日本産ミミズ大図鑑
タンボフトミミズ
Metaphire tanbode Blakemore, 2010: 193.
タイプ標本
タイプ産地：ホロタイプ・パラタイプ 滋賀県大津市黒津5丁目 35°1′N、135°51′E
タイプ標本所在地：ホロタイプ 滋賀県立琵琶湖博物館 LBM1380000094
パラタイプ 滋賀県立琵琶湖博物館 LBM1380000095、LBM1380000096
形態
＜外部形態＞
体長 70-100 mm、体幅 2-3 mm。体節数約 100。
剛毛は第 12 体節で 55 本で、それより後ろの体節では 50-60 本。
第一背孔は第 12/13 体節間溝。
環帯は第 14-16 体節を占める。受精嚢孔は 2 対で第 6/7/8 体節間溝にあり、体幅の 0.4 離れる。雌性孔は第 14 体節の中央に 1 個開口する。雄性孔は第 18 体節にあり、体幅の 0.4 離れる。雄性孔は少し盛り上がり、陥没状型。性徴はやや大きな膨れた吸盤状で、第 17/18 体節間溝から第 18 体節の剛毛線まで広がる。この性徴に対応するように、第 8 体節の腹面中央に皺がよった部分があり、交尾した痕跡であり、本来の性徴とは異なると考えられる。
＜変異個体＞左側の雄性孔が第 17 体節にずれた個体が発見され（右側の雄性孔は通常どおり第 18 体節）、右側の受精嚢孔は通常どおり第 6/7/8 体節間溝であるが、左側は第 6/7 体節間溝にしかなかった (Blakemore, 2010)。性徴は第 16/17 体節間溝と第 17/18 体節間溝にあった。また、右側雄性孔を欠き、左側受精嚢孔は通常どおりであったが、右側には第 7/8 体節間溝にしか受精嚢孔を持っていない個体が見つかっている (Blakemore, 2010)。
＜内部形態＞
隔膜は第 8/9/10 体節間溝で欠き、第 10/11 体節間溝では厚い。
砂嚢は第 7/8 体節間溝から始まる。腸管は第 15.5 体節から始まる。腸盲嚢は指状型で 4 本の小嚢に分かれ、第 27 体節に開口する。
最終心臓は第 13 体節。
精巣は第 10-11 体節にあり、貯精嚢は第 10-11 体節にある。受精嚢は 2 対で第 7-8 体節にある。受精嚢の副嚢の導管は長く、主嚢は赤唐辛子型もしくはパプリカ型。摂護腺の導管は長く筋肉質で U 字型。生殖腺は無柄で、第 17-18 体節の腹行神経の下にある。
Type material. Preliminary rice paddy survey of Tanakami region near Kurotsu, southern Otsu-shi, Shiga-ken, Kinki Japan sample stations #1-3, leg. RJB, all
deposited with initial Accession No.: Misc. Invert. FY2009-13 in Lake Biwa Museum (hereafter, LBM) initially tagged as “A. shigai sp. nov.?”. Holotype (H) ex samples from Kurotsu, 5-chome
(type locality), Otsu-shi, 35°1’N, 135°51’E, elev. 〜80 m, sketched, dissected and providing tissue for DNA extraction: LBM 1380000094; Paratypes (P1–P6) with same collection data as H but
including pooled specimens from three closely adjacent sites, only P1, a posterior amputee, dissected: LBM 1380000095 (6 specimens); P7 same collection data but from yet another paddy in
the same vicinity, male field figured and a tissue sample taken from posterior for comparative DNA analysis: LBM 1380000096.
Etymology. Japanese (genderless) noun phrase in apposition meaning “from the paddy”.
Diagnosis. Pheretimoid with spermathecal pores in 6/7/8, non-superficial male pores, manicate caeca and genital markings as a single, mid-ventral sucker from 17/18
to setal arc of 18 that lacks secondary papillae (as found in M. hilgendorfi spp-group members). Spermathecal diverticula are particularly elongated, more that twice the
ampulla length.
Distribution. Restricted to type-locality. It is surprising that this species, which is so patently a wanderer, appears to be not yet more frequently and more
widely recorded. Such a restricted distribution is more often characteristic of an introduced species, unless its superficial similarity to M. hilgendorfi (Michaelsen,
1892) has caused oversight.
External features. Holotype and all paratypes appear mature. H, P1 and P7 dissected. Body circular in section throughout. Slight brown
pigmentation mostly in anterior dorsum. Length ca. 70-100 mm by 2-3 mm [H, 92; P1, 60 (posterior amputee); P2, 95; P3, 85, P4-6, 70-90 and P7, 100 mm]. Segments ca. 100 (H,
92). Setae approx. 55 on 12 in H; or ca. 50-60 per segment thereafter. Prostomium open epilobous. First dorsal pore in 12/13 (H). Spermathecal pores small ca. 0.4U
apart in 6/7/8. Clitellum 14-16. Female pore single, central on 14. Male pores ca. 0.4U apart on slightly raised tumid mounds; primary pores on small porophores
withdrawn into slight invaginations (i.e. just classable as “non-superficial”). In H the male pores are in sunk in small pouches, but in P7 they protrude slightly and are seen to be
on the apices of small mounds protruding from puckered lips (see Fig. 1). Genital markings as moderately large tumid suker-like pad in 17/18 extending to setal arc of 18.
