Benthos Research, 46: 25-32, Mar., 1994

Occurrence of Brachyuran Larvae in the Surf Zone of Fukiage Beach, Kagoshima Prefecture, Japan

II. Families Leucosiidae, Xanthidae and

MOHAMAD ISMID, HIROSHI SUZUKI and TOSHIO SAISHO

Laboratory of Marine Biology, Faculty of Fisheries, Kagoshima University

Abstract

ISMID, MOHAMAD, HIROSHI SUZUKI and TOSHIO SAISHO (Laboratory of Marine Biology, Faculty of Fisheries, Kagoshima University). 1994. Occurrence of Brachyuran Larvae in the Surf Zone of Fukiage Beach, Kagoshima Prefecture, Japan. II. Families Leucosiidae, Xanthidae and Pinnotheridae. Benthos Research, 46: 25-32. This paper considers Brachyuran larvae of the families Leucosiidae, Xanthidae and Pinnotheridae collected from the surf zone of Fukiage beach, Kagoshima Prefecture. Descriptions are given of zoea I of sp., Xanthinae sp., Pilumnus sp., Pinnotheres pholadis, , and P. ? sinensis. Seasonal abundance of these zoeae throughout the 18-month study period showed high concentrations in the summer months (June to August) fol- lowed by a steady decline in autumn. The occurrence of only zoea I in the surf zone sug- gests that the larvae of these species are transient and not dependent on the surf zone for their development.

Introduction Leucosiidae, Xanthidae and Pinnotheridae which inhabit throughout coastal and shallow In our previous paper (ISMIDet al., 1994), de- waters. scriptions and occurrence of grapsid and ocypodid larvae in the surf zone of Fukiage Materials and Methods beach, Kagoshima Prefecture were presented. This paper deals with larvae of other families, The methods for larval collections, data analysis, and details of study area are given in Received September 28,1992: Accepted June 25, 1993 our previous paper (ISMID et al., 1994).

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Fig. 1 Ebalia sp., (SZ-K6), zoea I. (a) lateral view; (b) abdomen and telson; (c) antenna. All scale bars represent 0.1mm.

Descriptions previously described by AIKAWA(1937), RICE & WILLIAMSON(1977), SALMAN(1982), and QUINTANA All larval assignments are tentative and des- (1986). The absence of the carapace lateral and ignated with a letter and number following the dorsal spines are diagnostic of the sub-family prefix "SZ" (for surf zone). Ebaliinae, in which the characteristics were given as having either small carapace lateral spine, small lateral protuberances, or none at Leucosi idae all (RICE, 1980). On the basis of the absent cara- pace lateral spine, SZ-K6 zoea bears close re- Species SZ-K6, Ebalia sp. (Fig. 1) semblance with Ebalia nux A. MILNEEDWARDS

Zoea I described by RICE& WILLIAMSON(1977). Dimensions: T.T 0.46m, R.L 0.10mm. Carapace: Smooth and globular with small Xanthidae rostral spine. Dorsal and lateral spines absent. Abdomen: 5 somites plus telson. Somites 2 and 3 Species SZ-X7, Xanthinae sp. (Fig. 2) with small lateral knobs. Zoea I Telson: Triangular flat plate with slightly con- Dimensions: T.T 1.31mm, D.L 0.51mm, R.L 0.46mm cave posterior margin and 3 pairs of serrated se- Carapace: Dorsal and rostral spines well- tae. developed and prominent. Lateral spines small Antenna: Small unarmed bud. and reduced. The reduced antenna and triangular flat Abdomen: 5 somites plus telson. Somites 2 and 3

plate telson fairly identify this zoea as a with small lateral knobs. leucosiid. Although much of the larval morphol- Telson: Bifurcate. Telsonal furca well- ogy of the Leucosiidae is still very poorly developed and armed with 1 dorsal and 2 lateral known, several accounts of this family have been (1 very small) spines. 3 pairs of serrated setae

26 Brachyuran larvae in the surf zone (II)

Fig. 2 Xanthinae sp., (SZ-X7), zoea I. (a) leteral view; (b) abdomen and telson; (c) antenna . All scale bars represent 0.1mm.

