Wednesday, April 12, 2017

Bibliography Project Update

It has been a while and things have been busy. I wanted to post a note to let everyone know that the BENM Bibliography now has a live, downloadable spreadsheet available free to the public. I will continue to update the static text, but having the references in a spreadsheet format allows for some cool analysis of the publications as historical documents and allows us to see trends in research themes (which is part of my UFOP annual meeting talk coming up in late April).

Anyway, the spreadsheet is available here for anyone to use and will continue to be updated as I find more resources and new papers are published.

Next time on the PP Blog, a look at scientific accuracy in popular reconstructions of Dilophosaurus.

Tuesday, January 3, 2017

Red Canyon; Fossils and Silence

Red Canyon; Fossils and Silence

or: How not publishing data hurt fossil protection in the fight for Bears Ears National Monument

Some Background

          Okay everybody, gather 'round. Time for Uncle Rob to tell the story of Red Canyon. It is a magical place, with soaring red walls and seemingly endless badlands. Rocks from the Middle Triassic through the Early Jurassic are exposed in its depths, and numerous historic uranium mines, roads, and artifacts. Gorgeous, desolate, and isolated, Red Canyon is truly an amazing location and was rightly included in the Bears Ears Inter-Tribal Coalition's proposal for a Bears Ears National Monument. It was specifically excluded under Rep. Rob Bishop's Public Lands Initiative and was also dropped from the final Bears Ears National Monument boundaries.
Bears Ears National Monument Map - Department of the Interior
          Besides the odd isolate on the west side of the map (just east of Lake Powell), the Red Canyon/Moqui Canyon stretch of high deserts, plateaus, and canyons is not protected within the Monument boundaries. Why might that be? One reason is likely Energy Fuels' Daneros Mine, located in upper Red Canyon. The other reason might have something to do with paleontological discoveries that are more like tech "vaporware" than hard science at the moment.

Paleontology in Red Canyon

          I am not going to dwell long on current, ongoing projects in Red Canyon headed up by my friends and colleagues that have started in the last couple of years. For one that would be unfair and unethical since they are investing time and energy into their discoveries. For another, everyone involved in research in Red Canyon currently has a solid record of publishing their work. I am confident that any new discoveries that come out of the Red Canyon area will be properly published in the scientific literature.
          This is a tough subject to write about because the core of the issue are fossils that have never been published. This whole story exists, however, because these fossils have never been published. So I will not name institutions or people involved. I won't even really describe these fossils in any sort of detail because that would be inappropriate. Nonetheless, these fossils existence is known within the small community of paleontologists who work on the Triassic Period in western North America. The most famous are some small reptile skeletons, but other specimens played a role in this story. These specimens are far more interesting than I let on here but I don't want to say much more because the fossils are still undescribed. These reptile skeletons were discovered first back in either the 1960s or 1970s (depending on who is telling the story). They went to a museum back east where they have set ever since. They have been prepared, they have been seen by dozens of visiting researchers, and although they are remarkable they have never been described in a formal publication (or even in the "grey literature" as far as anyone seems to know). A couple of other scientific publications have come out of work done in Red Canyon but they were not describing anything new, unique, or spectacular for the most part: crocodylomorph scutes, phytosaur bones and teeth, etc. (Parrish and Good, 1987; Parrish, 1999). Not to say that these aren't important to document but they don't carry the scientific significance of a new species, for example.

Red Canyon on the Chopping Block

So why does this matter? Well, as I mentioned in my last blog post, I was asked to provide bibliographies of the paleontological and geological resources of the Bears Ears area. I was also eventually asked to go to Washington DC and present that information (and more) in person. I had produced, along with some of the conservation groups who I had been in contact with, a map highlighting several things. A modified version of this map is reproduced below.
Map of the Bears Ears Area before monument designation. Geologic data from Utah Geological Survey database.
          This map outlined both the Utah Public Lands Initiative and the Inter-Tribal Coalition's proposals, and overlaid both areas of known paleontological resources (red hashes in 1. Red Canyon, 2. Valley of the Gods, 3. Comb Ridge, and 4. Indian Creek) and areas pulled from the Utah Geological Survey's online public geologic map database showing where the fossil-rich Chinle and Morrison Formations are exposed (in green). This was done to highlight the potential for new discoveries in this region that has not been systematically explored by paleontologists. This is where I ran head-on into the realities of the wheels of power looking at the various conservation options. Anyone who says that this was a sort of midnight "swoop" into southeastern Utah without considering all the factors doesn't know how these proceedings work.

