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Phyllosoma larva of Scyllarus bicuspidatus (Crenarctus bicuspidatus), stage VII. A, ventral view; B, ventral view of eye, antennule and antenna; C, distal end of 2nd maxilliped; D, 2nd maxilla, 1st and 2nd maxillipeds; E, 1st maxilla; F, ventral view of abdomen; G, dorsal view of abdomen. Parenthetic names are new genera and species names established by Holthuis (2002).
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For understanding larval recruitment processes of Scyllarus and Panulirus lobsters, exact species identification of field-caught phyllosoma larvae, particularly those of the early stages, is essential. Using ichthyoplankton samples from waters along the west coast of Kyushu to the Japan Sea coast of Honshu and the Kuroshio and Kuroshio-Counter Curr...
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... TW, 1.8-2.5 mm (mean 2.2 mm); CL/CW, 0.9-1.0 (mean 0.9); CW/TW, 1.9-2.5 (mean 2.1). Of these larval specimens, we described the morphological features of a larva (BL 6.7 mm) collected at 33°32.1N, 129°24.1E on Oct. 31, 1986. Antennule (Fig. 8B) 3 segmented, outer flagellum bear- ing at least 15 minute setae on inner margin; antenna ( Stage VII (Fig. 9) BL (n15), 8.2-10.0 mm (mean 9.2 mm); CL, 5.2-6.2 mm (mean 5.8 mm); CW, 5.9-7.2 mm (mean 6.7 mm); TW, 2.7-3.9 mm (mean 3.2 mm); CL/CW, 0.8-0.9 (mean 0.9); CW/TW, 1.9-2.2 (mean 2.1). Of these larval specimens, we described the morphological features of a larva (BL 8.2 mm) collected at 31°00.0N, 129°29.5E on Nov. 8, 1986. Cephalon (Fig. ...
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... Stage VII (Fig. 9) BL (n15), 8.2-10.0 mm (mean 9.2 mm); CL, 5.2-6.2 mm (mean 5.8 mm); CW, 5.9-7.2 mm (mean 6.7 mm); TW, 2.7-3.9 mm (mean 3.2 mm); CL/CW, 0.8-0.9 (mean 0.9); CW/TW, 1.9-2.2 (mean 2.1). Of these larval specimens, we described the morphological features of a larva (BL 8.2 mm) collected at 31°00.0N, 129°29.5E on Nov. 8, 1986. Cephalon (Fig. 9A) leaving the bases of 1st pereiopod exposed. Antennule (Fig. 9B) outer flagellum bearing at least 20 minute setae on its inner margin. First maxilla (Fig. 9E) with anterior lobe bearing 3 stout masticatory terminal spines plus 5 short setae and with posterior lobe bearing 2 long and 2 short terminal setae plus 3 short subterminal seta; ...
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... mm (mean 5.8 mm); CW, 5.9-7.2 mm (mean 6.7 mm); TW, 2.7-3.9 mm (mean 3.2 mm); CL/CW, 0.8-0.9 (mean 0.9); CW/TW, 1.9-2.2 (mean 2.1). Of these larval specimens, we described the morphological features of a larva (BL 8.2 mm) collected at 31°00.0N, 129°29.5E on Nov. 8, 1986. Cephalon (Fig. 9A) leaving the bases of 1st pereiopod exposed. Antennule (Fig. 9B) outer flagellum bearing at least 20 minute setae on its inner margin. First maxilla (Fig. 9E) with anterior lobe bearing 3 stout masticatory terminal spines plus 5 short setae and with posterior lobe bearing 2 long and 2 short terminal setae plus 3 short subterminal seta; 2nd maxilla ( Fig. 9D) with developed scaphognathite lacking ...
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... (mean 0.9); CW/TW, 1.9-2.2 (mean 2.1). Of these larval specimens, we described the morphological features of a larva (BL 8.2 mm) collected at 31°00.0N, 129°29.5E on Nov. 8, 1986. Cephalon (Fig. 9A) leaving the bases of 1st pereiopod exposed. Antennule (Fig. 9B) outer flagellum bearing at least 20 minute setae on its inner margin. First maxilla (Fig. 9E) with anterior lobe bearing 3 stout masticatory terminal spines plus 5 short setae and with posterior lobe bearing 2 long and 2 short terminal setae plus 3 short subterminal seta; 2nd maxilla ( Fig. 9D) with developed scaphognathite lacking terminal setae. First maxilliped (Fig. 9D) small bud; 2nd maxilliped (Figs. 9C, D) with rudiment ...
