New Sicydiine-Gobies from Ponape and Palau, Micronesia, with Comments on Systematics of the Subfamily Sicydiinae (Teleostei, Gobiidae)

Five species of the rock-climbing, gobiid subfamily Sicydiinae are now known from Ponape, Eastern Caroline Islands, Micronesia, four of which are described herein as new: Sicyopus nigriradialus, Sicyoplerus lividus, Sicyopterus eudenlatus, and Sliphodon caeruleus. This increases the number of described freshwater/estuarine fish species from that volcanic island to 15. The fifth sicydiine species from Ponape, Stiphodon cf. elegans. is compared with other Pacific basin Stiphodon. Sicyopus fehlmanni is described as new from Babelthuap and Koror islands, Palau, Western Caroline Islands, Micronesia. Sicydiinae Bleeker, 1874, is the valid name for this subfamily. The widely used name Sicydiaphiinae Koumans, 1931, is an improperly formed synonym of Sicydiinae. A newly described character to support sicydiine monophyly involves relative position of the pelvic-fin spine and rays. A key to Ponapean sicydiines is provided. Gobioid fishes are common in streams of tropical and subtropical oceanic islands. Of 15 native freshwater/estuarine fish species known from Ponape, 10 are gobioids. Of these, five species in three genera (Maciolek and Ford, 1987) are in the gobiid subfamily Sicydiinae, commonly known as rock-climbing or toothedlip gobies (Table 1). Island-group endemism is high among the approximately 95 nominal sicydiine species, particularly in the Indo-Pacific (D. F. Hoese, pers. comm.). More new species remain to be described (Randall et aI., 1990; Ryan, 1991). Our objectives herein are to describe five new species from the Caroline Islands, add support to the hypothesis of monophyly of the subfamily Sicydiinae, and demonstrate that Sicydiinae is the valid name for this gobiid subfamily. Ponape (Pohnpei) is a volcanic island in the western Pacific at approximately 6°50'N, 158°1O'E. Politically, it is part of the Federated States of Micronesia; geographically, it is part of the Eastern Caroline Islands. Ponape is approximately 334 km2 in area, and has more than 40 radially arranged, perennial streams (Maciolek and Ford, 1987). Adult and subadult specimens offive sicydiine species, four undescribed, were collected in fast-flowing, rocky-bottom streams including the Nanpil-Kiepw, Meitik, Soundah, Ninduwi, Nanqui (Nankewi) and Pilen Salapwuk-Lehn Mesi stream systems (Fig. 1). A key to Ponapean sicydiines follows the species descriptions. A fifth new species is described from Babelthuap and Koror, two volcanic or volcanic/limestone islands in the Palau Archipelago at approximately 7°23'N, 134°33'E (Bayer and Harry-Rofen, 1957; Fig. 2). These two islands are politically part of independent Palau (Belau), western Caroline Islands, Micronesia. Babelthuap, with an area of approximately 396 km2, is the largest volcanic island in the Carolines (Birkeland et aI., 1976). Adult and subadult specimens of a new sicydiine species were collected from Tengyoi stream, Koror, and the Amekaud, Ngeremeskang, Iklong, Imengelngal, and Arakitaoch drainages, Babelthuap, by "Project Coral Fish" of the George Vanderbilt Foundation (Fig. 2; see Bayer and Harry-Rofen, 1957).