Distribution of Phyllosoma Larvae (Crustacea: Decapoda: Palinuridae, Scyllaridae and Synaxidae) in the Western North Pacific

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1 Journal of Oceanography, Vol. 60, pp. 963 to 976, 2004 Distribution of Phyllosoma Larvae (Crustacea: Decapoda: Palinuridae, Scyllaridae and Synaxidae) in the Western North Pacific NARIAKI INOUE, HIDEKI MINAMI and HIDEO SEKIGUCHI* Faculty of Bioresource, Mie University, 1515 Kamihama-cho, Tsu, Mie , Japan (Received 17 May 2003; in revised form 26 January 2004; accepted 2 February 2004) Phyllosoma larvae were identified and their distribution was examined, based on the larvae in ichthyoplankton samples collected in the Japanese Eel Expedition to the spawning area of A. japonica in the western North Pacific from August 30 to September 13, 1986 (Leg. 1), and from September 22 to 25, 1986 (Leg. 2), on board the R/V Hakuho-maru. Phyllosoma larvae belonged to 3 families (Scyllaridae, Palinuridae and Synaxidae) representing 6 genera and 14 species. A total of 336 palinurid and synaxid phyllosoma larvae were collected, of which 233 larvae (about 70%) were identical with P. longipes s. l, while a total of 362 scyllarid phyllosoma larvae were collected, of which 274 larvae (about 76%) were identical with S. cultrifer. Phyllosoma larvae of P. longipes s. l and S. cultrifer showed a similar distribution to each other. The larvae were abundant in the water close to Mariana Islands, although late stage examples were abundant in waters of Luzon and eastern Taiwan. Distributions of these larvae may be related intimately with the North Equatorial Current existing along 15 N. The North Equatorial Current approaches the eastern coast of the Philippines and then separates into two branches of northward and southward flows. The northward flow contributes to generating the Kuroshio Current while the southward flow goes to generate the Mindanao Current. Judging from distributions of phyllosoma larvae in the present study, it is assumed that the larvae of the above two species may have been released in Mariana Islands and transported westward from there through the North Equatorial Current. These larvae may then be transported to eastern Taiwanese waters. Keywords: Phyllosoma, spatial distributions, Mariana Islands. 1. Introduction Phyllosoma larvae are confined to palinurid, scyllarid and synaxid lobsters, having a transparent body with a unique shape. Palinurid and scyllarid phyllosoma larvae metamorphose into puerulus and nisto larvae, respectively, and these larvae settle on the sea bottom where their adults dwell (Cobb and Phillips, 1980). Palinurids and scyllarids have planktonic life for over 6 months (Booth and Phillips, 1994) and 2 or 3 months (Robertson, 1968; Ito and Lucas, 1990), respectively, while the planktonic life span of synaxids is not certain. However, information is limited on larval recruitment processes, which is vital for clarifying the population dynamics of most palinurid and scyllarid lobsters, including synaxid ones, throughout the world (Sekiguchi, 1986, 1997; Inoue and Sekiguchi, 2001), except for the work * Corresponding author. sekiguch@bio.mie-u.ac.jp Copyright The Oceanographic Society of Japan. Phillips and his colleagues (see Cobb, 1997) reported on Panulirus cygnus in western Australian waters. Moreover, there is little information on the species composition and spatial distribution of phyllosoma larvae in the western North Pacific, except for the paper by Minami et al. (2001). The present study has two objectives: (1) to examine species composition of phyllosoma larvae in the western North Pacific, and (2) to discuss recruitment processes of phyllosoma larvae collected in the western North Pacific. As in Minami et al. (2001), ichthyoplankton samples dealt with in the present study were originally collected for leptocephalus larvae in the western North Pacific. Leptocephalus larvae of the Japanese eel Anguilla japonica, the main spawning area of which may be located in Mariana waters of the western North Pacific, are transported through the Subtropical Gyre into Japan and its neighboring waters, where they metamorphose into glass eels (Tsukamoto and Umezawa, 1990). Because both leptocephalus and phyllosoma larvae have a long planktonic life, their larval recruitment 963

2 Fig. 1. Sampling area and ocean current system in the western North Pacific. Shadow area indicates sampling area (modified from Minami et al., 2001). processes, e.g. distribution pattern and mechanisms of transport, should be similar (Sekiguchi, 1994). 