Further Record of the Shallow Water Mysid Heteromysis Proxima W. M

CRUSTACEAN RESEARCH, NO. 41: 11–18, 2012 10 T. TAKAHASHI & S. GOSHIMA

This study concentrated on the basic 355. biology of C. isopus in Hakodate Bay, but ———, 1955b. The life cycle of the isopod Idotea Further record of the shallow water mysid Heteromysis this species is distributed widely throughout emarginata (Fabricius). Journal of Animal proxima W. M. Tattersall, 1922 (Mysida) from the Malacca Japan (Nunomura, 1995, 2011), and it is Ecology, 24: 270–281. Nunomura, N., 1995. Isopoda. In: S. Nishimura (ed.), Strait known that the breeding period and its Guide to Seashore Animals of Japan with Color extension are different among habitats. Pictures and Keys. Vol. II, Hoikusha, Osaka, Similar studies in different regions and in 205–233. (In Japanese) other related species are necessary to reveal ———, 2011. Crustaceans No. 2, Isopoda. Special Yukio Hanamura, Ryon Siow, Alias Man and Faizul Mohd Kassim the factors that affect the particularly plastic Publication of the Toyama Science Museum, No. life history traits of isopods. Such plasticity 24. Toyama Science Museum. (In Japanese) may well be the key to the success of this Orton, J.H., 1920. Sea-temperature, breeding and distribution in marine animals. Journal of the Abstract.—Heteromysis proxima W.M. species across its latitudinal range. O.S. Tattersall, 1967; H. singaporensis O.S. Marine Biological Association of the United Tattersall, 1922 (Mysida) was first reported from Tattersall, 1967; H. (Olivemysis) thailandica Kingdom, 12: 339–366. the Gulf of Manaar, off the south-eastern coast of Fukuoka & Murano, 2002; and Heteromysis Acknowledgments Robertson, A.I. & Mann, K.H., 1980. The role India. A recent sledge net survey conducted on the sp. sensu O.S. Tattersall, 1967 (Müller, 1993; of isopods and amphipods in the initial We would like to express our appreciation north-western coast of Malaysia yielded several Fukuoka & Murano, 2002; Sawamoto & fragmentation of eelgrass detritus in Nova specimens of this little-known mysid from a to the members of the Laboratory of Scotia, Canada. Marine Biology, 59: 63–69. Fukuoka, 2005). This gives the impression sandy beach located in the mouth area of Merbok Benthology, Faculty of Fisheries, Hokkaido Salemaa, H., 1979. Ecology of Idotea species of comparatively poor heteromysid diversity University, for their advice and cooperation (Isopoda) in the northern Baltic. Ophelia, 18: River, facing the Malacca Strait. Although the in South-East Asian waters compared with during this study. We are thankful to the 133–150. Malaysian specimens have a comparatively more than 20 species that have been found anonymous reviewers and Roberto C. Sheader, M., 1977. The breeding biology of Idotea smaller body size than those recorded from in the northern part of Australia (Băcescu India, the morphological features of these Lombardo for their reviews and comments pelagica (Isopoda: Valvifera) with notes on & Bruce, 1980; Băcescu, 1983; Murano, the occurrence and biology of its parasite specimens essentially agree with the typical ones. 1988, 1998b). The fewer recorded species, that helped to improve the manuscript. Clypeoniscus hanseni (Isopoda: Epicaridea). This paper provides further information on the however, may be due to the paucity of Journal of the Marine Biological Association of morphological characteristics of H. proxima on surveys, and this region is still considered to Literature Cited the United Kingdom, 57: 659–674. the basis of newly obtained specimens and extends Strong, K.W. & Daborn G.R., 1979. Growth and be an intriguing and unstudied field for many its geographical range to the Malacca Strait. Hastie, L.C., Nyegaard, M., Collins, M.A., Moreno, energy utilization of the intertidal isopod Idotea coastal marine life forms, including mysid A., Pereira, J.M.F., Piatkowski, U., & Pierce, baltica (Pallas) (Crustacea: Isopoda). Journal of G.J., 2009. Reproductive biology of the loliginid crustaceans. Experimental Marine Biology and Ecology, 41: During the hyperbenthic crustacean squid, Alloteuthis subulata, in the north-east 101–123. Introduction Atlantic and adjacent waters. Aquatic Living Suzuki, M., Watanabe, K., & Mukai, H., 2002. The genus Heteromysis S.I. Smith, 1874 surveys conducted in the coastal waters of Resources, 22: 35–44. Feeding habits and growth of an isopod, Idotea includes a large group of mysid crustaceans north-western Malaysia since 2004, several Healy, B. & O’Neill, M., 1984. The life cycle ochotensis Brandt, in Akkeshi Bay, Hokkaido, (Mysida), currently numbering some 80 specimens of the little-known heteromysid and population dynamics of Idotea pelagica northern Japan. Japanese Journal of Benthology, species world-wide (Anderson, 2010; Price H. proxima W.M. Tattersall, 1922 were found and I. granulosa (Isopoda: Valvifera) in south- 57: 13–20. (In Japanese with English abstract) & Heard, 2011). Heteromysis is regarded as at a shallow depth in the mouth of Merbok east Ireland. Journal of the Marine Biological Sywula, T., 1964. A study of the taxonomy, ecology Association of the United Kingdom, 64: 21–33. a highly adaptable group which is able to River, north-western Peninsular Malaysia. and geographical distribution of species of the thrive in diverse habitats, from open waters This rare heteromysid species is re-described Johnson, W.S., Stevens, M., & Watling, L., 2001. genus Idotea Fabricius (Isopoda, Crustacea) in the Reproduction and development of marine Polish Baltic. Ecological and zoogeographical to cryptic environments such as submarine on the basis of newly captured material, peracaridans. Advances in Marine Biology, 39: part. Bulletin de la Société des amis des sciences caves; some are even known to live in a providing supplementary information on 105–260. et des letters de Poznań (série B), 4: 173–199. commensal lifestyle with a variety of marine their morphology and as a new distribution Jormalainen, V., Tuomi, J. & Merilaita, S., 1992. invertebrates (Tattersall, 1967; Müller, 1993; record. Mate choice for male and female size in aquatic Fukuoka, 2005). Morphologically, this genus The body length (BL) was measured isopod Idotea baltica. Annales Zoologici Fennici, Addresses: (TT, SG) Graduate School of 29: 161–167. is remarkable among the mysids, as they from the anterior end of the rostral plate to Kjennerud, J., 1950. Ecological observations on Fisheries Sciences, Hokkaido University, 3-1-1 normally have a sub-chelate endopod, similar the posterior end of the telson excluding the Idotea neglecta G.O. Sars. Universiteteti Bergen. Minato-cho, Hakodate 041-8611, Japan. to those found in amphipods, in the third apical spines. The terminology in the setal/ Årbok (Naturvitenskapelig rekke), 7: 5–47. E-mails: (TT) tomohiro-takahashi@ thoracic limb. spine system followed Watling (1989). Lee, W.L., 1966. Color change and the ecology of the support99.com; (SG) [email protected]. To date, four species of Heteromysis, The specimens dealt with here have been marine isopod Idotea (Pentidotea) montereyensis ac.jp including one yet undetermined species, deposited in the National Museum of Nature Maloney, 1933. Ecology, 47: 930–941. Naylor, E., 1955a. The diet and feeding mechanism have been recorded from the Malacca Strait and Science, Tokyo (NSMT), and Fisheries Received: 17 February 2011. of Idotea. Journal of the Marine Biological and its neighbouring region: H. minuta Research Institute, Penang (FRI) Association of the United Kingdom, 34: 347– Accepted: 29 March 2012. FuRTHER RECORD OF HeterOMysis prOxiMa 13 12 12 ET AL. Taxonomic Account Y. HANAMURABasal segment of antennular peduncle of Family Mysidae Haworth, 1825 female (Fig. 1d) sub-equal to combined Genus Heteromysis S.I. Smith, 1874 length of anterior 2 segments when measured Heteromysis proxima W.M. Tattersall, along medial margin; second segment 1922 slightly shorter than half length of basal (Figs. 1, 2) one and distinctly shorter than wide; third segment slightly shorter than wide and again a Heteromysis proxima W. M. Tattersall, 1922, 496, longer than second one, bearing a few simple fig. 26; Pillai, 1965: 1726, fig. 93; ?Murano, setae around distomedial part. b 1998a: 52, fig. 6. Antennal scale (Fig. 1e) oval with rounded apex falling slightly short of anterior Material examined.—Two males (BL end of antennular peduncle, about 3.0 times 3.2 mm, 4.3 mm), 1 female (BL 3.8 mm), as long as wide, with setose margins; distal 1 ovigerous female (BL 4.2 mm), (NSMT- suture present; peduncle long, reaching Cr 22217), and 1 male (BL 3.0 mm) (FRI Cr or slightly overreaching anterior end of f 009), sandy shore off Merdeka Beach, mouth antennular peduncle. of Merbok River (N 05˚40.2´, E 100˚22.2´), Labrum (Fig. 1f) with anterior margin Kedah State, Malaysia, depth 1.0–2.5 m, sub-triangular, without discernible median sledge net, salinity 31.34 (psu), 7 Oct 2005, tooth or spine. Mouth parts not dissected. coll. Y. Hanamura. Ventral sternites (Fig. 1h) with distinct c Descriptions.—Body moderately robust lobular projections on third to seventh (Fig. 1a). somites, fourth one appreciably smaller and Carapace (Fig. 1a, b) slightly and evenly more slender than remaining ones. convex in lateral view, surface smooth Endopod of third thoracopod in male without discernible ornamentation; anterior (Fig. 1g) rather massive, ischium with flexor dorsal part produced into somewhat sharp margin smooth, with a few simple setae; e triangular rostral plate curving ventrally, merus about 2.5 times as long as maximum lateral margin of rostral plate concave, height, bearing about 6 flagellate denticles covering basal part of eye stalk; cervical along flexor margin; carpo-propodus slightly sulcus very shallow but feebly defined at more than 2.0 times as long as maximum anterior one-third; posterior dorsal margin height, with extensor margin distinctly excavate, leaving last thoracic somite visible convex in lateral view, without setae or dorsally: anterior ventral corner rounded; spines, flexor margin nearly straight in lateral lateral wing of carapace well developed, fully view, its distal corner with about 4 flagellate d covering thoracic somites and first abdominal denticles, 2 stout simple setae, and single somite in lateral aspect. distally bidentate seta so as to form powerful Cornea (Fig. 1b) well pigmented, sub-chela with dactylar nail; dactylus short, comparatively small and slightly narrower shorter than height, distoventral part well than eyestalk, latter smooth and not hispid, advanced into triangular projection. Female without finger-like process but forming third thoracic endopod similar in basic noticeable rim at distomedial corner of stalk. structure to that of male but slightly more h Antennule of male slightly stronger when slender than that of male, merus slightly compared with that of female. Male basal more than 2.0 times as long as its maximum segment of antennular peduncle (Fig. 1c) height, with about 8 flagellate setae; carpo- sub-equal to combined length of anterior propodus approximately 2.5 times as long 2 segments when measured along medial as its maximum height, bearing 8 flagellate g margin and again longer than broad; second denticles on flexor margin. Fourth to eighth segment less than half length of basal thoracopods (Fig. 2b, c) rather similar in segment and noticeably shorter than width; shape, endopods rather robust and distinctly Fig. 1. Heteromsysis proxima W.M. Tattersall, 1922. Male (BL 4.3 mm) (a–c, e–h) and ovigerous female (BL 4.2 third segment shorter than wide and again longer than exopods; carpo-propodi mm) (d): a, entire body, lateral view; b, anterior part of carapace and cephalic appendages, dorsal view; c, right antennule of male, dorsal view; d, right antennule of female, dorsal view; e, right antenna, dorsal view; f, labrum, slightly longer than second one, bearing a composed of 5 articles of sub-equal length, ventral view; g, right third thoracic endopod, lateral view; h, outline of ventral tubercles on third to seventh thoracic few simple setae around distomedial part. each sub-segment armed with a group of sternites of male, ventral view. FuRTHER RECORD OF HeterOMysis prOxiMa 13 12 ET AL. 13 Taxonomic Account Y. HANAMURABasal segment of antennular peduncle of Family Mysidae Haworth, 1825 female (Fig. 1d) sub-equal to combined Genus Heteromysis S.I. Smith, 1874 length of anterior 2 segments when measured Heteromysis proxima W.M. Tattersall, along medial margin; second segment 1922 slightly shorter than half length of basal (Figs. 1, 2) one and distinctly shorter than wide; third segment slightly shorter than wide and again a Heteromysis proxima W. M. Tattersall, 1922, 496, longer than second one, bearing a few simple fig. 26; Pillai, 1965: 1726, fig. 93; ?Murano, setae around distomedial part. b 1998a: 52, fig. 6. Antennal scale (Fig. 1e) oval with rounded apex falling slightly short of anterior Material examined.—Two males (BL end of antennular peduncle, about 3.0 times 3.2 mm, 4.3 mm), 1 female (BL 3.8 mm), as long as wide, with setose margins; distal 1 ovigerous female (BL 4.2 mm), (NSMT- suture present; peduncle long, reaching Cr 22217), and 1 male (BL 3.0 mm) (FRI Cr or slightly overreaching anterior end of f 009), sandy shore off Merdeka Beach, mouth antennular peduncle. of Merbok River (N 05˚40.2´, E 100˚22.2´), Labrum (Fig. 1f) with anterior margin Kedah State, Malaysia, depth 1.0–2.5 m, sub-triangular, without discernible median sledge net, salinity 31.34 (psu), 7 Oct 2005, tooth or spine. Mouth parts not dissected. coll. Y. Hanamura. Ventral sternites (Fig. 1h) with distinct c Descriptions.