Today I arrived in Zurich, Switzerland for a week-long research trip to the Sauriermuseum Aathal to study the Stegosaurs in their collections. The museum is closed on Mondays, so allow me to provide some background on my motivations undertaking for this trip, as well as what I hope to accomplish.
My name is Ariel Revan, and I am a senior major in the Geology and Geophysics department at Yale. I chose to spend my time at Yale focusing on the Paleontology and Geobiology track of the major, and my work has culminated in the year-long senior thesis project on the dinosaur Stegosaurus. I've been working as a student curatorial assistant at the Yale Peabody Museum (YPM) for the past four years, and this project represents an exciting way for me to collaborate with the museum by providing the staff with accurate data pertaining to the limb proportions and number and arrangement of the osteoderms of Stegosaurus. Both the Vertebrate Paleontology Department and the Yale Peabody Museum have been generous enough to help fund my research travel abroad, allowing me to gain access to the best specimens available to survey in my study. Eventually this data will be used as the basis for the remounting of the current YPM Stegosaurus specimen on display. This process is in its preliminary stages, and will involve removal of some of the skeletal elements on the current mount, as well as replacement of certain other elements.
So what am I doing in Switzerland, one might ask?
The YPM has the holotype of the iconic Stegosaurus in its collections, and plenty of isolated elements to spare. The problem is that the holotype for the genus, YPM 1850, Stegosaurus armatus, coined by O.C. Marsh in 1877, is not suitably diagnostic and consists of only a large dermal plate and a segment of caudal vertebrae. This is an inappropriate standard by which to judge membership to a particular species within a genus known for its wide range of dermal osteoderm shapes, and also does not give any pertinent information as to the rest of the skeleton. In his 2010 paper Galton suggests that the type specimen for Stegosaurus be re-designated, an idea with which I am in agreement. Many of the specimens at the Peabody are of an isolated or fragmentary nature, and many are also from rubble fauna containing more than one individual, making it near-impossible in most cases to say which bones belonged to the same animal. There are wonderful examples of certain elements at the YPM, but for the purpose of this study, well-documented individual must be used, so that we can be sure the proportions are accurate and represent the bone size ratios of a single dinosaur. For this we turn to the Sauriermuseum Aathal.
The Sauriermuseum Aathal in Aathal, Switzerland, houses the most complete and best preserved specimens of stegosaurs known from the Morrison Formation of North America. These specimens, which were excavated from the Howe Ranch Site in Wyoming, include the most complete stegosaur currently on display, nicknamed “Sarah” (cf. Stegosaurus armatus), as well as several other substantially complete stegosaur specimens including “Victoria” (Stegosaurus sp.), “Moritz”(cf. Hesperosaurus mjosi), and “Lilly” (cf. Hesperosaurus mjosi). In order to obtain the best anatomical data possible for the future remounting of the Peabody’s composite skeletal reconstruction of Stegosaurus, it is critical that I study these specimens, which were found in situ as individual skeletons, making them ideal for the purposes of my study. The specimens of the Sauriermuseum Aathal provide a unique opportunity to gather large amounts of data from well-preserved individuals that are housed at a single institution.