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... the bases of 1st pereiopod exposed. Antennule (Fig. 9B) outer flagellum bearing at least 20 minute setae on its inner margin. First maxilla (Fig. 9E) with anterior lobe bearing 3 stout masticatory terminal spines plus 5 short setae and with posterior lobe bearing 2 long and 2 short terminal setae plus 3 short subterminal seta; 2nd maxilla ( Fig. 9D) with developed scaphognathite lacking terminal setae. First maxilliped (Fig. 9D) small bud; 2nd maxilliped (Figs. 9C, D) with rudiment of exopod appearing as a slight protrusion, bearing at least 8 setae on propodus. Exopods of 1st to 4th pereiopods (Fig. 9A) bear- ing 13, 15, 13 and 10 pairs of natatory setae, respectively; 5th ...
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... at least 20 minute setae on its inner margin. First maxilla (Fig. 9E) with anterior lobe bearing 3 stout masticatory terminal spines plus 5 short setae and with posterior lobe bearing 2 long and 2 short terminal setae plus 3 short subterminal seta; 2nd maxilla ( Fig. 9D) with developed scaphognathite lacking terminal setae. First maxilliped (Fig. 9D) small bud; 2nd maxilliped (Figs. 9C, D) with rudiment of exopod appearing as a slight protrusion, bearing at least 8 setae on propodus. Exopods of 1st to 4th pereiopods (Fig. 9A) bear- ing 13, 15, 13 and 10 pairs of natatory setae, respectively; 5th pereiopod (Figs. 9A, F, G) difficult to observe due to damaged appendages. Abdomen ...
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... inner margin. First maxilla (Fig. 9E) with anterior lobe bearing 3 stout masticatory terminal spines plus 5 short setae and with posterior lobe bearing 2 long and 2 short terminal setae plus 3 short subterminal seta; 2nd maxilla ( Fig. 9D) with developed scaphognathite lacking terminal setae. First maxilliped (Fig. 9D) small bud; 2nd maxilliped (Figs. 9C, D) with rudiment of exopod appearing as a slight protrusion, bearing at least 8 setae on propodus. Exopods of 1st to 4th pereiopods (Fig. 9A) bear- ing 13, 15, 13 and 10 pairs of natatory setae, respectively; 5th pereiopod (Figs. 9A, F, G) difficult to observe due to damaged appendages. Abdomen (Figs. 9F, G) beginning to be segmented; 1st ...
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... bearing 2 long and 2 short terminal setae plus 3 short subterminal seta; 2nd maxilla ( Fig. 9D) with developed scaphognathite lacking terminal setae. First maxilliped (Fig. 9D) small bud; 2nd maxilliped (Figs. 9C, D) with rudiment of exopod appearing as a slight protrusion, bearing at least 8 setae on propodus. Exopods of 1st to 4th pereiopods (Fig. 9A) bear- ing 13, 15, 13 and 10 pairs of natatory setae, respectively; 5th pereiopod (Figs. 9A, F, G) difficult to observe due to damaged appendages. Abdomen (Figs. 9F, G) beginning to be segmented; 1st to 4th pleopods ( Fig. 9F) (Fig. 10) BL (n7), 12.5-14.3 mm (mean 13.3 mm); CL, 7.3-8.0 mm (mean 7.6 mm); CW, 8.3-9.4 mm (mean 8.8 mm); TW, ...