—Body moderately robust lobular projections on third to seventh (Fig. 1a). somites, fourth one appreciably smaller and Carapace (Fig. 1a, b) slightly and evenly more slender than remaining ones. convex in lateral view, surface smooth Endopod of third thoracopod in male without discernible ornamentation; anterior (Fig. 1g) rather massive, ischium with flexor dorsal part produced into somewhat sharp margin smooth, with a few simple setae; e triangular rostral plate curving ventrally, merus about 2.5 times as long as maximum lateral margin of rostral plate concave, height, bearing about 6 flagellate denticles covering basal part of eye stalk; cervical along flexor margin; carpo-propodus slightly sulcus very shallow but feebly defined at more than 2.0 times as long as maximum anterior one-third; posterior dorsal margin height, with extensor margin distinctly excavate, leaving last thoracic somite visible convex in lateral view, without setae or dorsally: anterior ventral corner rounded; spines, flexor margin nearly straight in lateral lateral wing of carapace well developed, fully view, its distal corner with about 4 flagellate d covering thoracic somites and first abdominal denticles, 2 stout simple setae, and single somite in lateral aspect. distally bidentate seta so as to form powerful Cornea (Fig. 1b) well pigmented, sub-chela with dactylar nail; dactylus short, comparatively small and slightly narrower shorter than height, distoventral part well than eyestalk, latter smooth and not hispid, advanced into triangular projection. Female without finger-like process but forming third thoracic endopod similar in basic noticeable rim at distomedial corner of stalk. structure to that of male but slightly more h Antennule of male slightly stronger when slender than that of male, merus slightly compared with that of female. Male basal more than 2.0 times as long as its maximum segment of antennular peduncle (Fig. 1c) height, with about 8 flagellate setae; carpo- sub-equal to combined length of anterior propodus approximately 2.5 times as long 2 segments when measured along medial as its maximum height, bearing 8 flagellate g margin and again longer than broad; second denticles on flexor margin. Fourth to eighth segment less than half length of basal thoracopods (Fig. 2b, c) rather similar in segment and noticeably shorter than width; shape, endopods rather robust and distinctly Fig. 1. Heteromsysis proxima W.M. Tattersall, 1922. Male (BL 4.3 mm) (a–c, e–h) and ovigerous female (BL 4.2 third segment shorter than wide and again longer than exopods; carpo-propodi mm) (d): a, entire body, lateral view; b, anterior part of carapace and cephalic appendages, dorsal view; c, right antennule of male, dorsal view; d, right antennule of female, dorsal view; e, right antenna, dorsal view; f, labrum, slightly longer than second one, bearing a composed of 5 articles of sub-equal length, ventral view; g, right third thoracic endopod, lateral view; h, outline of ventral tubercles on third to seventh thoracic few simple setae around distomedial part. each sub-segment armed with a group of sternites of male, ventral view. FuRTHER RECORD OF HeterOMysis prOxiMa 15 14 14 ET AL. Y. HANAMURA a few setae of varying lengths on anterior telson (8–10 vs. 10–12) and a comparatively margin; terminal dactylar nail moderately shorter antennal scale (slightly shorter than robust, bearing a few somewhat short setae antennal peduncle rather than as long as near basal part. its peduncle). Despite these differences, Penis slightly compressed and gently the basic structures are in good agreement curving outwards, reaching mid-length of between the two populations. basal plate of eighth thoracic exopod, with Murano (1998a) also provided another moderately long seta at apex. related record of H. proxima from the Abdomen (Fig. 1a) slightly depressed, Arabian Gulf. These specimens share several broader than its height, anterior 5 somites similar diagnostic features with H. proxima. sub-equal in length; sixth somite 1.3–1.5 Through the courtesy of Dr. Murano, we were times as long as preceding one. Telson (Fig. able to examine the Arabian Gulf specimens. 2a) sub-triangular, 1.3–1.4 times as long A preliminary observation revealed that as sixth abdominal somite, about 1.4 times the outer apical seta of the telson in the a c longer than width at base; lateral margin Arabian specimens is proportionately longer nearly straight, basally naked but armed (> 2.5 times as long as inner one) than that with 8–10 spinous setae on distal half, of the specimens from Malaysia and India increasing in length distally; posterior part (at most twice length). Furthermore, the noticeably forked, occupying about 1/4 times male from the Arabian Gulf appeared to m of entire telson length, with approximately have a comparatively shorter fifth pleopod, 20 denticles on whole medial margins, apical particularly in the distal narrowed part as lobe with pair of spinous setae, outer seta compared to the male from Malaysia. In approximately twice length of inner one. addition, the ventral lobular projections on Pleopods in males (Fig. 2d–h) the thoracic sternites differed in shape as the unarticulated, increasing in length posteriorly. male from the Arabian Gulf has a marked h g Pleopods of female (Fig. 2i–l) unarticulated distal concavity instead of a rounded apex as (first one not dissected), basically similar in found in the Malaysian counterpart. Although shape to those of males. we are inclined to believe that the observed f e d uropod (Fig. 2m) with oval exopod and differences represent a distinction of the two endopod, latter slightly shorter than exopod, populations at species level rather than intra- possessing a single rather stout seta in specific variations, the exact identity of the ventromedial part near statocyst. Arabian Gulf specimens recorded under H. remarks.