Field of Science

New North American Therizinosaur Nothronychus graffami I'm up into the Cretaceous rather than the Triassic or even the Jurassic. However, it is good to see this beastie finally published after a lot of hard work and many trials and tribulations. Today (July 15) a paper (I don't have the actual ref yet) comes out in Procedings of the Royal Society B by David Gillette and Lindsay Zanno describing a new therizinosaur from the Tropic Shale of Utah. I was a graduate student at Northern Arizona University when Merle Graffam discovered the holotype specimen. Dave Gillette, one of my graduate advisors, collected the specimen in 1999 and laboriously prepared the specimen in the lab where I was working on the skeleton of Desmatosuchus that was the focus of my Masters thesis.

The therizinosaur skeleton was difficult to prepare due to the matrix and diagenetic crushing of the elements, but at the time it was collected it represented the first evidence of therizinosaurs from North America. Doug Wolfe and colleagues had not yet figured out that part of the frill of Zuniceratops was actually the ischium of what would later be named Nothronychus mckinleyi; and the Crystal Geyser Quarry, which would produce Falcarius, had not yet yielded any recognized therizinosaur material. What made the MNA fossil even more spectacular was its stratigraphic control. It was found in a marine deposit and the bones were actually covered with ammonites!

Shortly afterwards the MNA had some problems and at one point the Geology program was terminated. Fortunately due to public outcry (among other things) the department was reestablished; however, these circumstances caused delays in the study of this specimen. A couple of years ago; however, it was the focus of an excellent new exhibit at the MNA and now the description is finally out. As I have not yet seen the paper I cannot comment on the content but there are some early news reports up here and here. Congrats to Dave Gillette (and to Lindsay Zanno) on the release of the results of this long awaited study. I know that he put a ton of work into this specimen.

You can read an earlier account of this excavation and specimen that came out in Arizona Geology back in the summer of 2007. There is also a good photo gallery of Utah fossils here which includes a reconstruction of N. graffami by artist Victor Leshyk (see photo above), pictures of a display of some of the bones, as well as a picture of Dave in front of a full scale reconstruction done by Rob Gaston.


  1. Several of the volunteers at the Utah Museum of Natural History paleo lab put in a lot of hours prepping this critter.

    I look forward to reading the paper, congratulations!

  2. Please remember my involvement with this specimen is restricted to the late 1990s and early 2000s when it was at the MNA. If I slight anyone who worked on it in Utah after it was transfered I apologize at this is not my intent. I'm just expressing what I remember of the specimens early history.

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  4. Derogatory, unsupported comments like these are deleted as I see fit. Especially if you post anonomously (i.e., you are not even willing to put your name on your comments).

    BTW.... even when professional paleontologists find specimens in the field, we often do not know what it is or its significance until the specimen is prepared and studied. This case was no different so credit was given where crdit was due.


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