Bull. nat. Hist. Mus. (Zool.) 59(1): 83-94 



Issued 24 June 1993 



A new species of Syrticola Willems & Claeys, 

 1982 (Copepoda: Harpacticoida) from Japan 

 with notes on the type species 



RONY HUYS 



Department of Zoology , The Natural History Museum, Cromwell Road, London SW7 5 BD 



SUSUMU OHTSUKA 



Fisheries Laboratory, Hiroshima University, 1294 Takehara-cho, Takehara, Hiroshima 725, Japan 



CONTENTS 



Introduction 83 



Materials and Methods 83 



Descriptions 84 



Family Cylindropsyllidae Sars, 1909 84 



Subfamily Leptopontiinae Lang, 1948 84 



Syrticola Willems & Claeys, 1982 85 



Syrticola intermedius sp . nov 85 



Syrticola flandricus Willems & Claeys, 1982 92 



Remarks 92 



Discussion 93 



Key to species 93 



Acknowledgements 93 



References 94 



Synopsis. A new species of Syrticola Willems & Claeys, 1982 (Harpacticoida: Cylindropsyllidae) is described from 

 Okinawa, Japan. Morphological notes on the type species S. flandricus Willems & Claeys, 1982 and a key to the 

 species are given. The inadequately described S. trispinosus A. Scott, 1896 is ranked as species inquirenda. The 

 diagnosis of the genus is amended and its position in the Cylindropsyllidae re-assessed. Both sexes of S. intermedins 

 sp. nov. were found to be infested by early parthenogenetic female stages of an as yet undescribed genus of 

 Tantulocarida. 



INTRODUCTION 



The interstitial harpacticoid fauna of Japan is very poorly 

 known, as is that of most east Asian countries. The paucity of 

 data on marine interstitial species stands in marked contrast 

 with the number of studies on subterranean copepods pro- 

 duced by workers like Miura and Takashi Ito. In fact, with 

 the possible exception of Microsetella norvegica (Boeck, 

 1864) only 11 genuinely interstitial harpacticoids have been 

 recorded from marine and brackish water habitats in Japan 

 (Table 1) and the majority of these was described by the 

 latter author's namesake, the late Tatsunori Ito, whose 

 activities were mainly focussed on the fauna from Hokkaido 

 in the north and the Bonin Islands in the southeast. The only 

 other information on mesopsammic harpacticoids is con- 

 tained in the papers of Kikuchi (1970, 1972) and Kikuchi & 

 Yokota (1984), reporting on species from Lake Hinuma, a 

 brackish lagoon near the central east coast of the Japanese 

 mainland. 



In the course of a survey of the sandy bottom copepods off 

 Nagannu Island, Okinawa (Ryukyu Archipelago) by one of 

 us (S.O.), several interstitial harpacticoids were found to be 

 infested with tantulocaridans (Huys et ai, in preparation). 

 This paper describes a new species of Syrticola Willems & 

 Claeys (Cylindropsyllidae) based on two specimens that were 

 parasitized by parthenogenetic females of an as yet unde- 

 scribed tantulocarid. 



MATERIALS AND METHODS 



Specimens of Syrticola intermedius sp. nov. were collected by 

 dredging of a sandy bottom off Nagannu Island, Okinawa, 

 South Japan (26° 14' N, 127° 32' E, depth 46.49 m; leg. S. 

 Ohtsuka) on 9 April 1992. The dredge (mouth area: 50 cm 

 wide x 15 cm high; mesh size 5 mm) was towed along the 

 bottom at a speed of 2 knots by the T/V Toyoshio-maru of the 

 Hiroshima University for about 5 minutes. Copepods were 



