チョウミミズ

フトミミズ科＞アズマフトミミズ属＞ チョウミミズ Amynthas glabrus (Gates, 1932)

Pheretima glabra Gates, 1932a: 395, 1960c: 262, 1972a: 187.

Amynthas glabrus Sims & Easton, 1972: 237; Easton, 1981: 50; Blakemore, 2003: 6, 19, 2008d: 61; 2012b: 18; Huang et al., 2006: 12.

Pheretima vieta 小林, 1941d: 376, 1941g: 513.

Amynthas vietus Sims & Easton, 1972: 237.

Amynthas tenellulus Sims & Easton, 1972: 237.

Pheretima papilio (= non Gates, 1930) Ohfuchi, 1956: 140; 大淵・山口, 1956: 550; 上平, 1973a: 60.

基産地

基産地：ミャンマーのNam Hpen Noi

タイプ標本所在地：Lost (Reynolds & Wetzel, 2015)

形態

＜外部形態＞

　全長 30-110 mm (30-110 [Gates, 1972a]、45-51 [Ohfuchi, 1956]、75-110 [Gates, 1932a])、体幅 1.5-5 mm (1.5-5 [Gates, 1972a]、3-4 [Ohfuchi, 1956]、4-5 [Gates, 1932a])、体節数 95-119 (95-123 [Ohfuchi, 1956]、114-119 [Gates, 1932a]、114-122 [Gates, 1972a])。

　体色は無色で、環帯は赤色味を帯びる。石垣島では、背面は緑色で、体前半部は緑バフ色、後半部では明緑色、原は灰色味を帯びる (Ohfuchi, 1956)。

　剛毛は第 7 体節で 19-22 本 (Ohfuchi, 1956)、第 8 体節で 48-63 本 (48-52 [Ohfuchi, 1956]、58-63 [Gates, 1972a])、第 19 体節で 6-10 本で平均 8.1± 1.1 本 (Gates, 1932a)、第 20 体節で 39-66 本 (39-66 [Gates, 1972a]、45-48 [Ohfuchi, 1956]、48-54 で平均 52.1±2.0 [Gates, 1932a])。第一背孔は第 12/13 体節間溝。

　環帯は第 14-16 体節の 3 体節を占め、体節間溝や剛毛を欠く。受精囊孔は第 6 体節の剛毛線と第 6/7 体節間溝の中間に、横筋のスリット状に開口する (Ohfuchi, 1956; Gates, 1972a)。なお、大淵・山口 (1965) は第 6/7 体節間溝と述べているが、これは誤記であろう (南谷, 私見)。雌性孔は 1 つ。雄性孔周辺は体表から盛り上がり、第 17 体節から第 18/19 体節間溝まで前後に細長く盛り上がる。この盛り上がりの前縁後端は丸みを帯びる。雄性孔はこの盛り上がりの中央にある溝の後端にあり、雄性孔は小さな横長の凹み。雄性孔間距離は剛毛 4-9 本分 (4-6 [Gates, 1932a]、7-9 [Ohfuchi, 1956])。雄性孔間剛毛は 0-5 本 (0-5 [Gates, 1972a]、2-3 [Ohfuchi, 1956])。

＜内部形態＞

　隔膜は第 4/5/6/7/8 体節にあり、第 5/6/7/8 体節間ではやや厚く筋肉質で、第 8/9 体節間では痕跡的、第 9/10/11 体節間では欠如する。第 11/12 体節間では薄い。

　腸管は第 20 体節 (Gates, 1932a) または第 17 体節 (Ohfuchi, 1956) から始まり、腸盲嚢は突起型で第 27 体節から第 18 体節まで (Gates, 1932a, 1972a) もしくは第 24 体節まで (Ohfuchi, 1956) 伸びる。