2. Materials and Methods Ichthyoplankton sampling was undertaken from August 30 to September 13, 1986 (Leg. 1), and from September 22 to 25, 1986 (Leg. 2), on board the R/V Hakuhomaru (Figs. 1 and 2). Samples were collected within an area from N to N and from E to E, east of Luzon Islands of the Philippines or west of Mariana Islands (Figs. 1 and 2). The North Equatorial Current and Subtropical Countercurrent exist along 15 N and 20 N. The former current approaches the eastern coast of the Philippines and then separates into two branches, viz., northward and southward flows. The northward and southward flows contribute to generating the Kuroshio Current and the Mindanao Current, respectively (Fig. 1). Using a 3 m Isaacs-Kidd Midwater Trawl (IKMT) with 0.5 mm mesh-openings and 2 m ORI net with 0.66 mm mesh-openings, ichthyoplankton samples were collected at Sts and St. A (Leg. 1, Fig. 2, Table 1). IKMT was towed obliquely from 500 m depth to the surface once at each station, with a towing speed of 4 5 knots. The ORI net was towed at the surface twice at each station, each time for 30 min with a ship speed of knot. IKMT and Hexagon net (10.4 m length, 1.0 mm mesh-openings) were then towed obliquely from 150 m depth to the surface at St. B (Fig. 2, Table 1). At St. C (Leg. 2, Fig. 2), ichthyoplankton samples being collected Fig. 2. Map of the study area and location of sampling stations. Solid circles and open squares: sampling stations of leg 1 and leg 2, respectively; solid and dotted lines: cruise courses of leg 1 and leg 2, respectively (from Minami et al., 2001). at 7 discrete depths (10, 20, 50, 80, 130, 200 and 400 m deep). IKMT was towed horizontally for 40 min at each depth with a towing speed of 4 5 knots and then towed obliquely from each depth to the surface. Minami et al. (2001) has already reported vertical distributions of phyllosoma larvae using samples collected by these IKMT samplings at St. C. In addition, ORI net was towed horizontally twice at the surface for 30 min with a ship speed of knot while Hexagon net was towed obliquely from 150 m depth to the surface twice with a towing speed of 4 5 knots (Table 1). Since the individual number of phyllosoma larvae collected by each net haul was very low, we examined spatial distributions of phyllosoma larvae by pooling the data on the larvae according to sampling station. Ichthyoplankton samples were fixed immediately in 10% buffered formalin seawater. All specimens of phyllosoma larvae were sorted in the laboratory. Late stage phyllosoma larvae were identified to the species level according to Sekiguchi and Inoue (2002), except for Justitia and Palinurellus, while early to middle stages of the larvae were identified based on their morphological similarity to the late stage ones. Justitia phyllosoma larvae were identified to the species level according to Johnson (1969), Johnson and Robertson (1970) and Robertson (1969a), while Palinurellus specimens were identified according to Sekiguchi and Saisho (1994) and 964 N. Inoue et al.

3 Table 1. Stations, dates, and sampling gear of ichthyoplankton sampling. Sampling station Sampling gear Sampling period Leg 1 Sts IKMT, ORI 30 Aug. 12 Sep. St. A IKMT, ORI 3 Sep. St. B IKMT, Hexagon net Sep. Leg 2 St. C IKMT, ORI, Hexagon net Sep. St. D IKMT 24 Sep. St. E IKMT Sep. Michel (1970). Stages of Panulirus and Scyllarus larvae were determined according to Braine et al. (1979) and Phillips and McWilliam (1986) while those of Scyllarides specimens were identified according to Robertson (1969b). It is difficult to determine stages of Justitia, Palinurellus and Parribacus samples. Accordingly, stages of Justitia and Palinurellus were tentatively determined according to Braine et al. (1979) while stages of Parribacus were identified according to Robertson (1969b). Holthuis (2002) re-examined the Indo-Pacific species of the genus Scyllarus, so that 13 new genera were established, besides the Scyllarus. However, we use the traditional genus name Scyllarus in this paper because Holthuis s revision has not gained consensus among lobster taxonomists. All figures were drawn with the aid of a drawing tube. 3. Results and Discussion 3.1 Phyllosoma larvae collected in the present study A total of 699 phyllosoma larvae were collected in the present study (Table 2). These phyllosoma larvae belonged to the 3 families (Palinuridae, Scyllaridae and Synaxidae) representing 6 genera and 14 species (Table 2). Of the family Palinuridae, 6 species of 2 genera were identified (Table 2): 4 species of the genus Panulirus (P. longipes s. l, P. ornatus, P. penicillatus and P. versicolor), and 2 species of the genus Justitia (J. japonica and J. longimanus). Of the family Scyllaridae, 7 species of 3 genera were identified (Table 2): 5 species of the genus Scyllarus (S. cultrifer, S. martensii, S. rugosus, Scyllarus sp. c and Scyllarus sp. d), 1 species of the genus Parribacus (Parribacus sp.), and 1 species of the Scyllarides (Scyllarides sp.). Of the family Synaxidae, 1 species of the genus Palinurellus (Pal. wieneckii) was identified (Table 2). A total of 336 palinurid and synaxid phyllosoma larvae were collected, of which 233 larvae (about 70%) were identical with P. longipes s. l (Table 2) while a total of 362 scyllarid phyllosoma larvae were collected, of which 274 larvae (about 76%) were identical with S. cultrifer (Table 2). Of the collected phyllosoma larvae in the present study, those of S. cultrifer and P. longipes s. l were most abundant, that is, the same as reported by Minami et al. (2001). Adults with 42 species have been reported to date in the present study area and its neighboring waters (Table 3), Panulirus and Scyllarus species being particularly abundant. These facts are also consistent with the mentioned above results of phyllosoma larvae. Adults of the Panulirus with 8 species (P. homarus, P. japonicus, P. longipes s. l, P. ornatus, P. penicillatus, P. polyphagus, P. vesicolor