Dendrobaena pygmaea ( Savigny, 1826 )

Blakemore, R. J., 2004, First record of Dendrobaena pygmaea (Oligochaeta: Lumbricidae) from Asia (Yokohama, Japan), Zootaxa 487 (1), pp. 1-8 : 2-4

Dendrobaena pygmaea ( Savigny, 1826)

( Fig. 1 )

Enterion pygmaeum Savigny, 1826: 183 [non Dendrobaena arborea pygmaea Friend, 1923: 23 ­ this secondary homonym is not replaced ( ICZN, 1999: Arts. 57.3; 59) as it is now thought ( Easton, 1983: 479) in synonymy of Dendrodrilus rubidus subrubicundus (Eisen, 1874) , although Csuzdi & Zicsi (2003: 136) overlook this]. Type locality Paris. Types in Paris Natural History Museum but their current status unknown.

Lumbricus pygmaeus . — Dugès, 1837: 17, 24.

Allolobophora minima Rosa, 1884: 39 [non Al. minima Muldal, 1952: 463 (= Murchieona muldali (Omodeo, 1956: 179) nom. nov.)]. From Piemonte, Italy. Types unknown.

Octolasion minimum . — Örley, 1885: 22.

Lumbricus (Octolasion) minimus . — Vaillant, 1889: 113.

Lumbricus (Dendrobaena) pygmaeus . — Vaillant, 1889: 120.

Allolobophora [( Dendrobaena )] pygmea (lapsus) et A. pygmaea . — Rosa, 1893: 424, 436.

Helodrilus (Dendrobaena) pygmaeus . — Michaelsen, 1900: 495 [syn. pigmea (lapsus) Ribaucourt, 1896: 94, minima Rosa, 1884 ].

Helodrilus (Helodrilus) ribaucourti Cognetti, 1901: 21 . From Sardinia. Types in Turin: 812.

Helodrilus (Eophila) cognettii Michaelsen, 1903: 140 [nom. nov. pro. Helodrilus (Helodrilus) ribaucourti Cognetti, 1901 non Allolobophora ribaucourti Bretscher, 1901: 220 (= Lumbricus rubellus ); name sometimes mispelt "cognetti"; non Eisenia veneta cognettii Cernosvitov, 1935 (= D. alpina alpina )].

Dendrobaena pygmaea cognettii . — Bouché, 1972: 391; [mispelt and miscited as "D. pygmea cognettii Mich, 1903 " by Qiu & Bouche (1998: 194)].

Dendrobaena cognettii . — Zicsi, 1981: 171; Csuzdi & Zicsi, 2003: 114 (syn. ribaucourti Cognetti, 1901 ).

Dendrobaena cognettii cognettii . — Rota, 1992.

Dendrobaena pygmaea . — Zicsi, 1959: 96; Gerard, 1964: 37.

Dendrobaena pygmaea pygmaea . — Bouché, 1972: 393.

Dendrobaena pygmaea . — Gates, 1972: 92; 1975: 8; Easton, 1983: 479 [syn. minima Rosa, 1884 (non Muldal, 1953 = Murchieona minuscula ); cognettii Michaelsen, 1903 ; ribaucourti Cognetti, 1901 ]; Sims & Gerard, 1985: 73; 1999: 73, fig. 23 (syn. minima , cognettii ).

Dendrobaena cognettii gallurensis Rota, 1992: 1383 . Syn. nov.? [Possible synonym; mispelt "cognetti gallurensis" in Qiu & Bouche (1998: 195)]. From Gallura , Sardinia. Types unknown.

Taxonomic Remarks. Sims & Gerard (1985: 45, 74; 1999: 44, 74) considered Michaelsen (1900) the first reviser to “fix” the name pygmaea although some later authors, on the fallacy that the original description was inadequate, attempt to replace this name with the subsequent cognettii Michaelsen, 1903 , even though a prior name, minima Rosa, 1884 , is also available. That both subsequent names are synonyms, as in Easton (1983) and Sims & Gerard (1985; 1999), is accepted here. In contrast, Csuzdi & Zicsi (2003: 114) retain D. cognettii and list Enterion pygmaeum as a "nom. nudum?" and Allolobophora minima as a "spec. inc. sed." (= species incertae sedis). Under the code ( ICZN, 1999: 111; 123), "A nomen nudum is not an available name" which clearly is not the case with pygmaeum .

Diagnosis. Length 10–45 mm. Light reddish anterior dorsum or unpigmented. Prostomium epilobous. Setal pairs widely separate. Dorsal pores absent or from 4/5–6/7. Spermathecal pores absent or dorsally in 9/10/11/12. Clitellum 33–37 or 32,33–36,37,38. Tubercula pubertatis absent or narrow ridge below b lines in 35–37. Genital setal tumescences absent.

Distribution. In Europe known from Britain (Cumbria, Devon, Hampshire and Suffolk), Germany (e.g. Graff, 1955), France, Spain (e.g. as D. pygmaea cognettii from Galicia or D. cognettii from Valencia), Portugal [as D. cognetti (sic)], Switzerland and Austria [as D. cognettii e.g. Christian & Zicsi (1999)], Italy, Sicily, Corsica, Sardinia (as D. pygmaea , D. cognettii cognettii and? D. cognettii gallurensis ), Greece [as D. cognettii e.g. Zicsi (1973)], Madeira and Tenerife (as D. cognettii ), Hungary [as D. cognettii e.g. Csuzdi & Zicsi (2003)], Romania, Bohemia in the Czech Republic [as D. pygmaea by Pizl (2000, 2002, 2003)]; also a single record from Constantine, Algeria [by Rouabah & Descamps (2001)]; in America from San Francisco, California [cited by Reynolds (1995: 11, 27) possibly from study by Gates (1975)], noted from Chile [by Csuzdi & Zicsi (2003: 115)]; and now from Asia (Yokohama, Japan). As yet unrecorded from Australasia/Oceania.

