ICVM-10 Symposium on Reptile Skeletal Biology

ICVMInterested in the latest research on reptile development, biomechanics and evolution? Come to our symposium at the International Congress of Vertebrate Morphology in Barcelona next Tuesday (July 9, 2013). If not, be sure to catch some of the other outstanding talks held in the neighboring rooms. 

Symposium 7: Reptile Skeletal Biology: Investigations Into Tissue Morphology, Development, and Evolution

Organizers: Casey Holliday, University of Missouri; Matthew Vickaryous, University of Guelph

Reptiles are one of the most ancient and morphologically diverse radiations of tetrapods.  An important feature underpinning this diversity is the skeleton. While the reptilian skeleton has a long history of appreciation by palaeontologists, morphologists and ecologists, it is now emerging as an important model for many developmental and biomedical biologists.  Furthermore, the adoption of various cutting edge approaches in molecular, imaging, and experimental techniques is leading to major revisions and re-interpretations of several longstanding ideas.  This symposium will focus on exploring some of the most intriguing and fundamental questions in evolutionary developmental biology from a uniquely reptilian perspective.  Our participants will bring forward important advancements in the study of the origin and evolution of body plans, morphogenesis and regeneration, and physiology and functional morphology . The goal of our assembled international panel (including participants from Japan, Germany, UK, France, Canada and the US) is to provide a productive and collaborative forum to share, critique and exchange approaches, techniques and species-specific expertise.  Building on the recent publication of the Anolis genome and recent funding to complete the Alligator genome, reptilian biology is undergoing an unparalleled renaissance and our symposium will highlight the latest research using turtles, lepidosaurs, crocodylians, and their fossil ancestors.  ICVM-10 presents an exceptional opportunity to highlight this next generation of reptilian skeletal biology, and its ever growing potential for the broader study of development, evolution, and functional morphology.

09:30

S-036 SKELETAL REGENERATION FOLLOWING TAIL LOSS IN LIZARDS

Vickaryous, Matt; Coates, Helen; Delorme, Steph University of Guelph, Guelph, Canada

10:00

S-037 SQUAMATE VERTEBRAL HISTOLOGY AND MICROANATOMY -DEVELOPMENT AND EVOLUTION

Houssaye, Alexandra Steinmann Institut für Geologie, Paläontologie und Mineralogie, Universität Bonn, Bonn, Germany

10:30

S-038 COMPARATIVE SKULL MECHANICS OF THE LIZARDS TUPINAMBIS MERIANAE AND VARANUS ORNATUS

Gröning, Flora (1); Jones, Marc (2); Curtis, Neil (1); O’higgins, Paul (3); Evans, Susan (2); Fagan, Michael (1) (1) University of Hull, Hull, United Kingdom; (2) University College London, London, United Kingdom; (3) University of York, York, United Kingdom

11:00

S-039 A COMPARISON OF TURTLE AND CHICKEN ONTOGENY REVEALS THE BASIS FOR DIVERGENT HARD PALATE MORPHOLOGY

Richman, Joy; Abramyan, John; Leung, KelvinLife Sciences Centre, University of British Columbia, Canada

12:00

S-040 HOW DID ENAMEL MATRIX PROTEINS EVOLVE IN REPTILE TEETH AND ARE THEY PRESENT IN OSTEODERMS?

Sire, Jean-Yves (1); Gasse, Barbara (1); Silvent, Jérémie (1); Delgado, Sidney (1); Belheouane, Meriem (1); De Buffrénil, Vivian (2) (1) Université Pierre et Marie Curie, Paris, France; (2) Muséum national d’Histoire naturelle, Paris, France

12:30

S-041 DEVELOPMENTAL PLAN OF THE AMNIOTE SHOULDER GIRDLE AND ITS EVOLUTIONARY DIVERSITY

Nagashima, Hiroshi (1); Hirasawa, Tatsuya (2); Sugahara, Fumiaki (2); Takechi, Masaki (3); Sato, Noboru (1); Kuratani, Shigeru (2) (1) Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan; (2) RIKEN Center for Developmental Biology, Kobe, Japan; (3) Iwate Medical University, Yahaba-cho, Japan

14:30

S-042 MORPHOLOGY AND FUNCTION OF THE REPTILE MANDIBULAR SYMPHYSIS

Holliday, Casey (1); Hieronymus, Tobin (2); Nesbitt, Sterling (3); Vickaryous, Matthew (4) (1) University of Missouri, Columbia, United States; (2) Northeastern Ohio Medical University, Kent, United States; (3) Field Museum of Natural History, Chicago, United States; (4) University of Guelph, Guelph, Canada