and P. stimpsoni) were reported in Taiwanese waters; particularly 3 species (P. japonicus, P. longipes s. l and P. stimpsoni) were of economic importance in Taiwan (Chan and Yu, 1993). P. japonicus was confined to Japanese and northern Taiwanese waters, although it was not reported from the Ryukyu Archipelago (including Okinawa waters), Mariana waters, where it was replaced with P. longipes s. l (Sekiguchi, 1995; Sekiguchi and Inoue, 2002), and southern Taiwanese waters, where it was replaced with P. homarus (Chan and Yu, 1993). Panulirus with 5 species (P. homarus, P. longipes s. l, P. ornatus, P. penicillatus, and P. vesicolor) was reported in Okinawa waters, particularly P. longipes s. l is abundant (Sekiguchi and Inoue, 2002). P. stimpsoni was abundant in southern Chinese waters and western Taiwanese waters while it was rare in eastern Taiwanese waters (Chan and Yu, 1993). Panulirus with 6 species (P. homarus, P. longipes s. l, P. ornatus, P. penicillatus, P. polyphagus and P. vesicolor) was reported in Luzon waters (Holthuis, 1991). In the eastern part of the present study area (Mariana, Caroline and Marshall Islands), Panulirus with 4 species (P. longipes s. l, P. ornatus, P. penicillatus and P. vesicolor) was reported by George (1972). Thus, Panulirus with 8 species (P. homarus, P. japonicus, P. longipes s. l, P. ornatus, P. penicillatus, P. polyphagus, P. vesicolor and P. stimpsoni) was found in the present study area and its neighboring waters (Table 3). According to Sekiguchi (1995), P. femoristriga and P. longipes bispinosus were reported in Okinawa waters, particularly P. longipes bispinosus was abundant. P. longipes longipes and P. longipes bispinosus were also reported in Taiwanese waters where P. longipes longipes Distribution of Phyllosoma Larvae in Western North Pacific 965

4 Table 2. Species list of phyllosoma larvae collected in the present study. Sampling stations Leg. 1 (Sts. 1 20) Species Panulirus longipes s. l* P. ornatus P. penicillatus P. versicolor Panulirus spp.** Justitia japonica J. longimanus Scyllarus cultrifer S. martensii S. rugosus Scyllarus sp. c Scyllarus sp. d Parribacas sp Scyllarides sp Pal. wieneckii Total N. Inoue et al.

5 Sampling stations Leg. 1 (Sts , Sts. A and B) Leg. 2 (Sts. C E) Species A B C D E Total Panulirus longipes s.l.* P. ornatus P. penicillatus P. versicolor Panulirus spp.** Justitia japonica J. longimanus Scyllarus cultrifer S. martensii S. rugosus Scyllarus sp. c Scyllarus sp. c Parribacas sp Scyllarides sp Pal. wieneckii Total Numerals in the table: number of collected phyllosoma larvae. *To include the following 3 species: P. longipes longipes, P. longipes bispinosus and P. femostriga. **Not identified to the species level because of damage to bodies. Distribution of Phyllosoma Larvae in Western North Pacific 967

6 Table 3. List of lobster species belonging to the three families (Palinuridae, Scyllaridae and Synaxidae) reported to date in the present study area. Palinuridae Scyllaridae Synaxidae Justitia Ibacus Palinurellus 1 J. chani 16 I. ciliatus 42 Pal. wieneckii 2 J. japonica 17 I. norvemdentatus 3 J. longimanus 18 I. pubescens Linuparus Parribacus 4 L. sordidus 19 Par. antarcticus 5 L. trigonus 20 Par. japonicus Palinustus Scyllarides 6 Pa. unicornutus 21 Sc. haanii 7 Pa. waguensis 22 Sc. squammosus Panulirus Scyllarus 8 P. homarus homarus 23 S. aesopius (Eduarctus aesopius) 9 P. japonicus 24 S. aurora (Galearctus aurora) 10 P. longipes s. l* 25 S. bicuspidatus (Grenarctus bicuspidatus) 11 P. ornatus 26 S. batei (Scammarctus batei) 12 P. penicillatus 27 S. bertholdii (Remiarctus bertholodii) 13 P. polyphagus 28 S. brevicornis (Petrarctus brevicornis) 14 P. versicolor 29 S. cultrifer (Chelarctus cultrifer) 15 P. stimpsoni 30 S. formosanus (Bathyarctus formosanus) 31 S. gibberosus (Gibbularctus gibberosus) 32 S. kitanoviriosus (Galearctus kitanoviriosus) 33 S. longidactylus (Biarclus vitiensis) 34 S. martensii (Eduarctus martensii) 35 S. rubens (Bathyarctus rubens) 36 S. rugosus (Petrarctus rugosus) 37 S. sordidus (Biarctus sordidus) 38 S. timidus (Galearctus timidus) 39 Bathyarctus chani** 40 Petrarctus veliger** Thenus 41 T. orientalis This list is based on Chan and Yu (1986, 1993), Holthuis (1991, 2002) and Sekiguchi and Inoue (2002). Parenthetic names were new genera and species names established by Holthuis (2002). *To include the following 3 species: P. longipes longipes, P. longipes bispinosus and P. femoristriga. **New species reported by Holthuis (2002). was abundant (Sekiguchi, 1995). P. longipes longipes was reported in Luzon and Mariana waters (Sekiguchi, 1995). Thus, P. longipes bispinosus, P. longipes longipes and P. femoristriga were distributed in the present study area and its neighboring waters. It is difficult to separate phyllosoma larvae of these 3 species/subspecies (Sekiguchi and Inoue, 2002). In the present study, phyllosoma larvae of P. longipes s. l were dominant in the water close to Mariana Islands (Sts. 16, C and E), particularly a total of 111 larvae were collected at St. C (Fig. 3). These larvae may have been transported from Mariana Islands where P. longipes longipes adults are common, so these larvae may be identical with P. longipes longipes. 968 N. Inoue et al.