Publications Count

          This is probably the best "real-world" example of why publishing your finds matter. It might not be a priority to you. It might be a pain, it might take more time than you want, it might get caught up in the chaos of a job change or move. It doesn't matter; publish what you find. Is it all going to be flashy? Hell no. Does it provide useful data for your future colleagues or students in 10, 20, 50, 150 years? It sure does. Perhaps most broadly applicable here, does it provide people outside the science entirely with something solid to point to when trying to decide on the "value" of the land? You better believe it. Without anything concrete to point to about the nationally significant scientific value of Red Canyon, when lawmakers, bureaucrats, and administration officials asked how I could show the area needed protection I couldn't respond. At the Department of the Interior I was repeatedly asked to support my claims that paleontology needed to be protected and what areas were most significant. There are publications, preprints, and abstracts to support the scientific value of Indian Creek, Comb Ridge, and Valley of the Gods. There was nothing to point to for Red Canyon.
          This also brings up a point that my friend Jim has raised on Facebook. The proclamation language heavily favors the Triassic fossils from the region. Part of this is likely due to some of my experience bias creeping in; I mainly work in the Triassic. The majority of that, however, comes again from the published record. While there are hundreds (thousands?) of acres of Middle Mesozoic sediments exposed in the Bears Ears area (see the map above), almost nothing has been published on fossils from those sediments in the Bears Ears. Comparatively the Late Paleozoic and Early Mesozoic comprise the vast majority of the published record for the region. In meetings with the DoI, again, I was essentially told that knowing that something might be out there is nice, the government can't set aside this land from all other purposes based on a possibility. In setting up proclamation language we didn't ignore mid-Mesozoic finds; those projects have either been sidelined, ignored, or not started by our own profession in favor of work elsewhere. And I recognize that it is a tough balancing act. My work in Bears Ears has meant I haven't been following up on leads in other places. We all only have so much time, energy, and funding.


          Would scientists publishing in the 80s or 90s on the Red Canyon reptile material have made a difference? Would Red Canyon now be part of Bears Ears National Monument had these reptiles (and other, more recent but unpublished finds) become part of the published scientific record? That's a what-if game that has no right answer; its inclusion would still have to fight against powerful interests looking to preserve uranium mining in Red Canyon. I do know that it couldn't have hurt and its absence was the weakest point by far in all my efforts to get paleontology covered under a BENM or any legislative action. We shouldn't be publishing for solely political cynicism but sitting on scientifically significant fossils for 40-50 years should not be considered normal or acceptable. This is especially true in this age of rapid, rigorous peer review and digital publication. Sitting on specimens for that long hurts science, hurts future work in the area, and may even end up hurting the very place the fossils came from.

Works Cited

Instead of my usual works cited section here I am going to take this space to say I am going to be creating a Bears Ears Bibliography page here on the blog. This will be a core page here on the blog and will be added to as new papers either come to light or are published. They will be live-linked when possible. Expect this to go live in the first week of 2017. It will start with the bibliography I prepared for the White House so you can see (if you didn't get an e-mail from me before all of this) what I was working from. If you think something is missing and should be included after it goes live, don't hesitate to point it out!

Monday, January 2, 2017

Help Save Dinosaur Ridge!!!