Fig. 3 Pilumnus sp., (SZ-G8), zoea I. (a) lateral view; (b) abdomen and telson; (c) antenna . All scale bars represent 0.1mm. on inner arch of telson separated by a wide and reduced with 1 terminal seta. shallow median cleft. Based on the general description of the Antenna: Well-developed protopod with 2 rows Xanthidae provided by RICE (1980), SZ-X7 zoea of spinules on distal surface and slightly longer possesses a combined characters of reduced than carapace rostral spine. Exopod small and carapace lateral spine, rudimentary antennal

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exopod, and outer spines on the telsonal furca spinulose, armed with 1 dorsal and 2 lateral (1 that are identifiable with a xanthid. However, it very small) spines. A row of spinules on inner is difficult to establish its position within the border of furca. 3 pairs of serrated setae on in- family mainly due to the wide variety of larval ner arch of telson separated by a deep median forms that exist within the Xanthidae. TERADA notch. (1990) divided xanthid subfamilies into 8 Antenna: Protopod slightly longer than cara- groups, based on the morphology of the an- pace rostral spine, and with 2 rows of spinules tenna, and provided a description key to several on distal surface. Exopod slightly longer than species of Japanese xanthid zoea. According to protopod, with spinules and 1 small seta this grouping SZ-X7 zoea is a Xanthinae. The medially. form of the carapace spines, antenna, and telson This zoea is clearly a xanthid, because the bears resemblance to those of Leptodius characteristics of the carapace spines, antenna exaratus H. MILNE EDWARDSand Cycloxanthops and telson match with the general features of the truncatus DE HAAN as described by SABA (1976) Xanthidae provided by RICE (1980). According and SUZUKI (1979), respectively. to the larval characteristics reported by TERADA (1990), it is possible to place SZ-G8 zoea within Species SZ-G8, Pilumnus sp. (Fig. 3) the Pilumnus. Several species of this genus have Zoea I been described by SANDIFER(1974), BOOKHOUT& Dimensions: T.T 1.14mm, D.L 0.44mm, R.L 0.35mm COSTLOW(1979), SALMAN (1982), and TERADA Carapace: Dorsal, rostral and lateral spines (1990). Having single seta on the antennal present. Dorsal and rostral spines well- exopod,this zoea differs from Pilumnus developed and prominent. vespertilio FABRICIUSand P. scabriusculus ADAM Abdomen: 5 somites plus telson. Somites 2 and 3 & WHITE, which have at least 2 setae on the with lateral knobs. exopod as described by TERADA (1990). Other Telson: Bifurcate. Telsonal furca long and zoea of this genus possessing a single seta on the

Fig. 4 Pinnotheres ?pholadis, (SZ-F9), zoea I. (a) lateral view; (b) Abdomen and telson; (c) an- tenna. All scale bars represent 0.1mm.

28 Brachyuran larvae in the surf zone (II)

antennal exopod are Pilumnus dasypodus SZ-F9. However, to date, there have been no re-

KINGSLEYand P. inermis A. MILNE EDWARDS & port of P. pisum from Japan; thus,the zoea is BOUVIERdescribed by SANDIFER(1974) and RICE & assigned to P. pholadis. Albeit some minor WILLIAMSON(1977), respectively. variation in the length of the carapace, there is very little other difference between SZ-F9 zoea Pinnotheridae and P. pholadis described by MURAOKA (1979).