7 Fig. 3. Abundance and distributions of phyllosoma larvae of Panulirus longipes s. l as related with frequency distribution of developmental stages. Solid circles: stations sampled by IKMT and ORI nets; solid square: stations sampled by IKMT, ORI and Hexagon nets; numerals with open triangles: individual number of larvae collected; numerals in vertical and horizontal lines of graphs: individual number collected and development stage, respectively. Fig. 4. Abundance and distributions of phyllosoma larvae of Scyllarus cultrifer as related with frequency distribution of developmental stages. Solid circles: stations sampled by IKMT and ORI nets; solid square: stations sampled by IKMT, ORI and Hexagon nets; numerals with open triangles: individual number of the collected larvae; numerals in vertical and horizontal lines of graphs: individual number collected and development stage, respectively. According to Chan and Yu (1986, 1993), adults of the Scyllarus with 9 species (S. batei, S. bertholdii, S. brevicornis, S. cultrifer, S. formosanus, S. kitanoviriosus, S. longidactylus, S. martensii and S. rugosus) were reported in Taiwanese waters (Table 3), particularly S. martensii was abundant. Then, S. brevicornis and S. longidactylus were occasionally collected while S. cultrifer and S. kitanoviriosus were rare (Chan and Yu, 1986, 1993). According to Sekiguchi and Inoue (2002), adults of the Scyllarus with 8 species (S. aurora, S. bicuspidatus, S. brevicornis, S. cultrifer, S. kitanoviriosus, S. longidactylus, S. martensii and S. rugosus) were reported in Japanese waters, S. brevicornis and S. longidactylus were occasionally collected while S. aurora was rare (Sekiguchi and Inoue, 2002). At least, adults of the Scyllarus with 10 species (S. aesopius, S. batei, S. bertholdii, S. cultrifer, S. gibberosus, S. martensii, S. rubens, S. rugosus, S. sordidus and timidus) were reported in Luzon and Mariana waters (Holthuis, 1991). Holthuis (2002) reported other two new species (Bathyarctus chani and Petrarctus veliger) in Luzon and Mariana waters. Thus, adults with 18 species were found in the present study area and its neighboring waters (Table 3). However, details of the abundance and regional distribution of adult Scyllarus species are not known in the present study area and its neighboring waters, except for reports by Holthuis (1991, 2002) and Chan and Yu (1986, 1993). Phyllosoma larvae of S. cultrifer were also dominant in the water close to Mariana waters (Sts. C and E), particularly a total of 119 larvae were collected at St. C (Fig. 4). As for P. longipes s. l larvae mentioned above, these S. cultrifer larvae may have been transported from the Mariana Islands. Based on the previous studies dealing with spatial distributions of Scyllarus and Panulirus phyllosoma larvae, it is safe to say that phyllosoma and nisto larvae of Scyllarus may be retained within the coastal waters while Panulirus phyllosoma larvae are flushed out from the coastal waters to offshore/oceanic waters (Sekiguchi and Inoue, 2002). However, in the present study, palinurid and scyllarid phyllosoma larvae were represented by a total of 336 and 362 individuals, respectively, of which P. longipes s. l and S. cultrifer were present with the same individuals of phyllosoma larvae (Table 2). This is also true for each station (Fig. 5). This may be due to the fact that the present study area is engulfed by Philippines, Distribution of Phyllosoma Larvae in Western North Pacific 969

8 Fig. 5. Relative abundance of collected palinurid and scyllarid phyllosoma larvae. Small solid circles: sampling stations; numericals with circular graphs: total individual number of palinurid and scyllarid phyllosoma larvae collected; black and white regions of graphs: relative abundance of palinurid and scyllarid phyllosoma larvae, respectively. Taiwan, Okinawa and Mariana Islands where P. longipes s. l and S. cultrifer larvae may have been transported from the Mariana Islands. 3.2 Spatial distributions of phyllosoma larvae Phyllosoma larvae of P. longipes s. l and S. cultrifer were dominant in the present study (Table 2). The larvae of P. longipes s. l were found in a wide area, particularly abundant in western Mariana waters (Sts. 16, C and E), southern Okinawa (St. 22) and eastern Taiwanese waters (St. 13) (Fig. 3). Of these larvae, stage VII examples were abundant at St. C located within western Mariana waters where a few individuals at stage IX (final stage) were collected. Stage VI and VII larvae were collected at St. 22 where those at with stage IX (final stage) were not collected, while specimens at stage VI and VII were collected at St. E. In addition, stage IX (final stage) larvae were collected at St. B located within eastern Taiwanese waters. Similar to the case of P. longipes s. l, larvae of S. cultrifer were found in a wide area, being particularly abundant in western Mariana waters (Sts. C and E), southern and southeastern Okinawa waters (Sts. 2 and 22) and eastern Taiwanese waters (St. B) (Fig. 4). Middle stage (stage IV to VI) larvae of S. cultrifer were abundant at St. C where a few individuals with late and final stages (stages VII and VIII) were collected. This