—Heteromysis proxima is proxima deserves further detailed studies. distinguished by having a combination of Heteromysis proxima also shows a the following features; 1) the third thoracic general resemblance to H. microps G.O. Sars, l k j i endopod with the ischium showing a smooth 1877 and H. digitata W.M. Tattersall, 1927. (not serrated) flexor margin and its dactylus However, the dactyl of the third thoracic with a distinct projection at the distoventral endopods of the latter two species are not corner, 2) the eye without a finger- modified to form a distinct projection but like projection, and 3) the telson in sub- bears a sharp spine (or a pair of spines) at the triangular form with rather straight lateral distolateral corner of its carpo-propodus. margins. The following two species share Some species of Heteromysis exhibit these features together with H. proxima; H. sexual dimorphism in pleopods but not nouveli Brattegard, 1969 and H. australica in others (cf. Tattersall, 1967). Moreover, b Băcescu & Bruce, 1980. The morphological Băcescu (1968) noted that the setae on the characteristics of these closely related species distomedial part of the antennular peduncle are given in Table 1. vary in shape among species within the The Malaysian specimens of H. proxima genus: thus, species with simple attenuate have a smaller body size when compared setae (+ pleopods not sexually dimorphic + Fig. 2. Heteromysis proxima W.M. Tattersall, 1922. Male (BL 4.3 mm) (a, b, d–h, m) and ovigerous female (BL with the Indian ones (ca. 3.0–4.5 mm vs. 6–7 4.2 mm) (c, i–l): a, telson, dorsal view; b, right sixth thoracic limb, lateral view; c, right eighth thoracic endopod, projections on ventral thoracic sternites) were lateral view (endopod and exopod detached); d–h, first to fifth pleopods of male; i–l, second to fifth pleopods of mm). The former also have a smaller number attributable to the subgenus Heteromysis female; m, right uropod, ventral view. of spinous setae on the lateral margin of the and those with modified setae (+ pleopods FuRTHER RECORD OF HeterOMysis prOxiMa 15 14 ET AL. 15 Y. HANAMURA a few setae of varying lengths on anterior telson (8–10 vs. 10–12) and a comparatively margin; terminal dactylar nail moderately shorter antennal scale (slightly shorter than robust, bearing a few somewhat short setae antennal peduncle rather than as long as near basal part. its peduncle). Despite these differences, Penis slightly compressed and gently the basic structures are in good agreement curving outwards, reaching mid-length of between the two populations. basal plate of eighth thoracic exopod, with Murano (1998a) also provided another moderately long seta at apex. related record of H. proxima from the Abdomen (Fig. 1a) slightly depressed, Arabian Gulf. These specimens share several broader than its height, anterior 5 somites similar diagnostic features with H. proxima. sub-equal in length; sixth somite 1.3–1.5 Through the courtesy of Dr. Murano, we were times as long as preceding one. Telson (Fig. able to examine the Arabian Gulf specimens. 2a) sub-triangular, 1.3–1.4 times as long A preliminary observation revealed that as sixth abdominal somite, about 1.4 times the outer apical seta of the telson in the a c longer than width at base; lateral margin Arabian specimens is proportionately longer nearly straight, basally naked but armed (> 2.5 times as long as inner one) than that with 8–10 spinous setae on distal half, of the specimens from Malaysia and India increasing in length distally; posterior part (at most twice length). Furthermore, the noticeably forked, occupying about 1/4 times male from the Arabian Gulf appeared to m of entire telson length, with approximately have a comparatively shorter fifth pleopod, 20 denticles on whole medial margins, apical particularly in the distal narrowed part as lobe with pair of spinous setae, outer seta compared to the male from Malaysia. In approximately twice length of inner one. addition, the ventral lobular projections on Pleopods in males (Fig. 2d–h) the thoracic sternites differed in shape as the unarticulated, increasing in length posteriorly. male from the Arabian Gulf has a marked h g Pleopods of female (Fig. 2i–l) unarticulated distal concavity instead of a rounded apex as (first one not dissected), basically similar in found in the Malaysian counterpart. Although shape to those of males. we are inclined to believe that the observed f e d uropod (Fig. 2m) with oval exopod and differences represent a distinction of the two endopod, latter slightly shorter than exopod, populations at species level rather than intra- possessing a single rather stout seta in specific variations, the exact identity of the ventromedial part near statocyst. Arabian Gulf specimens recorded under H. remarks.—Heteromysis proxima is proxima deserves further detailed studies. distinguished by having a combination of Heteromysis proxima also shows a the following features; 1) the third thoracic general resemblance to H. microps G.O. Sars, l k j i endopod with the ischium showing a smooth 1877 and H. digitata W.M. Tattersall, 1927. (not serrated) flexor margin and its dactylus However, the dactyl of the third thoracic with a distinct projection at the distoventral endopods of the latter two species are not corner, 2) the eye without a finger- modified to form a distinct projection but like projection, and 3) the telson in sub- bears a sharp spine (or a pair of spines) at the triangular form with rather straight lateral distolateral corner of its carpo-propodus. margins. The following two species share Some species of Heteromysis exhibit these features together with H. proxima; H. sexual dimorphism in pleopods but not nouveli Brattegard, 1969 and H. australica in others (cf. Tattersall, 1967). Moreover, b Băcescu & Bruce, 1980. The morphological Băcescu (1968) noted that the setae on the characteristics of these closely related species distomedial part of the antennular peduncle are given in Table 1. vary in shape among species within the The Malaysian specimens of H. proxima genus: thus, species with simple attenuate have a smaller body size when compared setae (+ pleopods not sexually dimorphic + Fig. 2. Heteromysis proxima W.M. Tattersall, 1922. Male (BL 4.3 mm) (a, b, d–h, m) and ovigerous female (BL with the Indian ones (ca. 3.0–4.5 mm vs. 6–7 4.2 mm) (c, i–l): a, telson, dorsal view; b, right sixth thoracic limb, lateral view; c, right eighth thoracic endopod, projections on ventral thoracic sternites) were lateral view (endopod and exopod detached); d–h, first to fifth pleopods of male; i–l, second to fifth pleopods of mm). The former also have a smaller number attributable to the subgenus Heteromysis female; m, right uropod, ventral view. of spinous setae on the lateral margin of the and those with modified setae (+ pleopods FuRTHER RECORD OF HeterOMysis prOxiMa 17 16 16 ET AL. Y. HANAMURA sexually dimorphic + no projection on ventral Băcescu, M., 1968. Heteromysini nouveaux des eaux thoracic sternites) to Olivemysis. However, Cubaines: trois espèces nouvelles de Heteromysis Bamber (2000) found in H. cyanogoleus et Heteromysoides spongicola n.g.n.sp. Revue Roumaine de Biologie, (Zoologie), 13: 221–237. that these setae show slight incongruence ———, 1983. New Heteromysini from the coral area in form between the sexes. Price & Heard near Heron Island (SE Queensland)–Australia. (2011) redefined the subgenus Olivemysis Revue Roumaine de Biologie, Biologie Animale, so as to have a combination of the following 28: 3–11. gin with 8-10 spinous features: distomedial part of third peduncular ———, & Bruce, A.J., 1980. New contributions to

