New and Newly Recorded Oribatid Mites (Arachnida, Acari, Oribatida) from the Ryukyu Islands

2006·1.4 MB·English

by  Aoki, J

Bull. Natn. Sci. Mus., Tokyo, Ser. A, 32(3), pp. 105–124, September 22, 2006
New and Newly Recorded Oribatid Mites (Arachnida,
Acari, Oribatida) from the Ryukyu Islands, Japan
Jun-ichi Aoki
3–8–12 Nishi-Azabu, Minato-ku, Tokyo, 160–0031 Japan
Abstract Thirteen new species of oribatid mites are described from the Ryukyu Islands of Japan.
They are: Lohmannia unsui sp. nov., Sadocepheus yakuensis sp. nov., Mycobates tricostatus sp.
nov., Birobates nasutus sp. nov. from Yaku Island, Mochlozetes ryukyuensis sp. nov. from Kuchi-
noshima, Akuseki and Ishigaki Islands, Dolicheremaeus magnussp. nov., Fissicepheus gracilissp.
nov., Austrocarabodes bituberculatussp. nov. from Okinawa Island, Fissicepheus defectussp. nov.,
from Okinawa and Tokashiki Islands, Austrocarabodes obscurussp. nov. from Tonaki Island, Ho-
plophthiracarus insularissp. nov. from Tokashiki Island, Defectamerus insularissp. nov. from Za-
mami Island, and Heteroppia setigera sp. nov. from Ishigaki Island. Seven species are newly
recorded from Japan. They are: Trhypochthonius javanusCsiszár, 1961 and Lamellobates oriental-
isCsiszár, 1961 known from Java, Neoliodes bataviensisSellnick, 1925 known from Java and Aus-
tralia, Dolicheremaeus orientalis Aoki, 1965 known from Thailand, Camisia invenusta (Michael,
1888) known from Europe, Neoliodes striatus (Warburton, 1912) known from Africa, and Ere-
maeozetes undulatusMahunka, 1985 known from the Antilles Islands.
Key words: Oribatida, new species, Ryukyu Islands, Japan.
The Ryukyu Islands are thought to be an ex- Lohmannia unsuisp. nov.
tremely interesting area by many biologists be- (Figs. 1–7)
cause of its rich flora and fauna representing a
subtropical biodiversity. Their oribatid fauna was Measurement. Body length 1015–1020mm,
also expected to be rich and not a few investiga- width 500–550mm.
tions were done in the Ohsumi Islands, the Prodorsum. Rostrum smoothly rounded (Fig.
Tokara Islands, the Amami Islands, the Okinawa 1). Rostral setae weakly broadened, with spines
Islands, the Kerama Islands, the Miyako Islands, on both sides, sharply pointed at tip, 2.2 times as
and the Yaeyama Islands, which constitute the long as their mutual distance (Fig. 3). Lamellar
Ryukyu Islands (Aoki, 1973, 1976, 1982, 1984, setae a little thinner and longer than rostral setae,
1987a, 1987b, Ito & Aoki, 1999, Karasawa & with spines on both sides (Fig. 2), 1.38 times as
Aoki, 2005, Nakatamari, 1978, 1980, 1982, long as their mutual distance. Interlamellar setae
1983, etc.). Although the results of these investi- as thick as and a little longer than lamellar setae;
gations gave proof for a very rich oribatid fauna their length and their mutual distance almost
there, a number of species are remaining un- equal. Sensillus weakly sigmoid, with 6–7 long
named and waiting for description. branches and a short branch near the tip (Fig. 7).
The present paper aims at describing a part of Anterior exobothridial seta (exa) curved near the
these unnamed oribatid mites from the Ryukyu base, directed forward, weakly thickened, beset
Islands. All the specimens of the type series are with small spines in two rows (Figs. 4–5). Poste-
deposited in the collection of the Department of rior exobothridial seta (exp) slender leaf-shaped,
Zoology, National Science Museum, Tokyo. with spines on both sides (Fig. 6). An irregularly
rounded porose area found between rostral setae
and one behind lamellar seta on each side; a
106 J. Aoki
transverse porose area between interlamellar areas on prodorsum is also a characteristic fea-
setae. ture of the new species.
