37
南太平洋海域調査研究報告 No.56（2015年3月）
OCCASIONAL PAPERS No.56（March 2015）㮵ඣᓥ┴᫛࿴◲㯤ᓥࡢⅆᒣᄇẼᏍ࿘㎶࡟⏕ᜥࡍࡿ
Xenograpsus testudinatus ࡢ⏕≀Ꮫⓗ◊✲㕥ᮌᘅᚿ࣭ᒾᓮ㉳☻࣭Ᏹ㒔ᐑᝆ࣭ᒾᮏᾏ⨾Biological Study of the Hydrothermal Crab,
Xenograpsus testudinatus Ng, Huang & Ho, 2000 (Crustacea:Decapoda: Brachyura: Grapsidae) Inhabit
in the Adjacent Water of Showa-Iwojima, Southern JapanSUZUKI Hiroshi, IWASAKI Tatsuki, UTSUNOMIYA Yu and IWAMOTO Amami

㮵ඣᓥ኱ᏛỈ⏘Ꮫ㒊
Faculty of Fisheries, Kagoshima Universityせ᪨2011 ᖺ 5 ᭶ࠊ㮵ඣᓥ┴୕ᓥᮧ◲㯤ᓥᮾ᪉⣙ 3km ࡟఩⨨ࡍࡿ᫛࿴◲㯤ᓥ࿘㎶ᾏᇦࡢⅆᒣᛶᄇẼ௜㏆࡛࢖࣡࢞ࢽ⛉࢝ࢽ㢮ࡀⓎぢࡉࢀࡓࠋᮏ✀ࡣྎ‴டᒣᓥࢆᇶ⏘ᆅ࡜ࡍࡿ Xenograpsus testudinatus ࡜ྠᐃࡉࢀࡓ㸦NG et al. 2014㸧ࠋᮏ✀ࢆྵࡴ Xenograpsus ᒓࡣୡ⏺࡛ 3 ✀ࡋ࠿ሗ࿌ࡉࢀ࡚࠾ࡽࡎࠊࡑࡢ⏕≀Ꮫⓗ▱ぢࡣ㠀ᖖ࡟ஈࡋ࠸ࠋ➹⪅ࡽࡣ 2014 ᖺ 5 ᭶ࡼࡾ㝶᫬ᮏ✀ࡢ⏕ែᏛⓗ◊✲ࢆ㐍ࡵࠊࡑࡢ⏕ᜥ㔞ࡀ 3,100㹼3,800ಶయ࡛࠶ࡿࡇ࡜ࠊᮏ✀ࡢศᕸࡀ᫛࿴◲㯤ᓥ༡ഃᾏ㠃࡟㝈ࡽࢀࠊ࠿ࡘࠊᓊᐤࡾࡢ୍㒊ࡢᆅᇦ࡟ࡋ࠿⏕ᜥࡋ࡚࠸࡞࠸஦ࢆ᫂ࡽ࠿࡟ࡋࡓࠋᮏ✀ࡢಶయ⩌⏕ែᏛⓗ◊✲ࡣ⌧ᅾࡶ⥅⥆୰࡛࠶ࡿࠋࡣࡌࡵ࡟࣍࢘࢟࢞ࢽᒓ㸦௬⛠㸧Genus Xenograpsus Takeda & Kurata, 1977 ࡣࠊ⌧ᅾ 3 ✀ࡢࡳࡀሗ࿌
ࡉࢀ࡚࠾ࡾࠊࡑࡢ඲࡚ࡀᾏᗏⅆᒣࡶࡋࡃࡣⅆᒣᛶᄇẼࡀᄇฟࡋ࡚࠸ࡿᾏᇦ࡟ࡢࡳ⏕ᜥࡋ࡚࠸ࡿࠋ
ࡑࢀࡽࡣ 1977 ᖺ࡟ᮾி㒔ᑠ➟ཎࡢすஅᓥ᪂ᓥ࠿ࡽ᪂ᒓ᪂✀࡜ࡋ࡚グ㍕ࡉࢀࡓࢽࢩࣀ
ࢩ࣐࣍࢘࢟࢞ࢽ X. novaeinsularis Takeda & Kurata, 1977ࠊྎ‴໭᪉ࡢடᒣᓥ࠿ࡽሗ࿌ࡉࢀࡓ
