Have Some Fossil Bone Fragments, a Bit of Patience; Add a Little Glue, and Voila!

A few days ago one of my summer interns, Rachel, discovered this pile of bone fragments in the Petrified Forest. A few key pieces suggested that they represented part of a skull so we carefully collected all of the fragments.

Later that evening, Rachel and my other student intern, Chuck, were able to work on this jigsaw puzzle and we were all pleasantly surprised to see that all of the fragments went together and formed the back of the right side of a phytosaur skull. Even better is that the bone in the upper left corner, the squamosal, is complete and thus we could identify the specimen as a "leptosuchine" phytosaur.

For those of you not familiar with these animals the photo below is a complete skull from a different locality which was found by one of my interns (Joanna) last summer.

The new partial skull is significant because it represents the best phytosaur specimen known from the locality in which it was found. Furthermore, phytosaurs have biostratigraphic significance so this is another data point for the Chinle Formation in the park (more on this at the SVP meeting in Bristol this year).

Finally, this specimen demonstrates the importance of thoroughly investigating all fragments no matter however insignificant they may seem at the time. This was a pile of badly busted up, hematite-encrusted chunks of bone, which actually represents a common condition for fossils found in the Chinle Formation, especially in sandstone units. A lot of patience on the part of Rachel and Chuck and a bit of glue revealed that this scattered mess was actually a scientifically important specimen. Likewise the complete skull found by Joanna last season was only represented on the surface by a small (golf ball circumference) patch of minute bone fragments in the bank of a small wash. Joanna astutely noticed these and carefully followed the fragments into the bank revealing the entire skull!

Also see David Hone's recent post on what a significant find may look like when you first find it.

Sorry Kids, the Dinosaur Museum is Closed...

Today for the first time in decades the University of Wyoming Geological Museum will not open to the public. To save a measly $80,000 a year the university decided to shutter the only place in the area where local children can experience the wonders of the dinosaur paleontology for which the state of Wyoming is famous. Ignoring public outcry, the bureaucrats who should be holding education, research, and outreach, the core values of any learning institution, in esteem have decided to follow through with these cuts, yet the university's sports programs stay pretty much intact? You can read about it more here at ReBecca Hunt-Foster's site.

I also could not help but notice the comment that while the Geological Museum is being closed, the anthropology museum will reopen soon. I have noted repeatedly that geology and paleontology often get the short end of the stick to archaeology and anthropology, and I feel that this may simply be due to the fact that geology and paleontology are fairly foreign topics to the majority of the public. Indeed, as all paleontologists and archaeologists know there is often much confusion between the roles of the two disciplines. Tell someone you are a paleontologist and they will mention all of the arrowheads they have found; mention you are an archaeologist and people will start asking you about dinosaurs. When I entered college expressing a desire to study fossils I was promptly referred to archaeology classes by the councilors and registrars.

Most people (presumably because they are human) seem to have a have a rudimentary knowledge, understanding, and interest in anthropology and archaeology; however, many of these same people do not even know what the study of geology even entails. Much of this I think is a result of the sad state of science education in the United States. I'm not saying that archaeology is lesser to geology and paleontology (I've done all three), I am just trying to understand why this dichotomy exists. Did you know that despite being responsible for some of the greatest geological wonders in the world (Grand Canyon, Zion, Arches, Yellowstone, etc...) there are more archaeologists employed at the Grand Canyon alone than there are geologists and paleontologists (total) in the entire National Park Service? This is mainly because of the need to satisfy law and policy; however, sometimes I wonder if often there is simply a misunderstanding of the fundamental differences between the two disciplines.

I've experienced leadership in institutions that were established for their paleontological resources who not only have little knowledge or interest in paleontology, but cannot even pronounce the word! I often "joke" with my students that because of the plethora of students and lack of positions in paleontology, many of them should train to become administrators and thus provide universities and museums with leadership who understand and appreciate the science. Of course, it is not really a joke, we desperately need this for the good of the profession; however, how many students will want to be a martyr to protect a job that they badly desire but will never get to have?

