Reference : Biol. Bull., 142 : 470-479. (June, 1972) A NEW SPECIES OF MARINE LEECH (ANNELIDA: HIRUDINEA) FROM SOUTH CAROLINA, PARASITIC ON THE ATLANTIC MENHADEN, BREVOORTIA TYRANNUS 1 ROY T. SAWYER AND NORMAN A. CHAMBERLAIN Department of Biology and Grice Marine Biological Laboratory, College of Charleston, Charleston, South Carolina 29401 The current systematics of marine leeches is in a confusing state in spite of recent attempts to review the group (Knight-Jones, 1961; Soos, 1965). Un-fortunately, the internal anatomy of many of the type species has been so inade-quately described that in most cases the exact limitations of the genera are only vaguely known. Recent workers have pointed out also that an initial dichotomy based on environment (;.('., freshwater or marine) is completely unsatisfactory (Hoffman, 1964). In contrast to the freshwater piscicolid leeches of the United States and Canada which have been thoroughly investigated by Meyer (1940, 1946a, 1946b), very little is known of American marine piscicolids. Although at least eight marine fish leeches have been reported along the eastern American coasts, a comprehensive morphological study is lacking and new species and even genera are not uncommonly encountered. Since 1963, we have sporadically en-countered a previously undescribed marine piscicolid of the CaUwbdeUa-Cysto-branchiis-Piscicola complex in the vicinity of Charleston, South Carolina. The mid-body segments of the young (3 mm) of the new species are made up of 3(6) annuli which, upon maturation, are further subdivided into the typical 7(14)-annulate condition of the adults. A similar subdivision of the mid-body annuli upon maturation was found in the marine leech Oceanobdella blcnnii by Sawyer (1970), who discussed the systematic significance of annulation in the piscicolids. In this paper we hope to contribute to the stabilization of the systematics of marine piscicolids by keeping with the modern approach of giving systematic emphasis to the more conservative internal structures, especially the reproductive systems, and minimizing the importance of such external characters as the degree of annulation, the emphasis on which in the past has led to a confusing prolifera-tion of genera. A detailed morphological examination has shown the reproductive systems and other internal structures of the new species resemble so remarkably those of the genus CaUiobdclla, which has only two known species (Soos, 1965) that the new species must be assigned to this genus. Family Piscicolidae, Johnston, 1865 Genus CaUiobdclla van Beneden and Hesse, 1863 TYPE SPECIES (by original designation) : C. lophli van Beneden and Hesse, 1863. REVISED DEFINITION OF GENUS : Body sub-cylindrical, not sharply divided into uro-some and trachelosome ; smooth without papillae or tubercles ; caudal sucker wider 1 Contribution No. 22 of the Grice Marine Biological Laboratory. 470
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