PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON 114(l):229-236. 2001. Haplostoma kimi, a new species and a redescription of Haplostomella halocynthiae (Fukui) from Korea (Copepoda: Cyclopoida: Ascidicolidae) In Soon Seo and Kyung Sook Lee (ISS) Ecosystem Conservation Division, Ministry of Environment, Gwacheon-si, Gyeonggi-do, 427-729, Korea, e-mail: insseo@hanmaiLnet; (KSL) School of Fundamental Science, Dankook University, Cheonan-si, Chungcheongnam-do, 330-714, Korea, e-mail: [email protected] — Abstract. A new species of the genus Haplostoma associated with the as- cidians Styela clava clava Herdman andAmarouciumpliciferum Redikorzev is described. The new species can be differentiated from its 13 congeners in having 4 simple spines on second segment of antenna, 3 spines and 1 seta on the exopod of legs 3 and 4, and 6 distinct projections on the posterior margin of labrum. In addition, Haplostomella halocynthiae (Fukui), a new record in Korean fauna is redescribed, based on the specimens collected from the ascid- ians, Styela clava clava and Halocynthia roretzi (von Drasche). — The subfamily Haplostomatinae, one of Type material. 20 ? 9 found inside in- the eight subfamilies in the family Ascidi- testine ofsolitary ascidian, Styela clava cla- & colidae (lUg Dudley 1980), consists of va at Gangneung (approximately 37°45'N, four genera {Haplostoma, Haplostemella, 128°50'E) in Sea of Japan, Aug 1992. Ho- Haplostomides, and Haplosaccus). Most lotype ? (EWNHM60258) and paratypes species are known to inhabit the common 14 ? ? (EWNHM60259) deposited in Nat- test of compound ascidians, but some spe- ural History Museum, Ewha Womens Uni- cies have been described from the branchial versity, Seoul, Korea. Remaining speci- sac and/or intestine of solitary ascidians & mens (dissected) in the collection ofthe au- (Ooishi Illg 1977). During the course of a survey ofthe Ko- thor. — rean ascidicolid copepods, two species of Other material examined. 20 ? ? on Haplostomatinae from Korean waters were common test of compound ascidian, Amar- found, one is a new species and the other a ouciumpliciferum, collected at Hupo in Sea species known only from Japan. This paper of Japan, on 3 Aug 1987; 5 females col- describes both species. lected from A. pliciferum at Seongsanpo in The specimens were cleared in lactic acid Jeju Island, on 27 Jun 1987. for approximately one day before taking Female: Body (Fig. lA-C) columnar, measurements and dissecting. Drawings vermiform and grub-like. Full grown adult were made with the aid of a camera lucida. 2.04 mm long (holotype, from tip of ce- phalosome to end of caudal rami excluding Description setae), with slightly tapering cephalosome Family Ascidicolidae Thorell, 1859 (Fig. lA, B) but in dorsal view becoming Subfamily Haplostomatinae Chatton and gradually broadened posteriorly (Fig. lA). Harant, 1924 Young adult with evenly rounded cephalo- Genus Haplostoma (Canu, 1886) some and evenly wide metasome (Fig. IC, Haplostoma kimi, new species E). Cephalosome with distinct rostrum, Figs. 1, 2 bearing antennule, antenna, mandible, and 230 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON maxilliped. Dorsal cephalic plaque repre- and fourth segments indistinctly segmented sented by 2 large sclerotized areas (Fig. (sometimes fused), short and unarmed. ID). Pedigerous somites demarcated from Fifth segment a small claw, with 1 subter- each other by moderately prominent con- minal, claw-like process on inner side. strictions. Each pedigerous somite bearing Legs 1-4 alike in general shape and be- 1 pair of minute protrusions on dorsolateral coming gradually larger from anterior to surface. Each protrusion prominent in posterior. Protopod non-segmented, with adults, with minute seta. Anal segment(Fig. thick