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... 9D) with developed scaphognathite lacking terminal setae. First maxilliped (Fig. 9D) small bud; 2nd maxilliped (Figs. 9C, D) with rudiment of exopod appearing as a slight protrusion, bearing at least 8 setae on propodus. Exopods of 1st to 4th pereiopods (Fig. 9A) bear- ing 13, 15, 13 and 10 pairs of natatory setae, respectively; 5th pereiopod (Figs. 9A, F, G) difficult to observe due to damaged appendages. Abdomen (Figs. 9F, G) beginning to be segmented; 1st to 4th pleopods ( Fig. 9F) (Fig. 10) BL (n7), 12.5-14.3 mm (mean 13.3 mm); CL, 7.3-8.0 mm (mean 7.6 mm); CW, 8.3-9.4 mm (mean 8.8 mm); TW, 4.3-4.9 mm (mean 4.5 mm); CL/CW, 0.8-0.9 (mean 0.8); CW/TW, 1.9-2.0 (mean 1.9). Of these ...
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... (Fig. 9D) small bud; 2nd maxilliped (Figs. 9C, D) with rudiment of exopod appearing as a slight protrusion, bearing at least 8 setae on propodus. Exopods of 1st to 4th pereiopods (Fig. 9A) bear- ing 13, 15, 13 and 10 pairs of natatory setae, respectively; 5th pereiopod (Figs. 9A, F, G) difficult to observe due to damaged appendages. Abdomen (Figs. 9F, G) beginning to be segmented; 1st to 4th pleopods ( Fig. 9F) (Fig. 10) BL (n7), 12.5-14.3 mm (mean 13.3 mm); CL, 7.3-8.0 mm (mean 7.6 mm); CW, 8.3-9.4 mm (mean 8.8 mm); TW, 4.3-4.9 mm (mean 4.5 mm); CL/CW, 0.8-0.9 (mean 0.8); CW/TW, 1.9-2.0 (mean 1.9). Of these larval specimens, we described the morphological features of a larva (BL 12.7 ...
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... of exopod appearing as a slight protrusion, bearing at least 8 setae on propodus. Exopods of 1st to 4th pereiopods (Fig. 9A) bear- ing 13, 15, 13 and 10 pairs of natatory setae, respectively; 5th pereiopod (Figs. 9A, F, G) difficult to observe due to damaged appendages. Abdomen (Figs. 9F, G) beginning to be segmented; 1st to 4th pleopods ( Fig. 9F) (Fig. 10) BL (n7), 12.5-14.3 mm (mean 13.3 mm); CL, 7.3-8.0 mm (mean 7.6 mm); CW, 8.3-9.4 mm (mean 8.8 mm); TW, 4.3-4.9 mm (mean 4.5 mm); CL/CW, 0.8-0.9 (mean 0.8); CW/TW, 1.9-2.0 (mean 1.9). Of these larval specimens, we described the morphological features of a larva (BL 12.7 mm) collected at 34°27.5N, 129°34.6E on Oct. 27, 1986. ...
Citations
... All morphometric measurements were obtained using the software Image J (Schneider et al. 2012). Finally, morphological ratios were obtained for BL/CW, CW/TW and the eyestalk length/antenna length (ES/ A2) ratio following previous studies (McWilliam 1995;Lindley et al. 2004;Inoue and Sekiguchi 2006;Genis-Armero et al. 2022). ...
... Difficulties distinguishing these larvae make generic identifications based on morphological highly unreliable. For example, Higa and Shokita (2004) have assigned putative Cr. bicuspidatus (De Man 1905) phyllosoma from previous works to Ch. cultrifer, but Wakabayashi et al. (2020) suggest that Ch. cultrifer phyllosoma described by Higa and Shokita (2004) and Inoue and Sekiguchi (2006) belong in fact to Ch. virgosus. Ueda et al. (2021) recently studied Chelarctus larvae from northern and central Pacific waters but, apparently due to the poor status of their specimens, illustrations and descriptions were deficient and their morphological results remain inconclusive. ...
... Morphometric measurements were obtained using the software ImageJ (Schneider et al. 2012). Different morphological characters were used to define genera and species groups following previous studies (Maigret 1978;Phillips & McWilliam 1986;Webber & Booth 2001;Inoue & Sekiguchi 2006), cephalon posterior margin (CPM), cephalon shape (CS), articulation of fifth pereiopod (P5), thoracic dorsal spines (TDS), and CL/CW ratio. The new characters proposed here with taxonomic value for Chelarctus and Crenarctus were, the cephalon edge (CE), relative length of carpus and propodus of maxilliped 3 (Crp/Prd) and PL/PW and BL/CW ratios. ...