X. testudinatus N. K. Ng, Huang & Ho, 2000ࠊཬࡧࢽ࣮ࣗࢪ࣮ࣛࣥࢻ໭᪉ᾏᇦ࡟࠶ࡿࢣ࣐ࣝࢹ
࢕ࢵࢡᾏᗏⅆᒣ࠿ࡽሗ࿌ࡉࢀࡓ X. ngatama McLay, 2007 ࡛࠶ࡿࠋ38
SUZUKI Hiroshi, IWASAKI Tatsuki, UTSUNOMIYA Yu and IWAMOTO Amami1993 ᖺࠊ㮵ඣᓥ┴༑ᓥᮧᝏ▼ᓥࡢᾏᗏ Ἠࠊཬࡧࠊᮾி㒔ᑠ➟ཎㅖᓥ໭◲㯤ᓥ࡛ࢽࢩࣀࢩ࣐࣍࢘࢟࢞ࢽࡢ⏕ᜥࡀሗ࿌ࡉࢀ㸦Ṋ⏣ࡽ 1993㸧
ࠊ2014 ᖺ࡟ࡣ㮵ඣᓥ┴୕ᓥᮧ᫛࿴◲㯤
ᓥ࿘㎶ᾏᇦ࠿ࡽ X. testudinatus ࡀሗ࿌ࡉࢀࡿ࡞࡝㸦NG et al. 2014㸸ᅗ 1&2㸧ࠊᮏᒓࡢ᪥ᮏ࿘㎶ᾏᇦ࡟࠾ࡅࡿ᪂ࡓ࡞⏕ᜥᆅࡀ᫂ࡽ࠿࡟࡞ࡾࡘࡘ࠶ࡿࠋࡋ࠿ࡋ࡞ࡀࡽࠊᮏᒓࡢ࢝ࢽ㢮࡟㛵ࡍࡿ◊✲ࡣࠊࡑࡢ࡯࡜ࢇ࡝ࡀศ㢮Ꮫⓗ◊✲࡛ࠊ⏕≀Ꮫⓗࠊ⏕ែᏛⓗ◊✲ࡣ JENG et al.㸦2004b㸧
࡟ࡼࡿ X. testudinatus ࡢᦤ㣵⏕ែ࡟㛵ࡍࡿ◊✲࡜ྠ᫬࡟⾜ࡗࡓྠ✀ᗂ⏕ࡢᙧែࢆグ㍕ࡋࡓ
ࡶࡢ㸦JENG et al. 2004a㸧ࡔࡅ࡛࠶ࡿࠋࡑࡇ࡛ࠊᮏ◊✲࡛ࡣࠊᾏᗏⅆᒣࡸⅆᒣᛶᄇẼࡢᄇฟࡍࡿ≉␗࡞⎔ቃ࡟⏕ᜥࡍࡿᮏᒓࡢ⏕ែࢆ◊✲ࡍࡿୖ࡛୙ྍḞ࡞⏕≀Ꮫⓗᇶ♏▱ぢࢆᚓࡿࡇ࡜ࢆ┠ⓗ࡜ࡋࡓࠋ
ᮏ◊✲ࢆᐇ᪋ࡍࡿ࡟ᙜࡓࡾࠊㄪᰝ᥇㞟࡟ࡈ༠ຊ࠸ࡓࡔ࠸ࡓᮏᏛỈ⏘Ꮫ㒊⦎⩦⯪༡ᫍ୸ࡢᖜ㔝᫂ṇ⯪㛗ࡣࡌࡵ஌⤌ဨⓙᵝ࡟῝ࡃឤㅰࡋࡲࡍࠋࡲࡓࠊ⌧ᆅ࡛ࡢ SCUBA ࡟ࡼࡿᶆᮏ᥇㞟࡟ከ኱࡞ᑾຊࢆ࠸ࡓࡔ࠸ࡓᮏᏛᢏ⾡㒊⫋ဨᯇᒸ⩫ዪྐࠊ୕ᓥᮧ◲㯤ᓥᅾఫࡢᲚཎẶ࡟῝ㅰ࠸ࡓࡋࡲࡍࠋ࡞࠾ࠊᮏ◊✲㈝ࡢ୍㒊ࡣᏛ㛗⿢㔞⤒㈝㺀ࢥ࢔◊✲㺁࡟ࡼࡿࠋᮦᩱ࠾ࡼࡧ᪉ἲ
ㄪᰝࡣࠊ2014 ᖺ 5 ᭶ࠊ8 ᭶ࠊ10 ᭶࡟᫛࿴◲㯤ᓥ༡ഃᾏ㠃ࡢᾏᓊ⥺࡟ἢࡗ࡚ 10 Ⅼࠊ8 ᭶ཬࡧ 10 ᭶࡟ࡣࡇࡢ 10 Ⅼ࡟ຍ࠼ᾏᓊ࠿ࡽἈ࡟ྥ࠿ࡗ࡚ 50m ࡢࣛ࢖ࣥࢆ 2 ᮏ୪⾜ࡋ࡚タ⨨ࡋ࡚⾜ࡗࡓࠋᾏᓊ⥺࡟ἢࡗࡓ 10 Ⅼ࡛ࡣࠊࡑࢀࡒࢀ 2 ಶࢆ 1 ⤌࡜ࡋࡓࢺࣛࢵࣉ㸦ᕷ㈍ࡢ㨶࣮࢟ࣛ㸸ࢧ࢖ࢬࡣ 26.5×26.5×39cmࠊ┠ྜ࠸⣙ 2mm㸧ࢆ 1 ᫨ኪタ⨨ࡋࡓࠋ50m ࡢࣛ࢖ࣥࢺࣛࣥࢭ