sclerotization along posterior margin. IF) about length ofwhole body, directed Endopod fused with protopod and repre- '/lo posteroventraly (Fig. IB, G), consisting of sented by large, conical protrusion. Exo- rounded, broad anterior part and narrower, pods unsegmented. Exopod of leg 1 (Fig. laterally parallel posterior part. Proximal 2C) with a trace of segmentation, armed section of anal segment with genital appa- with 1 proximal seta, 4 claw-like spines, ratus consisting a pair ofoviducal apertures and 1 small dentiform process. Exopod of on dorsolateral sides. Oviducal aperture at leg 2 similar to that of leg 1, but 1 spine each side with 3 spines (Fig. IF). Caudal less (Fig. 2D). Leg 3 (Fig. 2E) and 4 (Fig. rami divergent. Eachramus as long as wide, 2F) alike, protruded in the middle portion strongly tapering, triangular, inconspicuous- of outer margin near insertion of seta, and ly demarcated from anal segment, and armed with 1 proximal seta and 3 spines. armed with 1 lateral, 1 disterodorsal, and 1 Bases of these spines with rows of minute terminal spine. Terminal spine extremely spinules. thick, triangular and claw-like. Leg 5 (Fig. 2G) a small tapering lobe lo- Rostrum with a row of minute spinules cated on dorsolateral side oflast metasomal on both sides (Fig. IE). Antennule (Fig. somite, bearing 1 basal and 2 terminal se- IH) indistinctly segmented and tapering ter- tae. minally. Proximal part with 3 broad setae Male: Unkn—own. and 2 or 3 thin setules. Distal part incom- Etymology. The specific name, kimi, is pletely divided on posterior margin into 3 given after Dr. Il-Hoi Kim who provided segments, with 2 broad proximal setae specimens o—f the new species. mounted on a large elevation, 5 broad (1 Remarks. There are 13 species ofHap- being distinctly larger) and 1 slender setae lostoma, with five of them bearing process- in medial part, and 8 slender setae termi- es on the posterior margin of labrum. The nally. Antenna (Fig. II) 2-segmented. First new species has 6 processes, similar to the segment broad and slightly longer than dis- following three species: H. banyulensis tal segment. Second segment with sclero- (Brement, 1909), H. eruca (Norman, 1869), & tized margins, and bearing 3 lateral and 1 and H. minutum Ooishi Illg, 1977. These terminal spines. All spines thick and claw- three species are easily differentiated from like. H. kimi, by the armature on the exopod of Labrum with 6 rounded, distinct projec- legs 3 and 4, armed with either 2 (in H. tions on posterior margin (Fig. 2A). Man- eruca and H. minutum) or 4 spines (in H. dible a lobe bearing 2 terminal setae (Fig. banyulensis), instead of 3 spines and 1 seta 2A). Maxillule and maxilla absent. Maxil- as in H. kimi. liped (Fig. 2B) 5-segmented. First segment According to Ooishi (1998), Haplostoma nearly as long as wide, much wider than mizoulei Monniot, 1962 is synonymous distal segments but unarmed. Second seg- with H. brevicauda (Canu, 1886). H. mi- ment as long as wide, with 1 distal and 1 zoulei Monniot, 1962 is the only species subdistal setae on inner margin; location of that carries the same number of spines on subdistal seta varied, occasionally located the exopod of legs 3 and 4 as the new spe- in middle portion of inner margin. Third cies (Monniot, 1962). However, H. mizoulei VOLUME NUMBER 114, 1 231 Fig. 1. Haplostoma kimi new species. Female. A, habitus, dorsal; B, habitus, lateral; C, habitus, protrusion ofdorsal, D, cephalic plaque; E, oral area, ventral; F, anal segment and caudal rami; G, leg 5, anal segment and caudal rami, lateral; H, antennule; I, antenna. Scales : A-C = 0.2; D-G = 0.1; H, I = 0.02mm. 232 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON Fig. 2. Haplostoma kimi new species. Female. A, labrum and mandible, ventral; B, maxilliped; C, leg 