IMPROVED TECHNIQUE FOR PRODUCING HIGH QUALITY PHOTOGRAPHS OF FOSSIL RODENT TEETH

Using ammonium chloride (smoking) to coat fossil specimens in preparation for photography is a method practiced by many paleontologists. Originally used for invertebrate specimens, this technique has infrequently been used for fossil rodent teeth. Rodents of the families Ischyromyidae and Sciruavidae are too large for SEM and too small for using a digital camera without a microscope. One solution is to highlight crown pattern features by coating the specimens and then take a picture with a digital camera mounted on a dissection microscope. Here we describe a simple, inexpensive technique for coating fossil rodent specimens combined with taking pictures through the microscope to create crisp, clear digital images suitable for study and publication. Ammonium chloride powder is heated in a glass tube with a bulb at one end and then gently blown over the specimen to lightly coat the surface of the tooth. The specimen is placed under a compound microscope equipped with a digital camera. Once the images have been captured digitally, they can be used to study crown pattern variations and later for publication. The smoking technique is superior to line drawings, other coating and/or photographic methods for highlighting crown pattern features such as cusps, crenulations, and crests, which are characteristic of ischyromyid and sciuravid teeth. Adoption of this technique by paleontologists studying the alpha taxonomy of rodents will significantly improve communication among scientists interested in identifying ischyromyid and sciuravid rodents.