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119
THE RAFFLES BULLETIN OF ZOOLOGY 2006
THE RAFFLES BULLETIN OF ZOOLOGY 2006 54(1): 119-124
Date of Publication: 28 Feb.2006
© National University of Singapore
RARE SPIDERS OF THE GENUS CYCLOCOSMIA (ARACHNIDA: ARANEAE:
CTENIZIDAE) FROM TROPICAL AND SUBTROPICAL CHINA
M. S. Zhu*, J. X. Zhang and F. Zhang
College of Life Sciences, Hebei University, Baoding, Hebei 071002, P. R. China
Email: mingshengzhu@263.net (*Corresponding author)
ABSTRACT. – Two species of the ctenizid spider genus Cyclocosmia from tropical and subtropical China
are diagnosed, described and illustrated. One of them, Cyclocosmia latusicosta, is found to be new to science.
The relationships between all known species of the genus Cyclocosmia are discussed.
KEY WORDS. – Araneae, Ctenizidae, Cyclocosmia, new species, China
INTRODUCTION
Spiders of the genus Cyclocosmia Ausserer, 1871, are
fascinating because their abdomen is abruptly truncated and
ends in a hard, heavily sclerotized disc strengthened by series
of raised ribs separated by narrow grooves (Gertsch &
Platnick, 1975). The spiders usually live at steeply sloping
banks of sandy clay, covered with moist leaf litter, where
they dig 7-15 cm deep vertical burrows with a hinged door
attached to the entrance. Like all other trapdoor spiders,
Cyclocosmia leads an extremely sedentary existence. It is
distinct in having developed a morphological defense to cope
with intruders. When the spider retreats headfirst to the bottom
of its burrow, the abdominal disc fits tightly against the round
walls of the burrow and forms an impenetrable false bottom
(Gertsch & Wallace, 1936; Gertsch & Platnick, 1975). Due
to the successful camouflage of the trapdoor, Cyclocosmia is
very difficult to find and collect, and therefore it is often
considered as one of the rarest spiders.
Being a small genus of the family Ctenizidae, Cyclocosmia
only comprises six named species worldwide (Platnick, 2005;
Schwendinger, 2005): C. truncata (Hentz, 1841) and C.
torreya Gertsch & Platnick, 1975, in the USA, C. loricata
(C. L. Koch, 1842) in Mexico and Guatemala, C. ricketti
(Pocock, 1901) in China, C. siamensis Schwendinger, 2005,
and C. lannaensis Schwendinger, 2005, in Thailand. Gertsch
& Platnick (1975) revised the then known species of this
genus and pointed out that the ribs and grooves of the
abdominal disc, the number of setae on the seam of the disc,
and the shape of the spermathecae are valuable characters
for species discrimination. However, they found no significant
differences in the male palps among three American species,
but the male palps in the species from Thailand are distinct
from each other (Schwendinger, 2005).
This study is a part of our research on the taxonomy and
biogeography of Chinese mygalomorph spiders funded by
the NSFC, in which mygalomorphs are considered as
important objects for studies on biogeography and phylogeny.
Spiders of the genus Cyclocosmia are interesting
mygalomorphs with unique morphology and biology. In this
study, two species of Cyclocosmia from tropical and
subtropical China are reported and one of them is considered
to be new to science.
MATERIALS AND METHODS
All measurements in this paper are in millimeters. Leg
measurements are given as: total length (femur, patella, tibia,
metatarsus, tarsus). Dissected epigynes were cleared in 10%
KOH for approximately 15 minutes at room temperature of
18-25°C and then rinsed in distilled water. Abdominal rib
counts follow Gertch & Platnick (1975). SEM micrographs
were taken on a KYKY 2800 scanning electron microscope.
All specimens are deposited in the Museum of Hebei
University, Hebei, China (MHBU). The abbreviations used
are: ALE – anterior lateral eyes, AME – anterior median eyes,
PLE – posterior lateral eyes, PME – posterior median eyes,
MOA – median ocular area.
TAXONOMY
Cyclocosmia Ausserer, 1871
Cyclocosmia Ausserer, 1871: 144 (Type species by monotypy:
Mygale truncata Hentz, 1841); Gertsch & Platnick, 1975: 5.