(Malaysia) segment of antennule with medial flagellate the knowledge of the representatives of genus gin setae directed anteriorly as well as laterally, Heteromysis s.l. from the Australian coral reefs. Travaux du Muséum National d’Histoire Shorter than its peduncle Merus with distinct distoventral projection; carpo-propodus as long as merus; dactylus with well advanced sharp distoventral projection Carpo-propodus composed of 5 articles No sexual modification 1 mesial spinous seta near statocyst Lateral mar setae (excluding apical ones) on posterior half; outer apical seta longer than inner one; apical cleft armed with denticles on entire mar Ca. 4–4.5 mm (male and female) Malacca Strait, Peninsular Malaysia long simple seta directed laterally; third Naturelle “Grigore Antipa”, 21: 63–72. thoracic endopod moderately robust, some of Bamber, R., 2000. A new species of Heteromysis distal articles elongated; fourth male pleopod (Crustacea: Mysidacea) from a “blue hole” in the modified; uropodal endopod shorter than Bahamas. Species Diversity, 5: 129–134. gin exopod. Even in their updated definition, the Brattegard, T., 1969. Marine biological investigations W.M. Tattersall, 1922 Tattersall, oxima W.M. identity of H. cyanogoleus having sexually in the Bahamas. 10. Mysidacea from shallow

