THE TAXONOMIC RELATIONSHIP BETWEEN MALACLEMYSGKM , 1844 AND GRAPTEMYS AGASSIZ, 1857 (TESTUDINES: EMYDIDAE) JAMES L. DOBIE Department of Zoology-Entomology Auburn University, Alabama 36849 Abstract The turtle genus Graptemys is a distinctive group clearly separable from Malaclemys on the basis of external and osteological features. The difference between the groups indicate that the degree of genetic relationship is no closer than that resulting from their both having presumably arisen from a Pseudemys -like stock or Malaclemys from a Graptemys stock. INTRODUCTION Investigators of Malaclemys and Grapt-emys have based their taxonomic alloca-tions on penial, skull, shell, hind limb and pelvic girdle morphology and on head patterns. Osteological comparisons, when indicated, were usually limited to the skull, and in most cases, head patterns were used to distinguish taxa. The degree of evolutionary conservatism and paral-leUsm exhibited by turtles argues against the use of external characters (e.g., head striping), alone in determining taxonomic and phylogenetic relationships. Thus, both osteological and surficial features have been examined in this study. HISTORICAL REVIEW The controversy about the relationship between Malaclemys and Graptemys be-gan as a resuh of the lumping of Grapt-emys with Malaclemys by Boulenger (1889) and the re-establishment of the genus Graptemys by Baur in 1890. Since that time, W.P. Hay (1904) and O.P. Hay (1908) followed Baur in recognizing the two genera, as did Carr in 1949. Later, however, Carr (1952) questioned the validity of separating the two genera and McDowell (1964), without presenting sup-porting data, lumped Graptemys with Malaclemys. Zug (1966, 1971), on the basis of similiar penial, pelvic girdle, and hind limb morphology for the two genera considered them congeneric, and Parsons (1960, 1968) found the choanal structures of both genera to be so variable that the evidence did not particularly support or refute the congeneric idea. Several other authors (Ernst and Barbour, 1972; McKown, 1972; Dundee, 1974; Killebrew, 1979; Dobie and Jackson, 1979; Pritch-ard, 1979; Vogt, 1978, 1980) have not supported the synonymy of Graptemys with Malaclemys; they evidently must believe that sufficient evidence has not been presented to lump the two genera together. The purpose of this study is to clarify the generic status of Malaclemys and Graptemys. MATERIALS AND METHODS Representatives of each of the ten ex-tant Graptemys species (Vogt, 1980) and their subspecies and individuals of several subspecies of the monotypic Malaclemys were examined. External features, includ-Editorial Committee for this Paper: Dr. Eugene S. GAFFNEY, Associate Curator, Department of Vertebrate Paleontology, American Museum of Natural History, New York, New York 10024 Dr. John J. IVERSON, Assistant Professor of Biology, Earlham College, Richmond, Indiana 47374 85
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