The Division of Reptiles and Amphibians at the University of Michigan’s Museum of Zoology maintains a collection of radiograph film plates that are being digitized and associated with diagrams of individual specimens to make them more accessible for research. Many of the images include a mysterious order of amphibians dubbed caecilians.
What’s a caecilian? “Caecilians are legless amphibians, members of the Gymnophiona (or Apoda), one of three extant orders in the class Amphibia,” according to Greg Schneider, collection manager of reptiles and amphibians at UMMZ. “They are distributed worldwide across the tropics, mostly burrowing underground or in leaf litter in humid environments, although one family is totally aquatic. Because of their rather secluded existence, caecilians are unfamiliar to the layperson and are not usually considered in discussions about amphibians.” There is still much to be learned about this fascinating group of highly specialized amphibians.
While we’re asking questions, just what is a radiograph? It’s an image produced on a sensitive plate or film by X-rays or similar radiation.
Of all of the images of caecilians in the radiograph collection, 40 percent represent UMMZ specimens. The others were borrowed from various museums worldwide. UMMZ personnel borrowed research material from other museum collections with permission to film X-rays of them. “The digitization project not only makes the X-rays available for research, but by sharing the collection, other museums gain access to images of their specimens,” Schneider said. The UMMZ collection contains nearly 20,000 records and images of assorted amphibians and reptiles. Currently, only caecilians and pygopods have been digitized with nearly 6,000 images of caecilians available online.
Some project history follows, courtesy of Schneider. Radiographs were filmed with an old dental school X-ray machine mounted in a lead box. Professor Emeritus and Curator Emeritus Ronald Nussbaum and a former master’s student, Dr. Mark Wilkinson, now a scientist at the Natural History Museum, London, borrowed caecilians from museum collections worldwide to take measurements and data, including taking X-rays, for their research. Wilkinson likely took most of the X-ray images and developed the film in the mid-1980s. Mike Pfrender, a U-M undergraduate student, assisted, especially with the genus Shistometopum from specimens he and Nussbaum collected in São Tomé and Principe in the early 1990s. An important aspect of the research is the vertebral counts obtainable from the X-rays, an ongoing project. Wilkinson and his colleagues, Dr. David Gower of the Natural History Museum, London, Dr. Simon Maddock of Reaseheath College, United Kingdom, Dr. Hendrik Mueller of Jena University in Germany, and Nussbaum, are caecilian experts who were interested in having these data and images more accessible for research.
During winter term 2014, Jason Good, a School of Natural Resources and Environment Ph.D. student, worked for the Reptile and Amphibian Division as the curatorial assistant. Good and Schneider developed a method for digitizing the X-ray film plates by photographing them on an X-ray illuminator lightbox and enhancing them in Photoshop. Good completed the imaging in four months and Schneider performed the extensive database work.
Good and Schneider also created digital images of pygopod lizard radiographs, an excellently represented group of Australian legless lizards in the radiograph collection that will be added to the digital project. There are plans for undergraduate students to become involved in this project and other aspects of the museum’s digitization efforts. Schneider’s next digitization project has been approved by the U-M Digital Library Platform & Services and will involve presenting digital versions of the nearly 300 valuable division field notebooks documenting expeditions and collections since the early 1900s, the culmination of a project that began in 2010.
Visit the Herpetology radiographs collection.
With appreciation to Greg Schneider, the Library Copyright Office, Roger Espinosa, U-M Library app programmer/analyst and Rob McIntyre, U-M Library digital asset management consultant, for making the collection possible.