Species SZ-F9, Pinnotheres ?pholadis DE HAAN, Species SZ-T10, Pinnotheres ?sinensis SHEN 1932 1935 (Fig. 4) (Fig. 5) Zoea I Zoea I Dimensions: T.T 0.40mm, R.L 0.14mm. Dimensions: T.T 0.35mm. Carapace: Rostral and lateral spines present Carapace: Smooth and globular. Dorsal, Lateral spine with slight downward curvature. rostral and lateral spines absent. Abdomen: 5 broad somites plus telson. Somite: Abdomen: 5 broad somites plus telson. Somites 2 and 3 with small lateral knobs. 2 and 3 with small lateral knobs. Telson: Trilobed flat plate extended from a Telson: Trilobed flat plate extended from a broad abdominal somite. 3 pairs of serrated se- broad abdominal somite. 3 pairs of serrated se- tae separated by a median lobe. Postero-lateral tae separated by a median lobe. Postero-lateral margin with 2 unequal small spines. margin with 2 small unequal spines. Antenna: Reduced to a small bud. Antenna: Reduced to a small bud with 1 small This zoea bears strong resemblance with medial seta. Pinnotheres pholadis described by MURAOKA This zoea resembles Pinnotheres ?pholadis (1979). The morphological features of (SZ-F9) in the telson but differs from it in lack- Pinnotheres pisum PENNANTdescribed by RICE ing carapace spines. The trilobed telson and re- (1975) also carries similar characteristics with duced antenna resemble strongly those of

Fig. 5 Pinnotheres ?sinensis, (SZ-T10), zoea I. (a) lateral view; (b) abdomen and telson; (c) an- tenna. All scale bars represent 0.1mm.

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Pinnotheres boniensis STIMPSON described by I, and appeared common in the surf zone dur- MURAOKA (1977) and Pinnotheres sinensis de- ing the summer months in both years. Some scribed by MURAOKA& KONISHI(1977). However, zoea also appeared during the winter; but they P. boniensis was described as having several were inconsistent, being recorded only in small distinct protuberances on the carapace, which number. differs from the smooth globular carapace of SZ Zoea of Ebalia sp. (SZ-K6) appeared in the -T10 zoea. Apparently the characteristics of the surf zone with maximum numbers in June in carapace are more closer to P. sinensis serve as both years at 30.0 larvae/m3 in 1990 and 25.8 lar- the basis for the assignment of SZ-T10 zoea. vae/m3 in 1991 (Fig. 6a). The earliest appear- Nevertheless, out of 9 Pinnotheres species known ance of this zoea in 1991 was recorded in small to occur in Japanese waters (SAKAI, 1976), only number of 10.0 larvae/m3 in May and continued 3 has so far been adequately described, includ- till August. However, the results of 1990 show ing P. pholadis reported by MURAOKA(1979). the zoea to have a prolonged appearance which lasted till October. Seasonal Abundance Zoea of Xanthinae sp. (SZ-X7) appeared consistently from early summer to mid-autumn All three families were represented by zoea with maximum number of 55.0 larvae/m3 in

Fig. 6 Seasonal abundance of zoea I. (a) Ebalia sp., (SZ-K6); (b) Xanthinae sp., (SZ-X7); (c) Pilumnus sp., (SZ-G8); (d) Pinnotheres ?pholadis, (SZ-F9); (e) Pinnotheres ?sinensis, (SZ- T10).

