Yamaguchia toyensis n. sp., n. gen. (Annelida, Clitellata, Lumbriculidae) from profundal lake habitat in Japan

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ZOOLOGICAL SCIENCE 21: 677-683 (2004) @ 2004 Zoologlcal Societ yof Japan
Yamaguchia sp., n. gen.(Annel Clitetlata,

Lumbriculidtaoey)enfsriosmnP.rofundal Lake Habiitdata,inJapan

StevenV.Fendi*andAkifumiOhtaka2

IU.S. GeologicalSurve" 345 MiddlefieldRd.,A,VS465,Menlo Park,CA, 94025,USA

2Department of Natunal Science, facuby of Education ,Hirosak iUnivetsity]
Hirosaki, 036-8560 Japan
ABSTRACT-Ylarr]aguchia tq)tensi sn. sp,, n. gen. is described from an oligotrophic caldera lake ,Lake
Tbya, Hokkaido, Japan, Although the taxonomic affinitie sare unknown, the genus differ sfrom all other
Lumbriculidae in having the combination of testes and atria in X, a single, prosoporous male funnel per
atrium, and spermathecae in Xl, Unlike other Japanese lakes that have thus far been surveyed, Lake lbya
supports abundant populations of lumbriculid sin the profundal benthos.
Key words:Annelida, Clitella tOal,igochaeta ,Lumbriculidae,caldera lakes
tNTRODUCTION tthhee lsuarkfea creece ipvHed fr owamst e7 t ow a5t.e rTh ef rpoHm ah assul fruerc omvienree,d w htioc h6. 8d esicnrceea stheed
th e JMaapnayne soleig otirsoplhaicnds .cIanl dgereane ralla ,ktehs ea rfea udnias torf itbhuets eeda molnagkes cagteuesrsena tdi ooinen sp ronfoo itmiu nndiendgca rw] aeltaens re1s9 7 b2ies l(aopKpwur od8x0oi -maa9nt0de%l yM ast as4tuuCnrCaa,tg iaoa,nnd 1 a9dt8 i6sa)nsy. oT ltevimem pdoeex yro-t-
is poorly known, although in some surveys, unidentified oli- year (lmad a2,000). Lake Toya has been jnfluenced by the activity
gochaetes are a dominant component of the profundal of surrounding vojcanoes, includl nrgecent eruptions in 1977 and
z1o9ob7e5ntbh)os. Al t(hMouigyhad th1ie9,32Jaa,p a1n9e3s2eb; Kliutmbargiacwuali, d19f7a4u,n a197h5aas, 2h0a0v0e. Hnootw evbeere,n tshteu deifefde.ct s Moify tahde ise( 1ev9e3nt2s a )aonnd b oKtittaogm acwomamu ni{t1ie9s75a)
received considera ble study (Y amaguc h1i9 3,6, 19 37a, trheceoirrd esdpec ittihce pcormepsoesintcieon ,of oligochaetes in the lake, but did not study
1937b, 1953), members of the family have rarely been col- All specimens used in the presen tstudy were collected trom
lected from profundal lake habitat sin Japan. Recent collec- profunda lhabitat in Lake Toya, on a single date, 12 June, 1984.
tlaibauoknn des aifnntr oHm o lktukhmeab irpdiroc ou,Jflauipdn asdn, Oa,nb leeinn tdohifoc sat hto eefsa neL aucknoeuHse ucTatliooynsa ,f aa u incnaacl, dlewuriadthed C2wpeo2url5emi ie mccmm}teo, sitsoltn yos nfewr setro.eimn e d emmaupddet,hs cwroitalhnogr ieandng Ebfkrmroawonnm-i Bs6ih6r- ga8te2 t hbme.o t stBuoromfta ctseao,mmp leswreidtihm e(snotbmsease
several specimens of a small lumbriculi dthat is not cleariy Worms were preserve dwith 10% formali nsolutien. Sagittally
associated with any existing genus; that species is sectioned specimens were cut at 7 um increment sa,nd transverse
described in the presen tpaper. saencdti oenossin .we reOt hmaedre sp eacti me1nOs ym, w eSreec tsiloidne sw emroeunt setdaine din iKnl heeemramtoouxnytlTiMn,
e[ther as whole worms or Iongitudi ndailssection sB.ody width of
METHODS AND SITE DESCRIPTION specimens was measured using a dissecti nmgicroscope prle rto
mounting on slides; all other measurements were made from slide-
Lake Toya is a large caldera lake ln the southwestern part of mounted worm$, u$ing a compound microscope,
Hokkaido, Japan (42"36 'N, 140C51'E), The surface aiea is 70.4 Specimens of two potentially-relat esdpec[es were also exam-
km2, and the average and maximum depths are 116.3 and 179.0 ined .Suppjementa lobservations of Hrabea ogumai Yamaguchi,
m, respectively. The lake water is oligetrophic/ annual average con- 1936 were based on two new specimens, plu sa series of photo-
centrations of total phosphorus, tota lnitrogen, chlorophyll a, and graphs taken by R. Brinkhur sott sections of a type specimen. Spec-
chemical oxygen demand at the lake surface are 3, 150, O.3, and imens of ro'ncaidi ahneaidri Csook, l965 were collected by S. Fend
600 pLg 1"i ,respectively (Hokkai dRoesearch lnstitu ftoer Environ- from several sites in western North America, and compared with the
mental Pollutio n1,990) .Lake Toya is protecte das part of the original description and that ef Cook { 1971).