Dinosaur Ridge Needs Your Help
Dinosaur Ridge, a tourist attraction where the first specimen of Stegosaurus was found is under threat to become a car dealership. I implore everyone, especially Colorado natives, to express their disdain with the commissioners who will vote on whether to approve the dealership. Here's the post from the Facebook page 'Save Dinosaur Ridge':

We need all of the commissioners getting letters -- as many as possible -- saying that we do NOT want car dealerships at Dinosaur Ridge. The email can be simple and straight forward. You can just say whatever is in your heart, in a civil way. Help the Commissioners hear the message:VOTE NO on the re-zoning to allow a car dealership at the intersection of Alameda and C-470.
Here are the contacts to write to:
Libby Szabo, District 1 Commissioner:
Casey Tighe, District 2 Commissioner:
Donald Rosier, District 3 Commissioner:
Please cc the Case Manager, Heather Gutherless,

Trackway at Dinosaur Ridge

                             Edit: Here is "Save Dinosaur Ridge' most recent post: 


Board of County Commissioners
c/o Heather Gutherless, Case Manager
100 Jefferson County Pkwy, Golden, CO 80419

In the letter, please identify yourself as a concerned citizen, and simply state that you oppose a car dealership at the intersection of Alameda and C-470. (“Please vote “no” on Jan 17 at the meeting decide whether or not to rezone land around Dinosaur Ridge.”) or longer and more personal.

The important thing is that the letter get to the Board NO LATER THAN Jan 10.


303-271-8525 – Monday thru Friday – 7:30am to 5:30pm

The Case Manager is Heather Gutherless.
REACH OUT TO EACH OF THE COMMISSIONERS via social media, or their own websites and email addresses

These links will help you know what district you live in, so that you can contact the commissioner who represents you.
It is fine to contact all three of them, but they are most interested in hearing from citizens inside their own districts:

LIBBY SZABO - District 1 Website Submittable Form
Libby Szabo for JeffCo * P.O. Box 746048 * Arvada CO 80006-6048 * * 720-260-4722

CASEY TIGHE - District 2 - * * * 720-443-0619 *

DONALD ROSIER - District 3 -
Thanks to Tara Lepore and Ashley Hall for bringing this matter to my attention. Here is the Dinosaur Ridge website for those interested!

Thursday, December 29, 2016

The Fight for Paleontology in Bears Ears

The Fight for Paleontology in Bears Ears

As many of you may have seen, on December 28th, 2016, President Obama used the authority assigned to him under the Antiquities Act of 1906 by Congress to declare a Bears Ears National Monument. Now most of the public debate surrounding this area has focused on the wealth of ancient sites, artifacts, rock art, and tribal connections to the area. But the paleontological resources of the area are also highly significant. I had been following with interest and then growing alarm as various advocacy groups began pushing for additional protection for various cultural and scenic resources in the area. State legislators were talking about a public lands "Grand Bargain." Tribal leaders and conservationists were talking about a national monument. No one was talking about the paleontological resources of the area. This was a great concern to me since that has been my field area for several years now and an area I have been involved in and around for well over a decade.
Moonrise over Comb Ridge, where my work has focused for the last several years.

Pushing for Paleontology

                So I took action. I went down to Bluff in March 2016 to attend Friends of Cedar Mesa's Celebrate Cedar Mesa and agitate. I poked at people; organizers, legislators, BLM administrators, and conservationists. I made a general nuisance of myself and apparently it did some good. Though no Utah state or federal legislators ever got back to me, the folks involved with monument status began communicating about the fossils in the area. It started with simple descriptions of the paleo resources of the area. When I was asked to compile a bibliography of the same, though, that's when I think I opened lots of eyes. The bibliographic list of publications together ran for over 20 pages and left many mineral-geology resources off (as they were being dealt with elsewhere).
Looking west from Bluff at Celebrate Cedar Mesa 2016
                That is when things accelerated. In April I was brought down to Bluff to talk to folks from FoCM and The Wilderness Society about the importance of the area to paleontology and about the 300 million years of stories in the area, preserved in the rocks of the Bears Ears area. Some of this was eventually made into a video highlighting our personal connections to the area.

The video of the personal and deep-time aspects of the area, produced by TWS.