　精巣は 2 対。貯精嚢は小さいか (Gates, 1960c)、良く発達し第 11、12 体節にある (Ohfuchi, 1956)。卵巣は、第 12/13 体節間隔膜に接する (Ohfuchi, 1956)。受精嚢主嚢の導管は細く、嚢状部よりも短いか (Gates, 1972a)、嚢状部と同長で約 1 mm で幅 0.5 mm (Ohfuchi, 1956)。副嚢は主嚢よりも長く (Gates, 1972a)、先端は嚢状になるが曲がりくねらずまっすぐ (Ohfuchi, 1956)。受精囊を欠く個体もいる (Gates, 1932a, 1972a)。摂護腺は第 17-23 体節の 7 体節分を占め (Gates, 1972a)、導管は 4.5-8 mm と長く、湾曲するか (Gates, 1972a)、直線的 (Ohfuchi, 1956)。

＜原記載（クリックして展開）＞

“Manure”, Nam Hpen Noi, August, H. Young, 20 aclitellate and 4 clitellate specimens.

Description of the type specimen.

External anatomy. – (Statements in parentheses refer to other specimens.)

Length 75 mm (to 110 mm). Greatest diameter 4 mm (to 5 mm). Number of segments 114 (119, 117, 119, 116, 116). Unpigmented, clitellum reddish.

The setae begin on ii, on which segment there is an unbroken circle. A midventral break is usually lacking in the setal circles but a slight mid-dorsal break of variable width may be present. Setae are lacking ventrally on xvii and xviii and laterally on xix in a region just behind each genital marking. Setal numbers are indicated below. 8.1±1.1 (6-10) in xix, 52.1±2.0 (48-54) in xx.

The first dorsal pore is in 12/13. (The first dorsal pore is in 12/13 in all of the specimens, but one worm has a pore-like marking in 11/12).

The clitellum is annular, extending from 13/14 to 16/17, intersegmental furrows lacking; no setae recognized; pore-like markings in the region of 14/15 and 15/16.

There is a single female pore.

The male pores are tiny transverse slits at the posterior ends of the grooves on the genital markings.

The genital markings are two, each marking elongate, with rounded ends, flattened, but protuberant from the surface of the body (especially anteriorly), placed diagonally with the posterior end slightly nearer the midventral line than the anterior end, and extending antero-posteriorly from mid xvii to the region of 18/19. (The markings may be diagonal in position or parallel to the midventral line). Each marking is provided with a central, antero-posterior groove, the posterior end of which turns laterally to pass into the male pore. (The genital markings are about 4-6 intersegmental distances wide transversely. There is a smooth glistening region midventrally extending from 16/17 to the setae of xix on which intersegmental furrows and setae are lacking).

Internal anatomy. – (Opened 24 specimens).

Septa 4/5-7/8 are present, 5/6-7/8 slightly thickened and muscular, 8/9 is a ventral rudiment only, 9/10 and 10/11 apparently are lacking (a sheet of tissue attached peripherally to the anterior face of 11/12 which covers over ventrally both pairs of testis sacs may represent a rudiment of 9/10 or 10/11), 11/12 is thin, 12/13-13/14 and several succeeding septa are slightly strengthened.

The intestinal enlargement of the gut begins in xx (xix-xx). (The gut is narrow and light coloured through xviii even in the smallest specimens). The intestinal caeca are simple, extending from xxvii into xviii (xviii-xx).

There are masses of nephridia in v and vi.

The single commissure of ix is on the left side. (The single commissure of ix is on the left side in 11 specimens, on the right side in 11 specimens; a pair of commissures belonging to ix in one specimen). The last pair of hearts is in xiii. There are no hearts belonging to segment x. (All the commissures of ix, xi-xiii pass into the ventral vessel. The commissures of xi pass through the posterior testis sacs.)