, south-eastern water in the Bahamas and southern Florida. Part

H. pr dimorphic antennular setae remains unsettled. 1. Sarsia, 39: 17–106.

gin with 10-12 Aside from the taxonomic problem Fukuoka, K., 2005. A new species of Heteromysis (India) remaining unsolved, our specimens of (Mysida, Mysidae) associated with sponges, Indo-Pacific Ocean H. proxima showed good agreement in from the uraga Channel, central Japan, with morphological characteristics with the notes on distribution and habitats within the As long as its peduncle Merus with distinct distoventral projection; carpo-propodus as long as merus; dactylus with well advanced sharp distoventral projection Carpo-propodus composed of 5 articles No information 1 mesial spinous seta near statocyst Lateral mar spinous setae (excluding apical ones) on posterior half; outer apical seta longer than inner one; apical cleft armed with denticles on entire mar 6–7 mm (male and female) Gulf of Manaar India Băcescu’s (1968) definition of the subgenus genus Heteromysis. Crustaceana, 77: 1353–1373. Heteromysis. ———, & Murano, M., 2002. Mysidacea (Crustacea) Distribution.—Known with reasonable from the south-eastern Andaman Sea with certainty from off south-eastern India and descriptions of six new species. Phuket Marine the Malacca Strait (Tattersall, 1922; present Biological Center, Special Publication, 23: 53– 108. study). Haworth, A.H., 1825. A new binary arrangement of the macrurous Crustacea. 1980

gin with 7 spinous Acknowledgements

gin Philosophical Magazine and Journal, 65: This study was carried out as a part 183–184. of cooperative ecological research of the Müller, H.-G., 1993. World Catalogue and Malaysian mangroves between the Japan Bibliography of the Recent Mysidacea.