was true for Sts. 2 and 22 located within eastern and southern Okinawa waters, respectively. However, at St. E located within the water closer to Luzon Islands than St. C, stage VII larvae as well as stages V and VI specimens were collected. In addition, stage VIII (final stage) larvae were also collected at St. B where a few individuals at middle stage (stage IV to VI) were collected. Phyllosoma larvae of P. longipes s. l and S. cultrifer showed a similar distribution to each other as follows: the larvae were abundant in the water close to Mariana Islands, although late stage specimens were abundant in Luzon and eastern Taiwanese waters. The spatial distributions of these larvae may be related intimately with the North Equatorial Current existing along 15 N. The North Equatorial Current approaches the eastern coast of the Philippines and then separates into two branches flowing northward and southward. The northward flow contributes to generating the Kuroshio Current while the southward flow goes to generate the Mindanao Current (Fig. 1). Judging from this, it is assumed that the larvae of the above two species collected in the present study may have been released in the waters close to Mariana Islands and transported westward from there via the North Equatorial Current. These larvae may be transported to Taiwanese waters. A similar transport route was assumed for leptocephalus larvae of Japanese eel (A. japonica), the spawning ground of which is located within Mariana waters (e.g. Tsukamoto and Umezawa, 1990): small leptocephalus larvae were caught in the water close to Mariana Islands while large specimens were collected in the water close to Luzon Islands, and then leptocephalus larvae just before metamorphosis and metamorphosing examples were collected in eastern Taiwanese waters. According to Minami et al. (2001), who reported vertical distributions of phyllosoma larvae in the western North Pacific, the larvae of P. longipes s. l, S. cultrifer and leptocephalus larvae showed a similar distribution. We believe that the above transport route of phyllosoma larvae may be driven through a similar mechanism to A. japonica leptocephalus larvae. There is little information on the larval transport and dispersal by the Subtropical Countercurrent, except for the paper by Kimura et al. (1999), who studied leptocephalus transport of the A. japonica leptocephalus larvae using numerical simulation. According to Kimura et al. (1999), the Subtropical Countercurrent is a weak flow and generates the Subtropical Current Subgyre in the waters south of Okinawa Islands, and the subgyre con- 970 N. Inoue et al.

9 Fig. 6. Developmental stage composition of phyllosoma larvae of Panulirus longipes s. l. Fig. 7. Developmental stage composition of phyllosoma larvae of Scyllarus cultrifer. tributes to some degree to larval retention of the leptocephalus larvae. Kimura et al. (1999) explained why the previously estimated spawning ground of A. japonica was located in the waters south of Okinawa Islands and/or east of Taiwan. Based on the fact that phyllosoma larvae of P. longipes s. l and S. cultrifer, and leptocephalus larvae showed a similar vertical distribution to each other (Minami et al., 2001), the Subtropical Countercurrent may not contribute to the larval transport of the above larvae. 3.3 Identification of palinurid phyllosoma larvae a) Panulirus phyllosoma larvae Panulirus larvae with 4 species were identified (Table 2): 233 specimens of P. longipes s. l, 14 of P. ornatus, 49 of P. penicillatus, and 9 of P. versicolor. Panulirus larvae with 13 specimens were not identified to the species level because of their broken damage (Table 2). Panulirus longipes s. l A total of 233 specimens were collected (Table 2, Fig. 6): 100 specimens of stage VI (body length: BL mm), 86 of stage VII (BL mm), 39 of stage VIII (BL mm) and 8 of stage IX (final stage) (BL mm). As already mentioned above, the larvae of P. longipes s. l were found in a wide area, being particularly abundant in western Mariana waters, eastern Taiwanese and southern Okinawa waters (Fig. 3). Sibling species P. japonicus and P. longipes s. l were classified into the Panulirus japonicus group (George and Main, 1967). It is difficult to distinguish phyllosoma larvae of P. longipes s. l from those of P. japonicus based on morphological features (Inoue and Sekiguchi, 2001). However, we assumed that 234 specimens of Panulirus larvae collected in late August to early September might belong to P. longipes s. l based on the following facts: the final stage phyllosoma larvae of P. longipes s. l metamorphosed to the puerulus in October and onward, and their pueruli settled in October to April (Tanaka et al., 1984; Inoue et al., 2002). On the other hand, the final stage ones of P. japonicus metamorphosed to the pueruli in June to August (Yoshimura et al., 1999), and their pueruli settled in summer (Kanamori and Kanamaru, 1980; Kanamori, 1982). In addition, adults of P. japonicus were not distributed in the present study area, except in northern Taiwanese waters (Sekiguchi, 1997). Late stage phyllosoma larvae of P. longipes s. l were described from tropical and equatorial