from other, previously named, taxa is a hypothesis subject to further testing. Anytime someone refers material to a taxon, that is likewise a hypothesis. If we pretended to be any more certain about the referral than we actually are, we’d be lying. But we’d be equally in error if we didn’t point out that the null hypothesis is that all of the material belongs to one taxon. If contrary evidence comes to light, we’ll take it into account and move on–that’s how science works.
If someone find a complete titanosaur skeleton with an ilium like the holotype of Brontomerus, and someone else turns up a complete rebbachisaur with a scapula like the one currently referred to Brontomerus, great! Name the rebbachisaur (a North American rebbachisaur would rock!), remove the scapula from the Brontomerus Referred Material list, and move on. As we made clear in the paper, Brontomerus is based on, and diagnosed by, the holotype ilium alone.
Claim 4: There is no evidence that anything was stolen or destroyed from the site.
Source: Facebook, “There is no evidence that anything was stolen from the site or smashed for that matter. They simply uncovered it and inquired about a commercial permit.” Also repeated second-hand as a comment on Dinosaur Tracking, here.
Response: In an email with permission to cite, Rich wrote:
Yes, of course it had been excavated: we have proof in my notes and in Randy Nydam’s field notes. The comments about bone strewn around and being used to hold pieces of blue tarp are, unfortunately, accurate.
What’s more puzzling is that all three of us have received emails from Jim going back to 2007 that clearly state that the quarry was vandalized. For example (and note the explicit permission to cite):
Date: Mon, 17 Mar 2008 10:22:12 -0600
From: James Kirkland
To: Mike Taylor
Subject: Re: Another Hotel Mesa pers. comm.
[…]. The small ilium was under the scapula (completely hidden and the shim went through the middle of it, but we were able to prepare it with it’s entire margin reconstructed. (collected by Jim Kirkland, Scott Madsen, & Randy Nydam from site that had been uncovered previously by vandals). […]
Claim 5: The quarry is full of more and better sauropod material.
Source: Facebook, “To describe a dinosaur from scrap salvaged from site and to leave rest rotting in the ground is irresponsible!”
Response: Any material exposed near the surface at Hotel Mesa in 1994 and 1995 is long gone by now, crumbled by 16 years of freeze/thaw cycles and erosion by wind and water. There may be more material deeper down, a possibility that we have always acknowledged, but since no one has ever seen that material, it is impossible to say if it’s better than what we have, or if it even exists at all. This is actually not unusual for dinosaurs; many taxa are known from quarries that are not worked to exhaustion and later produce more material. One of our express aims in writing this paper was to to provide the impetus for further excavation in the quarry, and there was no prospect of that happening before we started working on it.
Claim 6: It was irresponsible of us to name a new dinosaur based on such incomplete material.
Source: Facebook, “We have all these sauropod skeletons in the Cedar Mountain, lets not describe scrap.”
Response: Although incomplete, the material still bears numerous autapomorphies that clearly indicate that it is a new taxon based on currently available data (see point 3, above, on hypotheses).
Since the material in the quarry was not articulated, we would have had to choose an isolated element as the holotype even if we had more material (and the ilium would still have been the obvious choice because it is so unusual). This is absolutely critical: in a bonebed of disarticulated elements, it wouldn’t matter if we had just the ilium or 5000 bones, we’d still have to pick one element as the holotype and refer everything else to it. Anyone describing a new taxon from disarticulated elements in a bonebed faces the same decision: for example, Kirkland et al. (2005), in their description of the basal therizinosaur Falcarius, nominated a partial braincase as the holotype and referred all the other material.
Claim 7: We erred in attributing Abydosaurus to the Mussentuchit member of the Cedar Mountain Formation.
Source: SV-POW! comment, “Abydosaurus mcintoshi from DNM is not from the younger Mussentichit Mbr. but the upper Albian (Chure et al.’s 2010, date of ~104 Ma says that) and as stated in … our abstract coming out at GSA this spring and to be submitted as a manuscript long before that,”
Facebook, “Abydosaurus mcintoshi and Brontomerus mcintoshi are essentially from the same stratigraphic horizon” [Brontomerus is from the Ruby Ranch member]
Response: The only published peer-reviewed work on the Abydosaurus quarry (Chure et al. 2010) places it in the Mussentuchit member. Jim’s abstract was not available to us when we were writing the paper, and if we had the option to choose between the conclusions of a peer-reviewed paper and those of an unpublished abstract, we’d still have followed the paper. Abydosaurus could actually be from the Ruby Ranch member, but we will wait for the published evidence, and to see what Chure et al. have to say in response.
Claim 8: Because Abydosaurus is from the Ruby Ranch member, Brontomerus might simply be Abydosaurus. (conflicts with Claim 3)
Source: Facebook, “Abydosaurus mcintoshi and Brontomerus mcintoshi are essentially from the same stratigraphic horizon ~ 150 kilometers apart and have no overlapping parts yet. It is an interesting synonymy”
Response: The hypothesis that Abydosaurus is from the Ruby Ranch member is far from convincingly demonstrated (see above). The Ruby Ranch member has at least two sauropods other than Brontomerus, and the Yellow Cat member has between three and five, so the idea that there is only one sauropod genus in each member of the CMF, and that therefore Brontomerus must be synonymous with Abydosaurus, is insupportable. Potential synonymies among Early Cretaceous North American sauropods are acknowledged and discussed extensively in the paper (Taylor et al. 2011: 87-88, 91-92).