There are two pairs of testis sacs; the sacs of a side are in contact and project anteriorly in a diagonal fashion from the anterior face of 11/12 so that the anterior sac is further from the nerve cord than the posterior sac. The sacs of a segment are widely separated from each other and without transverse communication or connection. The seminal vesicles of xi and xii are large, covering over the dorsal blood vessel in those segments, the anterior vesicles extending forward into contact with the gizzard, the posterior vesicles pushing 12/13 posteriorly into contact with 13/14. The prostates extend through segments xvii-xix (xvii-xx) but push 19/20 posteriorly and 16/17 anteriorly into contact with 15/16. The prostatic duct is about 4 1/2 mm long; an ental portion about 1 1/2 mm in length is narrow but pinkish and firm while the ectal two thirds or three quarters is much thickened.

There are no spermathecae. (There are no traces of the presence of spermathecae in the parietes even after removal of the longitudinal musculature).

Remarks. –

The prostatic ducts, the prostates, the seminal vesicles and the testis sacs are characteristically formed and well developed even in the smallest specimens. All specimens, even very short worms 40-50 mm in length have the genital markings.

This worm may be merely an athecal variety but the thecal from does not appear to have been found. There are some resemblances to P. doliaria but the genital markings and the testis sacs are quite different, while P. doliaria has paired hearts belonging to x as well as ventral setae on xvii and xviii. For these reasons P. glabra has not been regarded as a variety of P. doliaria.

分布

　国内では琉球列島でのみ記録され、沖縄本島 (小林, 1941g)、西表島 (Ohfuchi, 1956) に分布する。

　国外では、ミャンマー (Gates, 1932a, 1960c, 1972a)、ベトナム (Thai, 1982)、台湾 (Huang et al., 2006) に分布する。

図. これまでに出版された文献に基づくチョウミミズの分布確認地点.

生態

　Gates (1960c) は本種を単為生殖種としている。

備考

　大淵・山口 (1965) は papilio の和名をテフミミズとした。その後、上平 (1973) はチョウミミズとしたが、これは「てふ」が現代仮名遣いでは「ちょう」とされるためと考えられる。なお、この記載は glabrus の同定ミスであろうと考えられているため (Easton, 1981; Blakemore, 2003, 2012b)、本種の和名とした。

　Ohfuchi (1956) は西表島から Pheretima papillo Gates, 1930 を報告したが、形態学的特徴を総合的に判断すると本種の同定ミスであろうと考えられる (Easton, 1981; Blakemore, 2003, 2012)。

　Gates (1930) が新種記載した papilio は全長 90 mm、体節数 87、第一背孔が第 5/6 体節間溝、受精囊孔は第 5/6 体節間溝、雄性孔は第 18 体節に突出し、その前後に小さな唇状の縁取りがあるとされている。一方で、Ohfuchi (1956) が西表から報告した papilio は全長 45-51 mm、体節数 95-123、第一背孔が第 12/13 体節間溝、受精囊孔は体節間溝ではなく、第 6 体節の剛毛線より後ろ側の体節上、雄性孔は第 17-19 体節に達する大きな縦方向の陥没状型の性徴の中に開口すると述べられている。これらの特徴は、体サイズは小さいものの glabrus の特徴に一致する。

シノニムリスト

Pheretima glabra Gates, 1932a: 395. [形態記載]

Pheretima vieta 小林, 1941d: 376. [記述のみ]

Pheretima vieta 小林, 1941g: 513. [記述のみ]

Pheretima papilio Ohfuchi, 1956: 140 (non Gates, 1930). [形態記載]

Pheretima glabra Gates, 1960c: 262, 278. [特徴記述]

Pheretima papilio 大淵・山口, 1965: 550. [同定形質のみ]

Amynthas glabrus Sims & Easton, 1972: 237. [記述のみ] (Sep ?, 1972)

Amynthas tenellulus Sims & Easton, 1972: 237. [記述のみ] (Sep ?, 1972)

Amynthas vietus Sims & Easton, 1972: 237. [記述のみ] (Sep ?, 1972)

Pheretima glabra Gates, 1972: 187 (syn. tenellula, vieta). [形態記載]