30 Brachyuran larvae in the surf zone (II)

September of 1990 and 29.2 larvae/m3 in August STRATHMAN (1982) and MCCONAUGHA(1988) re- of 1991 (Fig. 6b). This zoea was also recorded in ported two distribution patterns of larvae which December of 1990 at 5.0 larvae/m3. However, included retention within the estuary and disper- this winter appearance was not repeated in the sal away from the estuary. The absence of lar- following year. vae following zoea I in Leucosiidae, Xanthidae Zoea of Pilumnus sp. (SZ-G8) appeared in and Pinnotheridae is considered to be result of small number compared to the other collected being dispersed away from the surf zone. zoea (Fig. 6c). The high concentration month Accordingly, the larvae of these families could and maximum number of appearance varied not be dependent on the surf zone during their throughout the 2-year study. The maximum development. number of 37.5 larvae/m3 and 15.0 larvae/m3 were recorded in September of 1990 and in July Acknowledgements of 1991, respectively. Zoea of Pinnotheres ?pholadis (SZ-F9) was The authors express their sincere thanks to relatively abundant in the surf zone, with the Dr. K. Konishi of the National Research maximum number of 87.5 larvae/m3 in August Institute of Aquaculture, Mie Prefecture for his of 1990 and 85.0 larvae/m3 in August of 1991 critical reading and suggestions in the prepara- (Fig. 6d). The earliest appearance of this zoea in tion of this manuscript. Part of this study was 1991 was recorded in April, followed by a grad- supported by a grant-in-aid from the Research ual increase in the summer till reaching its peak Institute of Marine Invertebrate. in August. Although no appearance was re- corded after August in 1991, the results of 1990 References show this zoea to be present in the surf zone till November. AIKAWA, H., 1937. Further notes on brachyuran Zoea of Pinnotheres ?sinensis (SZ-T10) larvae. Rec. Oceanogr. Whs. Japan, 9: 87- showed the maximum number in August in both 162. years at 50.0 larvae/m3 in 1990 and 36.6 larvae BOOKHOUT,C. G. and J. D. COSTLOWJr., 1979. /m3 in 1991 (Fig. 6e). This zoea was present in Larval development of Pilumnus dasypodus the surf zone especially during the summer and and Pilumnus sayi reared in the laboratory continued till autumn. No zoea was found in the (, Brachyura, Xanthidae). winter months in both years. Crustaceana, Suppl., 5:1-16. ISMID, M., H. SUZUKI and T. SAISHO, 1994. Discussion Occurrence of Brachyuran Larvae in the Surf Zone of Fukiage Beach, Kagoshima Our previous study (ISMID et al., 1994) re- Prefecture, Japan I . Families Grapsidae vealed the occurrence of consecutive zoeal stages and Ocypodidae. Benthos Res., 46:11-24. of Scopimera ?globosa and Ilyoplax ?pusilla in MCCONAUGHA, J. R., 1988. Export and reinvasion the surf zone. SUZUKI& KIKUCHI (1990) reported of larvae as regulators of estuarine decapod distribution of larvae of Scopimera globosa to populations. Am. Fish. Soc. Symp., 3: 90- be near their adult habitat. In contrast to the lar- 103. val distribution pattern of the two ocypodid spe- MURAOKA, K., 1977. Larval development of cies mentioned above, not all of the developmen- Pinnotheres boniensis STIMPSON reared in tal stages of Leucosiidae, Xanthidae and the laboratory (Crustacea, Brachyura, Pinnotheridae were present in the surf zone Pinnotheridae). Proc. Jap. Soc. Syst. Zool., throughout the study. SANDIFER (1975), 13: 72-80.