... Regarding P5 articulation in the last stage, Crenarctus larvae have 4-articled P5, whereas P5 in Chelarctus has only three articles. The presence of 4-articles mentioned by some authors (Higa & Shokita 2004;Inoue & Sekiguchi 2006;Ueda et al. 2021) is contradicted by previous works on North Pacific larvae (Johnson 1971(Johnson , 1979Sekiguchi 1990) and our results. This oversight is probably due to the apparent swelling, but lack of segmentation, of the P5 of Chelarctus final stage phyllosomae. ...
Chelarctus Holthuis, 2002 is widely distributed throughout the Indo-West Pacific, but its biogeographic patterns are unknown because Southern Hemisphere areas, such as the Coral Sea, remained poorly explored. Recent cruises organized by the Muséum national d'Histoire naturelle of Paris and the Australian Institute of Marine Science allowed the molecular identification of Crenarctus crenatus (Whitelegge, 1900), Chelarctus aureus (Holthuis, 1963) and Chelarctus crosnieri Holthuis, 2002 phyllosomae. The Coral Sea C. crenatus larvae are identical to stages IX and X of Scyllarus sp. Z, described in detail by Webber and Booth (2001). Descriptions of phyllosoma stages VI, IX and X of Ch. aureus and stages IX and X of Ch. crosnieri are also presented here. Morphological differences between Crenarctus and Chelarctus larvae are established for the first time and previous misidentifications in the literature are re-assessed.
... This procedure allowed us to select the phyllosomas from the subfamily Scyllarinae. Subsequently, mid-to final-stage larvae (V-VIII) were selected based on the criteria described by Inoue and Sekiguchi (2006); stage V: 5th pereiopod unsegmented or 2-segmented, pleopods bud, uropods unbiloed or slightly bilobed; stage VI: 5th pereiopod 2 or 3-segmented, pleopods unbilobed, uropods bilobed; stage VII: 5th pereiopod 3-segmented, pleopods bilobed; stage VIII: 1st to 4th pereiopods gilled, 5th pereiopod 4-segmented. We further selected 12 larvae that were as morphologically intact as possible (Table 1). ...
... 4) also shows great morphological agreement with C. virgosus, with this similarity was already noted by Inoue et al. (2000). True S. bicuspidatus (Crearctus bicuspidatus) phyllosomas reported by Inoue and Sekiguchi (2006) have round cephalic shield, V-shaped antennae, short posterolateral spine of the telson, and much smaller bodies than C. virgosus. Scyllarus sp. ...
Morphological descriptions of phyllosoma larvae are essential for correct species identification and investigating the spatiotemporal distribution and recruitment process of spiny and slipper lobsters. Species identification of the phyllosoma larvae in the Scyllarinae subfamily is particularly difficult because of the morphological similarities among species and the scarcity of morphological information describing correct species identity. We extracted mid-to final-stage (V to VIII) phyllosoma larvae (n = 12) belonging to the subfamily Scyllarinae from several plankton samples collected in the Pacific and then performed molecular species identification using mitochondrial DNA COI and 16S rDNA sequence analyses. Three larvae collected around the Ryukyu Archipelago were identified as Chelarctus aureus (stage VI to VIII), and four collected around the Ryukyu Archipelago and Ogasawara Islands were identified as C. virgosus (V to VIII). One larva (V) collected in the central South Pacific was determined to be a subspecies of C. crosnieri. DNA barcodes could not be made for the remaining four larvae (V to VIII) collected around the Ryukyu Archipelago (designated by ?Chelarctus sp-1). Based on the morphological characteristics of the C. virgosus phyllosoma described in this study and the adult distributions reported to date, C. cultrifer phyllosomas previously reported in Japanese and Taiwanese waters are likely to be C. virgosus. This paper also presents a set of diagnostic morphological characteristics that can be used to discriminate among these four species of Chelarctus and from other genera in the subfamily Scyllarinae.