ࢡࢺἲ࡛ࡣࠊ5m 㛫㝸࡟ 2 ಶ 1 ⤌ࡢࢺࣛࢵࣉࢆ 1 ᫨ኪタ⨨ࡋࡓࠋ᥇㞟ಶయࡣ⢭ᗘ 0.05 ੈࡢࣀࢠࢫ࡛⏥㛗ࠊ⏥ᖜࢆィ ࡋࠊ㞤㞝ࠊᢪ༸ࡢ᭷↓ࢆグ㘓ࡋࠊ୍㒊ࡢಶయࢆ㝖ࡁᨺὶࡋࡓࠋ
ࡲࡓࠊ5 ᭶࡜ 10 ᭶ࡢㄪᰝ࡛ࡣ࣐࣮࢟ࣥࢢἲࢆ⏝࠸࡚⏕ᜥ㔞ࢆ᥎ᐃࡋࡓࠋᐇ㦂ᐊ࡟ᣢࡕᖐࡗ
ࡓᢪ༸ಶయࡣ཮║ᐇయ㢧ᚤ㙾ୗ࡛༸ᩘࢆィᩘࡍࡿ࡜ྠ᫬࡟ࠊ
ࡑࡢ࠺ࡕ 50 ༸ࢆ㑅ࡧฟࡋ༸ᚄࢆ ᐃࡋࡓࠋྠ᫬࡟ࠊㄪᰝᾏᇦࡢỈ㉁㸦pH㸧࠾ࡼࡧẼἻ୰ࡢ඲◲໬≀㔞ࡶ ᐃࡋࡓࠋᅗ 1 ᫛࿴◲㯤ᓥᾏᇦ࡛᥇㞟ࡉࢀࡓ Xenograpsus
testudineatus Ng, Huang & Ho, 2000

ᅗ 2 ⏕ᜥᾏᇦᾏᗏࡢᵝᏊ39
Biological Study of the Hydrothermal Crab, Xenograpsus testudinatus Ng, Huang & Ho, 2000 (Crustacea: Decapoda: Brachyura: Grapsidae) Inhabit in the Adjacent Water of Showa-Iwojima, Southern Japan⤖ᯝ࠾ࡼࡧ⪃ᐹㄪᰝᾏᇦࡢ pH ್ࡣᖹᆒ 6.1±0.03㸦ࢹ࣮ࢱᩘ 11㸧࡜㏻ᖖࡢᾏỈࡢ್㸦⣙ 8.3㸧ࡼࡾప࠸್ࢆ♧ࡋࡓࠋẼἻ࡟ྵࡲࢀࡿ඲◲໬≀ࡣ 0.3ppm ࡛࠶ࡗࡓࠋࡇࢀࡽ◲໬≀㔞࡜ pH ࡜ࡢ㛫࡟ࡣఱࡽ࠿ࡢ㛵ಀࡀண᝿ࡉࢀࡿࡀࠊ
௒ᅇࡣㄪᰝ࡛ࡁ࡞࠿ࡗࡓࡢ࡛௒ᚋㄪᰝࡍࡿᚲせࡀ࠶ࢁ࠺ࠋ5 ᭶ࡢㄪᰝ࡛ࡣ࢜ࢫ 365 ಶయࠊ࣓ࢫ 93 ಶయࡀ᥇㞟ࡉࢀࠊ࣐࣮࢟ࣥࢢἲ࡟ࡼࡿ⥲⏕ᜥᩘࡣ3,717 ಶయ୪ࡧ࡟ 3,258 ಶయ࡜᥎ᐃࡉࢀࡓࠋ10 ᭶ࡢㄪᰝ࡛ࡣ࢜ࢫ 351 ಶయࠊ࣓ࢫ 52 ಶయࡀ᥇㞟ࡉࢀࠊ⥲⏕ᜥᩘࡣ 3,147 ಶయ࡜᥎ᐃࡉࢀࡓࠋᚑࡗ࡚ࠊᮏ✀ࡣ᫛࿴◲㯤ᓥ༡ഃᾏ㠃ࡢ⣙ 100m×50m ࡢ㝈ࡽࢀࡓ⠊ᅖ࡟ 3,100㹼3,700 ಶయࡀ⏕ᜥࡋ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿࠋࡲࡓࠊ
ᢪ༸ಶయࡀ 5 ᭶࡟☜ㄆࡉࢀ 8 ᭶࡟ࡣ☜ㄆࡉࢀ࡞࠿ࡗࡓࡇ࡜࠿ࡽᮏ✀ࡢ⏘༸᫬ᮇࡣ௚ࡢ࢖࣡
࢞ࢽ⛉ྠᵝࠊ᫓㹼ึኟ࡛ࡣ࡞࠸࠿࡜⪃࠼ࡽࢀࡿࠋ⏥㛗⤌ᡂࡢᏘ⠇ኚ໬ࢆࡳࡿ࡜ࠊ10 ᭶࡟ᑠᆺಶయࡢຍධࡀㄆࡵࡽࢀࠊࡑࡢᚋࠊ㞝࡛ࡣ⩣ࠎᖺࡢ 10 ᭶ࡲ࡛ࠊ㞤࡛ࡣ⩣ᖺࡢ 5 ᭶ࡲ࡛᫂░࡞ࢧ࢖ࢬ⩌ࡀぢ࠼ࡿࡇ࡜࠿ࡽࠊ㞝ࡣ⣙ 2 ᖺࠊ㞤ࡣ⣙ 1 ᖺ༙ࡢᑑ࿨࡛࠶ࡿ࡜⪃࠼ࡽࢀࡓࠋ