Shikotsu-Toya Nationat Park, AIthough the lake basLn supports In this description ,segments are designated by Roman numer-
eight thousand peTmanent residents and three million sightseers als; septa "ar4ef 5i"n.dica±ed by Arabic numbers of the adjacent seg-
per year ,the lake water remains oligotrophic. From 1965 to 1972 ments, as Specjmens from the type series have been depos-
' ite din the Division of Biologica lScience, Graduate School of
Corresponding author/ Tel. +t-650-329-4465; Science ,Hokkaido Universi t(yZIHU )J,apan, and the National
FAX, [phone]. Museum of Natural History (USNM) ,Smithsonia nlnstitut iWoans,h-
E-mail/[email protected] ingto nD,C, ,U,S,A,
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RESULTS atria lsegment, Male pore$ on small papillae ,posterio rto
ventral chaetae on X, Spermathecae paired ,with narrow
lamaguchia n, gen. ducts and irregula r,sacciform ampullae. Spermathecal
7)fpe species: Ylamaguchia toyensis n. sp, (monotypic}.pores posterio rto chaetae in ×1 ,but medial to ventral cha-
Diagnosis :Small worms with a conical prostomium. etal line so;blique muscles connect spermathecal pores to
Body wall unpigmented and bearing secondary annuli, Pos- dorso)atera lbody wall,
terio rlater abllood vessels absent. Nephridia present in Vll,
Xlll ,and some posterio rsegments. Testes paired in X. One Yamaguchia toyensis n. sp. (Fig s1-.3)
pai rof ovaries in Xl. One pair of fiattened c,lub-shaped atria Holotype: ZIHU 3082. A whole-mounted specimen,
in ×, each with one short vas deferens, serving funnel on 1O/ stained with hematoxylin,
11. Vasa deferenti ado not penetrate septum int othe post- Paratypes: Al ltrom the type localit yZ.IHU 3083-3087.
lk
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dv
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br
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Fig. 1. Yamaguchia toyensis. (a-b )Lateral view of anterior segments from cleared whole mounts/ external characters, segments 1-Xl l{la);
inte rnal characters in 1-Vll l(b) (.c )Dorsal view of segments 1-l it,rom a cleared whole mount. (d )Representati vcehaetal pairs: from ief tto right,
precliiel lmiadr-b,ody, and posteri osregments. (e )Lateral view of reproductive organs in segments X-Xl, reconstructed from sagittal sections.
Scale barsr (a-c )20,0 pm; (d )5,0 pm; (e) 1,OO gm. Abbreviations for alNllustrations/ aa, atr[al ampuila; br, brain; cv, latera lconnective bFood
vessel; dv, dorsal blood vessel; ff ,female funnel; gu, gut ;mf, ma[e funnel; mp, male pore; mu, musc[e; pr, prostate gland; sa, spermathecal
ampulla; sd, spermathecal ducO; vn, ventral nerve cord; vv, ventrat blood vessel
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Yamaguchia tqyensis n. sp., n.gen. 679
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as
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Fig ,2. Ylamaguchi atoyensis. (a )Transvers eview of segment Xl, showing spermathecae, reconstructed from sections, (b )Transvers eview
of segment X, showing atria and male pores, reconstructed from sections. Arrows show the positio nosf chaetae in ×. Scale bar :70 ym
N.
b
Fig .3. Ylamaguchi atoyensis. (a }Transverse section in ×1 ,showing a spermathecal duct.