... Scyllarid and palinurid lobsters are reported to be widespread along the southern coast of Japan (Brionez-Fourzan, 2014;Holthuis, 1991, De Bruin, 1962. The morphological developments of larvae has been studied by many researchers Inoue & Sekiguchi, 2006Prasad and Tampi, 1959Michel, 1968Saisho, 1964;Berry, 1974;Matsuda & Yamakawa, 2000;Chow et al 2006;Coutures & Booth, 2010;Murano, 1971;Yoneyama & Takeda, 1998;Miyake, 1962;Sarasu, 1985). Literature written on phyllosoma development describes the morphological features of approximately 40% of the palinurid and scyllarid species (Booth & Phillips, 2006). ...
... Literature written on phyllosoma development describes the morphological features of approximately 40% of the palinurid and scyllarid species (Booth & Phillips, 2006). Additionally, the occurrence and recruitment processes of phyllosoma larvae in the Indo-West Pacific waters has also been investigated by many researchers and recorded (Booth & Phillips, 1994in Sekiguchi, 1990Inoue & Sekiguchi, 2006). ...
... Scyllarid species were identified to the species level according to , Inoue & Sekiguchi (2006, Higa et al (2005, Prasad & Tampi (1959), Michel (1968), , Saisho (1964), Sekiguchi (1990), Johnson (1977, Berry (1974) Higa & Saisho (1983); Higa & Shokita (2004); Higa et al (2005); Yoneyama & Takeda (1998) and Sarasu (c.1985), Palinurid species were identified to species level according to Berry (1974), Prasad & Tampi (1959), (2006, Sekiguchi (1990), Coutures & Booth (2004), , , Inoue (1978), Sekiguchi (1986). ...
Scyllarid and palinurid lobsters are important species reported to be widespread in southern Japanese waters. This study aims to describe the occurrence of scyllarid and palinurid phyllosoma larvae in the southern Japanese waters of Satsunan, Amami and Okinawa waters. In total there were 171 specimens collected from the study areas; Satsunan (4), Amami (146) and Okinawa (21). . Okinawa specimens were collected in May, 2012 and Amami specimens were collected in June of 2011, 2012 and 2013. All the Amami and Okinawa specimens were collected at night. The Satsunan specimens were collected on five different months (February, March, May, August, November) in 2014 and 2015. The specimens collected from Satsunan were all collected during the day. This study identified four palinurid species belonging to two genera and eight scyllarid species belonging to three genera. There were three dominant species – Scyllarus cultrifer, S. kitanoviriosus and Panulirus longipes all found in Amami and Okinawa waters. The results show that scyllarid species distribution patterns coincide with the current movements. These species early stage and late stage phyllosoma were also confined to coastal waters and near the continental shelf. Palinurid species however do not follow a specific distribution pattern and their long larval lifespan allows for different stage phyllosoma to appear in the same station. This study is the first to describe Stage I phyllosoma of Puerulus angulatus from Japanese waters. Furthermore, all the scyllarid phyllosoma except for Scyllarus bicuspidatus were observed to be significantly influenced by the movement of the currents and were confined to nearshore waters or the continental shelf in their early and late larval stages. The giant phyllosoma larvae (Scyllarides squamosus and Parribacus sp.) have a tendency to move further into offshore waters as they develop into their late larval stage. This study concludes by providing a comprehensive mapping and distribution of scyllarid and palinurid phyllosoma species occurrences in Satsunan, Amami and Okinawa waters.
... All phyllosoma larvae were identified to species where possible and staged using relevant literature (e.g. Ritz and Thomas, 1973;Braine et al., 1979;Inoue and Sekiguchi, 2006). Concentrations of potential prey items were standardized as number per m 3 and those of phyllosoma as number per 1000 m 3 . ...
The western rock lobster, Panulirus cygnus, provides Australia's most valuable wild caught fishery but, in recent years, there has been a dramatic decline in settlement
of the post-larval phase into their natal coastal habitat. One hypothesis for this decline was that the oceanographic conditions
no longer favour the survival, feeding and growth of the larval (phyllosoma) phase. To explore this, the oceanography and
corresponding zooplankton prey field along five latitudinal transects in the south-eastern Indian Ocean were quantified during
July 2010. Leeuwin Current Water (LCW) and Sub-Tropical Surface Water (STSW) were distinguished and a prominent front at ∼30°S
characterized by strong eastward flow separated them. Although zooplankton abundance increased towards the north, the prey
field was unevenly distributed with patches of higher prey concentration associated mainly with LCW. Chaetognaths were the
most abundant prey item (means: 17.2 and 4.1 m−3 in LCW and STSW, respectively) and were positively correlated with chlorophyll a in both water masses. Panulirus cygnus phyllosoma had a highly patchy distribution but, despite lower prey concentrations, were more abundant in STSW than LCW,
particularly south of the front. Our results suggest that LC meso-scale features with strong fronts may be implicated in phyllosoma
aggregations and shoreward transport of late-stage larvae and that this warrants further investigation.