H. australica Băcescu & Bruce, As long as its peduncle Merus with distinct distoventral projection; carpo-propodus as long as or longer than merus; dactylus well advanced, anteriorly rounded distoventral projection Carpo-propodus composed of 5 or 6 articles No sexual modification 1 mesial spinous seta near statocyst Lateral mar setae (excluding apical ones) on posterior half; outer apical seta shorter than inner one; apical cleft armed with denticles on entire mar 4.6–5.8 mm (male) Heron Island, north-eastern Australia Laboratory for Tropical Ecosystems Research International Research Center for Agricultural and Information Service, Wetzler, 491 pp. Sciences (JIRCAS) and Fisheries Research Murano, M., 1988. Heteromysids (Crustacea; Institute Malaysia (FRI). We express our Mysidacea) from northern Australia with special thanks to Dr. Masaaki Murano for description of six new species. The Beagle, making available interesting specimens Records of the Northern Territory Museum of collected from the Arabian Gulf. We are Arts and Sciences, 5: 27–50. grateful to Ms. Chee Phaik Ean, Mr. Ismail ———, 1998a. Mysidae (Crustacea: Mysidacea) gin with 6 spinous Awang Kechik, and Mr. Raja Mohammad collected from the western Arabian Gulf. Plankton Biology and Ecology, 45: 45—54. Atlantic Ocean Noordin Raja Omar, executive officers at the ———, 1998b. Further study on Australian time in the FRI, Penang, for their support of heteromysids (Crustacea: Mysidacea). The H. nouveli Brattegard, 1969 As long as its peduncle Merus without distoventral projection but angulated; carpo- propodus as long merus; dactylus with weakly advanced sub-triangular distoventral projection Carpo-propodus composed of 4 articles No information 1 mesial spinous seta near statocyst Lateral mar setae (excluding apical ones) on posterior half; outer apical seta shorter than inner one; apical cleft unarmed posteriorly 3.0 mm (immature female) Bahamas our research. We also thank Ms. Hiroko Sato Beagle, Records of the Museums and Art Tattersall (1922, 1927), Tattersall (1967), Brattegard (1969), and Băcescu & Bruce (1980). Tattersall (1922, 1927), Tattersall for some technical assistance. This study was Galleries of the Northern Territory, 14: 29–39. supported in part by a research grant from the Pillai, N.K., 1965. A review of the work on the Japan Society for the Promotion of Science shallow water Mysidacea of the Indian waters. (No. 22405030). Proceedings of Symposium on Crustacea. Marine Biological Association of India, 5: 1681–1728. Price, W.W. & Heard, R., 2011. Two new species Literature Cited of Heteromysis (Olivemysis) (Mysida, Mysidae, Anderson, G. 2010. Mysida Classification, January Heteromysinae) from the tropical northwest 20, 2010. http://peracarida.usm.edu/ Atlantic with diagnostics on the subgenus elson

Heteromysis proxima and its related species. proxima 1. Morphological comparison of Heteromysis Table Character items Antennal scale Third thoracic endopod Fourth to eighth thoracic endopods Pleopods u ropod T

Body size Occurrence Data sources: Sars (1877), MysidaTaxa.pdf. (accessed on 11 March 2011) Olivemysis Băcescu, 1968. Zootaxa, 2823: 32– FuRTHER RECORD OF HeterOMysis prOxiMa 17 16 ET AL. 17 Y. HANAMURA sexually dimorphic + no projection on ventral Băcescu, M., 1968. Heteromysini nouveaux des eaux thoracic sternites) to Olivemysis. However, Cubaines: trois espèces nouvelles de Heteromysis Bamber (2000) found in H. cyanogoleus et Heteromysoides spongicola n.g.n.sp. Revue Roumaine de Biologie, (Zoologie), 13: 221–237. that these setae show slight incongruence ———, 1983. New Heteromysini from the coral area in form between the sexes. Price & Heard near Heron Island (SE Queensland)–Australia. (2011) redefined the subgenus Olivemysis Revue Roumaine de Biologie, Biologie Animale, so as to have a combination of the following 28: 3–11. gin with 8-10 spinous features: distomedial part of third peduncular ———, & Bruce, A.J., 1980. New contributions to

, south-eastern water in the Bahamas and southern Florida. Part

H. pr dimorphic antennular setae remains unsettled. 1. Sarsia, 39: 17–106. gin with 10-12 Aside from the taxonomic problem Fukuoka, K., 2005. A new species of Heteromysis (India) remaining unsolved, our specimens of (Mysida, Mysidae) associated with sponges, Indo-Pacific Ocean H. proxima showed good agreement in from the uraga Channel, central Japan, with morphological characteristics with the notes on distribution and habitats within the As long as its peduncle Merus with distinct distoventral projection; carpo-propodus as long as merus; dactylus with well advanced sharp distoventral projection Carpo-propodus composed of 5 articles No information 1 mesial spinous seta near statocyst Lateral mar spinous setae (excluding apical ones) on posterior half; outer apical seta longer than inner one; apical cleft armed with denticles on entire mar 6–7 mm (male and female) Gulf of Manaar India Băcescu’s (1968) definition of the subgenus genus Heteromysis. Crustaceana, 77: 1353–1373. Heteromysis. ———, & Murano, M., 2002. Mysidacea (Crustacea) Distribution.—Known with reasonable from the south-eastern Andaman Sea with certainty from off south-eastern India and descriptions of six new species. Phuket Marine the Malacca Strait (Tattersall, 1922; present Biological Center, Special Publication, 23: 53– 108. study). Haworth, A.H., 1825. A new binary arrangement of the macrurous Crustacea. 1980 gin with 7 spinous Acknowledgements

Body size Occurrence Data sources: Sars (1877), MysidaTaxa.pdf. (accessed on 11 March 2011) Olivemysis Băcescu, 1968. Zootaxa, 2823: 32– CRUSTACEAN RESEARCH, NO. 41: 19–25, 2012 18 18 ET AL.

