Copepoda, Siphonostomatoida, Pandaridae) Infesting the Goblin Shark Mitsukurina Owstoni Jordan, 1898 in Japanese Waters

Home , Carcharodon, Mitsukurina, Mitsukurinidae

ECHTHROGALEUS MITSUKURINAE SP. NOV. (COPEPODA, SIPHONOSTOMATOIDA, PANDARIDAE) INFESTING THE GOBLIN SHARK MITSUKURINA OWSTONI JORDAN, 1898 IN JAPANESE WATERS

KUNIHIKO IZAWA1) Izawa Marine Biological Laboratory, 795-16 Kannonji, Tsu, Mie 514-0062, Japan

ABSTRACT Echthrogaleus mitsukurinae sp. nov. (Copepoda, Siphonostomatoida, Pandaridae) is described based on a female recovered from the body surface of the goblin shark, Mitsukurina owstoni Jordan, 1898, captured on the slope of the Tokyo Canyon at about 400 m depth in Tokyo Bay, Japan. This new species is easily distinguishable from all its congeners in having the following unique features in the female: (1) the lateral lobes of the cephalothorax and the lateral plates of pediger 2 are devoid of marginal membranes, (2) the dorsal plates of pediger 4 have a smooth margin, (3) the posterolateral lobes of the genital complex are widely curved medially and overlap each other across the midline, (4) legs 2 and 3 have 3-segmented endopods, and (5) leg 4 has an incompletely 2-segmented exopod.

RÉSUMÉ Echthrogaleus mitsukurinae nov. sp. (Copepoda, Siphonostomatoida, Pandaridae) est décrit à partir d’une femelle prélevée à la surface du corps du requin lutin, Mitsukurina owstoni Jordan, 1898, capturé sur la pente du Tokyo Canyon à environ 400 m de profondeur dans la bale de Tokyo, au Japon. Cette nouvelle espéce se distingue facilement de tous ses congénères par les caractères uniques suivants chez la femelle : (1) les lobes latéraux, du céphalothorax et les plaques latérales du segment portant la deuxième paire de pattes sont dépourvues de membranes latérales, (2) les plaques dorsales du segment portant la quatrième paire de pattes sont à bord lisse, (3) les lobes postéro- latéraux du complexe génital sont largement écartés à leur base interne et se recouvrent ensuite sur la ligne médiane, (4) les pattes 2 et 3 ont des endopodites tri-segmentés, et (5) la patte 4 possède un exopodite incompletèment bi-segmenté.

INTRODUCTION After my redescription of the eight known pandarid copepod species infesting Japanese elasmobrachs was published (Izawa, 2010), I had the opportunity to

1) e-mail: [email protected] © Koninklijke Brill NV, Leiden, 2012 Crustaceana 85 (1): 81-87 Also available online: www.brill.nl/cr DOI:10.1163/156854012X623674 82 KUNIHIKO IZAWA examine a parasitic copepod recovered from the body surface of the goblin shark, Mitsukurina owstoni Jordan, 1898. The shark was captured in the autumn of 2010 on the slopes of the Tokyo Canyon at about 400 m depth in Tokyo Bay, Japan, and is deposited in the Mie Prefectural Museum (MPM), Tsu. Based on this specimen, Echthrogaleus mitsukurinae sp. nov. is described herein. Until now, no parasitic copepod has been reported from the goblin shark, as far as I am aware. Echthrogaleus Steenstrup & Lütken, 1861 currently includes five valid species: E. coleoptratus (Guérin-Méneville, 1837) and E. denticulatus Smith, 1874, both infesting a wide variety of pelagic sharks around the world (Cressey, 1967); E. disciarai Benz & Deets, 1987 recovered from the smoothtail mobula, Mobula thurstoni (Lloyd, 1908) [= M. lucasana Beebe & Tee-Van, 1938] (Myliobatidae) in the Sea of Cortez (Benz & Dees, 1987); E. pellucidus Shiino, 1963 from an unidentified thresher shark (Alopiidae) in Ecuador (Shiino, 1963) and the great white shark, Carcharodon carcharias (Linnaeus, 1758) (Lamnidae) in Hokkaido, Japan (Ho & Kim, 1996, as E. denticulatus); and E. torpedinis Wilson, 1907 from the electric ray, Torpedo nobiliana Bonaparte, 1835 [= T. occidentalis Storer, 1843] (Torpedinidae) at Woods Hole and Provincetown, Massachusetts, U. S. A. (Wilson, 1907). Other than these species, E. indistinctus (Krøyer, 1863), E. neozealanicus (G. M. Thomson, 1890), and E. pectinatus Kirtisinghe, 1964 have been enumerated as valid species on the website of the World of Copepods (Walter & Boxshall, 2011). However, neither of these species can be treated as valid species of the genus. E. neozealanicus has been relegated to a synonym of E. denticulatus by Cressey (1967). From the fact that Krøyer’s description is not very informative and is not accompanied by illustrations, E. indistinctus has been treated as a species inquirenda by Kabata (1979). Kirtisinghe’s (1964) E. pectinatus has many features unusual for the genus and should be investigated in greater detail before its final acceptance in Echthrogaleus as mentioned by Kabata (1979).

MATERIAL AND METHODS The specimen was ﬁxed and preserved in ethanol. It was stained with chlorazol black E in lactic acid and examined with a differential interference contrast microscope. Drawings were made with the aid of a drawing tube. Copepod terminology is based on Kabata (1979) and Huys & Boxshall (1991). The common and scientiﬁc names of the host conform to Froese & Pauly (2011).

Echthrogaleus mitsukurinae sp. nov. (ﬁgs. 1-2) Material examined. — A female (holotype) from the body surface adjacent to the gill slits of a female Mitsukurina owstoni Jordan, 1898, 119 cm TL (Lamniformes, Mitsukurinidae), captured by