There are probably more jobs in paleontology now than ever before, mostly because of the wave of interest stemming from a book and movie now rapidly approaching their two decade anniversary. Paleontologists are challenged with keeping our science fresh and engaging and judging by the media we still get regarding new finds, the interest is for the most part still there. Let's hope that events such as what happened in Wyoming aren't indicators of a future trend.

Latest Literature: Triassic redbeds, footprints, and Eshanosaurus

Thanks to Jerry Harris for pointing these out...

Zaghloul, M.N., Critelli, S., Perri, F., Mongelli, G., Perrone, V., Sonnino, M., Tucker, M., Aiello, M., and Ventimiglia, C. 2009. Depositional systems, composition and geochemistry of Triassic rifted-continental margin redbeds of the Internal Rif Chain, Morocco. Sedimentology. doi: 10.1111/j.1365-3091.2009.01080.x.

ABSTRACT: The Middle to Upper Triassic redbeds at the base of the Ghomaride and Internal 'Dorsale Calcaire' Nappes in the Rifian sector of the Maghrebian Chain have been studied for their sedimentological, petrographic, mineralogical and chemical features. Redbeds lie unconformably on a Variscan low-grade metamorphic basement in a 300 m thick, upward fining and thinning megasequence. Successions are composed of predominantly fluvial red sandstones, with many intercalations of quartzose conglomerates in the lower part that pass upwards into fine-grained micaceous siltstones and massive mudstones, with some carbonate and evaporite beds. This suite of sediments suggests that palaeoenvironments evolved from mostly arenaceous alluvial systems (Middle Triassic) to muddy flood and coastal plain deposits. The successions are characterized by local carbonate and evaporite episodes in the Late Triassic. The growth of carbonate platforms is related to the increasing subsidence (Norian-Rhaetian) during the break-up of Pangea and the earliest stages of the Western Tethys opening. Carbonate platforms became widespread in the Sinemurian. Sandstones are quartzose to quartzolithic in composition, testifying a recycled orogenic provenance from low-grade Palaeozoic metasedimentary rocks. Palaeoweathering indices (Chemical Index of Alteration, Chemical Index of Weathering and Plagioclase Index of Alteration) suggest both a K-enrichment during the burial history and a source area that experienced intense weathering and recycling processes. These processes were favoured by seasonal climatic alternations, characterized by hot, episodically humid conditions with a prolonged dry season. These climatic alternations produced illitization of silicate minerals, iron oxidation and quartz-rich red sediments in alluvial systems. The estimated burial temperature for the continental redbeds is in the range of 100 to 160 °C with lithostatic/tectonic loading of ca 4 to 6 km. These redbeds can be considered as regional petrofacies that mark!the onseern Pangea (Middle Triassic) before the opening of the western part of Tethys in the Middle Jurassic. The studied redbeds and the coeval redbeds of many Alpine successions (Betic, Tellian and Apenninic orogens) show a quite similar history; they identify a Mesomediterranean continental block originating from the break-up of Pangea, which then played an important role in the post-Triassic evolution of the Western Mediterranean region.

Gierlinski, G.D. 2009. A preliminary report on new dinosaur tracks from the Triassic, Jurassic and Cretaceous of Poland; pp. 75-90 in Salas, C.A.-P. (ed.), Actas de las IV Jornadas Internacionales sobre Paleontologia de Dinosaurios y su Entorno. Colectivo Arqueológico-Paleontológico de Salas de los Infantes, Burgos.