ampullae. (c )Sagitt aslection in X, showing atrium and male pore. ScaLe bars: 1OO ym(b)TransversesectioninXl1,showingspermathecal
Two sectioned specimens; one sagittal and one transverse, approximate[y equidistant bundles, simple-pointed and sig-
stained with hematoxylin and eosin. One longitudin adlilsy- moid <Fi gId.> ;those in preclitel lsaergments (] t1o ca. Vlll)
sected specimen, stained in hematoxylin and slide mounted. oriented anteriorly, those posteri otro about Vli loriented
Two whole-mounted specimens, stained in hematoxylin or posteriorl (yFig .Ia). Nodulus dista lto midpoint, about O.35-
carmjne. USNM 1023105-1023109. Two sectioned speci- O.3 of chaetal lengt hfrom tip jn anterior segments; may be
mens, one longitudinal ldyissected specimen, and two slightly nearer the midpoint in posteri osergments. Chaetae
whole-mountedspecimens. as short as 40 ,um in 11 ;maximum length 67-92 ym jn seg-
T),pe Locali4[ Japan, Hokkaido, Lake Toya, profundal ments near the clitellum; 60-70 pm in posterio rsegments.
habitat (66-8 2m in depth) .Collect edby A. Ohtaka, Male pores paired in ×, near septum 1Oll1, on ventral cha-
t2,Vi.1984. etal lines {Fi g2.b). Spermatheca lpores paired in XI, near
Etymolog)c Named for Professor Hideji Yamaguchi, 1IA2, slightly insid echaetal line s(Fi g2.a). Female pores
who made many important contributions to the understand- indistin cotn chaetal lines at 11t12. Most of body nearly
ing of Japanese oligochaetes, round to slightly triangular in cross section, but usually dor-
Description :SmaH worms, length of preserved speci- soventrally compressed andfor ventrally concave in Xl (Fig.
mens 7-11 mm, width in X 280-350 pm. Prostomium conF 2a), and sometimes in posterio rsegments as far as XIV. In
cal, 100-120 ym long (Fi gl,a) .Chaetae closely paired in some specimens the body wall is longitudinal liyndented at
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the chaetal and Iatera llines ,and the longitudin almuscle lined with an irregula rlayer of ciliated ,granula erpithelium
laye ris weakly separated int obands .Clitell uXm-Xlll ,often having indistin cctell boundaries (Fig sI.e, 3c). Multicellular
ending in mid- ×111. prostate gland sin a few (up to 1O) irregula rbundles, up to
Epidermis 1O-12 pm thick in anterior segments, but 24- 60 pm long, arranged along anterior and posterio rsides ot
30 um in the prostomium. Clitell uasm much as 30 pm thick, atria {Fig sI.e, 3c) ,but absent from latera lsides (Fi g2.b),
with distinct lgylandular cells in fully-matur eworms, Dorsal Prostate bundles on short stalks, which penetrat tehe atrial
pharyngeal wall distinct ltyhickened in l land 11 1;pharynx muscle and joi nthe laye rof atria llini ncgel]s. Male pore on
extending int oIV <Fi g1.b), Pharyngeal glands in IV-VI or Vll. a small, conical papill a5-12 LLm long, Papill ain a small
Septa weakly developed in anterior segments, Brain in 1, depression not associated with obvious glands ,or muscles,
deeply [obed posteriorl {yFi gI.c), but sometimes within a ring of slightly thickened epidermal
One pair of latera l,dorso-ventra lconnective vessels cells <Fi g3c.).
near posterio rseptum of most or all segments from 11 1to IX. Spermatheca eone pair ,with narrow ectal ducts in Xl,
Connective vessels rather short and not branched or lrregul aamrpullae begin in XI, usually extending into Xll or
strongly convoiuted; they joi ndorsal vessel near posterior Xl1 1(Fi g1e.). Spermathecal ducts 80-130 pm long; maximum
end of segment, then joi nventral vessel in the following width 18-26 "m, slightly narrowed ectally, Ducts with colum-
segment (Fi gI.b), No obvious latera lvessels in posterior nar epithelium in the ectal half ,and cuboidal epjthelium
segments. A blood vessel, probably one of the anterior con- entally (Fi g3.a). Lining cells of ampullae irregula rand often
nectives, loops int othe sperm sacs to near thei rental ends. vacuolar, sperm in a loose bundle {Fi g3.b). Ampullae con-
Dorsal vessel mostly in close contact with periviscer aslinlls, stricted at septa; greates tdiameter 70-130 ym, in ×1 ,or more
but separate in clitellar region. Ventral vessel divided in seg- commonly in ×11 .In the posterio rpart of Xl and sometimes to
ments anterior to Vll ,Periviscera lsinus usually weakly a lesser extent in Xll ,many long, oblique muscles attach lat-
developed, beginnin gas fa rforwar das IX in some speci- erally to the spermathecal pores, near the ventral chaetal
mens, but more strongly developed in middle segments lines ,and dorsally ,near the dorsal chaetal line s(Fi g2.a).