Description. Compiled from pers. obs. and from various sources in synonymy above.

Collection and Locality. Collected by R. J. Blakemore, 9–10th May, 2003 from YNU campus, Tokiwadai, Yokohama, Kanagawa­ken, Japan (35º26'00"N. 139º39'00"E, 57m). Other specimens collected from YNU campus in May–June 1999 by Tomoko Uchida .

Ecology. Found at YNU in relatively high abundance in loose association with various megascolecids, e.g. Amynthas acinctus (Goto & Hatai, 1899) , Amynthas corticis (Kinberg, 1867) spp.­complex, Amynthas micronarius (Goto & Hatai, 1898) , Amynthas vittatus (Goto & Hatai, 1898) , Metaphire hilgendorfi (Michaelsen, 1892) spp.­complex, and with the endemic lumbricid Eisenia japonica (Michaelsen, 1891) . Habitats. Well­drained soil and moist woodland litter, mossy banks of streams ( Sims & Gerard, 1999: 73), damp organic sites ( Csuzdi & Zicsi, 2003: 115); at YNU in organic layers mainly under stands of non­coniferous evergreen trees Cinnamomum camphora (L.) Sieb., Cyclobalanopsis glauca (Thumb.) Oerst. , and Pasania edulis Makino (soil pH 6.7); and less frequently under deciduous trees dominated by sakura, Prunus jamazakura F. Sieb. ex Koidz. (soil pH 5.3), in soils classed generally as Andosol with Carbon 14–22% and Nitrogen 5.2– 6.6% (Uchida & Kaneko, in press). Behaviour. Sluggish when handled, soil easily adheres to surface mucus; body naturally coils slightly on preservation. Biometry. Length 10–45 mm (current unamputated specimens 17–33 mm), width 0.5–1.2 mm; body cylindrical tapering to tail and, when preserved, gizzard region in 17–20 and clitellum are broadest; mean weight 0.03 g (n= 38); segments 90–111. Colour. Lightly pigmented reddy/brown anterior and dorsum especially first dozen segments, or unpigmented grey (with gut contents visible through transparent hind­body); clitellum white. Prostomium. Epilobous, furrows sometimes faint to give appearance of pro­epilobous. First dorsal pore. Occasionally reported from 4/5/6/7 but usually absent as in present specimens. Setae (ratio of aa:ab:bc:cd:dd). Eight per segment from 2, widely separate; (1.5:1:1:1:2).

Nephropores. Single row just above b lines from 3, especially obvious on clitellum; (sometimes reported above c lines?). Clitellum. Saddle­shaped 33–37 with mid­ventral gap widest on 33, range 32,33–37,38; or 32,33–36,37 according to Christian & Zicsi (1999). Male pores. Lateral slits in bc on large white­pigmented protuberant pads mostly confined to 15. Female pores. Visible just lateral to b on 14. Spermathecal pores. Reported dorsally in 9/10/11/12, frequently absent as in current specimens. Genital Markings. Tumescences and tubercula pubertatis usually absent, or reported as narrow ridges below b lines in 35–37 but this may be artefactual as the nephropores give appearance of separation of lower edges of clitellum.

Septa. None especially thick. Dorsal blood vessel. Single (visible through cuticle).

Hearts. 7–11 (last hearts in 11 seen in present specimens). Calciferous glands. White, moniliform dilations, vascularized with longitudinal striations internally in 11–12 and some incursion in 13; (diverticula reported by Csuzdi & Zicsi, not found). Gizzard. Muscular in 17–18. Intestine origin. Beginning with the crop in 15–16. Typhlosole. Not previously reported, in present specimens commencing after clitellum from about 40 and of simple lamellar type (lamelliform), narrow and only slightly thickened, that in the midbody is about one third of the intestinal diameter deep. Nephridia. Holoic with flattened bladders elongate and ocarina­shaped ducting to nephropores near setal b lines in present specimens; described as ocarina­shaped ( Sims & Gerard, 1999: 68) or as bilobate [ Csuzdi & Zicsi (2003: 46, 114) — but these authors show this type to actually be elongate ocarina­shaped (fig. 3.15A, E; fig. 6.18.1) while their "ocarina­shaped" is actually "J" or "S" shaped (fig. 3.15D)]. Testis/seminal vesicles. Iridescent testis (and sperm funnels) visible through body wall in 10 and 11 in Yokohama specimens suggest that it is not, or not entirely, a parthenogenetic morph; seminal vesicles in (9), 11 and 12 arc around gut, frequently small or absent. Ovaries/ovisacs. Paired in 13, band­like with single egg­string shedding largish non­yolky eggs; egg sacs not found. Prostates. None. Spermathecae. Usually absent, as in present specimens although three (or fewer pairs sometimes reported). Spermatophores. Not found on exterior. Longitudinal muscle layer. Pinnate type (Csuzdi & Zicsi). Gut contents. Dark, colloidal organic soil and litter debris, not much mineral soil. Cocoons. None recorded.

Figures

FIGURE 1. Author's sketch of Dendrobaena pygmaea (Savigny, 1826) showing ventral view with dorsal views of anterior (prostomium) and posterior (pygomere). Specimens from YNU to be lodged in Japanese National Science Muse­ um, Tokyo, and Kanagawa Prefectural Museum of Natural History, Odawara. Setae a, b, c, d are figured with their rel­ ative distances (ratios) on segment 12; np = nephropore; the white clitellum is shown shaded. A — cross section of body after clitellum showing intestinal typhlosole; B — nephridial bladders.