New Host and Ocean Records for the Parasitic Copepod Bobkabata kabatabobbus (Lemaeosoleidae: Poecilostomatoida)l

George W Benz,2,3 l.<£tzuya Nagasawa, 4 and Jeremy Wetmore3,5

Abstract: The parasitic copepod Bobkabata kabatabobbus Hogans & Benz is re­ ported for the first time from the Pacific Ocean and from the darkfin sculpin, Malacocottus zonurus (Psychrolutidae: Scorpaeniformes). Based on five speci­ mens, several morphological features are reported for the first time for B. kaba­ tabobbus, including a second protuberance on the cephalothorax, a pair ofvestigial legs on the neck, and two dark-staining sclerites on the trunk that may represent body segment boundaries or interpodal bars.

Bobkabata HOGANS & BENZ, 1990, is one of sculpins, Malacocottus zonurus Bean, 1890 two monotypic genera within Lernaeosolei­ (Psychrolutidae: Scorpaeniformes). One host, dae Yamaguti, 1963 (Poecilostomatoida: Co­ 114 mm standard length, was captured 24 pepoda). Until this report, B. kabatabobbus March 1976 in a fishing trawl at 360 m in the Hogans & Benz, 1990, was known only from western North Pacific Ocean east of Cape two collections consisting of three individ­ Erimo, Hokkaido (42 0 1.9' N, 143 0 44.4' E). uals taken from the pallid sculpin, Cottunculus This host was infected with one B. kabata­ thomsoni (Giinther, 1882) (Psychrolutidae: bobbus adult female that was attached at the Scorpaeniformes) in the western North At­ base of the soft-rayed portion of the dorsal lantic (Hogans and Benz 1990, Benz and fin. This intact specimen has been deposited Braswell 1998). Herein we present the first in the National Science Museum, Tokyo, record of B. kabatabobbus from the Pacific Japan (NsMT-Cr 14164). The second host Ocean as well as a new host fish for this par­ was captured 4 April 1984 in a fishing trawl asite. We also provide new information re­ at an unknown depth in the western North garding the morphology of B. kabatabobbus. Pacific Ocean east of Cape Erimo, Hokkaido (42 0 18' N, 1440 2.2' E). This host was in­ fected with four B. kabatabobbus adult females, MATERIALS AND METHODS one at the base of the spiny-rayed portion of A total of five B. kabatabobbus adult females the dorsal fin and three along the base of the was collected from two formalin-fixed darkfin soft-rayed portion of the dorsal fin. One in­ tact specimen and the posterior portion of a second specimen from this collection have 1 Manuscript accepted 7 November 2001. been deposited in the NSMT (NsMT-Cr 14165 2 Corresponding author: Tennessee Aquarium, One and NSMT-Cr 14166, respectively). Broad Street, Chattanooga, Tennessee 37401 (phone: B bk b k b b bb . . 706-694-4666; fax: 706-694-3957; E-mail: GWB@tenrus. 0 a ata a ata 0 us IS a mesoparaslte org). (sensu Kabata 1979), and all five specimens 3 Tennessee Aquarium Research Institute, 5385 Red reported here were found embedded in the Clay Road, Cohutta, Georgia 30710. musculature of the hosts with only a short ---.--'LNati~nal-~eseaFfoh-Instirute--0f-1\quaGultJrre~-~ikk0 portion of-me moracic-"neck"and--the-hurseco--- Branch, Flshenes Research Agency, Nikko, TochigJ 321- h lik . f th b d din 1661, Japan. S oe e postenor. 0 e 0 y pr~tru g. 5 Deparnnent of Biology, Southern Adventist Uni- After they were dissected from theIr hosts, versity, P.O. Box 370, Collegedale, Tennessee 37315- the copepods were studied using light (LM) OJ7l. ------and--scanning--electron- microscopy -(SE-M}- For LM studies copepods were cleared and Pacific Science (2002), vol. 56, no. 3:259-262 stained in a solution of lactic acid and lignin © 2002 by University of Hawai'i Press pink and subsequently examined using the All rights reserved wooden slide technique ofHumes and Good-