46. Y. HANAMURA In: Zoological results of the Cambridge Sars, G.O., 1877. Nye bidrag til Kundskaben om Expedition to the Suez Canal, 1924. Transactions A new species of cirolanid isopod, Eurydice nunomurai Middelhavets Invertebratfauna. I. Middelhavets of the Zoological Society of London, 22: 185– (Crustacea) from Izu–Ohshima Island, Sagami Sea, Pacific Mysider. Archiv for Mathematik og 198. Naturvidenskab, 2: 10–119, 36 pls. Watling, L., 1989. A classification system for coast of central Japan Sawamoto, S. & Fukuoka, K., 2005. Lists of mysid crustacean setae based on the homology concept, species and references for their identification pp. 15—26. In: Felgenhauer, B.E. et al. (eds.), in Southeast Asian waters. Bulletin of Institute Functional morphology of feeding and grooming of Oceanic Research and Development, Tokai in Crustacea. A.A. Balkema, Rotterdam, university, 26: 79–93. (in Japanese) Crustacean Issues 6. Nobuhiro Saito Smith, S.I., 1874. Crustacea. In; Verrill, A.E. & S.I. Smith, Report upon the invertebrate animals of Addresses: (YH) National Research Vineyard Sound and adjacent waters, with an Institute of Fisheries Science, Fuku-ura Abstract.—Eurydice nunomurai sp. nov. is beaches around Kagoshima Prefecture account of the physical features of the region. described from Izu–Ohshima Island, Sagami and Shijiki Bay, Nagasaki Prefecture; Report of Professor S.F. Baird, Commissioner of 2–12–4, Kanazawa-ku, Yokohama 236-8648, Japan; (RS) Freshwater Fisheries Research Sea, Pacific coast of central Japan from a single and E. saikaiensis Nunomura, 2008 from Fish and Fisheries, on the condition of the Sea. specimen collected from the body surface of the Shijiki Bay, Nagasaki Prefecture. Eurydice Fisheries of the South Coast of New England in Centre, Gelami Lemi, 71650 Titi, Jelebu, sea whip coral on subtidal sand bottoms. Eurydice species from Japan are occasionally found 1871–1872: 295–747, pls. 38. Negeri Sembilan, Malaysia; (AM) Fisheries nunomurai is most similar to E. orientalis Hansen, Tattersall, O.S., 1967. A survey of the genus abundantly on intertidal sandy beaches Research Institute, Kampung Acheh, 32000 1890 but distinguished by the longer antennule, Heteromysis (Crustacea: Mysidacea) with Sitiawan, Perak, Malaysia; (FMK) Fisheries and tidal sand flats (Bruce & Jones, 1981; descriptions of five new species from tropical large number of antennal flagellar articles, Nunomura, 1981). The new species, however, Research Institute, Batu Maung, 10960 complicated details of the serration and a large coastal waters of the Pacific and Indian Oceans, Penang, Malaysia. the first one which lives sub–tidally. with a key for the identification of the known number of setae of the pleotelson posterior species of the genus. Transactions of the E-mail: (YH) [email protected] margin, and having a large body size. Zoological Society of London, 31: 157–193. Material and Methods Tattersall, W.M., 1922. Indian Mysidacea. Records Received: 16 July 2012. The Eurydice specimen was picked of the Indian Museum, 24: 445–504. Accepted: 7 September 2012. Introduction ———, 1927. Report on the Crustacea Mysidacea. directly from body surface of a sea whip Use of SCUBA has made it possible to coral, at 35 m deep of “Aki–no–hama” point, directly collect small subtidal marine animals, northeastern coast of Izu–Ohshima Island, the biodiversity of which is still poorly on 5 March 2011, while SCUBA diving. understood, in subtidal habitats. Mr. Osamu Collected material was preserved in 70% Hoshino, Diving Service Chap, collected an ethanol, and transported to the laboratory. unidentified isopod specimen from a whip Observations were made under a binocular coral living on the subtidal sand bottom of microscope (Olympus X–II). Measurements northeastern coast of Izu–Ohshima Island, and drawings were made with the aid of Sagami Sea, Japan during his fieldwork, and an Olympus BHB–Tr microscope with an kindly made the specimen available to me for attached drawing tube. examination. Examination of the specimen Abbreviations used: BL, body length revealed that it is a new species of Eurydice of isopod, from the tip of the cephalon to Leach, 1815. the posterior margin of the pleotelson; PS, Eurydice is a large genus with 54 plumose seta/e; RS, robust seta/e; SS, slender named species (Schotte et al., 2012), and seta/e. Other measurements and terminology is well–known from shallow–water marine is essentially the same as that of cirolanid environments world wide (Jones & Naylor, isopods used by Keable (2006). The type 1967; Bruce, 1986; Brusca et al., 1995). specimen was deposited at the Kitakyushu Four species are known from Japan (Saito et Museum of Natural History and Human al., 2000; Nunomura, 2008; Shimomura & History, Kitakyushu, Japan, with a code of Nunomura, 2012): E. akiyamai Nunomura, KMNH IvR. 1981 from the estuary of Ichinomiya River, Chosei–mura, Chiba Prefecture to Nago, Okinawa Prefecture; E. longiantennata Taxonomic Account Nunomura & Ikehara, 1985 from Tobishima, Genus Eurydice Leach, 1815 Sakata, Yamagata Prefecture; E. nipponica Bruce & Jones, 1981 from Fukiage Beach, Eurydice nunomurai sp. nov.