                Around this time I was also asked to draft language that would protect paleontology in a monument, should the president move forward with a monument. I would have been happy to have provided similar input to the PLI as well, but considering they barred non-San Juan County residents from participating in the Bears Ears portion it isn't surprising that they didn't contact me. A rumor also began circulating that Sally Jewell, the Secretary of the Interior, would be visiting the region over the summer. I sent her a message inviting her to our field camp at Comb Ridge. While the invitation was turned down, I did get a response from her scheduling secretary; encouraging.

Increased Advocacy

                Over the summer the Secretary's travel plans firmed up and it became clear she would be visiting Bluff in July. I made the three hour trek down there and saw loads and loads of people. The line to get inside the community building in Bluff stretched back on itself multiple times in the heat and the organizers had set up an outside listening area. I patiently waited in line to get a number to speak. Despite arriving at (what I had assumed was) a decent time, I was unable to secure a seat inside. Instead I guzzled water outside with my friend Chris and listened to the first half hour of speakers come and go. The atmosphere was charged but no one was being too terribly rude. I got a text from an inside person and worked my way into the building where the atmosphere was more tense, more dense, but only slightly less hot than outside. 

View inside the Bluff Community Center. Photo by ReBecca Hunt-Foster.

                My number wasn't drawn as the day drew near its end but then the Secretary announced that she would be extending the meeting on account of all the people still in attendance. While several people had to leave, including Chris, most of the folks stayed. The Community Center did not seem to empty out, though as people from outside filled in the spaces. As luck/fate/random chance of the draw would have it, my number was called. In fact it was the second-to-last number called to speak. Like the Hamilton song says, I wasn't going to throw away my shot. Many folks had pre-written speeches in hand when they approached the mic but not me. I had an outline in my head and key ideas to touch on; I got up there and spoke based on that. I would like to think my lack of notes in hand and ease with the subject I was discussing helped but I cannot be sure.
Speaking to the panel in Bluff. Photo by David Rankin.
                After probably the most stressful two minutes of my career the meeting was essentially over. I helped pick up the best I could and chatted with folks from FoCM, TWS, the Utah legislature, and various friends before heading to a field camp just up the road. My conscience was clear at this point; I'd made my case to people who would make the decisions. I figured that my work was essentially done at this point.

Rob Goes to Washington

                As the summer progressed the Bears Ears radar went quiet for the most part. In September, though, things began to pick back up. I was asked for updated information to provide to the Administration and to speak around Colorado. Again, all of this was coming from the monument advocacy side; the PLI crowd still had not been in contact with me, though they had consulted with (and apparently not taken the advice of) other geoscientists who had been active in the Bears Ears area. Also in September the idea was broached to me by Scott of TWS of going to Washington DC and presenting to the White House, the Department of the Interior, and the USDA/Forest Service about paleo in the Bears Ears area. After a fair bit of stop-and-start action, along with an intervening paleontology conference, I ended up visiting DC for the first time ever on Halloween.
Yours truly standing inside the White House Council on Environmental Quality office.
                Having never been to DC before this was sort of a double whammy. Here I was, seeing historic buildings, sites, monuments, cemeteries, and departments for the first time but also going into these "Halls of Power" to meet with folks and talk about the land and science that is essentially my consuming passion. People asked if I was nervous going into this part. I wasn't, not really. I know the science, the landscape, the geology, and the region like the back of my hand.
                In the meetings questions came up about the publication record of certain regions, the relative rarity of certain resources, why certain areas on our map (more on that in a later post) weren't identified as "high potential", and what work was currently happening in the region (along with many others). These are questions I was able to answer but was also happy to be asked; it meant that the people in these departments were taking paleontology seriously and had done their background reading. I left DC knowing that the folks I had talked to were energized about paleontology and hopeful that their enthusiasm and the new information from me would be transformed into paleontology being protected in any future proclamation. Scott from TWS was likewise hopeful.