waters of the South Pacific by Michel (1969), from the South China Sea by Johnson (1971a), from the Indian Ocean by Prasad et al. (1975), and from Mariana waters by Sekiguchi (1990). Matsuda and Yamakawa (2000) succeeded in culturing this species from eggs to juveniles in the laboratory. Panulirus penicillatus A total of 49 specimens were collected (Table 2): 14 specimens of stage VI (BL mm), 12 of stage VII (BL mm), 20 of stage VIII (BL mm) and 3 of stage IX (final stage) (BL mm). Phyllosoma larvae of P. penicillatus were found in the wider area, but their distribution pattern was unidentified due to the small number of phyllosoma larvae collected. The larvae of the species have been described from Hawaiian waters and the South China Sea and by Johnson (1968a, 1971a), and from Japanese waters by Murano (1971). Minagawa (1990) succeeded in culturing this species from eggs to middle stage phyllosoma larvae in the laboratory. Panulirus ornatus A total of 14 specimens were collected (Table 2): 2 specimens of stage VI (BL 7.8 mm and 8.8 mm), 4 of stage VII (BL mm), 8 of stage VIII (BL mm). Phyllosoma larvae of P. ornatus were found in Taiwanese (Sts. 28 and B) and eastern/northeastern Luzon waters (Sts. 16, 17, 19 and C), described from the Indian Ocean by Prasad and Tampi (1959) and Prasad et al. (1975), from the South China Sea by Johnson (1971a), and from Japanese waters by Murano (1971). b) Justitia phyllosoma larvae Justitia japonica Materials: Twelve specimens were collected (Ta- Distribution of Phyllosoma Larvae in Western North Pacific 971

10 Fig. 8. Phyllosoma larva of Justitia japonica (stage IX). A: ventral view; B: ventral view of abdomen; C: dorsal view of abdomen; D: second maxilla, first and second maxillipeds; E, F, G and H: fifth and top of fourth segment of third, second and first pereiopods, respectively; I: fifth and top of fourth segment of second maxilla; J: first maxilla. ble 2): 2 specimens of stage V? (BL 6.3 mm and 7.1 mm), 4 of stage VI? (BL mm), 2 of stage VII? (14.3 mm and 18.6 mm), 2 of stage VIII? (21.2 mm and 24.1 mm) and 2 of stage IX? (30.2 mm and 32.7 mm). Phyllosoma larvae of J. japonica were collected in eastern Taiwanese waters (St. B), southern Okinawa (St. 22) and eastern/northeastern Luzon waters (Sts. 4, 19, 26, C and E). We describe here the final stage phyllosoma larva (stage IX) with BL 32.7 mm, collected at St. 19 (19 00 N, E) on 22 September. Morphological features (Fig. 8): Cephalic shield oval, 21.0 mm long and 16.1 mm wide, with a low, stout spine near each antennule peduncle on the dorsal surface of cephalon. Cephalic shield covering the bases of a pair of third maxillipeds. Thorax 16.7 mm wide. Width ratio of chephalon to thorax Antennule as long as eyestalk, peduncle cylindrical with 3 segments. Antenna elongate, peduncle cylindrical with 3 segments, 3 spines on third segment. First maxilla 2-lobed, basal endite with 2 stout terminal spines bearing minute denticles and with 4 setae, coxal endite with 5 long and 6 short setae. Second maxilla with developed scaphognathite bearing setae. First maxilliped 2-segmented, first segment with lobe and elongate second segment lacking setae. Second maxilliped 5- segmented, elongate exopod bearing 18 pairs of setae, first segment with spine and lobe. Third maxilliped 5-segmented, elongate exopod bearing 26 pairs of setae. Third maxilliped and first to fourth pereiopods bearing gill buds and vental-directed coxal spins on first segment. First pereiopod with well-developed chela, and second and fourth pereiopods with subchela on fifth segment. Fifth pereiopod elongate, uniramous with 5 segments lacking setae. Abdomen 5-segmented, first to fourth segments with pleopods. First to fourth pleopods bud-like, oval, 2- lobed with shallow cleft on inner margin of endopods. Uropods enlarged bud-like, segmented, oval, 2-lobed with shallow cleft on lateral margin of endopod bearing two short setae and exopod, reaching a little beyond posterior margin of telson. Telson tapered, a narrow truncated tip lacking setae with shallow cleft on lateral margin. Remarks: Phyllosoma larvae of J. japonica have been described from Philippine waters by Johnson (1969) and Molucca waters by Johnson and Robertson (1970). Justitia longimanus Materials: specimens with 6 individuals were collected (Table 2): 5 specimens of stage V? (BL mm), 1 of stage VIII? (BL 27.2 mm). Phyllosoma larvae of J. longimanus were collected in eastern Taiwanese (St. B) and southern Okinawa waters (Sts. 21 and 22) and eastern/northeastern Luzon waters (Sts. 19, C and E). We describe here the stage VIII phyllosoma larva with BL 27.2 mm, collected at St. B (24 48 N, E) on 12 September. Morphological features (Fig. 9): Cephalic shield oval, 19.0 mm long and 15.0 mm wide, with a low, stout spine near each antennule peduncle on the dorsal surface of cephalon. Cephalic shield not covering the bases of a pair of third maxillipeds, postelo-lateral margin hollowed. Thorax 16.0 mm wide. Width ratio of chephalon to thorax Antennule as long as eyestalk, peduncle cylindrical with 3 segments. Antenna elongate, peduncle cylindrical with 3 segments, without spines on each seg- 972 N. Inoue et al.

