A new species of the genus Cosmochthonius (Acari, Oribatida) from the Imperial Palace, Tokyo

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NNaatitoinaolnScaieln ceSMcusieuemnce Museum
Mem, Natn. Sci.Mus., Tokyo, (35)D,ecember 25,2eOO

A New Speciesof the Genus Cosmochthonius(Acari,

Oribatidaf)rom the ImperialPalace,Tokyo

By
Jun-ichiAoki')

fi*e-t):gEdo>6ndi astl.krb-JSiJ e V M;esOMpt

In the farni lCyosmochthoniid taheree species of the genus Cosmochthoni uCs ,reticulatus Grandjean,
1947, C: lanatusfoveolat BteLcsk, 1962 and C, nayoroensis Fiijikawa 1,980, have hitherto been known from
Japan. The fourth species fbund from litt esrample taken in the Imperia lPalace wi11 be describe dbelow

as a new.
Cbsmochthoniu simpet:t2ic stpu.s n.
(Fig s1-.3)
Adleasuremen tB.ody lengt h305-320 ym, width 180 pm,
Prodorst"n. Rostrum with 8-9 short longitudin alline sof ligh tspots. Rostral seta with a thick stem
and nurnerous spines bilatera lbleyi,n ginsert eond a prominen tapophysis, Lamella rseta arboraceeus,
with many branches ;each branch divided again apically. Interlamell aserta with a thick stem, similar in
shape to rostral one, but smaller than the latte arnd most of spines divided apically. Exobothridia lseta
with a thin stem and nurnerous spines divide dapically, Mutual distance sro:-ro z in-i n> le-l eS.ensillus
with a thin stem slightly thickened in it sdistal half bearing numerous spines, longer on one side and
shorter en the other side. A thin transverse ridge between insertio pnores ofinterlamellar setae.
Nbtogaster ,Oval in shape, divide dinto four field bsy three transverse ridges; the second and third
ridges each divide dinto four parts ,each bearing a strong seta sparsely barbed (e ie,2, fl and A) ,The
field 3 barbed (ci
anteriormest of notogaster with pairs of setae and c!) anteriorly and one pair ef setae
(di p)osterolateral lTyh.e second fiel dwith 2 pairs ef shert barbed setae (d iand th )anteriorly inserted
close together. Aleng posterolater amalrgin of notogaster inserte d6 pair sof curved setae with dense
spines (ht- hanid pi-ps) .Surface of notogaster smooth on 1st-3r dfield asnd foveolat eonly on 4th field;
the fbveolae scattered rather sparsely and not completely circulaT, but incomplet eand 2-4 of them often
connected together (Fi g2.) .A shallow concavity found near the pesterio rend of notogaster.
VZintralside Genital opening large ,as long as wide. Genita lplat eweakly pointed anteriorly,bearing
6 setae along median margin and 2 setae laterall yA.nal plat ewith 4 setae, a litt llearge rthan genital
setae. Left and right adanal plate sfused posterior ltyo form a U-shaped plate, the posterior end project-
') Institu tofe Environmenta lScienoe and Technology, Yokohama National University ,Tokiwadai, Hodogaya-
ku, Yokohama-shi, 240-8501 Japan
E-mail:aoki@kan,ynu,ac.jp
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Figs ,1-3 , CbsTnochtnoni iumspecfect usps.n. 1. side of body.2, Surface sculpture on the posterior
half of notogaster, 3, Ano-genit arlegion.Dorsal
ing a littl beeyond the posterio mrargin ofnotogaster (Fig s1-.3) ,Aggenita lplate long and very slender,
417 as long as genita lplate ,Adanal fissur leocate doutside anterior end of adanal plate on each side.
Setal formul aof epimerata: 3-1-3-3; seta 2a distinct lbyarbed and far longer than the remaining setae.
Hypostomal seta mi inserte din leye la litt lpcosterio rto that of m!.
7)lp eseries. Holotype (NSMT-Ac 11130) and a paratype (NSMT-Ac 11131) :East side of Kami-
Dokanbori, 4-XII-1997, J. Aoki ,From litte arccumulated in a root hole of a large tree (Zetho sverarata
Makino) PP-W],

Remarics .In havin gsculpture only in the posteriormos tfiel dof notogaster behind the thir dtrans-
verse suture, the new speies resembles Coswochthoni supsinosu sGil ,Subias et Candelas ,1991, fror nSpain,
C semijbveolatus Subias ,1982, from Spain and C! tenuisett LGsordeeva, 1980, from Russia ,The new
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NNaatitoinaolnal　 sSocieineoence　 MMuusesuemum
New　Specie　sof　Cosmochthoni　ufsrom　the　Imperial　Palace　Tokyo 149
，
Fig．4．　 The　habita　tof　Cosmochthoniu　ismperfectu　ssp．　n．　Litte　raccumulated 　in　a　root 　hole　of　Zelたovα
　　seア砌 置α Makino 　near 　Kami −Dokanbori ，
species　is　however　distinguishab丘loem 　these　species　by （1）short　dersa　lsetae　dL　and 　di　only 　slightly 　ex・
， ， ，
tending　beyond　the　second 　transverse　suture ，（2）dorsa　flbveol　aoen　the　posterio　rpart　of　notogaster 　not
completely 　circular ，　but　incomplet　eand 　2−40f 　them 　o丘en　connected 　together ，（3）the　posterior　end 　of
adanal 　Plate　sprojectin　bgeyond　the　posterio　mrargin 　of　notogaster ，　and （4）1arge　rbody　sセe．　The　long
and 　sle皿der　aggenital 　plate　smust 　be　also　one 　of　the　characteristic　feature　sof　the　new 　species ．
要 約
　東京の都心部にある皇居内の調査で 68種のササラダニ 類が採集されたが，その中にカザリヒワダ
ニ 科の新種が含まれて おり，ミカ ドカザリヒ ワダニ Comochthonius　imperfectusと命名し，記載した．
本種の特徴は背毛d お よびd が短い こ と，胴背面の 凹穴が完全な円で なく，い くつ かが連結してい
、 、
ること，肛側板の後部が体縁を越えて少し突出 してい ること，性側板が きわめて細長い ことな どによっ
て，従来日本か ら知られてい る同属の 3種か ら区別される，なお，本種は上道灌濠の 東側の ケヤキの
大木根本の ウロ の 中に たまっ た落葉か らのみ発見され，他の場所か らは見出されて い ない．
Refξ∋rences
Gil，　J．，　L．　S．　Subias＆ E．　Candelas，1991．　 La　famili　aCosmochthoniidae　Gran（ljea，n1947，　en　la　Peninsula
　　　Iberica（Acari，　Oribatida）．　ZooL ゐαεこごcα，2：47−70，
Gordc巳va ，　E．　V、，1980．　Oribati　dmi竃es　of　the　famil　yCosmochthoniida（eOribate）．i　Zoo此Z乃．，59；83＆−850．（ln
　　　Russian．）
S　u　bi　as，　MLu．rSc、，i1a，93882：．　13O3r−i1b5a1．tido　dse　Murcia　I（Oribatido　isnferiore．　sPart¢ 1）（Acarida，　Oribatida），　 Anat．　Univ．
一
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