Rhynchocinetes rathhunae, a New Shrimp from the Hawaiian Islands (Crustacea: Decapoda: Rhynchocinetidae)l

A new species of caridean shrimp of the family Rhynchocinetidae, Rhynchocinetes rathbunae Okuno, is described and illustrated based on six males, an ovigerous female, a second female, and a juvenile from the Hawaiian Islands. It is closely related to R. brucei Okuno from the tropical western Pacific and R. rugulosus Stimpson from southern Australian waters, but is readily distinguishable from the two latter species by absence of a podobranch on the second maxilliped, the longer rostrum, forms of the stylocerite and endopod of male first pleopod, meral dentition of the ambulatory pereiopods, and the color in life. IN THE ORIGINAL DESCRIPTION of Rhynchocinetes brucei Okuno, 1994, it was suggested that another Hawaiian rhynchocinetid shrimp in the collections of the B. P. Bishop Museum, Honolulu, Hawai'i, might be an undescribed species. Through the courtesy of L. G. Eldredge, I examined the specimens in question during a short visit to the museum. In addition, John Hoover, an underwater photographer in Honolulu, kindly sent me some specimens of the shrimp captured at Waimea Bay and Hanauma Bay, O'ahu. This shrimp resembles R. brucei and R. rugulosus Stimpson, 1860, but differs in morphology and the life color, and I describe it here as new to science. Abbreviations are as follows: CL: postorbital carapace length; BPBM: Bernice P. Bishop Museum, Honolulu, Hawai'i; CBM: Natural History Museum and Institute, Chiba, Japan; NSMT: National Science Museum, Tokyo, Japan; NTM: Northern Territory Museum, Darwin; USNM: National Museum of Natural History, Smithsonian Institution, Washington, D.C. Rhynchocinetes rathbunae Okuno, n. sp. Figures 1-3, Tables 1,2 1 Manuscript accepted 25 October 1995. 2 Natural History Museum and Institute, Chiba, 955-2 Aoba-cho, Chuo-ku, Chiba 260, Japan. Rhynchocinetes rugulosus: Rathbun, 1906, 911, fig. 64; Edmondson, 1952,70 (in part), fig. 2 (not Stimpson, 1860). ? Rhynchocinetes rugulosus: Edmondson, 1925, 6; Hiatt, 1948, 79 (not Stimpson, 1860). TYPE MATERIAL: Holotype: Male (BPBM S11275, 7.0 rom CL), Hawaiian Islands, O'ahu, Waimea Bay, 21 0 38.0' N, 158 0 04.0' W, 29 November 1994, colI. J. Hoover and J. Earle. Paratypes: 1 male (BPBM S11276, 11.6 rom CL) and 1 ovigerous female (BPBM SI1277, 8.0 rom CL), Hawaiian Islands, O'ahu, Kahe Pt., 21 0 20.0' N, 158 0 11.0' W, 4 February 1977; 3 males (NSMT Cr 2420, 11.3, 6.9, and 6.3 mm CL), same data as holotype; 1 female (CBM ZC 1964, 4.7 mm CL), Hawaiian Islands, O'ahu, Hanauma Bay, 21 0 16.3'N, 15]0 42.0' W, 25 June 1995, colI. J. Hoover; ajuvenile (USNM 31008, 2.4 rom CL), French Frigate Shoals, 17-17~ fathoms (3132 m) depth, colI. Steamer Albatross. OTHER MATERIAL EXAMINED: male (NSMT Cr 11104, 8.6 rom CL), Hawaiian Islands, exact collection site unknown, colI. aquarium traders. DESCRIPTION: Body subcylindrical, typical form of Rhynchocinetes. Carapace (Figure lA) covered with fine transverse striae, armed with two acute spines on median carina, anterior spine just behind rostral articulation, posterior spine feebly articulated with car-