フトミミズ科 ＞ アズマフトミミズ属 ＞
ヤンバルオオフトミミズ Amynthas yambaruensis (Ishizuka et al., 2000)
Pheretima
yambaruensis Ishizuka et al., 2000: 90.
Amynthas
yambaruensis Blakemore, 2003: 25, 2007e: 106, 2008: 81, 2012b:
18.
タイプ産地：西銘岳（沖縄島）
タイプ標本所在地：ホロタイプ 国立科学博物館（NSMT-An-330）
パラタイプ 国立科学博物館（NSMT-An-331）
琉球大学資料館（風樹館）（RUMF-ZO-1, 2）
＜外部形態＞
全長 210-410 mm (Ishizuka et al., 2001; 安座間, 2015)、体幅 7.5-11.2 mm (Ishizuka et al.,
2001; 安座間, 2015)、体節数 85-150 (Ishizuka et al., 2001; 安座間, 2015)。
剛毛は第 7 体節で 36-46 本、第 20 体節で 60-74 本。
体色は背面は黒紫褐色で、腹面は黃灰色。剛毛線が明褐色であり、縞模様に見える。
第一背孔は第 12/13 体節間溝もしくは第 13/14 体節間溝に開口する。
受精囊孔は 3 対で、第 6/7/8 体節間溝にあり、1 対の受精囊孔間距離は体周の 1/3 ほど。環帯は第 14-16 体節を占める。雌性孔は第 14 体節の腹側中央に 1 個。雄性孔は第 18 体節にあり、突起状型で、雄性孔間距離は体周の 1/3
ほど。性徴は吸盤状で、受精囊孔と同一線上に、第 8 体節の剛毛線より後ろに 1 対、第 9 体節の剛毛線より前に 1 対、腹中央寄りに第 9 体節に 1 対あるが、個体により欠如する場合がある。第 18 体節には、雄性孔に近接して 1 対、雄性孔近くのやや腹中央寄りの剛毛線の前後に 1
対ずつの吸盤型性徴を持つ。生殖腺を欠く外部表徴として、第 6–8 体節の受精囊孔に近接して剛毛線より後ろに 1 対ずつが存在する。
＜内部形態＞
隔膜は、第 8/9/10 体節間で欠く。
腸管は第15体節から始まる。腸盲嚢は鋸歯状型で、第 27 体節に開口し、3–5 体節前方に伸びる。
受精嚢は 3 対で第 7–9 体節にあり、主嚢はシャベル型で導管は太い。副嚢は小さなソーセージ型で、導管は長い。貯精嚢は第 11–12 体節に、卵巣は第 13 体節にある。卵胞は欠く。摂護腺は 3
体節分を占める。生殖腺は胞状で、第 8、9、18 体節にある。
Description. Body. Length 210-410 mm, width 7.5-11.2 mm.Number of segments 85-150.Blackish purple brown dorsally, yellowish grey ventrally; a light brown band in setae-lines
showing a banded pattern in appearance.
External characters.Three pairs of spermathecal pores situated in furrows 6/7/8/9, in ventro-lateral sides, separated by a distance of ca. 1/3 body circumference.Genital
markings paired, circular sucker-shape; preclitellar to the line of the spermathecal pores, postsetal on segment VIII, presetal on segment IX, close to the median line of the spermathecal
pore, presetal on segment IX, variable in the number and occasionally absent; postclitellar closely associated with the male pores, postsetal on segment XVIII, pre- and postsetal slightly
median to the line of the male pores on segment XVIII.External markings (genital glands absent) paired, circular sucker-shape; preclitellar closely associated with spermathecal pores,
postsetal on segments VI-VIII.Male pores large, simple, superficial on segment XVIII, separated by a distance of ca. 1/3 body circumference.Femal pore single, mid-ventrally on segment
XIV.First dorsal pore beginning in furrow 12/13 or 13/14.Setal number 36-46 in segment VII, 60-74 in segment XX.
Internal characters. Serrate intestinal caeca, paired, originating in segment XXVIII, extending anteriorly for 3-5 segments. Intestine begins in XV.Genital glands, paired,
glandular masses, in segment VIII, IX and XVIII, associated with genital markings restricted to body wall. Septa absent in 8/9/10, very thickened and muscular in 5/6/7/8 and 10/11/12/13/14.
