A morphological review of the Cuora flavomarginata complex (Testudines: Geoemydidae) Carl H. Ernst*, Arndt F. Laemmerzahl, and Jeffrey E. Lovich (CHE, AFL) Department of Environmental Science and Policy, George Mason University, Fairfax, Virginia 22030-4444, U.S.A. (current address of CHE: Division of Amphibians and Reptiles, MRC 162, Smithsonian Institution P.O. Box 37012, Washington, D.C. 20013-7012, U.S.A.), e-mail: chernst@frontiernet.net, alaemmer@gmu.edu; (JEL) U.S. Geological Survey, Southwest Biological Science Center, 2255 North Gemini Drive, Flagstaff, Arizona 86004, U.S.A., e-mail: jeffrey_lovich@usgs.gov Abstract.—A reevaluation of the morphometric and color pattern differences within the Asiatic box turtle, Cuora flavomarginata sensu latu, was conducted in view of determining the taxonomic position of the three currently recognized subspecies: C. f. flavomarginata (Taiwan), C. f. sinensis (southern mainland China), and C. f. evelynae (Ryukyu Islands, Japan). Recent analyses indicate that the allopatric population of C. f. evelynae is the most divergent of the three taxa and shares little possibility for gene exchange with the other two populations. In contrast, the populations of C. f. flavomarginata and C. f. sinensis share many characters. We recommend the recognition of the Ryukyu population as a full species, C. evelynae. The Asian box turtle, Cuora flavomar- ginata, is currently considered polytypic, consisting of three subspecies: Cuora flavomarginata flavomarginata (Gray, 1863) of Taiwan; C. f. sinensis (Hsu ¨, 1930) of southern mainland China (Fong et al. 2002); and C. f. evelynae Ernst & Lovich, 1990, of the Japanese Ryukyu Islands (Ernst et al. 2000, Hennen 2004, Schilde 2005, Bonin et al. 2006, Fritz & Havas ˇ 2007). The validity of C. f. sinensis and the taxonomic rank of C. f. evelynae, both of which were described as full species, have been questioned (McCord & Iverson 1991, Zhao & Adler 1993, Fritz & Obst 1999, Yasukawa & Ota 1999, Fritz & Havas ˇ 2007). The goal of this study is to examine morphometric and color pattern differ- ences between the three populations to reevaluate the taxonomic status of three geographic disjunct populations. We now possess significantly larger samples of the three separate populations of C. flavo- marginata sensu latu than in our former analysis (Ernst & Lovich 1990). Our results and those of other studies are presented below. Materials and Methods A total of 125 turtles were examined (Ryukyu Islands, 38; Taiwan, 50; south- ern mainland China, 37; see Appendix 1). Notes and drawings were made of head, neck, limb, carapacial and plastral pat- terns of each specimen. Sexes were determined by the characters given by Ernst & Barbour (1989) and Ernst et al. (2000). Straight-line measurements of each specimen were taken with dial calipers accurate to 0.1 mm. Variables included: the greatest carapace length (CL, not midline), carapace width (CW) and depth (CH) at the level of the seam separating vertebral scutes 2 and 3, * Corresponding author. PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON 121(3):391–397. 2008.