15:00

S-043 DEVELOPMENT AND EVOLUTION OF MESOPODIALIZATION IN THE ICHTHYOSAURIAN LIMB SKELETON

Maxwell, Erin (1); Scheyer, TorstenM. (1); Fowler, Donald (2) (1) Universität Zürich, Paläontologisches Institut und Museum, Switzerland; (2) McGill University, Department of Biology, Canada

15:30

S-044 FRONTIERS IN THE EVOLUTION AND DEVELOPMENT OF THE REPTILIAN SKULL

Bhullar, Bhart-Anjan (1); Marugan-Lobon, Jesus (2); Racimo, Fernando (3); Bever, Gabe (4); Rowe, Timothy (5); Norell, Mark (6); Abzhanov, Arhat (1) (1) Harvard University, Cambridge, United States; (2) University of Madrid, Madrid, Spain; (3) University of California, Berkeley, United States; (4) New York College of Osteopathic Medicine, Old Westbury, United States; (5) The University of Texas at Austin, Austin, United States; (6) American Museum of Natural History, New York, United States

16:00

S-045 CONSERVATION OF PRIMAXIAL REGIONALIZATION IN THE EVOLUTION OF THE SNAKE BODY FORM INDICATES HOMOPLASY IN HOX GENE FUNCTION

Head, Jason (1); Polly, P.David (2) (1) University of Nebraska-Lincoln, Lincoln, United States; (2) Indiana University, Bloomington, United States

17:00

S-046 IN VIVO CRANIAL BONE STRAINS DURING FEEDING IN THE LIZARDS TUPINAMBIS AND UROMASTYX

Porro, Laura (1); Ross, Callum (2); Herrel, Anthony (3); Evans, Susan (4); Fagan, Michael (5); O’Higgins, Paul (6) (1) University of Bristol, Bristol, United Kingdom; (2) University of Chicago, Chicago, United States; (3) CNRS/Muséum National d’Histoire Naturelle, Paris, France; (4) University College London, London, United Kingdom; (5) University of Hull, Hull, United Kingdom; (6) University of York, York, United Kingdom

 17:30

S-047 ARCHOSAUROMORPH BONE HISTOLOGY REVEALS EARLY EVOLUTION OF ELEVATED GROWTH AND METABOLIC RATES

Werning, Sarah (1); Irmis, Randall (2); Nesbitt, Sterling (3); Smith, Nathan (4); Turner, Alan (5); Padian, Kevin (1) (1) University of California, Berkeley,CA, United States; (2) Natural History Museum of Utah & University of Utah, Salt Lake City, UT, United States; (3) The Field Museum, Chicago, IL, United States; (4) Howard University, Washington, DC, United States; (5) Stony Brook University, Stony Brook, NY, United States

It’s a Veggie-raptor, Lex! Veggi-raptor!

A discussion by Henry Tsai

Most dinosaur fans would agree that theropods are among the best characterized of dinosaurs. From agile speedsters like Velociraptor to lumbering powerhouses like Tyrannosaurus, these bipedal beasts appear to the public as ideal killing machines, with jaws full of sharp teeth and the legwork to keep up with their prey.

However, recent studies of maniraptorans, the theropod group that included both dromaeosaurs like Velociraptor and modern birds, have revealed a variety of odd theropods that seem to have abandoned the predatory way of life. Therizinosaurs, a group of pot-bellied, long-necked theropods, possessed leaf-shaped teeth and slightly curved claws. Since none of these features appear useful for predation, popular hypotheses suggest ground sloth-like herbivory for these animals.

Oviraptors add to the puzzle with sharp, recurved claws at the end of powerful forelimbs and robustly built, yet toothless, beaks. This mishmash of seeming carnivorous and herbivorous traits has led to hypotheses of oviraptor diets ranging from leaves, fruits, shellfish, nuts, and even the eggs of other dinosaurs.

Finally, troodonts, the closest relatives of the obviously carnivorous dromaeosaurs, appear to have had teeth more suitable for dicing plants than for ripping meat. These lines of evidence suggest herbivory either evolved multiple times independently; or that herbivory was primitive to the entire Maniraptora, with the carnivorous dromaeosaurs as the odd-‘saurs out. Future studies on bite mechanics and tooth wear will certainly be necessary for uncovering more about the behavior and ecology of these mysterious plant-eating “raptors.”

Figure. Feeding strategy of various maniraptorans. A) The herbivorous therizinosaur Nothronychus. (picture credit: Victor Leshyk) B) The oviraptor Gigantoraptor, whose diet is still under dispute. (picture credit: Nobu Tamura) C) The carnivorous dromaeosaur Deinonychus, shown feeding on a hapless Zephyrosaurus. (picture credit: Emily Willoughby)

Transactions of the Royal Sounds of SVP

Yes, the seats squeaked upon sitting on them at this year’s Society of Vertebrate Paleontology meeting. During talks, most people sought to avoid the chirping by gently sliding laterally onto the cushion. But at the banquet, every applause was followed by waves of seat barks. Stay classy SVP!