Also, we note that back in January, Jim was concerned that Brontomerus was synonymous with Abydosaurus (not enough new sauropods in the quarry), and now in his comment he is concerned that there might be more than one taxon in the quarry (too many new sauropods). Which is it, and what aspects of our discussion of these problems in the paper does he find incomplete?
Claim 9: Jim’s photo of the reconstructed ilium shows that our reconstruction is wrong and that our conclusions are therefore suspect.
Source: Facebook, “I just realized that they reconstructed the ilium of Brontomeris [sic] wrong! See my Hotel Mesa album. It is not thunder thighs, but at most quivering thighs! I would say it throws a big hook into the entire thing.”
Response: Yesterday (February 23) we received an email from Jim, with this photo:
The body of the email:
I just realized that the ilium is reconstructed wrong in the paper. Here is how we reconstructed it straight in from the field..
Jim’s reconstruction is different from ours, but that does not automatically make it correct. This just in by email (with permission to cite) from Brontomerus co-author Rich Cifelli, who is curator at the Oklahoma Museum of Natural History where the fossils are curated:
From: Rich Cifelli
To: Mathew Wedel, Mike Taylor
Date: 25 February 2011 00:45
Subject: restorations of Kirkland vs. Taylor et al.
I have re-examined the various pieces of the holotype ilium (OMNH 66430). Our restoration stands as the only one that is really plausible, and is the best match considering the thickness, curvature, preservation, and surface texture of the three main pieces (large section including acetabulum, peduncles, and pre-acetabular blade; followed by thin strip of margin; followed posteroinferiorly by “Oklahoma-shaped” piece with margin). The other piece shown by Kirkland (roughly rhomboidal in outline) was omitted by us because it does not include any of the bone margins (contra Jim’s restoration) or contacts with other pieces: it fit somewhere in the large space posterior to the pre-acetabular blade and dorsal to the acetabulum.
Kirkland’s restoration cannot be “straight from the field” because it is obviously incorrect in placement, orientation, and side shown for the rhomboidal piece. As said, this fragment does not contain any of the bone margin: all of the edges, including that which he depicts as lying along the posterior-posterodorsal margin of the ilium, are jagged and broken. Color, surface texture, and an important morphological feature also show that he depicts this piece upside down. That feature is a ridge which separated attachment places for two sacral ribs, shown by Kirkland to be lateral (facing outward) but which of course should be medial.
But, all right, suppose Jim had been right about how the pieces should fit together: here’s a new recon by Mike that follows the photo Jim sent. Note that all the pieces fit comfortably within the very same dotted reconstruction line as in Fig. 2 of the paper.
It is also important to realize that the ilium is oriented differently in the two photos. The photo on the left in the comparison image, from Taylor et al. (2011: fig. 2), is a straight lateral view, looking straight down the laterally-oriented axis of the acetabulum. The preacetabular blade of the ilium angles out anterolaterally, as shown in our Figure 2B. In Jim’s photo, on the right of the comparison image, the preacetabular blade is lying flat on a table, which puts the acetabulum at an angle to the camera; the photo is effectively in posterolateral view rather than orthogonal, and this is the source of all the significant differences between the two photos. Take Jim’s reconstruction, mentally rotate it laterally through 20-30 degrees to look straight down the acetabulum, and his post-acetabular expansion would fit comfortably into the dotted line we drew, as Mike’s new recon shows.
The diagnostic features (autapomorphies) of the ilium are (Taylor et al. 2011: 78):
- Preacetabular lobe 55% of total ilium length, longer than in any other sauropod;
- Preacetabular lobe directed anterolaterally at 30 degrees relative to the sagittal plane, but straight in dorsal view and vertically oriented;
- Postacetabular lobe reduced to near absence;
- Ischiadic peduncle reduced to very low bulge;
- Ilium proportionally taller than in any other sauropod—height is 52% of total length, compared with a maximum of 45% in other sauropods.
If Jim’s reconstruction were right, it would only change the margin of the iliac crest, so it couldn’t affect characters 1, 2, or 4. His reconstruction still shows the postacetabular lobe reduced to near-absence (3), which still leaves the ilium proportionally taller than in any other sauropod (5). In short, the version he favors doesn’t affect the proportions or autapomorphies one whit.
The alternative reconstruction is valuable because it points out the existence of a missing piece of the wing of the ilium. However, not only is it wrong in the position of that piece, even if it was right it wouldn’t affect our morphological, taxonomic, or functional interpretations of Brontomerus at all.
Thanks for slogging through this long, probably not-terribly-interesting post. We’ll soon return to normal service, with more information on Brontomerus — and that awesome life restoration.
- Chure, D., Britt, B.B., Whitlock, J.A., and Wilson, J.A. 2010. First complete sauropod dinosaur skull from the Cretaceous of the Americas and the evolution of sauropod dentition. Naturwissenschaften (online preprint). doi:10.1007/s00114-010-0650-6
- Kirkland, J. I., Zanno, L. E., Sampson, S. D., Clark, J. M. and DeBlieux, D. D. 2005. A primitive therizinosauroid dinosaur from the Early Cretaceous of Utah. Nature 435: 84-87.
- Taylor, M. P., Wedel, M.J., and Cifelli, R.L. 2011. A new sauropod dinosaur from the Lower Cretaceous Cedar Mountain Formation, Utah, USA. Acta Palaeontologica Polonica 56(1):75-98. doi: 10.4202/app.2010.0073