(start aibnougt XIV), Chloragoge nweakly developed, mostly Remarics: Most specimens were complete, and
associated with dorsa lblood vessel, usually begjnnin ign Vlll. appeared full ymature. Mature specimens had a well-devel-
Usually a nephridium {o ra pair }in Vll ,each with a small oped clitellum, sperm in the spermathecae, and mature
tunnei; an irregula rg,ranular ,postsepta lmass; a simple ectal eggs in the egg sacs. The material appeared to be in good
duct to a nephropore jus atnterior to the ventral chaetae; and histologic aclondition.
a posterio rtubule ,usually forming a dorsal [oop extending to The extensjve musculature surrounding the spermathe-
near the dorsal blood vessel, then running midventrally for cal pores appears to raise the entire floo rof segment Xl,
one or two segments posterior lEyc.tal duct sljghtly and to some extent Xll .Although the resulting concavity is
expanded at nephropore, but without a distinc atmpulla. Sim- quite shallow, i tcould form a chamber to facilita tspeerm
ila rnephridia usually paired in Xlll ,then irregular locycurring exchange, Flattenin gof the spermathecal segment ls
in a few posteri osergments; posterio rtubules may extend unusual, but similar musculature is associated with the male
posterio rtlhyrough two or more segments. pores in other lumbriculid s(e, gl,atriel iHarabe, 1936 and
Ovaries paired in Xl, Usually one egg sac developed, Secubelmis Fend and Gustafson, 2001), and dorsoventral
with mature eggs in one or two segments behin done of the muscles flatte nthe ventral side of the atrial segment in other
sperm sacs, Female funnels about 80 ym long, on 11112. oligochaete families ,Dorsoventral musculature apparently
A single pair of testes in X, with two sperm sacs extend- serves to retract the eversible penes of some lumbriculids
ing posterior lays far a$ XVII. A single pair of male funnels (e,g .R,hynchelmis rostiata [Eise n1,888] and Eclipidrilus
on 10/11, directed posteriorl yand extending back into patustri s[Smit h,1900), and the spermathecal porophores
sperm sac (Fi gl,e); maximum funnel width about 100 pm. of Eremidril tuesti nFiend and Rodriguez, 2003, but the cop-
Vasa deferenti ado not penetrat seeptum into the post-atrial ulatory organs of Y. toyensis are weakly developed in com-
segment. Vasa deferenti ashort, 90-130 pm long; diameter parison .The lateral lcyompressed atria and the restriction of
1O-19 pm; joini ningner side of atria at about the ectal 114. the prostates to the anterior and posterjo rsides of the Y,
In one specimen, vasa appear to run between atria llining toyensis atria are also unusual, but these characters could
and outer muscle Iayer ,entering lumen near the midpoint simply be a consequence of packing large organs int oa
<Fi g2.b). In other specimens, the atria lIini nig sindistinct small worm, Laterall ycompressed atria also have been
(Fi g3,c), and vasa appear to enter Iumen directl yA,tria one reported tor in'chodrilu hsrabeiCook, 1967,
pair ,entirely in X; lateral lcyompressed, broadly club-shaped The male pores are rather consistent i nsize and form,
(Fi g1.e), 180-250 pm long and 65-105 pm wide at the wid- and thus do not appear to vary much with state ot contrac-
est poin tu;sually extending to near the dorsum and some- tion .In some whole-mounted specimens there appears to
what curving over the gut {Fi g2.b). Short eetal duct of be a slight change in texture of the epidermis in a small ring
atrium about 12-20 pm wide. Atria lmuscle a single Iayer ,6- around the male pore, and in some there is a small accu-
10 pm entally, thinner ectally; with fiber sarranged in an mulation ot possibly glandular cells. The small papillae,
irregularly circular (transve rdsiere)ction T.he wide Iumen is which could be describe das "penes]', appear to be simple
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Fig.4.matheca oHgrumaabLea Latera vliews of reproductive organs, from dissected specimens. (a )Atrium, vas deferen sand male funnet .(b )Sper-
Scale bar/ 1OO ym
extensions of the atria lduct ,The spermathecal pores are thus would be considered plesioporous (Brinkhu 1r9s8t9).