259 260 PACIFIC SCIENCE· July 2002

ing (1964). One specimen was examined observed on four of the five specimens. The using SEM. This specimen was prepared for basal portions of the right and left vestigial gold-palladium sputter coating by placing it legs were connected by a thin, dark-staining in 100% ethanol (two changes, 1 hr each) sclerite (? = interpodal bar) that was not followed by immersion in a small volume raised above the body surface. Each leg con­ of hexamethyldisilazane (15 min). Before sisted of an unsegmented exopod and endo­ mounting on a metal stub with two-sided pod (Figure IF). All five specimens also sticky tape, drying was achieved by placing exhibited two thin, dark-staining sclerites on the specimen under a slight vacuum to re­ the ventral surface of the trunk posterior to move the hexamethyldisilazane. Illustrations the aforementioned legs that may represent were prepared with the aid of a camera lucida segment boundaries or interpodal bars (see (LM) or they were drawn with some inter­ Figure 1A). No legs were associated with pretation from SEM micrographs. Specimens these sclerites; however, each (as well as the were measured using an eyepiece graticule interpodal bar [?] associated with the vestigial (LM) and measurements in millimeters are legs) had bands of striated muscle attached reported as the mean followed in parentheses to them (see Figure 1A) that were visible by the standard deviation, range, and sam­ through the cleared exoskeleton. If these ple size. Conventions for measurements are sclerites are interpodal bars then B. kabata­ shown in Figure 1A. Terminology regarding bobbus may possess three pairs of legs at some copepod morphology follows Huys and Box­ point in its ontogeny. The caudal rami of the shall (1991). Host systematics follows Nelson specimen observed using SEM each possessed (1994). six setae: one long and stout and five short and thin (Figure 1G). Specimen NSMT-Cr 14166 possessed one multiseriate egg sac. RESULTS AND DISCUSSION The two known hosts of B. kabatabobbus each have wide distributions, with Cottunculus All of the specimens of B. kabatabobbus re- thomsoni found on both sides of the North ported here generally matched the descrip- Atlantic Ocean at depths of between 182 and tions of the species provided by Hogans and 1462 m (Scott and Scott 1988) and Mala­ Benz (1990) and Benz and Braswell (1998). cocottus zonurus found on both sides of the However, some specimens exhibited features North Pacific Ocean at depths between 400 not previously observed, and based on these and 1980 m (Yabe 1984). Thus we should new specimens the following additional in- expect that future collections of these host formation on the species is provided: total species may expand the known range of B. length, 9.46 (±1.515, 8.32-12.06, 5); head kabatabobbus throughout these regions. Fur­ length, 2.08 (±0.232, 1.80-2.42, 5); head thermore, because C. thomsoni and M. zonurus width, 1.77 (±0.364, 1.35-2.17, 5); primary are each psychrolutids (Psychrolutidae), we head protuberance width, 0.49 (±0.125, might also expect that other members of this 0.37-0.62, 3); neck length, 2.74 (±0.558, family serve as hosts for B. kabatabobbus. Fi­ 2.26-3.69, 5); neck width, 0.50 (±0.144, nally, in spite of the aforementioned mor­ 0.37-0.74,5); trunk length, 4.64 (±0.78, 4.1- phological and host differences between the 5.95, 5); trunk width, 4.712 (±1.41, 3.4-6.97, Bobkabata specimens collected from the At- ----5-);-tnmk-JolJewidth;L~()5-(Itt596-;-1-;J~=J:-44;-lantlc-atcd-Pacinc-Oceans, we nerein act con 10). One specimen (NsMT-Cr 14165) pos- servatively by assigning the five Bobkabata sessed a second cephalothoracic protuberance, specimens collected from the Pacific Ocean 1.23 mm in diameter, just posterior to its to B. kabatabobbus. Additional collections of -antennae-(see--Figure-1-B=D);-'Fheintact -an~---Bobkabata -representatives--are-- necessary -to­ tennae of specimens each possessed a small thoroughly assess these variations regarding medial basal seta (Figure IE). A pair ofvesti- the possibility that the Pacific and Atlantic gial legs (Figure IF) located ventrally in the Oceans are home to different Bobkabata spe­ anterior region of the neck (Figure lA) was cies. F t h t 1 10 Ilm n 1

FIGURE 1. Bobkabata kabatabobbus. Adult females. A, Schematic of general habitus (ventral view) showing conventions JJ~e(Lt~unea@fJ:~Recimf:m and [email protected] ofvestigiallegsjyl),_dark,staining5derites-

ACKNOWLEDGMENTS new family of parasitic copepods, the Ler­ naeosoleidae (Poecilostomatoida), from We thank Kunio Amaoka, Kazuhiro Nakaya, demersal fishes in the Northwest Adantic, and Mamoru Yabe (all Faculty of Fisheries, with a description of Bobkabata kabatabob­ Hokkaido University, Hakodate) for allowing bus n.gen., n.sp. and a redescription of K.N. to use facilities and examine fish in the Lernaeosolea lycodis Wilson, 1944. Can. J. collection at Hokkaido University; Jeffrey Zoo1. 68:2483-2488. Braswell (Dupont, Chattanooga) and Du­ Humes, A. G., and R. U. Gooding. 1964. A ~enter pont's Fiber Engineering Technology method for studying the external anatomy Analytical-Services for access to and aSSIstance of copepods. Crustaceana (Leiden) 6:238­ with SEM equipment; and the Southeast 240. Aquatic Research Institute for general lab­ Huys, R., and G. A. Boxshall. 1991. Copepod repre~ents oratory support. This study a evolution. The Ray Society, London. portion of an undergraduate mternshIp com­ Kabata, Z. 1979. Parasitic Copepoda of Brit­ pleted by J.W. at Southern Adventist Uni­ ish fishes. The Ray Society, London. versity, Collegedale, Tennessee. Nelson, J. S. 1994. Fishes of the world, 3rd ed. John Wiley and Sons, New York. Scott, W. B., and M. G. Scott. 1988. Adantic Literature Cited fishes of Canada. Can. Bull. Fish. Aquat. Benz, G. W., and J. S. Braswell. 1998. Sci. 219:1-731. Morphology of the deep-sea copepod Bob­ Yabe, M. 1984. Malacocottus zonurns Bean. kabata kabatabobbus (Lernaeosoleidae: Poe­ Page 330 in H. Masuda, K. Amaoka, C. cilostomatoida) and amended diagnosis of Araga, T. Uyeno, and T. Yoshino, eds. Lernaeosoleidae. J. Parasito1. 84: 109-113. The fishes of the Japanese Archipelago. Hogans, W. E., and G. W. Benz. 1990. A Tokai University Press, Tokyo.