PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON lll(2):257-262. 1998. A new species of Hesionidae, Glyphohesione nicoyensis (Annelida: Polychaeta), from the Gulf of Nicoya, Costa Rica Harlan K. Dean Department of Invertebrate Zoology, 26 Oxford St., Cambridge, Massachusetts 02138, U.S.A.; and John Hazen White School of Arts and Sciences, Johnson and Wales University, 6 Abbott Park Place, Providence, Rhode Island 02903, U.S.A. Abstract. — A new species, Glyphohesione nicoyensis (Family Hesionidae), is described from the Gulf of Nicoya on the Pacific coast of Costa Rica. Several morphological characters described for the species G. klatti Friedrich, 1950, and G. longocirrata Licher, 1994 are clarified. The species Glyphohesione klatti Fried-rich, 1950 was first collected from Helgo-land and originally included in the family Hesionidae (Friedrich 1950). Eliason (1962) subsequently transferred this species to the genus Ancystrosyllis in the family Pi-largidae due to the presence of emergent notopodial spines similar to those described for Synelmis albini (Langerhans, 1881) (=Ancistrosyllis albini). Pettibone (1966) later assigned this species to the genus Sy-nelmis Chamberlin, 1919, and suggested that S. klatti was perhaps a juvenile form of S. albini. In a review of the gross morphology of the pilargid brain, Fitzhugh & Wolf (1990) noted significant differences between the brain of 5. klatti and that of other species within the genus (S. ewingi Wolf, 1986, and S. acuminata Wolf, 1986). Fitzhugh & Wolf (1990), therefore, recommended that S. klatti be removed from Synelmis and per-haps returned to its original genus, Glypho-hesione Friedrich. Licher & Westheide (1994) formally removed Glyphohesione from synonomy with the genus Synelmis based on its lack of emergent neuropodial spines, which are considered apomorphic for Synelmis. Results of a cladistic analysis of the family Pilargidae by Licher & West-heide (1994), based on 28 morphological characters, also indicated that G. klatti shares many plesiomorphic characters with juveniles of the family Hesionidae Licher (1994) thus transferred the genus Glypho-hesione Friedrich to the family Hesionidae based on its elongate palpostyles, anteriorly situated lateral antennae and well developed antennae, tentacular cirri, parapodial cirri, and anal cirri. Licher (1994) restricted the known distribution of G. klatti Friedrich, 1950, to northern Europe and the Mediter-ranean and described a new species, G. lon-gocirrata Licher, 1994, from material col-lected in the Gulf of Mexico and originally identified as S. klatti by Wolf (1984). Material collected during benthic sam-pling in the Gulf of Nicoya, Costa Rica (see Maurer & Vargas 1984 for station data), and previously identified as Synelmis klatti Friedrich by Dean (1996), was re-examined in light of Licher 's (1994) redescription of G. klatti and a new species of Glyphohe-sione is here described. Glyphohesione nicoyensis, new species Figs. 1, 2 Synelmis albini (Langerhans). — Maurer & Vargas, 1984:101 (in part); Maurer et al., 1988:48 (in part). Synelmis klatti (Friedrich). — Dean, 1996: 74. Material examined. — Gulf of Nicoya, Sta. 23, 9°48'35"N, 84°43'50"W, 35 m, mud, Jul 1980, (1, USNM 079958). Sta. 24,
BioStor