also very simple, other than the later amlusculature; their
sootmheewrha tlumb rimecduiiain dsp ecpioessi.tion ,although unusual, occurs in DISCUSSION
Taxonomy
Hrabea ogumai Yamaguchi, 1936 (Fig 4.) The most comprehensive taxonomic treatments of lum-
ntiateri aEt>camined Toma Cave, Kamikawa, Hokkaido, bricul igdenera have been the review by Cook (1971 )and
Japan, collected by A. Ohtaka 29.Vlll,1985 .Two sagittally the phylogenetic analysis {base don characters in published
dissected specimens, stained in borax carmine and slide descriptions )by Brinkhurs t(1989) .However, our subse-
mounted. quent attempts at phylogeneti canalyses of the Lumbricul-
Remarks: The original descriptio n(Yamaguch i19,36) idae, using those characters with some corrections and
include pdhotographs of atrial sections, but did not describe additions of newly-described taxa, have been lnconclusive,
their morphology in detail .The short atria are divided into an suggesting that a rigorous phylogenetic argument is not
ectal duct and an ental ampulla (Fig ,4a). The ectal par tof possible at this time. A revision of the family would require
the duct appears to be a broad epidermal infoldin gs,imilar an extensive review of the characters, and is beyond the
to the penial sacs of other Lumbricuiidae .More entally, the scope of the presen tstudy, particular liyn view of current
epithelial cells become more tightly packed and elongate, work in progress using molecular and ultrastructural charac-
and the lumen is constricted (Pla tVe, Fig .7 in Yamaguchi, ters (Ers6u asnd Kallersj 62,004; Dr. M. Ferraguti ,University
1936). The ampulla is about as wide as long, with an irreg- of Milan ,personal communication). Therefore we take the
ular lumen; a distinc etctal muscle layer ,about 5 pm thick, appreach of relating the new species to similar taxa in terms
surrounds a thick epithelium with basai nuclei. A dense layer of (1 )the Brinkhur s(t1989 a)nalysis, <2 )the generi cdefini-
of pyrifo rmprosta tgelands ,each containing several cells, tions presented in Cook (1971 )an,d (3 )overall morphologi-
covers the atrial ampu[la, The vasa deferenti aare very short cal similarity to other lumbriculids.
and thick (diamet 2e5r-34 pm in the dissected specimens); Using the character definiti ofnrsom the Brinkhurst
a single vas deferens join esach atrium at the ental end. The (1989 a)nalysis, character states of the new species and the
spermathecal pores are within a shallow concavity, but are three most similar taxa are gjven below. The positio nof the
not associated with extensive musculature, The spermathe- female pores (Charact 1e6r) in Hrabea was indicate das
cal ducts have a distjnc tmedian expansion in the two dis- "unknown", but based on the new specimens; they are now
sected specimens (Fi g4.b); part of a similar expansion may coded as plesioporous ,ln the original matrix, Characte r19
be illustrat ejdn the original descriptio n(Pla tVe, Fig .4 in was erroneously given the value 1 for K, freidr (isposterior
Yamaguchi, 1936). One additional character not mentioned latera lblood vessels present) .Cook (1971 )described that
in the original descriptio nis that the female pores are slightly specjes as lacking these biood vessels, and this was verifjed
posteri otor septum in segment Xl, in the groove forming the by our observations of many new specimens.
anterior secondary annulus. In both of the djssected speci-
mens, the femal efunnel sextend through septum 1OXI 1 , and OOOOO r i1030 01010 11000 01 1000 frichodriJu scernosvitovi group
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OOIOO 11030 1eOlO 13000 "1OOO K)'ncaidian aheidris toyensis i nseveral characters/ large penes (Charact 1e4r),
OOIOO 11OIO OOOOO OIOOO 111OOO Hrabea ogumai longer, petiolat eatria (Charact e")r, and spermathecal
OOOOIOOOOO 1131002300 OOlOOOOOOO 111O1OOOOO OO1I"OOOOO OanceYsatmraajgu clhuimabritcouylei nd(shiyspothetical) pores having distinc vtestibules, but without extensive mus-
culature (Cook ,1971),
According to the matrix, the closest match to the new Two additional lumbriculi dgenera, Lumbriculus Grube,
species is the monotypic Hrabea ogumai Yamaguchi, 1936, 1844 and Mchodrilus Claparede, 1862, include members
which differ smainly in having spermathecae in the pre-atrial with spermathecae in the firs tpost-atri aslegment. Lumbric-
segment <Charact 9e)r, BrinkhursVs {1989 p)arsimon yanal- ulus is unlikely to be closely related; although i tis quite vari-
ysis suggested that a trend in lumbriculi dphylogen ywas able, i tusually has two or more spermathecal segments
from semiprosoporous (tw ovasa deferent ipaer atrium, beginning in the second post-atri aslegment, with spermath-