1; D, leg 2; E, leg 3; F leg 4; G, leg 5. Scales : 0.02 mm all. differs from H. kimi, in having 2 spines and parable with the new species on the basis 2 setae instead of 1 spine and 2 setae on of morphology of the labrum and legs. Ac- the caudal ramus, 3 setae instead of 2 setae cording to Ooishi and Illg (1977), H. gib- on the apex of leg 5, and no subterminal berum has 3 spines on the terminal segment process on the terminal claw of maxilliped. of the antenna. This character differs from Haplostoma gibberum (Schellenberg, that of the new species which has 4 simple 1922) is incompletely known but not com- spines. VOLUME 114, NUMBER 1 233 It is remarkable that although H. kimi is 3F) tapering, with 17 setae and several se- associated with both solitary and compound tules, and 2 traces of segmentation in distal ascidians, specimens from either host do portion. Antenna (Fig. 3G) curved, consist- not show noticeable differences in mor- ing of 2 parts. Basal part comprises 75% phology. length of antenna, with 1 inner distal seta. Distal part armed terminally with 1 blunt Genus Haplostomella Chatton and Harant, process and 3 setae; innermost setaglobular 1924 and tipped with a setule. Labrum unarmed, posterior margin with Haplostomella halocynthiae (Fukui, 1965) round medial projection. Mandible (Fig. Figs. 3, 4 3H) fringed with a hyaline layer, armed in Rhabdomorpha halocynthiae.—Fukui, distal half with 2 rows of ±10 denticles. Maxillule not identified. Maxilla (Fig. 31) 1965:61. — indistinctly 2-segmented. First segment ro- Haplostomella halocynthiae. Ooishi and bust. Second segment distinctly narrower, lUg, 1974:365, figs. 1-3. — about twice as long as wide, and half as Material examined. From Styela clava long as first segment; protrudedpostero dis- clava Herdman: 2 ? ? from Busan in tally and tipped with a small tubercle Tsushima Strait, on 1 Jul 1986; 2 ? ?, from (sometimes absent), in addition to bearing Busan, on 3 Nov. 1986; 1 9 from Gang- 1 large antero distal, spiniform seta. Max- neung in Sea of Japan, on 3 Nov 1979. illiped (Fig. 4A, B) 3-segmented stout and From Halocynthia roretzi (von Drasche): 1 massive. First segment unarmed. Second ? from Yeosu in Tsushima Strait, on Feb segment with many rows of spinules on 1993. outer dorsal surface and 2 unequal process- mm Female: Body elongate, 10.3 long, es on inner margin, with larger one distally. non-segmented and vermiform. Segmenta- Terminal segment represented by a strong tion in some cases identifiable by lateral pointed claw, with its tip inserting between constrictions. Body roughly divided into 3 two processes on second segment. sections: cephalosome, metasome and uro- Legs 1-4 uniform in shape. Protopod in- some, with length proportion of 1 : 21 : 7.4. distinctly demarcated from body surface, Ventral surface of body, especially around represented by sclerotized integument cov- legs, with numerous rows of minute spi- ered by rows of spinules and hairs. Exopod nules as in Fig. 4C; each row consisting of divided into ventral and dorsal lobes ventral 4 to 15 spinules. Cephalosome small, with lobe claw-like and smaller, dorsal one discernible cephalic shield. Metasome in- tipped with a setule. Body surface near ex- distinctly 5-segmented, with 5 pairs oflegs. opod with 4 prominent digitiform process- Each metasomal somite with a pair of su- es. Endopod fused to protopod, represented boval dorsal plates (Fig. 3A). Urosome ta- by posterior bilobed bulge and covered by pering, without any trace of segmentation, rows of spinules (Fig. 4C). Leg 5 (Fig. 4F) about 20% as long as body. Oviducal ap- represented by 2 setae and 2 or 3 minute erture (Fig. 4D) located dorsolaterally on setules. genital somite, with hood-like semicircular Male: Unk—nown. projection