ᮏ✀ࡢศᕸࡀỈ㉁ࠊ≉࡟ప࠸ pH ್࡜㛵㐃ࡍࡿࡢ࡛ࡣ࡞࠸࠿࡜⪃࠼ࠊⅆᒣ⏤᮶ࡢẼἻࡀᄇฟࡍࡿ⟠ᡤࡢᩘ࡜ಶయᩘࡢ㛵ಀࢆ᳨ウࡋࡓࡀࠊ᫂░࡞ṇࡢ┦㛵ࡣㄆࡵࡽࢀ࡞࠿ࡗࡓࠋࡋ࠿ࡋ࡞ࡀࡽᮏ✀ࡢศᕸᵝᘧࡣ᫂ࡽ࠿࡟୍ᵝศᕸ࡛ࡣ࡞ࡃࠊἢᓊ㒊࡟㞟୰ࡋ࡚࠸ࡿࡇ࡜ࡀศ࠿ࡗࡓࠋࡉࡽ࡟ࠊἢᓊ࠿ࡽ 20㹫㞳ࢀࡓἈྜ࡛ࡶ 4 ಶయ௨ୖฟ⌧ࡍࡿⅬࡀ࠶ࡾࠊ࠿ࡘἢᓊ㒊ࡢಶయࡢ⏥㛗ࡀࠊἈྜࡢᆅⅬࡢಶయ࡟ẚ࡭࡚኱ࡁ࠸ഴྥࢆ♧ࡋࡓࠋࡑࡢᆅⅬࡢ pH ್ࡣ7.58ࠊ୪ࡧ࡟ 7.94 ࡜㏆ഐࡢᆅⅬࡢࡑࢀࡼࡾప࠿ࡗࡓࠋ௒ᅇࡢㄪᰝ࡛ࡣࡲࡔ୙༑ศ࡛࠶ࡿ
ࡢ࡛ࠊ௒ᚋࢢࣜࢵࢻㄪᰝ࡞࡝ヲ⣽࡞ㄪᰝࡀᚲせ࡛࠶ࡿࠋᘬ⏝ᩥ⊩JENG, M. S., CLARK, P. F. and NG, P. K. L. 2004a. The First Zoea, Megalopa, and First Crab Stage ofthe Hydrothermal Vent Crab, Xenograpsus testudinatus (Decapoda: Brachyura: Grapsoidea)and Systematic Implications for the Varunidae. Journal of Crustacean Biology, 24: 188-212.
JENG, M. S., NG, N. K. and NG, P. K. L. 2004b. Hydrothermal Vent Crabs Feeds on Marine Snow.
Nature, 432: 969.
MCLAY, C. L. 2007. New Crabs from Hydrothermal Vents of the Kermadec Ridge Submarine
Volcanoes, New Zealand: Gandalfus gen. nov. (Bythograeidae) and Xenograpsus (Varunidae)(Decapoda: Brachyura). Zootaxa, 1524: 1-22.