The Final Days

                After the election there was some serious concern among folks that despite all the legwork done by experts, advocates, and lawmakers on both sides of the issue that nothing would happen. Despite Rob Bishop et al. proclaiming that a Bears Ears National Monument would be a midnight monument, that the State of Utah would sue, etc., it was clear at the meeting (and from the amount of work that Bishop put in) that both sides of the issue wanted to see the area protected. There was frantic scrambling to make sure everything was in place should the President decide to act. In the midst of all this chaos some of my colleagues and I managed to put out a preprint on the first vertebrate traces from Comb Ridge, in the Bears Ears area. Everything was poised and ready but no one was really sure it was going to happen until it did. I got a call from an advocate about half an hour before the White House made the announcement; even then I was on pins and needles. Would paleo actually be protected?
                It is with great relief that I read the proclamation and saw that paleontology was explicitly called out and protected under the proclamation. Perhaps even more surprising (and gratifying) is that a large portion of the paleontology-specific text was mine. I had helped craft this. I had made a difference here. Before I got involved in the process no one on either side of the issue had considered paleontology in the region seriously. No matter what happens going forward we know that paleontology in the region will be protected. By explicitly mentioning it in the proclamation, the president has acknowledged that the resources are significant not only to the area but to the country as a whole.
The paleontological resources in the Bears Ears area are among the richest and most significant in the United States, and protection of this area will provide important opportunities for further archaeological and paleontological study. Many sites, such as Arch Canyon, are teeming with fossils, and research conducted in the Bears Ears area is revealing new insights into the transition of vertebrate life from reptiles to mammals and from sea to land. Numerous ray-finned fish fossils from the Permian Period have been discovered, along with other late Paleozoic Era fossils, including giant amphibians, synapsid reptiles, and important plant fossils. Fossilized traces of marine and aquatic creatures such as clams, crayfish, fish, and aquatic reptiles have been found in Indian Creek's Chinle Formation, dating to the Triassic Period, and phytosaur and dinosaur fossils from the same period have been found along Comb Ridge. Paleontologists have identified new species of plant-eating crocodile-like reptiles and mass graves of lumbering sauropods, along with metoposaurus, crocodiles, and other dinosaur fossils. Fossilized trackways of early tetrapods can be seen in the Valley of the Gods and in Indian Creek, where paleontologists have also discovered exceptional examples of fossilized ferns, horsetails, and cycads. The Chinle Formation and the Wingate, Kayenta, and Navajo Formations above it provide one of the best continuous rock records of the Triassic-Jurassic transition in the world, crucial to understanding how dinosaurs dominated terrestrial ecosystems and how our mammalian ancestors evolved. In Pleistocene Epoch sediments, scientists have found traces of mammoths, short-faced bears, ground sloths, primates, and camels.
- Proclamation establishing Bears Ears National Monument, December 28th, 2016 
                We are continuing our research in the area with two aggressive excavations scheduled for 2017 in the Bears Ears along with continuing high school field camp work, and I am glad that the administration was willing to listen to the concerns of scientists from around the country about this area and the importance of paleontology to understanding its history. Looking forward, this proclamation serves as a framework for future paleontological work in the region. Nearby Grand Staircase-Escalante National Monument has similar language in its proclamation. This language has enabled a flowering of scientific research across the Grand Staircase. Virtually all of the new dinosaur species coming from that area (>95% of them) have been described since the Monument was declared and the wording of the proclamation has allowed that to happen. Horned dinosaurs, duck-billed dinosaurs, and young relatives of Tyrannosaurus rex have all been named in the last two decades. Hopefully, with paleontology being singled out and protected in Bears Ears National Monument, a similar explosion in our knowledge of the past will occur here.
                There is still work to be done. The fossil-rich areas in and around Red Canyon, currently being worked by colleagues from the Museum of Moab and Appalachian State University, were excluded from the Monument. Of course, with the new administration coming in there are other questions about funding for this and other public lands. We have our work cut out for us. I am mostly happy but I am not content and complacent. More blogs will be forthcoming on this topic too - both about Bears Ears paleo and the process of making a monument.
                I would like to extend my tremendous thanks to all of my friends and colleagues. Field crews from SGDS and NHMU, under Andrew Milner and Randy Irmis were vital to me getting started in paleo in the Bears Ears, as was a GeoCorps internship with the BLM's Canyon Country District in 2013. Canyonlands Natural History Association, the Museum of Northern Arizona, and the Museums of Western Colorado have also directly made my work in this area possible. Conservationists Josh Ewing, Amanda Podmore, and Scott Miller listened when I started poking things with a sharp stick and ranting about paleo in the area. Thank you to all the folks who listened to me at the meeting in July in Bluff as well as in the offices of DC. All my colleagues who signed my letter that I pestered you about; many thanks! It made a difference. Thank you also to Randy, Jeff, and Kenshu for all the hard work getting the SVP to send a letter talking about the importance of paleo, regardless of how (monument vs. NCA) it would be preserved. Special thanks go out to Julie McHugh, Brian Engh, Tara Lepore, May Blueotter, Xavier Jenkins, and all the people who have been part of our Comb Ridge field crews. Many special thanks especially go to Jen McCollough and Abby Landmeier for all their support during this whole process. Now, prepare for more Bears Ears blogs in the coming year!
Portal to the Triassic in Bears Ears National Monument
Edited 12/30 to reflect more accurately how Bishop's PLI planning team interacted with other paleontologists.