... The specific identity of the scyllarinid phyllosoma larvae has been confirmed only for a few species in the world (Webber & Booth, 2001;Holthuis, 2002), which makes any attempt to carry out a systematic comparative study almost impracticable. Nevertheless, the final-stage phyllosomata of both S. arctus and S. pygmaeus are larger than most Scyllarinae species described to date (Eduarctus martensii: Phillips & McWilliam, 1986; Crenarctus bicuspidatus: Inoue & Sekiguchi, 2006). The phyllosomata of both S. arctus and S. pygmaeus can be easily distinguished from other species of scyllarinid lobster that have distinctly different morphologies and never develop elongate telson spines (Scyllarus americanus: Robertson, 1968;Petrarctus demani: Ito & Lucas, 1990). ...
Advanced stages of Scyllarus phyllosoma larvae were collected by demersal trawling during fishery research surveys in the western Mediterranean Sea in 2003–2005. Nucleotide sequence analysis of the mitochondrial 16S rDNA gene allowed the final-stage phyllosoma of Scyllarus arctus to be identified among these larvae. Its morphology is described and illustrated. This constitutes the second complete description of a Scyllaridae phyllosoma with its specific identity being validated by molecular techniques (the first was S. pygmaeus). These results also solved a long lasting taxonomic anomaly of several species assigned to the ancient genus Phyllosoma Leach, 1814. Detailed examination indicated that the final-stage phyllosoma of S. arctus shows closer affinities with the American scyllarid Scyllarus depressus or with the Australian Scyllarus sp. b (sensu Phillips et al., 1981) than to its sympatric species S. pygmaeus.
... Scyllarine phyllosomas are abundant in coastal waters, whereas Panulirus ones are often collected in offshore/oceanic waters (Inoue and Sekiguchi, 2005). Based on previous studies dealing with morphological features of phyllosomas to specific andgeneric levels Sekiguchi et al., 2007), identification keys for phyllosomas of scyllarines and the Panulirus were compiled in Inoue and Sekiguchi (2006). ...
Larval recruitment and fisheries of the spiny lobster J. Mar. Biol. Ass. India, 52 (2) : 195 -207, July -December 2010 Introduction In Japanese waters, nine Panulirus species have been reported (Sekiguchi, 2008): P. brunneiflagellum Sekiguchi and George, 2005; P. femrostriga (von Martens, 1872); P. homarus homarus (Linnaeus, 1758); P. japonicus (von Siebold, 1824); P. longipes bispinosus (Borradaile, 1899); P. ornatus, (Fabricius, 1798); P. penicillatus (Olivier, 1791); P. stimpsoni (Holthuis, 1963) and P. versicolor (Latreille, 1804). Of the nine species of Panulirus in Japanese waters, P. japonicus is found commonly in waters under the influence of the Kuroshio and its branches. The Abstract Panulirus japonicus is an important target for fisheries in Japan. Characteristics of long distance larval transport and recruitment of P. japonicus have been revealed based on drifter studies and larval sampling. Larval recruitment of the lobster is completed within the Kuroshio Subgyre circulation, i.e., early stage phyllosomas that are released in Japanese coastal waters in summer (July-September) are transported into the Kuroshio region; larvae are then transported to the Kuroshio Counter-Current region south of the Kuroshio; these larvae are then transported into the waters east of the Ryukyu Archipelago where subfinal/final-stage phyllosomas and pueruli enter the Kuroshio again and are transported to different locations of Japanese coastal waters through the Kuroshio in the summer of the following year. Using mtDNA sequences for the COI region of P. japonicus juveniles and adults, no significant population subdivision was detected among distant locations. There was no characteristic geographical distribution pattern for haplotypes, supporting the hypothesis that these benthic individuals are sustained by a common pool of phyllosomas through long distance larval transport by phyllosomas within the Kuroshio Subgyre circulation. This scenario is also supported by the examination of long-term variation in P. japonicus catches as follows. Two clusters (A, B) of regions located east (A) and west (B) of the cape Shionomisaki at the southern tip of the Kii Peninsula were identified. There was a significant positive relationship between the Kuroshio index and the catch index two years later for cluster A. This relationship suggests that annual variation in P. japonicus catch may be determined by the variation in puerulus recruitment through the Kuroshio. Relationships between these two clusters varied depending on three periods, which corresponded to the three climate regimes (i.e., years before 1976, from 1977 to 1988, and after 1989). Significant negative relationships were detected between the catch index of these two clusters from 1975 to 2001.