Corresponding puckered area mid-ventrally on 8 construed as an artefact of copulation and not an actual marking (it is also missing from P3, P6). Variations: P2 is abnormal as
male pores are on 17lhs and 18rhs, spermathecal pores are in 6/7/8rhs but only 6/7lhs and genital markings are in 16/17 as well as in 17/18; P3 lacks 18rhs male pore and spermathecal
pores are 6/7/8lhs but only 7/8rhs.
Internal anatomy. Septa 8/9/10 absent, 10/11 thin. Gizzard after 7/8. Last heart in 13. Nephridia meroic in forests, absent from spermathecal
ducts. Male organs holandric with testis in 10 and 11 and seminal vesicles in 10 and 11 (possibly slightly in 12 but not clear). Spermathecae in 7 and 8: usual ampulla with
diverticulum having long stalk and cayenne-chili or paprika-shaped bulb, all charged with sperm in H but are uncharged and displaced to 9lhs in P3. Ovaries quite small with funnels
in 13; ovisacs absent from 14. Prostates glandular with long, muscular U-shaped duct in 18 that is joined at its junction with gland by vas deferens. Couplatory pouch not
pronounced internally. A sessile glandular pad under ventral nerve cord in 17-18 corresponds with genital marking. Intestine from ½15. Typhosole simple, dorsal ridge
from about 20. Intestinal caeca from about 27, manicate, e.g., with four ‘fingers’ on rhs in H.
Ingesta. Organic silt and decayed plant stems and organic debris (paddy soil).
Behaviour. Found wandering on road surface between paddy fields early in the morning (~8:00 AM) thus probably stranded on the hard asphalt – to which no earthworm
is yet accustomed – after a night’s excursion on the surface. There was evidence of recent sex (puckered marks and spermathecae charged), thus it may be surmised both that
copulation occurs above ground and that only semi-permanent burrow systems are maintained, or that the ability to follow a return trail to a particular burrow is unreliable.
Genetics. Small tissue samples taken from non-essential posterior segments of H and P7 for DNA extraction, amplification and sequencing (results in Appendix 1a and
GenBank).
Parasites and predators. Numerous nematodes were found in coelom near prostates in H and some are stored in a separate vial in the sample jar.
Ecology/Species associations. Little is yet known of its ecology except that it appears to survive in periodically cultivated and waterlogged paddy soils.
Other species found on the same collecting trip. (Table 1 below) were: Moniligastridae: Drawida eda Blakemore, 2010 (as described in accompanying paper – Part 1);
Ocnerodrilidae: Eukerria saltensis; Megascolecidae: Amynthas megascolioides; A. corticis; A. gracilis; A. hupeiensis; Metaphire
hilgendorfi spp-complex; Lumbricidae: Eisenia japonica; Dendrodrilus rubidus and Helodrilus hachiojii. Some species, in mixed assemblages, were in
remarkable high numbers in the moist paddy soils; several leeches were also found and two of their cocoons collected.
Remarks. Summary of the current taxon is: spermathecal pores in 6/7/8, intestinal caeca manicate – as is frequently found in Japanese/ Korean speices – plus a
single, central, genital-making pad presentally in 17/18, 18 only. In Easton (1981) this taxon keys out as either a component of what is now the Metaphire hilgendorfi/
Amynthas tokioensis species complex, or as ‘Pheretima koellikeri’. Approximately 74 valid species have spermathecae in 6/7/8 (Blakemore, unpubl.); of these, about
21 are known to have manicate caeca plus having genital markings, when present, sometimes unpaired (but excluding such members of the M. hilgendorfi/ A. tokioensis that
are known to have paired markings or central markings comprising numerous papillae). Comparable regional species and most are poorly described and require extensive revision in
chronological order, are:
Amynthas vittatus (Goto & Hatai, 1898: 74) inadequately described with glandular genital markings equatorial in 7 and 8 (that Goto & Hatai mistook for
spermathecal pores) and often lacking male pores. It has striped coloration (pers. obs.).
Amynthas parvicystis (Goto & Hatai, 1899: 18) inadequately described with glandular genital markings paired anteirorly in 7 and 8 that (Goto & Hatai
mistook for spermathecal pores) plus paired markings median to male pores (when present).
Amynthas? yunoshimensis (Hatai, 1930: 655, fig. 4) has papillated markings midventrally in 8 and 18, similar to those in Metaphire hilgendorfi proper,
and in M. glandularis (Goto & Hatai, 1899: 18, fig. 9) where the equivalent markings are shown to be in 7 and 17/18. Its spermathecae and male pores were defective.