Pheretima papilio 上平, 1973a: 60 チョウミミズ. [同定形質のみ] (?, 1973)

Amynthas glabrus Easton, 1981: 50 (syn. vieta, papilio Ohfuchi, 1956). [同定形質のみ] (Apr 30, 1981)

Amynthas glabrus Blakemore, 2003: 6, 19 (syn. tenellula, vieta, papilio Ohfuchi, 1956). [同定形質のみ]

Amynthas glabrus Huang et al., 2006: 12. [記述のみ]

Amynthas glabrus Blakemore, 2008d: 61 (syn. tenellula, vieta, papilio Ohfuchi, 1956). [同定形質のみ] (Dec ?, 2008)

Amynthas glabrus Blakemore, 2012b: 18 (syn. tenellula, vieta, papilio Ohfuchi, 1956). [記述のみ] (Feb 28, 2012)

引用文献

Blakemore, R.J., 2003. Japanese earthworms (Annelida: Oligochaeta): A review and checklist of species. Organisms Diversity and Evolution 11: 1-43.

Blakemore, R.J., 2008d. A review of Japanese earthworms after Blakemore (2003). 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, R.J., 2012b. Japanese earthworms revisited a decade on. Zoology in the Middle East 58 suppl 4: 15-22.

Gates, G.E., 1932a. The earthworms of Burma. III. The Megascolecinae. Records of the Indian Museum 34: 357-549.

Gates, G.E., 1960c. On Burmese earthworms of the family Megascolecidae. Bulletin of the Museum of Comparative Zoology123: 203-282.

Easton, E.G., 1981. Japanese earthworms: A synopsis of the Megadrile species (Oligochaeta). Bulletin of the British Museum Natural History (Zoology) 40(2): 33-65.

Gates, G.E., 1972a. Burmese earthworms- An introduction to the systematics and biology of megadrile oligochaetes with spacial reference to southeast Asia. Transactions of the American Philosophical Society 62(7): 1-326.

Huang, J., Qin, X., Zheng, J.S., Chong, W., Dong, M.Z., 2006. Research on earthworm resources of China: I. Check-list and distribution. Journal of China Agricultural University 11(3): 9-20.

上平幸好, 1973a. 日本産陸棲貧毛類フトミミズ属(Genus Pheretima), 種の検索表. 函館大学論究 7: 53-69.

小林新二郎, 1941d. 西日本に於ける陸棲貧毛類の分布概況. 動物学雑誌 53(8): 371-384.

小林新二郎, 1941g. 九州地方陸棲貧毛類相の概況. 植物及動物 9(4): 511-518.

Ohfuchi, S., 1956. On a collection of the terrestrial oligochaeta obtained from the various localities in Ryu-Kiu Islands, together with the consideration of their geographical distribution (Part 1). Journal of Agricultural Science, Tokyo Nogyo Daigaku 3(1): 131-176.

大淵真龍, 山口英二, 1965. 環形動物貧毛綱. In: 内田亨 (編), 新日本動物図鑑上. 北隆館、東京 p.533-563.

Reynolds, J.W., Wetzel, M.J., 2015. Nomenclatura Oligochaetologica. A Catalogue of Names, Descriptions and Type Specimens of the Oligochaete 2nd Ed. http://wwx.inhs.illinois.edu/people/mjwetzel/nomenoligo/nomenclatorspecierum/nomspec-g/

Sims, R.W., Easton, E.G., 1972. A numerical revision of the earthworm genus Pheretima auct. (Megascolecidae: Oligochaeta) with the recognition of new genera and an appendix on the earthworms collected by the Royal Society North Borneo Expeditions. Biological Journal of the Linnean Society 4: 169-268.

[要検討]

glabrus

Thai(1982):818, Nakamura(1999):24, Blakemore(2005):19, Blakemore(2007c):61

vieta

Ishizuka(1999a):66, Nakamura(1999):24