Notogaster. Notogaster gently swollen on both
sides. Sixteen pairs of notogastral setae whip-
Hoplophthiracarus insularissp. nov.
like, barbed unilaterally; RLN (relative length to
(Figs. 8–12)
notogaster) of them 19.4–26.4; setae c and d
3 3
nearly as long as the distance c –d , longer than
3 3 Measurement. Length of notogaster 450–510
d –e .
3 2 mm, length of aspis 250–265mm.
Anogenital region. Genital plate divided into 2
Aspis. Median ridge well developed. Inter-
plates by a transverse suture. Each part bearing 5
lamellar seta rod-like or weakly bending,
long setae. Anal and adanal plates separated, the
21–26% in length of aspis. Rostral seta curved
former with 2 setae and the latter with 4 setae;
downward, shorter than interlamellar setae (Fig.
anterior anal setae (an ) situated in a level be-
2 8). Sensillus bearing a weakly swollen and splin-
tween ad and ad ; posterior anal setae (an ) al-
3 4 1 tery apical part (Fig. 9). Posterior half of bothrid-
most in the same level with ad . Praeanal plate
2 ium covered by bothridial scale with a rectangu-
broad transversely.
lar margin. A faint lateral carina making a round-
Type series. Holotype (NSMT-Ac 11851) and
ed or angular curve over bothridium. Surface of
6 paratypes (NSMT-Ac 11852–11854): Shiratani
aspis covered by distinct foveolae larger in mid-
Unsui Valley, Yaku Island, the Ohsumi Islands,
dle and smaller in posterior and lateral parts.
31-VII-1981, H. Harada.
Notogaster. Rather elongate in lateral view.,
Remarks. The most characteristic feature of
covered by distinct large foveolae, interspace of
the new species is the shape of posterior exoboth-
them dark-colored. Fourteen pairs of notogastral
ridial setae, which are lanceolate or narrow leaf-
setae rather thick, weakly bending forward and
shaped. The setae in most of congeneric species
blunt at tip (Fig. 10).
are strongly rounded (as in L. banksi Norton,
Anogenital region. Genital setae g –g fine,
Metz & Sharma, 1978 and L. jornoti Mahunka, 1 5
arranged on the anterior edge; setae g –g leaf-
1985) or broadly leaf-shaped (as in L. bifoliata 6 9
shaped (Fig. 11), inserted on median margin of
Willmann, 1936, L. embryonalisMahunka, 1978,
genital plate. Adanal setae ad and ad long, in-
L. hispaniola Pérez-Iñigo, 1967, L. javana 1 2
serted close together in the posterior part of
Balogh, 1961, etc.). A few species have posterior
anoadanal plate; seta ad short, somewhat leaf-
exobothridial setae not broadened, but they are 3
shaped (Fig. 12); anal setae an and an medium
similar in shape to notogastral setae (as in L. re- 1 2
long, inserted close together and bending anteri-
galis Berlese, 1923 and L. reticulata Mahunka,
ad.
1980). Only four species, L. coreanaChoi, 1985,
Type series. Holotype (NSMT-Ac 12022) and
L. serrata Hu & Wang, 1989, L. guzhanensis Hu
1 paratype (NSMT-Ac 12023): Southern part of
& Wang, 1989 and the new species, have posteri-
Tokashiki Island, the Okinawa Islands, 14-XII-
or exobothridial setae which are lanceolate or
2004, J. Aoki.
nearly leaf-shaped. These three known species
Remarks. The new species is readily distin-
are, however, different from the new species as
guishable from the known species of the genus
below: L. coreana has rostral setae longer than
Hoplophtiracarus by (1) dark-colored body, (2)
lamellar setae (le/ro(cid:1)0.97), L. serratahas longer
very distinct and large foveolae on the body sur-
notogastral setae (RLN of the longest setae 30.7)
face, (3) leaf-like genital setae g –g , (4) adanal
and seta c longer, or as long as, distance be- 6 9
1 setae ad and ad inserted close together and lo-
tween c and d , and L. guzhangensis has rostral 1 2
1 1 cated far posteriorly.