Thursday, December 22, 2016

Ceratosaurus Part 2: What do we actually know about Ceratosaurus teeth?

What you'll notice about both of these diagnoses, however, is that they contain little in the way of dental characters. Sure they both say the premaxilla only contains three teeth, but that is of little help if you are trying to ID isolated teeth. This brings me to the crux of this post in the first place

As I said in a previous post, "Teeth attributed to Ceratosaurus do turn up in the field, however, and are usually distinguished by the presence of ridges near their bases."

 Madsen and Welles (2000) found "longitudinal grooves" in the anterior dentary teeth of Ceratosaurus magnicornis (this is not listed in their diagnosis. Another tooth character is though: "the teeth are longer and stouter."), and also cited "persistent parallel grooves on the medial surfaces of the premaxillary teeth and the anterior three teeth of the dentary," in the etymology for C. dentisulcatus (this morphology is not listed as an autapomorphy in their diagnosis - though "teeth more massive" is). Later in their publication, however, Madsen and Welles (p. 35) do state that, "lateral grooves are diagnostic of the premaxillary and anterior three teeth of the Ceratosaurus dentary," when discussing Ceratosaurus sp. from Tanzania. In the next paragraph they discuss "lingual grooves" as being characteristic of Ceratosaurus. They point out that these grooves are not diagnostic to the species level. There are two problems with this: there is now only one recognized species of Ceratosaurus, and the holotype lacks premaxillary and anterior dentary teeth.

While Gilmore does use some dental-based characters, they are not tied to a specific tooth morphology and instead deal with the number of teeth in the various tooth-bearing bones.

So what do we actually know about Ceratosaurus teeth?
Plate 17, Figure 1 from Gilmore (1920), showing the right side of the holotype of Ceratosaurus

Plate 17, Figure 2 from Gilmore (1920), showing the left side of the holotype of Ceratosaurus
The holotype lacks the apparently diagnostic teeth of Madsen and Welles' C. dentisulcatus. As you can see from Gilmore, the left hand side of the skull features no anterior teeth. The right side is equally bleak when it comes to anterior dentition. So we are now faced with a tooth morphology that may be diagnostic (but not used in a formal diagnosis) of a junior synonym that cannot be directly be compared with the holotype.