NG, N. K., HUANG, J. F. and HO, P. H. 2000. Description of a New Species of Hydrothermal Crab,
Xenograpsus testudinatus (Crustacea: Decapoda: Brachyura: Grapsidae). In: Proceedings of theInternational Symposium on Marine Biology in Taiwan – Crustacean and Plankton Taxonomy,Ecology and Living Resources (Eds. HWANG, J. S., WANG, C. H. and CHAN, T. Y.), 191-199,Figs 1-3, National Taiwan Museum Special Series, No. 10, Taiwan.

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NG, N. K., SUZUKI, H., SHIH, H. T., DEWA, S. I. and NG, P. K. L. 2014. The Hydrothermal Crab,
Xenograpsus testudinatus Ng, Huang & Ho, 2000 (Crustacea: Decapoda: Brachyura:Grapsidae) in Southern Japan. Proceedings of the Biological Society of Washington, 127(2):391-399.
TAKEDA, M. and KURATA, Y. 1977. Crabs of the Ogasawara Islands. IV. A Collection Made at theNew Volcanic Island, Nishino-Shima-Shinto, in 1975. Bulletin of National Science Museum(A) Zoology, 3(2): 91-111.
Ṋ⏣ṇ೔࣭Ṋෆᏹྖ࣭Ⳣ἟ᘯ⾜ 1993㸬ࢽࢩࣀࢩ࣐࣍࢘࢟࢞ࢽࡢ෌Ⓨぢ㸬⮬↛⎔ቃ⛉Ꮫ◊✲㸪6㸸59-64㸬