setae as long as lamellar setae and smaller body
size (866–876mm). The presence of six porous
New Oribatid Mites from the Ryukyu Islands 107
Figs. 1–7. Lohmannia unsuisp. nov. 1: Dorsal view of body. 2: Lamellar seta. 3: Rostral seta. 4 and 5: Anterior
exobothridial setae (exa). 6: Posterior exobothridial seta. 7: Sensillus. Fig. 8–12. Hoplophthiracarus insularis
sp. nov. 8: Lateral view. 9: Sensillus and bothridium. 10: Notogastral seta. 11: Posterior genital setae. 12: An-
terior adanal seta. Scale bars: 100mm in Figs. 1 and 8, 50mm in Figs. 2–7, 20mm in Figs. 9–12.
108 J. Aoki
Trhypochthonius javanusCsiszár, 1961 Japanese specimen are not so long as those of the
(Figs. 13–14) Javanese ones. Csiszár (1961) did not mention on
the number of genital setae, but only four pairs of
Trhypochthonius javanus Csiszár, 1961: 349,
the setae are found on the Japanese specimen
fig.10.
(Fig. 14).
Measurement. Body length 590mm, width 330
Specimen examined. One specimen: North-
mm.
eastern part of Tokashiki Island, the Okinawa Is-
Remarks. The Japanese specimen is well
lands, 6-XII-2004, J. Aoki.
in accord with the original description of
Distribution. Java and Japan (new record).
Trhypochthonius javanus from Java in having
clavate sensilli, especially long notogastral setae
h and ps , and notogaster weakly constricted Camisia invenusta(Michael, 1888)
3 3
near humeral part (Fig. 13). The only difference (Fig. 15)
between them is in that interlamellar setae of the
Nothrus invenustusMichael, 1888: 500.
Figs. 13–14. Trhypochthonius javanus Csiszár, 1961. 13: Dorsal view of body. 14: Anogenital region. Fig.15.
Camisia invenusta(Michael, 1888). Dorsal view of body. Scale bars: 100mm in Figs. 13–15.
New Oribatid Mites from the Ryukyu Islands 109
Camisia invenusta: Sellnick & Forsslund, 1955: (new record).
488, Fig. 13; Sitnikova, 1975: 76, fig. 123;
Balogh & Mahunka, 1983: 188, pl. 113, fig. C. Neoliodes bataviensisSellnick, 1925
Measurement. Body length 530–650mm,
(Figs. 16–17)
width 310–360mm.
Neoliodes bataviensis Sellnick, 1925: 463, figs.
Prodorsum. Rostral seta short, Glabrous, di-
7–9.
rected anterolaterally. Lamellar seta thick, with
Measurement. Body length 1040–1100mm,
strong spines and inserted on a small but distinct
width 710–800mm.
apophysis. Interlamellar seta long, reaching just
Remarks. This species is easily recognized by
apophysis of lamellar seta, also inserted on a
the structure on prodorsum, a pair of swellings
small apophysis. A pair of longitudinal ridge
well separated by a rather wide interspace (Fig.
found in the middle part of prodorsum, each
16) and rod-like sensilli without distinctly thick-
curving posteriorly and approaching apophysis of
ened head (Fig. 17). Sculpture on notogaster is
interlamellar seta. Lamellar seta thick, with
obscure except for lateral striae consisting of
strong spines and inserted on a small but distinct
faint granules, ridges and longitudinal furrows on
apophysis. Interlamellar seta long and glabrous,
anteromedian part.
reaching just apophysis of lamellar seta. Sensil-
Specimens examined. Nine specimens:
lus short, bearing a rounded head with fine barbs.
Ohkaneku Beach, Yoron Island, the Amami Is-
Notogaster. Notogaster broad, nearly rectangu-
lands, 19-I-1980, J. Aoki.
lar, with gently arched anterior margin, strongly
Distribution. Java, Australia and Japan (new
undulating lateral margins and weakly angulate
record).
posterior margin. Fifteen pairs of notogastral
setae (two pairs visible only in ventral aspect);
the posteriormost two pairs rather long and Neoliodes striatus(Warburton, 1912)
straight, with strong spines, the remaining 13 (Figs. 18–19)
pairs short, barbed and curved. A pair of longitu-
Neoliodes striatus Warburton, 1912: 357, pl. 19,
dinal ridges found in the middle part of noto-
fig. 23.