Amynthas tappensis (Ohfuchi, 1935: 409) with synonyms as per Blakemore (2003, 2005, 2007a) including ?Amynthas sanchongensis Hong & James, 2001 that
although said to be similar to sympatric Amynthas jiriensis (Song & Paik, 1971: 193) that is itself most likely a junior synonym of A. tokioensis (Beddard, 1892), if
not synonymous to A. tappensis, possibly qualifies for Metaphire due to its probable non-superficial male pores.
Metaphire servina (Hatai & Ohfuchi, 1937: 1) [? praeocc. Hatai, 1924] with genital markings small, paired, median to male pores equatorially on 18.
Amynthas gomejimensis (Ohfuchi, 1937: 18) that was stated by Ohfuchi (1937: 19) to resemble Pheretima servinus Hatai & Ohfuchi, 1937 (=
Metaphire servina) in all characters except its lack of genital markings; thus, because no fully mature specimens were found [hence it is difficult to understand how Ohfuchi
(1937: 20) could describe the clitellum in 14-16], it is possibly in synonymy of that taxon, or some other prior taxon.
Metaphire soulensis (Kobayashi, 1938: 131), revived by Blakemore (2003) from unlikely synonymy in M. yamadai (Hatai, 1930) by Easton (1981); this taxon
is believed to have genital markings median to spermathecal pores in 7 and 8 and within its copulatory pouches. A synonymis Pheretima aokii Ishizuka, 1999.
Amynthas gucheonensis (Song & Paik, 1970: 106) has paired genital patches in the neighborhood of male pores medially and anteriorly close to the setal line
of 18.
Metaphire geomunensis (Hong & James, 2001: 82) from Korea described with “male pores at tips of conical porophores” (= penes?) and with genital papillae
centered between male pores and in paired groups presetally in 7 near spermathecae. With respect to genital papillae, it is said to be similar to A. alveolatus Hong &
James, 2001: 81 [that is a junior synonym of Amynthas kanrazanus incretus (Kobayashi, 1937: 343)] and to A. yongshilensis Hong & James, 2001: 80 [that is a probable
junior synonym of A. k. kanrazanus (Kobayashi, 1937: 340)].
Amynthas songnisanensis Hong & Lee, 2001: 284 from Korea described with genital markings as slightly elevated, circular spots on segments 8-19 variably with
none or up to 18 per segment. However, the possibility that these are at least partly parasitic artifacts would account for their variation and for the thinning or reduction of the
clitellum ventrally where these occur. Thus the so-called uniqueness of the unlikely “saddle-shaped” clitellum would be explained and the possibility aired of synonym with
Amynthas multimaculatus Hong & Lee, 2001 that has only slight quantitative differences.
Amynthas ephippiatus Hong & Lee, 2001: 286 from Korea that has multiple genital markings and can thus be excluded from consideration, although it is probably
a junior synonym candidate from several of the prior taxa listed above.
The current taxon complies with Sims & Easton’s (1972: 238) now outmoded glandularis-group. In addition to Metaphire glandularis, this group had comprised:
Metaphire levis (Goto & Hatai, 1899: 20) that has spermathecal pores in 6/7/8 surrounded by small papillae with glands internally but typically lacking male pores (thus it is
known how Sims & Easton could reliably transfer this taxon to Metaphire) and possibly it is in synonymy of A. vittatus, etc.; also Metaphire servina and
Metaphire soulensis as noted above, and Metaphire vesiculata (Goto & Hatai, 1899: 21, figs. 13-15) with its current synonyms from Blakemore (2003, 2007a) that all
typically lack genital markings.
Similarly to the parasitic artifacts already noted for several Drawida taxa (Blakemore & Kupriyanova, 2010) that do not represent primary identifiers, the puckered ‘markings’
in segment 8 are considered artefactual due to copulation. These patches resemble those (RJB pers. obs.) found in Amynthas agrestis (Goto & Hatai, 1899) and in
Metaphire hataii (Ohfuchi, 1937), for example. Henceforth, such dark or puckered patches, as with any parasitic artifacts, are not to be considered as genital markings
proper in morphological keys and analyses, merely as identification support indicators.
分布
タイプ産地である大津市黒津5丁目でのみ採集されている (Blakemore, 2010)。新種記載以降の記録は見当たらない。
生態
水田地帯に生息する (Blakemore, 2010)。早朝に、アスファルトの上に這い出したものが採集された (Blakemore, 2010)。
腸管から、有機物の混じったシルトや分解されかけた植物の茎、有機物の破片が見つかっている (Blakemore, 2010)。
備考
種小名の由来は、田んぼで採集されたことを示している（from the paddy）(Blakemore, 2010)。
引用文献
Blakemore RJ, 2010. Unravelling some Kinki earthworms (Annelida: Oligochaeta, Megadrili: Megascolecidae)- Part II. Opuscula Zoologica, Budapest 41(2): 191-206.