ABSTRACT: Dinosaur tracks in Poland are mainly recognized in the Lower Jurassic (Hettangian) of the Holy CrossMountains. There are only few finds, so far reported, from the Upper Triassic of the Tatra Mountains and Silesia. Dinosaur footprints in the Upper Jurassic of the Holy Cross Mountains are also little recognized. Field investigations, in 2006 and 2007, revealed new finds of dinosaur footprints in the Upper Triassic (Norian), Lower Jurassic (Pliensbachian) and Upper Jurassic (Oxfordian) of the Holy Cross Mountains (central Poland), and the Upper Cretaceous (Maastrichtian) of the Roztocze region (southeastern Poland). Norian material comprises prosauropod tracks, which came from the coarse-clastic sequences exposed in the Skarszyny outcrops. New Jurassic finds, in the Holy Cross Mountains, are the Pliensbachian sauropod and small theropod footprints from the Smilow sandstone quarry, and the Oxfordian theropod, and small ornithopod tracks from Baltow limestones. Dinosaur footprints, in the Roztocze carbonates, are discovered in the lowermost part of Szopowe quarry on the Mlynarka Mount. The material from Mlynarka Mount resembles Asiatic ichnotaxa, a small didactyl maniraptoran track of Velociraptorichnus, bird-like ichnite similar to Saurexallopus and a large tetradactyl footprint of Macropodosaurus, a form recently supposed of the therizonosauroid origin.

Barrett, P.M. 2009. The affinities of the enigmatic dinosaur Eshanosaurus deguchiianus from the Early Jurassic of Yunnan Province, People's Republic of China. Palaeontology. doi: 10.1111/j.1475-4983.2009.00887.x.

ABSTRACT: Eshanosaurus deguchiianus is based on a single left dentary from the Lower Lufeng Formation (Lower Jurassic) of Yunnan Province, China. It was originally identified as the earliest known member of Therizinosauroidea (Theropoda: Coelurosauria), a conclusion that results in a significant downward range extension for this clade (>65 million years) and for many other major lineages within Coelurosauria. However, this interpretation has been questioned and several authors have proposed that the anatomical features used to refer Eshanosaurus to Therizinosauroidea are more consistent with attribution to a basal sauropodomorph dinosaur. Detailed consideration of the holotype specimen suggests that several features of the dentary and dentition exclude Eshanosaurus from Sauropodomorpha and support its inclusion within Therizinosauroidea. If accepted as an Early Jurassic coelurosaur, Eshanosaurus has important implications for understanding the timing and tempo of early theropod diversification. Moreover, its provenance also suggests that substantial portions of the coelurosaur fossil record may be missing or unsampled. However, the Early Jurassic age of Eshanosaurus requires confirmation if this taxon is to be fully incorporated into broader evolutionary studies.

Bill Mueller and his Field Notes on the Paleontology and Geology of the Dockum Group

I have had this link up on my sidebar since first starting this blog, but I would like to point out Bill Mueller's great Field Notes site to everyone who has not yet visited. Bill is a professional photographer and a staff member at The Museum at Texas Tech University in Lubbock, Texas and for years now he has been detailing his Late Triassic work in the Dockum Group of Texas at his fine arts website. The amount of material he and his field partner Gretchen routinely uncover is nothing short of astounding. I highly recommend his site to anyone interested in ongoing paleontological field work.

The Coelophysis Quarry at Ghost Ranch

I'm back from a couple of days at the Hayden Quarry near Ghost Ranch, New Mexico. As usual it was a great experience with great people and absolutely amazing fossils. My student interns were able to meet quite a few paleontologists including Sterling Nesbitt, Randy Irmis, Nate Smith, Alan Turner, Alex Downs, Mike Getty, and Mark Loewen. Plus they got to get really dirty and find fossils. A great experience for them.

Another perk is that we took some time off to go visit the classic Coelophysis Quarry. For those of you who have never seen it....here it is in all of its glory. The main bone horizon is now a big flat area where the footprints going up end. This is the siltstone member of the Chinle Formation and the sandstone blocks are fallen blocks from the overlying Entrada Sandstone (Jurassic).

This is the famous "Barney-rock" that overlooks the quarry and all workers were always afraid of it possibly coming down on their heads while they were digging.

Here are the interns (Chuck, Adrian, and Rachel) relaxing after the hike up to the quarry and enjoying the view.