gaster, between setal lines D –D –E ; the ridges
1 2 1 Measurement. Body length 800–910mm,
extending posteriorly to make a weak arch on
width 515–590mm.
each side and reaching insertion of seta PN ; the
2 Remarks. The original description by Warbur-
ridges connected by weak transverse ridges at
ton is short and simple, but the characteristic fa-
levels of D , E and PN ; seta K inserted on a
1 1 2 1 tures of the species were mentioned enough. The
small apophysis located just behind a transverse
extract from his description: Samaller body size
edge of posterolateral corner of notogaster.
about 0.9mm, pitted cephalothorax, pseudostig-
Anogenital region. Nine pairs of genital setae,
matic organ with oval head, abdomen widest near
2 pairs of aggenital setae, 3 pairs of anal setae
the posterior end, with a short, blunt, caudal
and 3 pairs of adanal setae. Setae an and ad as
1 2 process arising from a raised pitted oval area, and
well as an and ad situated nearly on the same
3 3 anterior median field exhibits a few longitudinal
level.
striae.” This is well in accord with the features of
Specimens examined. Fourteen specimens:
the Japanese specimens. The only difference is in
Near the top (1710m) of Mt. Nageshi-dake, Yaku
the anterior median field which is “deeply pitted”
Island, the Ohsumi Islands, 30-VII-1981, J. Aoki.
in the Warburton’s description and “densely
From the soil under the alpine grassland of
granulate” in the Japanese specimens. The longi-
Dioscarea carexand Miscanthus.
tudinal striae on the anteromedian field of noto-
Distribution. Britain, Sweden, Faeroe Island,
gaster are, however, formed by longitudinal fu-
Switzerland, Soviet Union, Poland and Japan
110 J. Aoki
Figs. 16–17. Neoliodes bataviensisSellnick, 1925. 16: Dorsal view of body. 17: Sensillus. Figs. 18–19. Neoliodes
striatus(Warburton, 1912). 18: Dorsal view of body. 19: Sensillus. Scale bars: 100mm in Figs. 16 and 18, 20
mm in Figs. 17 and 19.
sion of many granules (Fig. 18). lamellar cusps. Interlamellar setae thick and
Specimens examined. Six specimens: Ugan in long, reaching mid-distance along the length of
Aguni Island, the Okinawa Islands, 5-XII-2005, J. lamellae (Fig. 20). Sensillus slender, rod-like, al-
Aoki. From bark of a dead tree in a natural forest. most of the same thickness throughout its length,
Distribution. The Seychelles Islands and Japan gently curved in proximal portion, strongly
(new record). barbed apically (Fig. 21).
Notogaster. Notogaster broad, wider than long.
Anterior margin straight, consisting of triple
Sadocepheus yakuensissp. nov.
transverse ridges. Humeral appendage well de-
(Figs. 20–22)
veloped, forming three lateral arches, the third
Measurement. Body length (lamellae exclud- one pointed at tip. Nine pairs of notogastral
ed) 750mm, width 620mm. setae: 5 pairs of them thick and long, situated
Prodorsum. Lamellae broad, extending well rather laterally on dorsal side and each of them
beyond rostral tip; lamellar cusps well separated, longer than distance to succeeding seta; one pos-
median margins weakly undulated, bearing each teriormost pair shorter and thinner (Fig. 20); the
an incurved lamellar seta. Rostral setae very remaining 3 pairs visible only in ventral aspect,
short and fine, invisible from above, covered by very short and fine, situated close to margin of
New Oribatid Mites from the Ryukyu Islands 111
ventral plate (Fig. 22). two short anal setae situated far anteriorly and
Anogenital region. Genital aperture wider an- posteriorly, respectively. Three pairs of adanal
teriorly, with straight lateral margins. Genital setae longer than anal setae (Fig. 22).
plate framed with a strong, dark-colored ridge; Type. Holotype (NSMT-Ac 11862): Shiratani
the anterior part of frame straight. In the single Unsui Valley, Yaku Island, the Okinawa Islands,
specimen examined, the number of genital setae 8-2003. J. Aoki.