Three pairs of spermathecae in segments VII-IX; ampulla consisting of a shovel-shaped pouch and a thick duct; diverticulum consisting of a small sausage-shaped pouch and a long duct. Seminal
vesicles small, extending to the dorsal line in segment XI, XII. Prostate extending through segments XVII-XIX, associated with the male pores.
Material examined.Holotype (NSMT-An-330): Mt. Nishimedake, Okinawa Island, 24-V-1984, Y. Azama, on a road just after the rain under the natural forest dominated by C.
sieboldii. One paratype (NSMT-An-331): Mt. Nishimedake, Okinawa Island, 14-II-1999, Y. Azama, on a road just after the rain under the natural forest dominated by C. sieboldii. Two paratypes
(RUMF-ZO-1, 2): 1 ex. Mt. Nishimedake, Okinawa Island, 21-X-1999, T. Sasaki, 1 ex. Mt. Tamatsuji, Okinawa Island, 24-VI-1999, Y. Azama, on a road just after the rain under the natural forest
dominated by C. sieboldii. Other specimens examined: 1 ex. Yambaru area, Okinawa Island, 1-II-1990, S. Baba. 1 ex. With same data as paratypes (RUMF-ZO-1). 1 exs. [sic] Mt. Nishimedake,
Okinawa Island, 18-XII-1998, K. Ishizuka. 1 ex. Mt. Nishimedake, Okinawa Island, 14-II-1999, Y. Azama.
Remarks. The new species resembles Pheretima pingi Stephenson 1925, but is distinguishable from the latter species by (1) three pairs of spermathecal pores situated
in furrows 6/7/8/9 (four pairs of spermathecal pores in Pheretima pingi), (2) serrate intestinal caeca (simple intestinal caeca in Pheretima pingi) and (3) Genital markings
paired close to the median line on segment IX. The new species is characterized as the largest-sized species in Okinawa Island and the color of the body. Therefore, this species is one of
representive animals from Yambaru, Okinawa Island.
シイが優占する天然林に生息する（Ishizuka et al., 2000）。
林床に高さ 10 cm、径 5 cm 前後の糞塚を形成する (安座間, 2015)。
Pheretima
yambaruensis Ishizuka et al., 2000: 90. [形態形質の記述] (Feb 29, 2000)
Amynthas
yambaruensis Blakemore, 2003: 25. [同定形質の記述]
Amynthas
yambaruensis Blakemore, 2007e: 106. [記述のみ]
Amynthas
yambaruensis Blakemore, 2008: 81. [同定形質の記述]
Amynthas
yambaruensis Blakemore, 2012b: 18.
ヤンバルオオフトミミズ 安座間, 2015: 585. [同定形質のみ] (Apr, 2015)
安座間安史, 2015. ミミズ類. In: 沖縄県立図書館資料編集室 (編), 沖縄県史 各論編1. 自然環境. 沖縄県教育委員会, 那覇. pp. 583-585.
Blakemore RJ, 2003. Japanese earthworms (Annelida: Oligochaeta): A review and checklist of species. Organisms Diversity and Evolution 11: 1-43.
Blakemore RJ, 2007e. Updated checklist of pheretimoids (Oligochaeta: Megascolecidae: Pheretima auct.) taxa. In: Ito MT, Kaneko N,
(eds.), A Series of Searchable Texts on Earthworm Biodiversity, Ecology and Systematics from Various Regions of the World, 2nd Edition (2006) and
Supplemental. COE soil Ecology Research Group, Yokohama National University, Japan. CD-ROM Publication.
Blakemore RJ, 2008. A review of Japanese earthworms after Blakemore (2003), a checklist and excel key. In: Ito MT, Kaneko N,
(eds.), A Series of Searchable Texts on Earthworm Biodiversity, Ecology and Systematics from Various Regions of the World, 2nd Edition (2006) and
Supplemental. COE soil Ecology Research Group, Yokohama National University, Japan. CD-ROM Publication.
Blakemore RJ, 2012b. Japanese earthworms revisited a decade on. Zoology in the Middle
East 58 suppl 4: 15-22.
Ishizuka K, Azama Y, Sasaki T,
2000a. Two new species of the genus Pheretima s. lat. (Family Megascolecidae) from the Yambaru District, Okinawa Island, Japan. Edaphologia 65:
89-95.
日本産ミミズ大図鑑