11 Fig. 9. Phyllosoma larvae of Justitia longimanus (stage VIII). A: ventral view; B: ventral view of abdomen; C: dorsal view of abdomen; D, E and F: fifth and top of fourth segment of third, second and first pereiopods, respectively; G: second maxilla, first and second maxillipeds; H: first maxilla; I: fifth and top of fourth segment of second maxilla. ment. First maxilla 2-lobed, basal endite with 2 stout terminal spines bearing minute denticles and with 4 setae, coxal endite with 4 long and 7 short setae. Second maxilla with developed scaphognathite bearing setae. First maxilliped 2-segmented without lobe on first segment and elongate second segment lacking setae. Second maxilliped 5-segmented without spine and lobe on first segment, elongate exopod bearing 9 pairs of setae. Third maxilliped 5-segmented, elongate exopod bearing 23 pairs of setae. Third maxilliped and first to fourth pereiopods without vental-directed coxal spins on first segment. First pereiopod with well-developed chela and third pereiopod with subchela on fifth segment. Fourth pereiopod 4-segmented but no yet well-developed. Fifth pereiopod elongage, uniramous with 5 segments lacking setae. Abdomen 5-segmented, first to fourth segments with pleopods. First to fourth pleopods bud-like, oval, 2-lobed with shallow cleft on inner margin of endopods. Uropods enlarged bud-like, segmented, oval, 2-lobed and exopod reaching a little beyond posterior margin of telson. Telson tapered, a narrow truncated tip lacking setae. Remarks: According to Houlthuis (1991), J. longimanus has been found from the Atlantic Ocean and J. mauritiana or J. longimanus mauritiana from the Indo- West Pacific Ocean. However, recent studies (Chan and Yu, 1991; Poupin, 1994) indicate that the above two may belong to the same species. Phyllosoma larvae of J. longimanus have been described from the West Atlantic Ocean by Robertson (1969b), from Hawaiian waters by Johnson (1969), and from Philippine waters by Johnson and Robertson (1970). The late stage phyllosoma larvae of J. longimanus are separated from those of the J. japonica based on the shape of posterior margin of cephalic shield. 3.4 Identification of scyllarid phyllosoma larvae a) Scyllarus phyllosoma larvae Scyllarus cultifer A total of 274 specimens were collected (Table 2, Fig. 7): 22 specimens of stage IV (BL mm), 164 of stage V (BL mm), 25 of stage VI (BL mm), 47 of stage VII (BL mm) and 16 of the final stage (stage VIII, BL mm). As already mentioned above, phyllosoma larvae of the species were abundant in western Mariana waters, eastern Taiwanese and southern Okinawa waters (Fig. 4). The morphology of the present specimens accords well with that of S. bicuspidatus described by Phillips et al. (1981) from the Indian Ocean, Scyllarus sp. a described by Johnson (1971a) from the South China Sea, S. bicuspidatus described by Sekiguchi (1990) from Mariana waters, and S. cultrifer described by Inoue et al. (2000) from Japanese waters. Scyllarus martensii A total of 12 specimens were collected (Table 2): 4 specimens of stage VII (BL mm), 8 of the final stage (stage VIII, BL mm). Phyllosoma larvae of the species were collected in eastern Taiwanese (St. B) and eastern/northeastern Luzon waters (Sts. 3, 15, 16 and C). Phillips and McWilliam (1986) described phyllosoma larvae in the first to final stages of the species from Australian waters. The larvae of the species have Distribution of Phyllosoma Larvae in Western North Pacific 973

12 been reported from Japanese waters as Scyllarides sp. by Shojima (1963) and S. martensii by Inoue et al. (2000), from South African waters as Scyllarides sp. by Gurney (1936), from Natal coast of South Africa as Scyllarus sp. B by Berry (1974), from the Indian Ocean as Scyllarides sp. by Saisho (1966), as S. martensii by Tampi and George (1975) and Prasad et al. (1975), from the South China Sea as S. martensii by Johnson (1971a). Scyllarus rugosus A total of 9 specimens of the final stage (stage VIII, BL mm) were collected in the present study (Table 2). Phyllosoma larvae of the species were collected in eastern Taiwanese waters (St. B), southern Okinawa (Sts. 21 and 22) and eastern/northeastern Luzon waters (Sts. 5, 16 and C). The larvae of the species have been reported from the South China Sea as Scyllarus sp. C by Johnson (1971a), from Natal coast of South Africa as Scyllarus sp. A by Berry (1974), from the Red Sea as S. martensii by Tampi and George (1975), from Indian Ocean by Prasad et al. (1975) and Prasad (1983). Bernett (1989) described the larvae of this species from the Great Barrier Reef. Scyllarus sp. c A total of 10 specimens were collected (Table 2): 1 specimen of stage IV (BL 6.8 mm), 1 of stage V (BL 12.8 mm), 2 of stage VI (BL 14.7 and 17.2 mm), 4 of stage VII (BL mm) and 1 of the final stage (stage VIII, BL 34.8 mm). Phyllosoma larvae of the species were collected in the waters of eastern Taiwanese