Eukerria saltensis

　カイヨウミミズ科＞ Eukerria 属＞ Eukerria saltensis (Beddard, 1895)

タイプ標本

基産地：バルパライソ（チリ）、サルタ（アルゼンチン）

タイプ標本所在地：アメリカ合衆国国立自然史博物館 (USNM 21025)、ロンドン自然史博物館 (BMNH 1904: 10:5:928)

形態

＜外部形態＞

　全長 25-100 mm (25 [原記載]、25-100 [Jamieson, 1970c])、体幅 1-2 mm (Jamieson, 1970c)、体節数 118-135 (Jamieson, 1970c)。

　体色は無色。

　剛毛配列は、aa = bc、ab = cd、dd:u = 0.35-0.39 (Jamieson, 1970c)。環帯にも、a 剛毛は全て存在するが、b剛毛は第 17-19 体節のみに存在する (Jamieson, 1970c)。

　腎管孔は外部からは認められない (Jamieson, 1970c)。

　環帯は第 13 1/2-20 体節 (14-20 [原記載]、13 1/2、14-19、20 3/4 [Jamieson, 1970c]) の 7-8 体節分を占め、第 17-19 体節では腹側で環帯が途切れる (原記載)。雌性孔は第 14 体節前半の b 剛毛線周辺に開口する。摂護腺孔はごく小さな突起状で、第 17、19 体節の b 剛毛線の側方に近接している (Jamieson, 1970c)。両方の摂護腺孔は精溝でつながり、第 18 体節で湾曲し、第 18 体節に雄性孔が開口する (Jamieson, 1970c)。受精囊孔は第 7/8/9 体節間溝で、bc剛毛線間の 2/3 の位置もしくは中間にある (Jamieson, 1970c)。

＜内部形態＞

　隔膜は、第 5-9 体節で厚い (原記載では第 5/9 体節と記述)。

　心房は 3 対で、第 9-11 体節にあり (Jamieson, 1970c)、最終心房は第 11 体節。

　砂嚢は第 7 体節で、あまり発達しない。石灰腺は細い洋梨形で (Jamieson, 1970c)、第 9 体節。腸管は第 12-13 体節 (12 [Jamieson, 1970c]、13 [原記載]) から開始する。

　受精囊は第 8-9 体節にあり、副嚢を欠く。受精囊は全長 0.5-0.8 mm で (Jamieson, 1970c)、嚢状部と導管部に別れ、同長。嚢状部は長卵形 (Jamieson, 1970c)。精巣は第 10 体節、貯精嚢は第 11 体節 (原記載)、もしくは第 9、11 体節か、第 11 体節のみ (Jamieson, 1970c)。卵巣は第 13 体節 (Jamieson, 1970c)。摂護腺はとても細長く、幅 0.06-0.1 mm (Jamieson, 1970c)。摂護腺は後方に第 26 体節まで伸びる (Jamieson, 1970c)。摂護腺の導管は細い (Jamieson, 1970c)。

＜原記載（クリックして展開）＞

　　The general aspect of this apparently new species recalls that of the species Kerria halophila. But it evidently differs from that species, though not in very important points; indeed, all the American species of the genus come near together. I leave out in the following description the majority of the characters which are, so far as our present knowledge goes, of generic value and confine myself to those characters which appear more or less to distinguish the species. It is a small species, about an inch in length; there is no pigmentation at all discernible. The clitellum occupies segments XIV-XX, and is incomplete ventrally on the genital segments, i.e. segments XVII-XIX. On those segments only the inner of the two ventral setae are present.

　　There is a not very well developed gizzard in segment VII. The calciferous glands, as usual, are in IX. They are rather thick-walled but are without any folds of the lining epithelium. The walls are vascular, but whether there is the mass of tubules which I have described in the last species I am unable to say. The intestine appears to begin in segment XIII. At any rate in this segment the lining epithelium undergoes a sudden change in thickness, being from that segment onwards much thinner; at the end of the twelfth segment the thick epithelium projects into the lumen of the gut of the next segment and forms a kind of trap which would allow of the passage of food backwards, but would not allow of its passage in the opposite direction. The first segment of the intestine, however, as I find it, is of less calibre than the section which commences in the fourteenth segment; but it differs from the section which begins in that segment by being rather folded.

