CORYCAEUS AND FARRANULA (COPEPODA, CYCLOPOIDA) IN HAWAIIAN WATERS

Abstract

The marine copopods of the genera Corycaeus and Farranula ( =Corycella) occur in tropical and subtropical seas.However, some of them appear, and even reproduce, in certain high latitudes where warm ocean currents exist.M. DAHL's (1912) monograph on these groups has contributed much to the knowledge of their classification and geographical distribution.TAN AKA (1957 a) reported that twenty-four species belonging to these genera have been observed from the North Temperate Pacific, from as far as north as the Japanese coast where the Kuroshiwo Current and its tributaries prevail.These groups of copepods are easily recognized by the peculiar structure of their bodies and by their large paired eyes, and thus are very useful indicator forms of warm ocean currents.This study attempts to extend the present known distribution, and is based upon taxonomic work conducted on specimens collected in Hawaiian waters.The materials consisted of plankton samples collected on Cruise 30 of the research vassel, Hugh M. Smith, of the U.S. Fish and Wildlife Service, at ten stations between Hawaii and about 50°N in August 1955 (McGARY et al., 1956); on Cruise 29 of the research vessel, John R. Manning, of the same agency, at six stations around Oahu Island, Hawaiian Archipelago, in January 1956; on Cruise 35 of the Hugh M. Smith at five stations around Oahu Island in August 1956 : and on Cruise 34t of the research vessel, Makua, of the Division of Fish and Game, Board of Agriculture and Forestry, Hawaii, at two stations off the north-eastern coast of Oahu Island in December 1956 (Figs. 1, 2).The plankton samples had been collected by oblique hauls (except those collected by the Makua in shallow waters by surface tows) with a 1-meter net equipped with flow-meter (KING and DEMOND, 1953).The sample volume varied considerably.In the case of large samples an appropriate aliquot (1/2, -----------------Publ.Seto Mar.Bioi.Lab., XI (2), 1963.(Article 15) 1. Corycaeus (Corycaeus) speciosus DANA, male and female 2. Corycaeus (Corycaeus) crassiusculus DANA, male and female 3. Corycaeus (Corycaeus) vitreus DANA, male 4. Corycaeus (Monocorycaeus) robustus GIESBRECHT, male and female 5. Corycaeus (Agetus) typicus KROYER, male and female -41 211 212 S. MoTooA 6. Corycaeus (Agetus) flaccus DANA, male and female 7. Corycaeus (Agetus) limbatus BRADY, male 8. Corycaeus ( Urocorycaeus) longistylis DANA, male and female 9. Corycaeus (Urocorycaeus) lautus DANA, male and female 10.Corycaeus (Ditrichocorycaeus) asiaticus F. DAHL, male 11.Corycaeus (Onychocorycaeus) agilis DANA, male 12. Corycaeus (Onychocorycaeus) latus DANA, male 13.Corycaeus (Onychocorycaeus) catus F. DAHL, female 14.Farranula gibbula (GIESBRECHT), male and female 15.Farranula carinata (GIESBRECHT), male and female 16.Farranula concinna (DANA), female Several specimens assignable to genus Mimocorycella RosE 1929 were found in the samples examined during this study.There is a possibility that these are young forms of Corycaeus.In this paper the references which contain at least some mention of the identification or a drawing, were listed in the synonymy list.However, in the distribution list, all available papers including those which only listed species' names, without mentioning any taxonomic characters, were cited.The length of body was expressed by measuring length from the tip of the forehead to the distal end of the furca when the body is stretched.Most of specimens identified were put in separate vials with the species' name and other data on the label.They were deposited at the Biological Laboratory of the Bureau of Commercial Fisheries, U.S. Fish and Wildlife Service, in Honolulu, Hawaii.The permanent slides in Hoyer's medium of the appendages (1st antennae, 2nd antennae, maxillipeds, 1st swimming feet, 2nd swimming feet, 3rd swimming feet, 4th swimming feet and 5th feet) and also the abdomen with the furcae, were also deposited at that laboratory.Permanent preparations were made of the following species:-Corycaeus (Corycaeus) speciosus, male (Box 1, No. 2) Corycaeus (Corycaeus) crassiusculus, male (Box 1, No. 9, Box 2, No. 23) Corycaeus (Corycaeus) vitreus, male (Box 1, Nos. 8, 14, 16) Corycaeus (Monocorycaeus) robustus, female (Box 1, Nos. 3, 5, 6) Corycaeus (Monocorycaeus) robustus, male (Box 1, No. 13) Corycaeus (Agetus) typicus, female (Box 1, No. 18) Corycaeus (Agetus) flaccus, female (Box 1, No. 17) Corycaeus (Agetus) flaccus, male (Box 2, No. 28) Corycaeus (Urocorycaeus) lautus, female (Box 1, Nos. 4, 7) Corycaeus (Onychocorycaeus) agilis, famale (Box 1, Nos. 15, 19) Corycaeus (Onychocorycaeus) latus, male (Box 2, No. 21) Corycaeus (Onychocorycaeus) catus, female (Box 1, No. 12) Corycaeus (Onychocorycaeus) sp.(Box 2, Nos.26, 27) Farranula carinata, female (Box 2, No. 24) Farranula carinata, male (Box 2, No. 25) Farranula concinna, female, young (Box 2, Nos. 30, 31) Corycaeus sp.young (Box 1, Nos. 1, 2, 10, 11, Box 2, Nos.22, 29) 213