All in all, the meeting was well executed, at a great location. Well done Host and Program Committees, and all the participants that made it possible.

Calls of the Wild

By: Ally McEntire

The calls of the baby gator in the Holliday lab got me thinking about alligator vocalizations. On a whim, I decided to look this up and found a little more than I had bargained for. Alligators and other crocodilians have a different vocal structure than any other reptile, amphibian or bird– all nearby relatives. Their vocal structure is actually quite similar to that of mammals. Instead of a syrinx like birds have, which involves air passing through the trachea while it vibrates at different rates; they have vocal folds—a larynx—just like humans.

This article details a study done on live juvenile crocs to study their vocalizations. It discusses a number of very specific things like sexual dimorphism in calls and amount of time the noises lasted. What I find more interesting than all of that is that their vocal structure is so unique. Even though they are evolutionarily related to these 3 other branches, their system of making noise is not really like any of their closest relatives. Basically, they have vocal folds, which contract and/or relax when the gator breathes out, like mammals.

This made me want to find out more about the ancestral line, if the present one is so estranged. Would other archosaurs resemble birds, lizards or crocs more closely? I’m not sure there’s a way to know this, considering the vocal cords are a soft tissue, and therefore incredibly difficult to preserve. But, if there were tissue attachments that could be identified, I think it’s something worth looking into.

Also, if you’re curious to hear our captive alligator making his own vocalizations, check Romer out here:

Romer Chirping

Reaching Out for Science

What is it that scientists do all day while they are watching their shrimp walk on a treadmill?  How do scientists know how Tyrannosaurus may have chewed or ran? How do they know if a molecule will work as a drug to target some disease? Scientists often find it difficult to translate their work’s importance to the public in a way they can understand without losing some of its content. Often “laypeople” are left confused with what looks like a waste of money in the name of big science.

So, how can the general public learn more about the inner workings of a research laboratory? Perhaps the key is to train student researchers early in their careers on how to write about science to the average person.

As a social experiment this year, members of the Holliday lab will try to bridge this gap by writing their own short pieces on relevant and interesting science.

By learning to translate often wonky, jargon-laden research to more palatable, engaging prose, lab members will hope to shed light on what happens in our lab, what questions we are asking, what discoveries we hope to make, and most importantly, why anyone should care.  

Of course, this should help the writers learn about science as well. Although the lab focuses on Vertebrate Functional Anatomy and Evolution, do not be surprised if other topics creep in. 

Ruminations on sauropsid cheeks

I noticed some FB flareup over dinosaur cheeks and had written all this in the box Facebook page and then decided it would be ludicrous to post so I moved it here…Apparently, dinosaur cheeks have become all the rage again in the blogosphere. Having only seen one published paper on the topic ever (Fabian Knoll’s 2008 paper) I’m still perturbed there aren’t other papers. But this region is way cool, apparently there is a new paper coming out on the topic. Being well aware of Witmer’s early work with Mike Papp on the cheeks vs freaks, Tobin H’s work on osteological correlates of skin (jeez I hope someone is pestering Tobin with a hot poker about this instead of just taking heavily from his published papers) and Ashley M’s still-evolving work on foramina…it is not an easy topic. My research on jaw muscles bumped into the buccinator/cheek/rictus problem alot, so I’m aware of the available evidence. (By the way, my favorite branch of the trigeminal nerve is the n. anguli oris—what’s your favorite CN V branch? Hmmm?)

 I hate the term cheeks as it always suggests the mammalian variety with a buccinator muscle (for which there is ZERO evidence for in saurpsids [yes, dinosaurs are also sauropsids!]).  The German anatomists (Luther, Lakjer, et al.) used either Mundplatte, and then later, the rictal plate, or rictus to describe the corner of the mouth in sauropsids (see my 2007 J Morph paper if you want more lit cited). Its rich with nerve endings, vasculature, glands etc and is easily seen in the corner of that snapping turtles mouth (see link above), crocodilian mouths, most birds. The rictus tends to directly cover the corner of the mouth where the temporal and  pterygoideus muscles cross paths as they attach to the mandible near the coronoid process, usually just underneath or caudal to the orbit.  Mammals have a rictus too– its the really sensitive edge of the cheek that lacks muscles but is packed with sensory receptors–go ahead, pinch it. Some snakes developed venom glands within the rictus (McDowell SB. 1986. The architecture of the corner of the mouth of colubroid snakes. J Herpetol 20:353–407.).

