10. the Marine Fishes of Rennell Island
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10. THE MARINE FISHES OF RENNELL ISLAND BY ROBERT R. ROFEN RESEARCH DIRECTOR, GEORGE VANDERBILT FOUNDATION AT STANFORD UNIVERSITY CONTENTS Introduction ................................................. ....149 Gobiidae .........................................................176 Methods for counts and measurements . 150 Kraemeriidae.witharevisionof the family 178 Dussumieriidae ...............................................151 Blenniidae......................................................... 195 Synodontidae......................................................152 Ostraciontidae................................................ 204 M uraenidSe.........................<............................153 Balistidae......................................................... 205 Exocoetidae ................................................. ....154 Fishes from Rennell Island colleclcd by Mugilidae............................................................156 the 1933 Templeton Crocker Expedition 206 Atherinldae..........................................................157 Acknowledgments......................................... 211 Pseudochromldae...............................................168 Checklist of the marine fishes from Apogonidae ................................................. ....170 Rennell Island................................................ 212 Pomaceniridae...................................................171 Table I ............................................................. 214 Acanthuridae......................................................174 Literature ciled ............................................ 215 Siganidae............................................... .. 176 INTRODUCTION The Danish Rennell Expedition 1951 which was part of the "Galathea" Deep-Sea Expedition Round the World 1950-1952 inade a collection of approximately 30 spe cies of smaller reef fishes froin several localities at Rennell Island, Solomons in the fall of 1951. Although this material represents only a small part of the fish fauna existing on the reefs at Rennell, it is a valuable addition to our knowledge of the ichthyology of the tropical Pacific, including many new records for the Solomon Is lands and several species apparently new to science. In an effort to make the present report on this collection useful to ichthyologists and to document each species, the means of identification are given for each species, as w’ell as the presently understood diagnostic characters. When it seemed advisable, more complete descriptions of the specimens and discussions of species are included in order to elucidate further the natuce of the various species involved. As is well appreciated by ichthyologists, it is often very difficult to identify unquestionably to species fishes from such a poorly known area as the Solomon Islands. It has been necessary in several cases to under take studies on species groups from a more extensive region than the Solomons. A survey is presented of the silversides of the genus Atherion (family Atherinidae) from Oceania. The Indo-Pacific family of sand fishes (Kraemeriidae) is reviewed with one subgenus (Schidokraemeria) and three species of the genus Kraemeria described as new (galatheaensis from Rennell Id., cunicularia from the Palau Is., and tongaensis from the Tonga Is.). All of the marine fishes collected at Rennell Island by the Danish Expedition were taken in the region of Kanggava Bay and in the vicinity of Lavanggu, 11 ° 39' S. Lat., 160° 14' E. Long., on october 20th to November 2nd, 1951. They were collected by Dr. Torben W olff and are in the following referred to as “Galathea material” . The collection is kept in the Zoological Museum, Copenhagen. M. 516a In Kanggava Bay, October 20, 1951: three flying fishes, Cypselurus anton- cichi Woods & Schultz. M. 516b Water depth 0-0.25 meters, rock along beach, coral and sand, tidal zone, October 25, 1951; a collection of twelve species of reef and sand inhabiting fishes: gobies, damsel fishes, coral bass, sand fishes, silversides, blennies, surgeon fish, moray eel. M. 516d On the fringing coral reef, at low tide, depth O.J-0.5 meters, October 26, 195!; a collection of seven species of fishes, all small reef inhabitants: blen nies, cardinal fishes, damsel fishes, goby, spine fishes. M. 516e Near beach, bottom coral sand, depth 50 cm., October 28, 1951; two species of open water fishes: mullet and silversides. M. 516f Bottom coral, depth about 5 meters, October 30, 1951; five species of larger reef fishes: trigger fishes, lizard fish, surgeon fishes. November 2, 1951; two species of fishes: a box fish and the unicorn fish Naso lituratus (Bloch & Schneider). M. 516g Depth 0.75-1.50 meters, November 