serving testes in the atria land pre-atri aslegments) to pros- ecal pores dorsal to the ventral chaetal line .In addition,
oporous (a single vas deferens per atrium, serving testes Lumbriculus has branched latera lblood vessels, character-
only i nthe atria lsegment). This would invo[ve Characters 3 isti cpenes, and sometimes additional atrial, testicula ro,r
(O- 1t/estes presentiabsent in pre-atri aslegments) and 12 ovarian segments. In other genera with post-atr ispaelrmath-
(1-O /each atrium with II2 vasa deferentia) ,and these ecae {Lamprodri tMiucshaelsen, 1901; Lampiortus Rod-
changes could thus be synapomorphies for a group contain- riguez, 1994), the spermathecae always begin in the second
ing the new species plus H, ogumai. Character 21 (O-1: post-atr isaeglment, and, as in the case of Lumbriculus,
posteri ovras deferens penetratesldoes not penetrate the none of the species bears much resemblance to X toyensis,
post-atri asleptum) provides another possible synapomor- The new species could be associated with some Tlricho-
phy, but the derived state also occurs in several other gen- drilus ,particula trhloyse referred to by Brinkhurs t0989) as
era. Most other characters associating the new species with the "cernosvitovi group", which have spermathecae oniy in
H. ogumai (e,g .la,ck of penes and latera lblood vessels, the firs tpost-atri aslegment, and lac klater abllood vessels
Characters 14 and 19) appear to be plesiomorph iicn the in posteri osergments. The primary difference sare the semi-
Brinkhurs tanalysis. Although Character 22 (presenc eof prosoporous atria (th eplesiomorphic state for Characters 3
atria) is considered an apomorphy with respect to the hypo- and 12), and 21, Characte r21 i scoded ℃" for T)'ichodMus
thetica lancestor, "atria present i"s the character state for all because the posterio rvasa deferenti apenetrate the poste-
lumbriculi dgenera .The positio "nouf ntkhneo fwenm"ale pores {Char- rior septum in most species: nevertheless, the alternate
acter 16) was indicate das in the original condition occurs in some species. The implied loss of the
Brinkhurs tmatrix, but based on the new specimens, they anterior pair of testes and male funnels in Yamaguchia is
are now coded as plesioporous. not unlikely, as i toccurs within other lumbriculi dgenera
Like the new species, H. ogumai has short, prosopo- (Rhynchetm iEsc,lipidrit usL,umbriculus ,and Phagodrilus
rous male ducts, and is endemic to Japan. However, addi- McKey-Fender and Fender, 1988). However, in some of
tiona lcharacters not included in the above matrix do not these gene"rian,t tehrims epdrioacteess s"may be inferr efdrom the occur-
provide strong evidence for relating the two species, The rence of with reduced or vestigiaj anterior
atria of H. ogumai have a thick ,complex ectal duct, in con- vasa deferentia .No such reduction of anterior testes or vasa
trast to the simple papill aof Y. tayensis .The very small deferent ihaa$ been described in any Mchodritus species.
atrial ampuila of H. ogumai contrasts with the club-$haped In summary, although Y. toyensis lacks novel charac-
ampulla of Y. toyensis ,and suggests the possibili ttyhat ters that would indicat eunambiguous apomorphies, the
Character 11 (atr ipeaar-shapedfelongate) also should be combination of prosoporous male ducts in X and a single
reconsidered. pair of spermathecae in Xl is not found in any of the previ-
Cook (1971 d>efined genera in the family Lumbriculidae ously-described genera. Inclusio nin Hrabea would be con-
primaril yby the numbers and relative position sof the genital trary to tradition agleneric definitio ns(Cook ,1971), as it
organs. According to those definitions, the new species is would associate species having spermathecae in post-atrial
closest to Kincaidiana freidri sw,hich differ sin having the versus pre-atr isaeglments; the only genus in which thi sis
gonads shifted forwar dby two segments from the X-Xlll accepted is Styloscoiex Michaelsen, 1901. However, the
regarded by Brinkhurs t{1989 )as plesiomorphic within the three Styfoscolex species having post-atri aslpermathecae
Lumbriculidae (Charact e17r>, Kincaict'an ais a Nearctic instead of (o rin addition to) the usual pre-atri aolnes can be
genus containing two species having litt lmeorphological associated with congeners by several synapomorphies,
simiiarity ,and Brinkhurst' (s1989 a}nalysis suggests that i tis including elongate penes, a forward shift of the reproductive
not monophyletic. As in the case of Hrabea, the prosopo- segments, and ovaries two segments posterio rto the testes
rous condition could be considered a synapomorphy for K. (Timm ,1994).