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MURAOKA, K., 1979. On the first stage of in recruitment to populations of adult Pinnotheres pholadis DE HAAN (Crustacea, decapod in the York River estu- Brachyura, Pinnotheridae). Res. Crust., 9: ary and adjacent lower Chesapeake Bay, 52-56. (In Japanese with English abstract.) Virginia. Est. Coast Mar. Sci., 3: 269-279. MURAOKA,K. and K. KONISHI, 1977. Note on the STRATHMAN, R. R., 1982. Selection for retention first zoea of Pinnotheres sinensis SHEN or export of larvae in estuaries. Estuarine (Crustacea, Brachyura, Pinnotheridae) Comparisons. Academic Press, Inc., pp. 521 from Tokyo Bay. Res. Crust., 8: 46-50. -536. QUINTANA, R., 1986. On the early post-larval SUZUKI, H., 1979. Studies on the zoea larvae of stages of some leucosiid from Tosa two xanthid crabs, Paramedaeus noelensis Bay, Japan (Decapoda, Brachyura, (WARD) and Cycloxanthops truncatus (DE Leucosiidae). J. Fac. Sci. Hokkaido Univ. HAAN) (Crustacea, Brachyura, Xanthidae). Ser. VI, Zool., 24: 227-266. Jap. Soc. Syst. Zool., 16: 35-52. RICE, A. L., 1975. The first zoeal stages of Cancer SUZUKI, H, and T. KIKUCHI, 1990. Spatial distri- pagurus L., Pinnotheres pisum PENNANT bution and recruitment of pelagic larvae of and Macrophthalmus depressus RUPPELL sand bubbler , Scopimera globosa. La (Crustacea, Decapoda, Brachyura). Bull. mer, 28:172-179. Br. Mus. Nat. Hist. (Zool.), 28: 237-247. TERADA, M., 1990. Zoeal development of five spe- RICE, A. L., 1980. Crab zoeal morphology and cies of the xanthid crabs reared in the labo- its bearing on the classification of the ratory. Res. Crust., 18: 23-47. (In Japanese Brachyura. Trans. Zool. Soc. Lond., 35: 271- with English abstract.) 424. RICE, A.L, and D. I. WILLIAMSON, 1977. MoHAMAD ISMID and HIROSHI SUZUKI Planktonic stages of Crustacea Laboratory of Marine Biology, Faculty of from Atlantic Seamounts. Fisheries, Kagoshima University, Kago- "Meteor" Forsch -Ergebn ., 26: 28-64. shima City 890, Japan. SAGA, M., 1976. Studies on the larvae of crabs of the family Xanthidae. I. On the larval devel- 鹿 児 島 県 吹 上 浜 の 砕 波 帯 にお け る短 尾 類 幼 生 の出 現 opment of Leptodius exaratus H. MILNE (II)コ ブ シ ガ ニ科,オ ウ ギ ガ ニ科 お よ び EDWARDS. Res. Crust., 7: 57-67. カ ク レガニ 科 SAKAI, T., 1976. Crabs of Japan and the adjacent seas. Kodansha, Tokyo, 773pp. モ ハ マ ド イ ス ミ ド ・鈴 木 廣 志 ・税 所 俊 郎 SALMAN,D. S., 1982. Larval development of the crab Pilumnus hirtellus (L.) reared in the 本 研 究 は砕 波 帯 に お け る短尾 類 幼 生 の 出 現 を 明 らか laboratory (Decapoda, Brachyura, に し,短 尾 類 幼 生 の生 態 に お け る砕 波 帯 の役 割 を 検 討 Xanthidae). Crustaceana, 42:113-126. す るた め に 行 な わ れ た.コ ブシ ガ ニ科,オ ウ ギ ガ ニ 科 SALMAN,D. S., 1982. Observations on the larvae お よ び カ ク レガ ニ科 に 属 す る種 類 の う ちEbalia sp., of North European crabs of the genus Ebalia Xanthinae sp.,Pilumnus sp.,Pinnotheres (Brachyura, Leucosiidae). Crustaceana, 42: ?pholadisお よ びP.?sinensisの 第1期 ゾ エ ア が 採 集 256-269. さ れ,そ れ らの形 態 を記 載 した.こ れ ら の ゾ エ ア幼 生 SANDIFER,P. A., 1974. Larval stages of the crab は主 に夏 期 の6月-8月 に 多 く出 現 す る傾 向 が み られ Pilumnus dasypodus KINGSLEY (Crustacea, た.今 回 採 集 され た5種 の短 尾 類 幼 生 で は第1期 ゾ エ Brachyura, Xanthidae) obtained in the ア の み が砕 波 帯 に 出現 し,こ れ らの種 で は,砕 波 帯 は laboratory. Bull. Mar. Sci., 24: 378-391. 孵 化 後 一 時 的 に生 息 す る通 過 地 域 と考 え られ る. SANDIFER, P. A., 1975. The role of pelagic larvae

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