CLAESON*, Kerin M.*; LUNDBERG, John G.; Amherst College, Amherst, MA; Academy of Natural Sciences, Philadelphia, PA; *University of Texas, Austin: Micro Catfish Micro CATscans

Tendencies toward extremely small body size occurred several times during the course of teleost evolution. The catfishes (Siluriformes) are a group of fishes in which miniaturization occurred multiple times. We present new information on two distantly related miniaturized catfishes from South America, Micromyzon akamai (Aspredinidae) and Sarcoglanis simplex (Trichomycteridae). Data were collected with the classical technique of clearing and staining (C&S) and the more contemporary approach of microfocus computed tomography (CT). CT was developed in the mid 1970s and used to examine humans and other vertebrates in veterinary sciences. Around 20 years ago, CT was adapted for examining paleontological specimens. Microfocus CT (conducted at Amherst College), is similar to traditional CT scanning but allows for significantly greater resolution on small specimens. The remarkably small size of these fishes (<20mm, SL) and the sparse number of specimens raise difficulties for detailed examination of the skeletal anatomy in comparative morphological and phylogenetic research. Results of this study demonstrate fundamental differences between these techniques, warranting discussion of the benefits of C&S and CT as separate entities and in combination. CT images are ready at once for illustration, are non-destructive, and results are easy to distribute for study by others. C&S is inexpensive, cartilage can be counterstained, and improved digital imaging such as automontage for depth of field produces sharp illustrations. Additionally, when a small sample set is available, using both CT and C&S on the same specimen greatly reduces the need to dissect, disarticulate, and otherwise modify rare specimens.