1 and 2, 1951; two young unidentified fishes, one a scorpaenid. Following the account of the Galathea collection the only other fishes reported in the literature from Rennell Island are reexamined. The Templeton Crocker Expedi tion of 1933 under the auspices of the California Academy of Sciences collected at Rennell Island, particularly in Kanggava Bay, in June of 1933. These fishes were previously reported upon by S e a le (1935). METHODS FOR COUNTS AND MEASUREMENTS The methods used in this study for counts and measurements on the fishes are as follows, unless specified otherwise. All measurements were taken by means of dividers and recorded in millimeters. The standard length is the distance between the anterior tip of the snout and the base of the caudal fin (= the posterior edge of the hypural fan). S. L. is an abbreviation for standard length. The body depth is the greatest height of the body behind the head. The head length is the distance between the anterior tip of the snout to the most distant point on the operciflar margin including membranous flaps. The snout length i s the distance between the tip of the snout and anterior bony rim of the,eye socket. The eye d'ameter is the greatest horizontal distance between the free orbital rims. The interorbital width is the least bony width. The predorsal and preanal distances are the lengths between the anterior tip of the snout and the origins of the corresponding fins. The lengths of the pectoral and pelvic fins are of the longest ray of each fin. The cauda!pedude'depth is its narrowest height posterior to the dorsal and anal fin bases. The caudal peduncle length is the distance from the center point at the posterior tip of the hypural fan measured anteriorly to the base of the last dorsal or anal fin ray as stated. Unless indicated otherwise, measurements in percent o f stand ard length have the range of all measured specimens in parentheses preceded by the mean. The fin counts are by standard procedure. Spiny (unsegmented) rays are indicated by roman numerals: capital letters for relatively stiff rays; small letters for weak flexible spines. Soft (segmented) rays are indicated by arabic numerals. A comma separating the count of spnes and soft rays means the spinous fin is not separate from the soft rayed fin, but joined by membrane at least at the base. When the fins are separate, a dash is used to separate the counts. The last two fin rays in the dorsal and anal fins are counted as one, if closely applied; otherwise they are counted separately. The principal‘caudal rays are the branched rays plus one simple ray above and below. The gill rakers are counted on the first arch only, with the number of rakers above the angle of the arch presented first. Lateral line scales are counted from origin behind head to the end of the hypural fan. FAMILY DUSSUMIERIIDAE ROUND HERRINGS Spratelloides delicatulus (Bennett) Clupea delicatula Bennett 1831, p. 168 (original description; Mauritius). Spratelloides delicatulus Weber and de Beaufort 1913, p. 20 (synonymy; description; distribution). S e a le 1935, p. 238 (name only; specimens from Malaita I., Guadal- canar I., Rennell I., Samoa). S c h u l t z and W e l a n d e r in S c h u l t z et al 1953, p. 26 (descrfption; specimens from Bikini I., Rongelap L, Rongerik I., Eniwetok I., Kwajalein I., Likiep I.). Stolephorus delicatulus Fowler 1928, p. 29 (synonymy; description; numerous records and distribution). F o w le r 1934, p. 387 (synonymy; name only; examples from Roviana, British Solomons; Vila, New Hebrides; Ontong, Java). F o w le r 1949, p. 40 (synonymy). Stolephorus delicatulus (in part) Herre 1931, p. 4 (name only; Hathorn Sound; Tulagi; Shortland I., Solomon Is.). H e r r e 1936, p. 32 (synonymy; description; Ovalau, Fiji; Turtle Bay, Espiritu Santo I., New Hebrides; 65 specimens Tulagi Harbor, Solomon Is.; 40 specimens Hathorn Sound, New Georgia L). • This species has been previously recorded in the literature from the Solomon Is lands by H e r r e (1931, 1936), F o w le r (J934), and S e a le (1935), but the Hathorn Sound record of H erre* is actually Spratelloides atrofasciatus Schultz and not 5. delicatulus (Bennett). The determination of the Galathea specimens was made on the basis of the de scriptions of W eber and de Beaufort (1913), Be r t in (1943), Schultz (1943), Schultz and W elander (1953) and comparative material in the Stanford University collections from Samoa, New Hebrides, Solomons,= New Guinea, Borneo and Philippines. Galathea material examined: Three specimens 29.0, 28.9, 27.8 mm. in standard length from station 516e, Rennell Id., Solomons. Description o f Galathea specimens: Measurements and counts are presented in the order given for standard length above. Head strongly compressed, snout not as wide as region across eyes. Lower