heidris and the new species, Y, toyensis .Both species have Inclusio not Y. toyensis within Kincaidiana would add
a single pair of spermathecae with long ectal ducts and furth erconfusion to an already paraphyleti cgenus ,and
elongate ampullae, and short vasa deferenti athat enter the would associate species having very differen tcopulatory
atrium in the ectal portio nH.owever, in addition to the for- structures. Also, a distributio naelxpansion of Kincaidiana
ward shift in gonadal segments, KL freid rdiisffe rfsrom Y, int othe Palearcti cshould be justif biye dmore convincing
NNIII-IE-leEcltreoncitcronic Library Service
TThheZeo olZoogiocalloSogciiectyal Society ooff JJaapapnan
Ytamaguchia toyensis n. sp., n.gen. 683
synapomorphies. Inclusio nin T)ichodrilu wsould require fur- Cook DG (1971 F)amily Lumbriculida eI.n "Aquatic Oligochaet aof
ther expanding the definiti oonf that genus, which is already the Worid" Ed by Brinkhur sRtO, Jamieson BGE. Univ Toronto
leraar g(e Ganida snaonimde tRimoedsrig uweeazkl, y19 9d4i)f, fTehries ncthainaget efdr owmo ulodther p rgoebna-- E r s eu(PsrAe nsCns,, e TlKotiriod 1nZ1atoe}oro,,s l pjS6pMc 2r0i{0p2-t2 0a380534 : )1188S7- 1rD9NA6 phyiogeny of clitellata
bly aiso require the inclusio nof Kincaidiana freidr iisn T?'i- Gian[ N, Rodriguez P (1994 N)ew species of the genus ftichodrilus
chodrilus. In the absence of synapomorphies that are (Oligocha eLtumab,riculidae). Zool Scripta 23 (1) 3/3-41
complex, unique, or othervvise compelling, i tseems that the Giani N, Sambugar B, Rodriguez P, Martfnez-Ansemil E (2001 O>li-
most conservative approach is to designate a new genus. ganodch aaent eosver viien w.sou tHhyerdnrob iEojuorgoipae 4a6n3 :g r6o5u-n7dw4ater/ new records
Hokkaido Research lnstituteforEnvironmental Pellution(1990)
Ecologica lnotes Lakes and Mars hes in Ho kkai do, Hokkaido Research lnstitute
Lumbriculids are an important component of some for Envlronmental Pollution ,Sapporo (i nJapanese}
northern oligotrophic lakes (Mani n1,996), but the family has lmada K (2000 )Changes ln the fisheries and lake environmental
rhaarveely bbeeenen surrevepyoerdted ifn rJoam patnhe (mOoshtltya k eaauntdro pKhiikcu chlia, k1e9 s9t7h).at Ki t agc1ao 5nw3dal/t i8oN3n -s(971 9i (n7 iL4 naJS)katepu adTnioeeyssae .)on R etshe Rbeoptt oNma ttl alunnsat Eofn vsierveonn S tluadk eJs pont
Although an unidentified lumbriculid was once recorded north Japan. Jpn J Limnol 35/ 162-172 (i nJapanese with
from profundal habita tin formerly oligotrophic Lake Biwa Englis habstract)
(Stephens o1n91,7), that Iake has suffered from eutrophica- Kitagawa N (1975a )Studies en the bottom fauna of five Iakes in
tpiroon fiunn dtahel zlonaes t 30h ayveea rnso.t R edceetnetc tseudr velysumb roif ctuhlei dL sa,aklet hBoiuwgah sJHoaautpnhagernenetss eu H-woiktk ohkaan dEidn ogOls ih(siL hmaabaks etOrs a-cSnth)uimkao)t. sJup-n k Jo K,Luitmtnaorla -3k6o/, 4T8o-y5a4-k o(,in
Lumbriculus species have been collected in littor ahlabitats Kitagawa N (1975b )Studies on the bettom fauna of lakes Mashu-
(Nishi neto al., 1999}, A report of Lumbriculus variegatus ko, Akan-Panke-ko and Toyoni-ko, Hokkaido, Japan. Jpn J
(MOII er17,74) from oligotrophic Lake Towada (Ohtaka, Ecol25/155-159
2an0e0s1e) ips rtohfe uonndlayl loathkee rh apbuibtlaits ,hlen d croenctorradst, o f [tuhmeb fraimciullyi idwon rJmsap- KMua dr otiJ np1 , nPMJ a {tL s19iu9nm6ang)o a O]4l 7iK/ g 3(o5c11h9-a83e56t 4D>aainsdt rAibpuhtaino onofn ecuadrmai uimn an ciien nLtak lea Tkoeysa /.a
are abundant in the profundal benthos of Lake Toya. Imma- review. Hydrobiologia 334/ 63-72
ture and partially-ma tsuperceimens that are probabl yattrib- Miyadi D (t932 aS)tudies on the bottom fauna ot Japanese lakes.