armed with 4 dorsal denticles, Remarks. Haplostomella halocynthiae outermost denticle 3 or 4 small points. Cau- has so far been known only from Halocyn- dal rami widely separated from each other thia roretzi in Japan. The Korean specimens (Fig. 3C), 167 X 81 |JLm, 2.06 times as long of H. halocynthiae are very similar in mor- as wide, armed with 5 setae (Fig. 3D). Egg phology to the Japanese specimens. There- mm sac elongate, 5.0 long. fore, the present record adds another ascid- Rostrum not discernible. Antennule (Fig. ian host, {Styela clava clava) from another 234 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON Fig. 3. Haplostomella halocynthiae (Fukui). Female. A, habitus, dorsal; B, cephlosome, dorsal; C, urosome, dorsal; D, caudal ramus; E, oral area, ventral; F, antennule; G, antenna; H, mandible; I, maxilla. Scales ; A = 1; B, C = 0.5; D, E = 0.1; R G, I = 0.05; H = 0.02mm. — VOLUME 114, NUMBER 1 235 Fig. 4. Haplostomella halocynthiae (Fukui), Female. A, maxilliped, outer; B, maxilliped, inner; C, leg 1; D, oviducal aperture, dorsal; E, oviducal aperture, ventral; F, leg 5. Scales : A-E = 0.1; F = 0.05 mm. country. This species was thoroughly re- Bulletin de la Societe ZoologiquedeFrance49: described by Ooishi and Illg (1974); it is 413-422 (not seen). redescribed herein as one of its hosts, H. Fukui, T. —1965. On some parasitic copepods of Ja- pan. Kokakurui no Kenkyu 2:60-66. roretzi, is the most important ascidian cul- Illg, R L., & R L. Dudley 1980. The family Ascidi- tured along the Korean coast. colidae and its subfamilies (Copepoda, C—yclo- poida), with descriptions ofnew species. Me- Acknowledgement moires du MusumNational d'HistoireNaturelle 117:1-191. The present research was supported in Monniot, C. 1963. Haplostoma mizoulei n. sp., Co- part by a research grant obtained fromDan- pepode parasite d'une Ascidie interstitielle. kook University (2000). Bulletin de la Socit Zoologique de France 87: 570-574. Norman, A. M. 1869. Shetland final dredging report. Literature Cited Part n. On the Crustacea, Tunicata, Polyzoa, Brement, E. 1909. Contribution a I'etud—e de Copepo- Echin—odermata, Actinozoa, Hydrozoa and For- des ascidicolesdu Golfe duLion. Archivesde ifera. ReportoftheBritish Associationforthe Zoologie ExperimentaleetGenerale 1 (Noteset Advancement of Science, 38th Meeting, Nor- Revue 5):61-89 (not seen). wich, 247-336 (not seen). Canu, E. 1886. Description de deux Copep—odes nou- Ooishi, S. 1998. Haplostoma dudleyae sp. now. (Cy- veaux parasites des Synascidies. Bulletin clopoida: Ascidicolidae), ParasiticinEudistoma Scientifique de la France et de la Belgique 17: olivace—um from the Indian River in southern 309-320 (not seen). Florida. Journal of Marine Systems 15:273- Chatton, E., & H. Harant, 1924. Notres sur les Cope- 279. podes ascidicoles, 18. Haplostoma canuin. sp., , & P L. nig. 1974. Haplostomella halocynthiae Etat acturel de la systematique des Haplosto—m- (Fukui), an ascidicoUd copepod associated with a inae n. subf. Le nouveau genre Haplosaccus. simple ascidian, Halocynthia roretzi (von Dras- 236 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON — che), from Japan. Publications from the Seto liner und Hamburger Museums mit einerUber- M,a&rine Biolog.i1c9a7l7L.abHoarpaltoosrtyo2m1i:n3a6e5-(3C7o5p.epoda, Asircthetn.d—erMiatstceiidliuenngbeenwoahunsenddeenmGaZtotoulnoggeinscuhnedn Cyclopoida) associated with compound ascidi- Museum in Berhn, 10:219-274 (not seen). ans—from the San Juan Archipelago and Vicin- Thorell, T. 1859. Till kannedome—n omvissaparasitiskt ity. PublicationsfromtheSetoMarineBiolog- lefvande Entomostraceer. Ofversigt af Kongl ical Laboratory 5:1-153. Ventenskaps-AkademiensForhandlingar,Stock- Schellenberg, A. 1922. Neue Notodelphyiden desBer- holm, 8:335-362 (not seen).