waters (Sts. 34 and B), southern Okinawa (Sts. 2, 20 and 22) and eastern/northeastern Luzon waters (Sts. 5, 6 and C). The larvae of the species have been reported as Scyllarus sp from Hawaiian waters by Johnson (1971b), as Scyllarus sp. B from the South China Sea by Johnson (1971a), as Scyllarus species D from South African waters by Berry (1974), and as S. cultrifer from the Indian Ocean by Prasad et al. (1975). Scyllarus sp. d A total of 8 specimens were collected (Table 2): 1 specimen of stage VII (BL 17.2 mm) and 7 specimens of the final stage (stage VIII, BL mm). Phyllosoma larvae of the species were collected in eastern Taiwanese (Sts. 34 and B) and eastern/northeastern Luzon waters (Sts. 5, 27 and C). Similar phyllosoma larvae were reported from Taiwanese waters by Inoue et al. (2001). These phyllosoma larvae are closely similar to those of S. bicuspidatus described by Phillips et al. (1981) and Sekiguchi (1990), and Scyllarus sp. a described by Johnson (1971a). However, phyllosoma larvae of Scyllarus sp. d were distinguishable from the previously reported phyllosoma larvae (Inoue et al., 2001). b) Scyllarides phyllosoma larvae Scyllarides sp. A total of 37 specimens were collected (Table 2): 36 specimen of stage VIII (BL mm), 1 of stage IX (BL 28.2 mm). The larvae of this species were found in the wider area, particularly abundant in southern Okinawa waters (Sts. 2 and 22) and eastern Luzon waters (St. C). Adults of the Scyllarides with 2 individuals (Scy. haanii and Scy. squammosus) were reported in the present study area (Holthuis, 1991; Chan and Yu, 1993). According to Sekiguchi (1990), late stage phyllosoma larvae of Scy. squamosus were distinguishable from those of Scy. haanii by occurrence of coxal spine on 5th pereopod. However, as all phyllosoma larvae of the genus Scyllarides collected in the present study were in middle stages, it was difficult to identify these phyllosoma larvae to the species level. The larvae of Scy. squamosus have been reported from New Caledonia waters by Michel (1968), from South African waters by Berry (1974), and from Hawaiian waters by Johnson (1977) while those of Scyllarides sp. or Scy. hannii have been from Taiwanese waters by Inoue et al. (2001) and from western Australian waters as Scyllarides sp. A by Phillips et al. (1981), respectively. c) Parribacus phyllosoma larvae Parribacus sp. A total of 13 specimens were collected (Table 2): 11 specimen of stage VII? (BL mm), 2 of stage VIII? (BL 27.6 mm and 34.5 mm). Phyllosoma larvae of this species were collected in Taiwanese waters (Sts. 30 and B), southern Okinawa (Sts. 2 and 3) and eastern/northeastern Luzon waters (Sts. 3, 4, 6, 13 and 18). Two adult specimens of the genus Parribacus (Par. antarcticus and Par. japonicus) have been reported in the present study area (Holthuis, 1991; Chan and Yu, 1993). As mentioned below, we have several reports of morphological features of Par. antarcticus, but only one report existed for Par. japonicus (Yoneyama and Takeda, 1998). Further, as all phyllosoma larvae of the genus Parribacus collected in the present study were in middle stages, it was difficult to identify these phyllosoma larvae to the species level. The larvae of Par. antarcticus have been reported from the Indian Ocean by Saisho (1966), from the South China Sea by Johnson (1971a), from Hawaiian waters by Johnson (1971b), and from Mariana waters by Sekiguchi (1990) while those of Par. japonicus have been from Ogasawara waters by Yoneyama and Takeda (1998). 3.5 Identification of synaxid phyllosoma larvae a) Palinurellus phyllosoma larvae Palinurellus wieneckii A phyllosoma larva (stage VI, BL 5.2 mm) was collected at St. 27 (Table 2). The larvae of this species have been reported from Hawaiian waters by Johnson (1968b), from the Indian Ocean by Prasad et al. (1975), from New Caledonia waters by Michel (1970), and from Okinawan waters by Sekiguchi and Saisho (1994). 974 N. Inoue et al.

13 Acknowledgements The authors would like to thank the captain and crew of R/V Hakuho-Maru and all scientists for sampling on board. References Barnett, B. M. (1989): Final-stage phyllosoma larvae of Scyllarus species (Crustacea: Decapoda: Scyllaridae) from shelf waters of the Great Barrier Reef. Invertebr. Taxon., 3, Berry, P. F. (1974): Palinurid and scyllarid lobster larvae of the Natal coast, South Africa. Invest. Rep. Oceanogr. Res. South Africa, 34, Booth, J. D. and B. F. Phillips (1994): Early life history of spiny lobster. Crustaceana, 66, Braine, S. J., D. W. Rimmer and B. F. Phillips (1979): An Illustrated Key and Notes on the Phyllosoma Stages of the Western Rock Lobster Panulirus cygnus George. CSIRO Aust. Div. Fish. Oceanogr. Rep. 102, 13 pp. Chan, T. Y. and H. P. Yu (1986): A report of the Scyllarus lobsters (Crustacea: Decapoda: Scyllaridae) from Taiwan. J. Taiwan Mus., 39, Chan, T. Y. and H. P. 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