　　The thick septa occupy segments V/IX, but the next two are thicker than those which follow. The last heart is in XI.

　　The spermathecae, without any diverticula, are in VIII, IX; they consist of a thick-walled duct and of a thin-walled portion which is stored with sperm. The length of the two regions of the spermathecae is about the same.

　　The epithelium which lines the thick-walled section of the organ which may be regarded as the duct is thrown into folds; there is no folding of the distal section. The testes are, as usual, in segment X. This segment also contains the sperm-duct's funnels. There seems to be only a single pair of sperm-sacs, which are in segment XI, and are not racemose in character. The cavity of the tenth segment contained a mass of developing sperm; but this cannot be regarded as the equivalent of a sperm-sac, for it was not surrounded by any membrane. The sperm-ducts were not developed in the specimen which I examined by means of transverse sections; on the other hand, the oviducts were fully developed, and their openings on to the exterior in segment XIV were quite obvious. The spermiducal glands reached back as far as the twenty-fifth segment.

　　Hab. Valparaiso, Salto.

Jamieson (1970c) p. 150 Fig. 4 より

分布

　国外では、イギリス (Rota, 2013)、フランス (Rota, 2013)、イタリア (Rota, 2013)、ミャンマー (Jamieson, 1970c; Reynolds, 2009b)、台湾 (Tsai et al., 2009)、ニューカレドニア (Jamieson, 1970c)、オーストラリア (Jamieson, 1970c)、アメリカ合衆国 (Reynolds, 2011a)、ボリビア (Zicsi, 1995; Christoffersen, 2008a)、ブラジル (Righi, 1968; Brown & James, 2006; Sautter et al., 2006; Christoffersen, 2008a)、チリ (Beddard, 1895a; Cognetti, 1905a; Jamieson, 1970c; Zicsi, 2004; Christoffersen, 2008a)、アルゼンチン (Beddard, 1895a; Jamieson, 1970c; Righi, 1984; Mischis & Righi, 1999; Christoffersen, 2008a)、コンゴ (Zicsi & Csuzdi, 2000)、南アフリカ (Jamieson, 1967b; Jamieson, 1970c; Sims, 1978) に分布する。

　世界に広く分布しているが、起源はアルゼンチンからパラグアイにかけてと推定されている (Brown et al., 2006)。

　イースター島に分布する。

Michaelsen, 1898; Mischis & Gleiser, 1999; Mischis, 1999; Mischis & Brigada, 1985; Gavrilov, 1952; Ljungstrom et al., 1973, 1975l Zicsi, 1995a

生態

　洪水や道路網の整備によって、本種が分布拡大を行っていると考えられる (Rota, 2013)。

備考

　Gates (1982) による32年間の植物検疫では、本種は発見されていない (Rota, 2013 による引用)。

シノニムリスト

Kerria saltensis Beddard, 1895: 225. [形態記載]

Kerria saltensis Michaelsen, 1900: 371.

Kerria saltensis Cognetti, 1905a: 49.

Eukerria saltensis Jamieson, 1967b: 61 (syn. Acanthodrilus sydneyensis, Kerria gunningi, K. nichollsi).

Eukerria saltensis Righi, 1968: 370.

Eukerria saltensis Jamieson, 1970c: 152 (syn. sydneyensis, gunningi, ? K. nichollsi). [形態記載] (Dec 31, 1970)

Eukerria saltensis Gates, 1976c: 2. [記述のみ] (Apr, 1976)

Eukerria saltensis Sims, 1978: 671.

Eukerria saltensis Gates, 1982: 66.

Eukerria saltensis Righi, 1984: 11. [記述のみ]

Eukerria saltensis Zicsi, 1995: 604.

Eukerria saltensis Mischis & Righi, 1999: 63.

Eukerria saltensis Zicsi & Csuzdi, 2000: 129. [記述のみ]

Eukerria saltensis Zicsi, 2004: 124. [記述のみ]

Eukerria saltensis Brown & James, 2006: 147.