We have performed DNA barcoding and morphological analyses for scyllarine phyllosoma larvae. Five phyllosoma larvae having subrectangular-shaped cephalic shields with straight posterior margins were selected from plankton samples collected in the central North Pacific. Mitochondrial 16S rDNA sequence analysis indicated Crenarctus crenatus to be the closest species for these larvae. Based on the nucleotide sequence divergence (K2P: 1.66 ± 0.61 %) between these five larvae and C. crenatus and the geographic distribution of C. crenatus restricted to the South Pacific, we tentatively determined these larvae to be a subspecies of C. crenatus (designated as C. crenatus sub sp. 1).
Four species (Chelarctus aureus, C. crosnieri, C. cultrifer, and C. virgosus) have been described in the genus Chelarctus of the subfamily Scyllarinae, of which mid to final stage phyllosoma larvae in three species (C. aureus, C. crosnieri, and C. virgosus) have been reported. Ueda et al. (2021) found phyllosoma larvae morphologically assigned to the genus Chelarctus but having distinct DNA sequences from the above four species, designating ?Chelarctus sp-1. Additional specimens (n = 8) of mid to final stage phyllosoma larvae of this species were collected in the western North Pacific. The 16S rDNA sequence data supported ?Chelarctus sp-1 to be a member of the genus Chelarctus. Based on the shape of the cephalic shield, the ratio of the cephalic shield width and length, length of posterolateral spines on the telson, and body size of each stage, mid to final stage phyllosoma larvae of ?Chelarctus sp-1 could be discriminated from those of the other species of the genus reported to date. 緒言 セミエビ科(Scyllaridae)に属するヒメセミ エビ亜科(Scyllarinae)のツノヒメセミエビ属 (Chelarctus)には現在 4 種 2 亜種(Chelarctus aureus, C. crosnieri, C. cultrifer cultrifer, C. cultrifer meridionalis, C. virgosus)が記載されて おり(Holthuis 2002; Yang and Chan 2012; WoRMS 2022) 、これらの DNA 情報はデータ ベースに登録されている。Ueda et al.(2021) は北西太平洋と南太平洋中部で採集されたヒ メセミエビ亜科のフィロソーマ幼生について DNA バーコーディングを試みたところ、一致 する DNA 情報がデータベースに無い個体を 見出した。彼らは南太平洋で採集された 1 個 体はミトコンドリア DNA の COI 配列におい て C. crosnieri に最も近縁であったことから (K2P 距離: 6.9 %)、 C. crosnieri の亜種として Chelarctus crosnieri sub sp. 1 と定義した。また、 北西太平洋で採集された 4 個体とツノヒメセ ミエビ属の他種との間の K2P 距離が COI 配 列において 15-21.9 %、 16S rDNA において 8.5-16.9 %であったことから、これら 4 個体をツ
A gilled (final) stage slipper lobster phyllosoma larva (BL = 23.8 mm) collected in the western North Pacific (27º N, 130º E) was determined to be Chelarctus aureus using mitochondrial 16S rDNA sequence analysis. Morphological characteristics of this larva agreed well with the final stage larva of this species reported previously (Ueda et al. 2021). Mid to final stage phyllosoma larvae of this species can be distinguished from those of the other congeneric species based on their large cephalic shield width and length ratio (1.404-1.587) and the sub-rectangular shape cephalic shield.