Continuing to muddy (or clarify?) the waters is C. ?meriani, from the Late Jurassic of Switzerland. Madsen and Welles (2000) figure it and refer it to Ceratosaurus sp., and Mickey Mortimer over at the Theropod Database says, "It differs from Genyodectes and Ostafrikosaurus in lacking mesial serrations. As it is of identical size and found in temporally equivalent beds, I believe it should be called Ceratosaurus meriani." Well there are other teeth from the Late Jurassic that have fluting and lack mesial serrations. Specifically some teeth referred to Ceratosaurus from the Morrison Formation of the American West. But why are they referred to Ceratosaurus? It is the right size and shape and comes from the right aged beds...but that's usually not good enough to assign to a highly exclusive clade.

So let's sum up what we can say about the teeth of Ceratosaurus (and please chime in if I've goofed somewhere):

  • Ceratosaurus nasicornis has no known premaxillary or anterior dentary teeth
  • C. magnicornis has both premaxillaries preserved but, again, no teeth preserved in situ. It also lacks a dentary
  • C. dentisulcatus preserves both an toothed premaxilla and dentary with the lingual surfaces of the premaxillary and anterior dentary teeth preserving apicobasal grooves.
  • C ?meriani lacks mesial serrations and appears to preserve apicobasal fluting
  • C. "stechowi" from Tendaguru has apicobasal fluting
  • C. "sulcatus" from Como Bluff, Wyoming preserves apicobasal fluting
  • Several teeth from the Mygatt-Moore Quarry have been referred to Ceratosaurus on the basis of apicobasal fluting.
So it seems that people are treating these apicobasal flutes (and in some cases the lack of mesial serrations) as diagnostic to Ceratosaurus. But apicobasal flutes are known in more taxa than just Ceratosaurus; several Triassic archosauriform tooth morphotypes possess them, as do temnospondyls, some phytosaurs, some early Jurassic dinosaurs (WFtP), spinosaurs, crocs, and gators. That's just tetrapods; I haven't wanted to dive deep into what sort of crazy dentition fish might have. As I understand it (though I don't have any sources right next to me at the moment) this adaptation would be useful for resisting strain on the tooth; basically the animal was punching through tough, wriggling stuff with its face. Understandable then that many things that eat tough prey would have this sort of adaptation.

Where does that leave us with Ceratosaurus? Well it leaves us with the possibility (not the certainty) that Ceratosaurus had apicobasal fluting on its anterior teeth. Certainly specimens with non-dental remains seem to suggest at least one species referred to Ceratosaurus previously had these flutes. I would urge caution, however, in assigning all Late Jurassic stout, fluted theropod teeth to Ceratosaurus. First off, the holotype doesn't have them, so the referral is based on previously referred specimens. That sort of secondary referral is done relatively frequently but it should give one cause for consideration. The second point is that we really don't have a good idea of the dental variation in other Late Jurassic theropods. We know the teeth of Allosaurus fairly well, but what can we say of the tooth structure at all major tooth positions in Torvosaurus, for example (especially considering derived megalosaurs, the spinosaurs, developed fluted tooth crowns as well)? Do we really know what the teeth were like in some of the mid-sized Morrison taxa as well? Since most aren't represented by good cranial remains we don't know what tooth variation is out there.

In closing, we can say that it is likely Ceratosaurus had fluted front teeth but because of problems with the type specimen and the plesiomorphic nature of dental fluting, the rampant homoplasy in tetrapod dentition in general, and the lack of information about other Morrison theropods' teeth it is unwise to assign isolated fluted teeth to Ceratosaurus at all. Hopefully descriptions of other Ceratosaurus specimens with preserved anterior teeth along with a better understanding of Morrison theropod tooth diversity will lead to more accurate diagnoses of these fluted theropod teeth.

Minor aside

Life happens. I've been off the blog game for almost the whole year but I am hoping to be back at it through 2017, especially in terms of blogging about our next publications we have coming out. I've also brought a couple amigos on board here at the Prehistoric Pub so we plan on at least not letting you all down too much this next year. Onward to the next paleo discovery!

Works Cited

Madsen, James H.; Welles, Samuel P. 2000. "Ceratosaurus (Dinosauria, Theropoda) a revised osteology." Utah Geological Survey Miscellaneous Publication 00-2. pp. 80