Eukerria saltensis Sautter et al., 2006: 298.

Eukerria saltensis Christoffersen, 2008a: 100 (syn. sydneyensis, gunning, nichollsi, saltiness bellavistensis). [記述のみ]

Eukerria saltensis Blakemore, 2008d: 33 (syn. sydneyensis, gunningi, nichollsi). [記述のみ] (Dec ?, 2008)

Eukerria saltensis Tsai et al., 2009: 38.

Eukerria saltensis Reynolds, 2009b: 67. [記述のみ] (Aug, 2009)

Eukerria saltensis Blakemore, 2010b: 203. [記述のみ]

Eukerria saltensis Reynolds, 2011a: 284. [記述のみ] (Apr, 2011)

Eukerria saltensis Blakemore, 2012b: 17. [記述のみ] (Feb 28, 2012)

Eukerria saltensis Blakemore et al., 2012: 302. [NIBR IV0000213619]

Eukerria saltensis Rota, 2013: 4.

[要検討]

Kerria saltensis Beddard, 1896:42, Michaelsen, 1898: 479; 1904: 286, 1907: 23, 1935a: 103, 1935b: 40; Pickford, 1928: 378; Gates, 1942: 73; Gavrilov, 1952: 692; Jamieson, 1967: 61.

Eukerria saltensis Gates, 1954: 243, 1979: 163.

Acanthodrilus sydneyensis Sweet, 900: 124.

Kerria gunningi Michaelsen, 1913b: 1, 1913c: 419, 1913e: 276

Kerria nichollsi Jackson, 1931: 121

Eukerria saltensis

引用文献

Beddard, F.E., 1895a. Preliminary account of new species of earthworms belonging to the Hamburg Museum. Proceedings of the General Meetings for Scientific Business of the Zoological Society of London 63(2): 210-239.

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 RJ, 2010b. Unravelling some Kinki earthworms (Annelida: Oligochaeta, Megadrili: Megascolecidae)- Part II. Opuscula Zoologica, Budapest 41(2): 191-206.

Blakemore, R.J., 2012b. Japanese earthworms revisited a decade on. Zoology in the Middle East 58 suppl 4: 15-22.

Blakemore, R.J., Cho, J.L., Park, T.S., 2012. Six exotic terrestrial earthworms (Oligochaeta: Megadrilacea: Moniligastridae, Lumbricidae, Ocnerodrilidae & Megascolecidae) newly added to Korean species biodiversity list. Zootaxa 3368: 300-304.

Browon, G.G., James, S.W., 2006. Earthworm biodiversity in Sao Paulo state, Brazil. European Journal of Soil Biology 42: S145-S149.

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Jamieson, B.G.M., 1967b. New records of Ocnerodrilidae and Lumbricidae (Oligochaeta) from South African rivers. Zoologica Africana 3: 59-86.

Jamieson, B.G.M., 1970c. A taxonomic revision of the oligochaete genus Eukerria Michaelsen, 1935 (Ocnerodrilinae, Megascolecidae). Bulletin of the British Museum (Natural History), Zoology 20: 131-172.

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Tsai, C.F., Shen, H.P., Tsai, S.C., Lin, K.J., Hsieh, H.L., Yo, S.P., 2009. A checklist of oligochaetes (Annelida) from Taiwan and its adjacent islands. Zootaxa 2133: 33-48.

Zicsi, A., 1995. Regenwürmer aus Bolivien (Oligochaeta). Revue Suisse de Zoologie 102(3): 585-608.

Zicsi, A., 2004. Die Regenwurmfauna Chiles mit Bestimmungsschlüsseln der Chilota-, Yagansia- und Eodrilus- Arten (Oligochaeta: Acanthodrilidae) Regenwürmer aus Südamerika 40. Berichte des naturwissenschaftlichen-medizinischen Verein Innsbruck 91: 111-128.

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Michaelsen, 1898; Mischis & Gleiser, 1999; Mischis, 1999; Mischis & Brigada, 1985; Gavrilov, 1952; Ljungstrom et al., 1973, 1975l Zicsi, 1995a