5 on the right side and 6 on the left side (6 must Remarks. Most of the known species of the
be the normal number). All the setae minute and genus Sadocepheus have minute interlamellar
fine. Anal plate also framed with a dark ridge; setae. Only S. granulatus (Balogh & Mahunka,
Figs. 20–22. Sadocepheus yakuensissp. nov. 20: Dorsal view of body. 21: Sensillus. 22: Anogenital region. Figs.
23–24. Defectamerus insularissp. nov. 23: Dorsal view of body. 24: Variations in rostral tips. Scale bars: 100
mm in Figs. 20, 22 and 23, 20mm in Figs. 21 and 24.
112 J. Aoki
1969) and S. franzi (P. Balogh, 1986) have long Remarks. The new species is peculiar in hav-
interlamellar setae as in the new species. They ing five long notogastral setae including setae p .
1
are, however, distinguishable from the new The five long setae of the known species (D. se-
species by the humeral appendages strongly pro- tata Berlese, 1916, D. qinlingensis Chen et al.,
jecting anterolaterally and long genital setae. The 2004, D. lindquisti Chen et al., 2004 and D. yu-
remaining species with minute interlamellar nanensis Aoki & Yamamoto, 2000) are always
setae are also distinguishable from the new lm, lp, h , h and h and not lm, h , h , h and p
1 2 3 1 2 3 1
species by one of the following features: (1) sen- as in the new species.
silli without apical barbation, (2) lamellar cusps
situated close to each other and (3) undulating
Heteroppia setigerasp. nov.
dorsal setae.
(Figs. 25–26)
Measurement. Body length 590–640mm,
Defectamerus insularissp. nov.
width 340–390mm.
(Figs. 23–24)
Prodorsum. Rostral setae rather thick, barbed,
Measurement. Body length 605–665mm, nearly as long as their mutual distance. Lamellar
width 350–420mm. setae thinner than rostral setae, almost twice as
Prodorsum. Rostrum tongue-shaped between long as rostral ones and their mutual distance. In-
incisions, often notched at tip in various ways terlamellar setae straight, twice as long as lamel-
(Fig. 24). Lamellar ridge has an anterior apoph- lar setae (Fig. 26). Sensillus with a short pedun-
ysis with lamellar seta and small posterior tooth. cle and a large oval head (Fig. 25). Exobothridial
Lamellar setae thick, nearly as long as their mu- setae rather long and curled anteriad. The lateral
tual distance, inserted each on an apophysis. Two part outside bothridia strongly swollen, densely
more pairs of ridges found posterior to lamellar covered with granules. Several light spots found
ridges. Interlamellar setae as thick as and a little laterally on prodorsum. A pair of short indistinct
longer than lamellar setae, longer than their mu- longitudinal ridges found medially between both-
tual distance, inserted each on a distinct apoph- ridia.
ysis. Bothridium with posterolateral tooth. Sen- Notogaster. Notogaster rounded, with a broad
sillus long and whip-like. All the prodorsal setae dark-colored band anteriorly; a rectangular ridge
slightly barbed. found on anterior margin of notogaster. Six pairs
Notogaster. Nine pairs of notogastral setae; of very long whip-like dorsal setae (da, dm, dp,
setae lp absent; 5 pairs of them (lm, h –h , p ) h , h and h ), a pair of shorter, thicker posterior
1 3 1 1 2 3
long and whip-like, the remaining 4 pairs (c , la, setae (p ) and 2 pairs of minute posterolateral
2 1
p , p ) short; among the long setae, lm extraordi- setae (p and p ); their length (mm): da 280, dm
2 3 2 3
nally long, nearly as long as notogaster; h the 400, dp215, h 200, h 250, h 175, p 95, p 10,
1 1 2 3 1 2
second longest, distinctly longer than the remain- p 10.
3
ing long setae (h , h and p ) (Fig. 23). Anogenital region. Genital aperture small,
2 3 1
Anogenital region. Anogenital chaetotaxy: wider posteriorly than anteriorly, with 6 pairs of
6–1–2–3. Mutual distance ag–aga little longer or fine setae. Two pairs of anal setae; an longer
2
shorter than ad –ad , always longer than ad –ad . than an ; mutual distance an –an (cid:2)an –an .