utable to Stytoscolex faponic uYasmaguchi, 1937 were the Vl1 ,Lakes of Hokkaido. Jpn J Zool 4/ 223-255
mMoasty aanbdun daJnutne, o1l9ig8o4ch, aeatses wel l onas tihnr eae rceoclelenctti onsur vedyat ecos m-in MNii ys ahdiV[nl o1D 1 M .L,(a rk9Oei3hst2 abokf) a SN otAru,t dhi NaJer asiopntaa ntT.h Je( pb1n o9Jt 9Zt9o oo)Sm ltf ua4du/ in2ea5s 8 o-of2n 8J 7tahpea naqeusate icla koel$i.-
plete din 2001; other oligochaetes in those collections gochaete fauna in Lake Biwa, central Japan. 111 ,Dlstributio nof
included haplotaxids and both rhyacodriline and tubificine respective taxa within the lake .Jpn J Limno l60: 539-558
tubitici d(sOhtak aun,published). Ohtaka A (200 1O)ljgochaete sin Lake Towada, Japan, an eligo-
su b seCqauelndtera tol atkhees mions tJa praecnen tge ngelraaclila ylmoarxiigmiunmated (dSuariin jag noodr O h t atbkreao npAth,hi co Kcs iailkdn uectrhha.ie HpHr yo(df1ruo9nb9dia7ol ) lCroeoggmiipao on4s 6io3tf/i oL8na3k- 9ea 2ndKi taabuunrda anc,ceentral oJfa zpoao-n,
Sakaguchi, 1978); as a consequence, Ohtaka (2001 a)ttrib- durin g1980-1985, with special reterence to oligochaetes. Publ
uted the benthic fauna of another oligotrophic caldera, Lake ltak oHydrobiol Stat ,lbaraki Univ 9: 1-14
Towada, to colonization from loti chabitat sin the surround- Saij oY, Sakaguchi Y (1978 L}akes in Japan, Kagaku 48/ 352-362
(inJapanese)
inenngt w atoefr sthhede, gr ouLnudmwbartiecru lbiido stala so( Gairea noefitt enal. , a2 0ma0j1or), acnodmpo -the St e phAeqnusaonti cJO l(i1g9oc1h7 aZ)eoot iatorgoicm aJl arpesaunl tsan dof Cah tlonuar .iMn etmhe AFsaira Et aSsotc.
dominant Lake Toya species, S, japonic uiss t,ypical lfyound Bengal 6/ 85-99
in groundwate ror springs in Hokkaido (Yamaguch i19,37b; Timm T (1994 A) new species of Stytoscolex Michaelsen (Oligocha-
Ohtaka unpublished data) .A]though i tis possibie that the eta, Lumb ricul idae ) fr om t he Magadan Region, Russia. Proc
nsepwrin gssp ehcaivees noits bdeeerni vdeed tefcrtoemd ongr tohuen fdlwoaot roe fr pLaokpeu lTaoytai.ons, Ya m agELusuctmhebinriiac nuHl iA(dc 19sa 3df6r)So cSmit uBHdioiokelks4a 3io:dno2 .t0 h9Je- 2aF1qau5act icSci O iHiogkokcahiadeota U nofi vJa pSaenr. Vl1.
Zool 51 73-94
ACKNOWLEDGEMENTS Yamaguchi H ( 1937a) Studies on the aquatic Oligochaeta of Japan.
11 1.A descriptio nof Lumbricutus multiatriatus n. sp., with
The authors thank Drs. Ralph Brinkhurs tT,armo Timm, Mark remarks on distribut ioonn genit aoligans in the Lumbriculidae.
Wetzel, and an anonymous reviewer for their constructive reviews J Fac Sci Hokkaido Univ Ser Vl Zool 6: 1-12
of the manuscript, and Saelon Renkes for assistance with the Hlus- Yamaguchi H ( 1937b) Studie son the aquatic Oligochaeta of Japan,
trations. IV. StyioscolexJ'apon inc. ussp. Annot Zool Japon 16/ t67-172
Yamaguchi H (1953 S)tudie son the aquatic Oligochaet aof Japan
REFERENCES Vl. A systematLc repert, with some remarks on the classlfication
and phyiogeny of the Oligochaet aJ. Fac Sci ,Hokkaido Univ
Brinkhurst RO (1989 A) phylogeneti acnalysis ot the Lumbriculidae Ser Vl Zool 11/ 277-343
(Annel iOdliag,ochaeta )Ca.n J Zool 67/ 2731-2739
(ReceiveSdeptember 12,2003 fAcceptedApril22,2004)

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