Anyway. I don’t see what’s so contentious aside from having a cutesy Dinocheek media event. Well endowed Mundplattes are not uncommon among sauropsids as people keep pointing out.  Why does there have to be one Dinosaurian bauplan for “cheeks” (ugh). Clearly with all the evolution that has happened in these groups, needing more/less skin over the mouth must have been necessary for chewing vs gape?  Clearly having a freaking giant osteoderm there lends cred to ankylosaurs having cheeks. but IMO, I never thought the old addage (err hypothesis?) “food would fall out of their mouth otherwise” to ever be a good approach to support the presence of skin there otherwise.  But perhaps there is upcoming evidence via SVP abstract to support it (yay!).  I feel like this whole debate is driven by paleoart, and not some true scientific endeavor (no offense artists-I understand the pains you often take to get things accurate). I sent most of this same information to Tylor Keillor, like 5 years ago to help with his sculptures-so its way cool to see his work progress that way it has been (see Project Dryptosaurus).

To me, a true cheek is when the rictus becomes decoupled from the true corner of the mouth (back near the coronoid process) and extends rostrally beyond to serve some function with the oral cavity.  So the cheekiest archosaur? My vote is the flamingo. Flamingos stretch the corner of the mouth past the corner of the mouth, past the orbit, past the antorbital cavity! past the transition from bony mandible to beaky mandible (holy crap!). And there is fairly clear function for this given the flamingo’s derived lingual pumping/filtration method of feeding. Here is an unpublished picture from our 2006 Anat Rec Flamingo Head Vessel paper.  Now that’s a @#$@# dinosaur cheek!

Flamingo extended rictus err dinosaur cheek

SVP 2011 Report- Education & Outreach Poster

Yes, it’s been over a month since SVP met in Las Vegas. Shoot, I never blogged about my Argentina trip either. I’m so behind. I flew out during the day from Memphis, and being a clear day, I was able to basically lean my head on the window and watch Texas, New Mexico, and Arizona pass under us-always an amazing view. I took a few good pictures of the Grand Canyon from 30k ft up.

Grand Canyon from the plane

It was a good meeting, we had 2 Undergraduates and 2 PhD students give talks and a poster, and lab alumnus Nick Gardner also gave a great talk. I was really proud of all of their effort in making SVP go so well. To reward them, I punished them by taking them to the Banquet dinner and sitting through the awards ceremony. It was a horrifically sick joke, perhaps the meanest one I have ever subjected someone to. For that, I apologize.

SVP had some personally notable sessions including the Croc sessions (duh), the symposium on Laramidia, and the symposium on limb development. Of course there were interesting presentations scattered about the other sessions and posters.

Posters and orals presented by Holliday lab denizens were:

Gant CA, Skiljan BJ, Tsai HP, Folk B, Holliday CM. Alligators near and far: Using the Maps in Medicine: Inside Alligator high school workshop and 3D Alligator website as educational tools in anatomy and evolution.

Gardner NM, Bullar BA, Holliday CM, O’Keefe FR. Cranial anatomy in the basal diapsid Youngina capensis and its relevance to higher radiations of Permo-Triassic neodiapsida.

George ID, CM Holliday. Trigeminal nerve morphology in Alligator mississippiensis: Implications for inferring sensory potential in extinct crocodyliforms.

Holliday CM, Gardner NM. A new eusuchian crocodyliform with novel cranial integument and the origin of Crocodylia.

Skiljan BJ, Gant CA, Holliday CM. Structure and function of a protosuchian mandibular symphysis using anatomical insights from Alligator mississippiensis.

Tsai HP, Ward CV, Holliday CM. Pelvic anatomy of Alligator mississippiensis and its significance for interpreting limb function in fossil archosaurs

I’m happy to say that Ian’s paper on Alligator trigeminal nerve scaling is in review and the Shieldcroc paper is hopefully through its last minor revisions at PLoS ONE, so we should hopefully see those publications on the horizon. We’re currently developing Becci and Cortaiga’s work on Alligator and Protosuchian symphyses into papers.  The Shieldcroc presentation was selected by SVP to be a part of the media event. That made for some excitement before, during, and after the meeting. I’ll save my thoughts on that whole experience for when the actual paper comes out.

Among all these things, I had the most fun talking at the Outreach and Education posters which included a number of great methods, techniques, and ideas about how to broaden participation of various demographic groups in paleontology, anatomy and evolution education. We presented our own poster which served as a hybrid approach to how we are using Alligators as educational tools in regional High School education and Internet outreach. I’ve written about both of these events here previously: 3D Alligator; Inside Alligators. You can download a small version of the poster here.