1 1 3 3 1 2 2 1 1
Type series. Holotype (NSMT-Ac 11866) and Three pairs of adanal setae; mutual distance
2 paratypes (NSMT-Ac 11867–11868): Northern ad –ad (cid:2)ad –ad . Adanal fissure iad close and
3 3 2 2
slope of Mt.Yoko-dake, Kuchinoshima Island of pararell to lateral margin of anal opening, located
the Tokara Islands, 19-III-1987, J. Aoki—1 in level with anal seta an . Aggenital setae far
2
paratype (NSMT-Ac 11869): Zamami Island of longer than adanal setae.
the Okinawa Islands, 6-X-2005, J. Aoki. Type series. Hototype (NSMT-Ac 11873): Mt.
New Oribatid Mites from the Ryukyu Islands 113
(five pairs).
Dolicheremaeus magnussp. nov.
(Figs. 27–28)
Measurement. Body length 900–950mm,
width 480–525mm.
Prodorsum. Rostrum without a marginal rim.
Rostral setae densely barbed unilaterally. Lamel-
lae thin. Lamellar setae longer than their mutual
distance, densely barbed unilaterally, curved in-
ward near the base, inserted a short distance be-
hind lamellar tip. Interlamellar setae thick,
straight, weakly barbed, 2.6–2.7 times as long as
their mutual distance. Prodorsal surface densely
foveolate; the foveolae becoming smaller in ante-
rior part and arranged more sparsely in posterior
part (Fig. 28). Fine and dense granules found
along lamellae, around bothridia and near poste-
rior margin of prodorsum. Bothridium opening
laterally, accompanied by short anterior and pos-
terior ridges. Sensillus with a long thin pecuncle
and a spindle-shaped head (Fig. 27). Exoboth-
ridial setae very short and fine. Prodorsal
condyles very poorely developed; co.pl triangu-
lar; co.pmdiscernible as very low and broad pro-
trusions.
Figs. 25–26. Heteroppia setigera sp. nov. 25: Lat-
Notogaster. Notogaster large and broad, about
eroposterior part of prodorsum (right side). 26:
1.2 times as long as wide. Notogastral condyles
Dorsal view of body. Scale bars: 30mm in Fig.
25, 100mm in Fig. 26. very poorely developed; co.nl triangular; co.nm
absent; anterior margin of notogaster showing
Omoto, Ishigaki Island, the Yaeyama Islands, 5- only weakly waving margin. Notogastral surface
X-1978, J. Aoki—1 paratype (NSMT-Ac 12014): covered with inconspicuous foveolae and fine
Mariudo Fall, Iriomote Island, the Yaeyama Is- striae like “capillaries”. Ten pairs of notogastral
lands, 23-VI-2005, J. Aoki. setae rather thick and long, weakly barbed; their
Remarks. Three species have hitherto been RLN (relative length to notogaster, %):
known in the genus Heteroppia, which is charac- 17.1–36.2; seta da longer than c; h longer than
1
terized by globose sensilli and very long whip- h ; p longer than p or p . Lyrifissure imin level
2 2 1 3
like notogastral setae. These long setae in the with seta dm.
new species are six pairs, while they are four Anogenital region. Genital plates glabrous,
pairs in H. globigera Balogh, 1970, from Fiji Is- with 4 pairs of setae; mutual distance g –g (cid:1)
1 1
land. The remaining species, H. orthodactyla g –g (cid:3)g –g (cid:3)g –g . Anal plates weakly foveo-
2 2 4 4 3 3
Willmann, 1932, from Java, must have five pairs late, with 2 pairs of setae; mutual distance
of long notogastral setae, though all the setae ex- an –an far longer than an –an . Adanal setae
2 2 1 1
cept those of p-series were broken and lost in the ad inserted in level posterior to anterior margin
3
type specimen, leaving only their insertion pores of anal opening and in level with adanal fissures
114 J. Aoki
Figs. 27–28. Dolicheremaeus magnussp. nov. 27: Lateroposterior part of prodorsum (right side). 28: Dorsal view
of body. Fig. 29. Dolicheremaeus orientalis(Aoki, 1965). Dorsal view of body. Scale bars: 100mm in Figs.
28 and 29, 20mm in Fig. 27.