We're Off to the Hayden Quarry

Every year I treat my student interns to a weekend working somewhere else in the Chinle Formation with groups from other institutions. For example in 2002 we worked with Sterling Nesbitt in the Moenkopi Formation excavating an excellent skeleton of Arizonasaurus and in 2003 we joined the Yale Peabody Museum crew in Escalante National Monument in Utah and helped with their Poposaurus excavation (also see this link). I feel that it is important to give my students the opportunity to network with other researchers and to see how others work and collect data. This weekend we are headed out to Ghost Ranch, New Mexico to work in the Hayden Quarry (the type locality of Dromomeron romeri and location of a portion of the Dinosaurs Alive IMAX film) with Sterling Nesbitt, Randy Irmis, and others. This is our third summer there and it is always a great experience.

Photos are from past seasons and were lifted from here and here.

Alan Turner preparing his afternoon siesta spot.

Amazing views from the quarry.

Another photo that proves that from the quarry you really can see scenes like the last one.


A bone that I wish that I had found instead of my usual scrap.

Randy protecting his lunch from other ravenous quarry workers.

Limusaurus inextricabilis, a Bizarre Beaked Ceratosaur from the Late Jurassic of China

OK...OK....This post is regarding the Jurassic, and the Late Jurassic specifically, but it is almost Triassic right? Sort of? Still, this is just to cool of a discovery not to mention.

Today's issue of Nature contains an article by Dr. James Clark (George Washington University) and Xu Xing (Chinese Academy of Science's Institute of Vertebrate Paleontology and Paleoanthropology in Beijing) and colleagues titled "A Jurassic ceratosaur from China and its significance fortheropod digit reduction and avian digital homologies". The paper describes a new beaked ceratosaur (yes, beaked ceratosaur) from the Jurassic of China. This new specimen also offers key information regarding the interpretation of digit homology between non- avian and avian dinosaurs.

As Tom Holtz noted to me in an earlier e-mail message....this is a "ceratosaur convergent on Effigia (a Triassic pseudosuchian): Truly weird!". I could not have summed it up any better!

Kudos also to my friend and colleague Sterling Nesbitt and to fellow blogger David Hone who are co-authors on this paper.

The following text is from the Reuters News Release . Photos are from here.

Limusaurus inextricabilis (meaning "mire lizard who could not escape") was found in 159 million-year-old deposits located in the Junggar Basin of Xinjiang, northwestern China. The dinosaur earned its name from the way its skeletons were preserved, stacked on top of each other in fossilized mire pits that were the subject of a 2008 National Geographic film, "Dino Death Trap."

A close examination of the fossil shows that its upper and lower jaws were toothless, demonstrating that the dinosaur possessed a fully developed beak. Its lack of teeth, short arms without sharp claws and possession of gizzard stones suggest that it was a plant-eater, though it is related to carnivorous dinosaurs.

The newly discovered dinosaur's hand is unusual and provides surprising new insights into a long-standing controversy over which fingers are present in living birds, which are theropod dinosaur descendants. The hands of theropod dinosaurs suggest that the outer two fingers were lost during the course of evolution and the inner three remained. Conversely, embryos of living birds suggest that birds have lost one finger from the outside and one from the inside of the hand.

Unlike all other theropods, the hand of Limusaurus strongly reduced the first finger and increased the size of the second. Drs. Clark and Xu and their co-authors argue that Limusaurus' hand represents a transitional condition in which the inner finger was lost and the other fingers took on the shape of the fingers next to them. The three fingers of most advanced theropods are the second, third and fourth fingers -- the same ones indicated by bird embryos -- contrary to the traditional interpretation that they were the first, second and third.

Limusaurus is the first ceratosaur known from East Asia and one of the most primitive members of the group. Ceratosaurs are a diverse group of theropods that often bear crests or horns on their heads, and many have unusual, knobbyfingers lacking sharp claws.The fossil beds in China that produced Limusaurus have previously yielded skeletons of a variety of dinosaurs and contemporary animals described by Drs.Clark and Xu and their colleagues. These include the oldest tyrannosaur, Guanlong wucaii; the oldest horned dinosaur, Yinlong downsi; a new stegosaur, Jiangjunosaurus junggarensis; and the running crocodile relative, Junggarsuchus sloani.

REFERENCE

Xing Xu et al, 2009. A Jurassic ceratosaur from China helps clarify avian digital homologies. Nature 459:940. doi:10.1038/nature08124