Chorizops Ausserer, 1871: 144 (Type species by monotypy:
Actinopus loricatus C. L. Koch, 1842); Roewer, 1942: 146;
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Zhu et al.: Chinese Cyclocosmia
Bonnet, 1956: 1078. First synonymized by Banks (1910), but
removed from synonymy by Petrunkevitch (1911) and all
subsequent authors until resynonymized by Gertsch & Platnick
(1975).
Halonoproctus Pocock, 1901: 209 (Type species by monotypy:
Halonoproctus ricketti Pocock, 1901). First synonymized by
Simon, 1903.
Diagnosis. – Cyclocosmia can be easily distinguished from
all other ctenizids by its distinctly truncate abdomen forming
a caudal disc bearing ribs and grooves. Although two other
genera, Galeosoma and Idiosoma of the family Idiopidae,
have similar abdominal form, they are not closely related to
Cyclocosmia. These idiopid spiders possess eyes arranged in
three rows rather than two, which is characteristic for
ctenizids. In addition, the abdomen of the genus Galeosoma
is abruptly truncate but bears no ribs or grooves, whereas
that of the genus Idiosoma bears ribs or grooves but is only
moderately truncate (Gertsch & Platnick, 1975).
Description. – See Gertsch & Platnick (1975).
KEY TO CHINESE SPECIES OF CYCLOCOSMIA
1. Abdominal disc with 23-33 ribs on each side; an elevated central
zone inside each of the upper muscle impressions absent; length
of spermathecae less than one and a half times their width ....
................................................................ Cyclocosmia ricketti
–Abdominal disc with 20-23 ribs on each side; an elevated central
zone inside each of the upper muscle impressions present; length
of spermathecae two times their width.....................................
.......................................................... Cyclocosmia latusicosta
Cyclocosmia ricketti (Pocock, 1901)
(Figs. 1-2)
Halonoproctus ricketti Pocock, 1901: 209, pl. 21, fig. 1.
Cyclocosmia ricketti: Simon, 1903: 885, Figs. 1044-1047; Gertsch
& Platnick, 1975: 18-19, Figs. 28, 29, 32, 36 (part); Chen &
Zhang, 1991: 32, Fig. 25; Song, Zhu & Chen, 1999: 36, Figs.
16H, K-L (part); Schwendinger, 2005: 227, Figs. 2-8, pl. 1D.
Fig. 1. Abdomen of Cyclocosmia ricketti (Pocock, 1901), caudal
view.
Fig. 2. Cyclocosmia ricketti (Pocock, 1901): A, habitus of female; B, ocular area, dorsal view; C, abdomen, caudal view; D, same, lateral
view; E, spermathecae, dorsal view. Scale bars: A, B, E = 1.0 mm, C-D = 2.0 mm.
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THE RAFFLES BULLETIN OF ZOOLOGY 2006
Material examined. – 1 female, Taishun, Zhejiang, China, coll. Z.
F. Chen, Dec.1989.
Diagnosis. – Cyclocosmia ricketti differs from the American species
of Cyclocosmia in the abdominal disc with 23-33 ribs on each side
(Fig. 2C) and the parallel-sided spermathecae (Fig. 2E). It is similar
to Cyclocosmia latusicosta, new species, in the shape of
spermathecae, but can be distinguished from the latter by the length
of spermathecae being less than one and a half times its width (Fig.
2E), abdominal disc with 23-33 ribs on each side, and an elevated
central zone absent inside the upper pair of muscle impressions (Fig.
2C). It is also similar to Cyclocosmia siamensis Schwendinger, 2005
(Schwendinger, 2005: 231, Figs. 9-30, pl. 1C) in the shape of
spermathecae, but differs from the latter in the upper and median
pair of muscle impressions on opisthosomal disc separated by one
transversal rib, all ribs lacking hairs with dark, short, cylindrical,
upright proximal portion and light, long, flat, reclining distal portion,
rib angles lacking bottlebrush-like bristles bent toward the centre
(Fig. 2C).
Description of new female. Total length, including chelicerae,
25.83; chelicerae 4.32 long; carapace 11.07 long, 8.91 wide;
abdomen 15.57 long, 15.30 wide.
Carapace (Fig. 2A) red-brown and smooth, with a few
marginal hairs and a long bristle in front of ocular area, four
long bent bristles in longitudinal row running through ocular
area. Carapace curved in front and straight behind, widest at
coxae II. Ocular area black, with a black band in front of
fovea and beside ocular area respectively. Cervical groove
and radial furrows distinct. Fovea deep and procurved, U-
shaped, its greatest width occupying one fourth of carapace
width at that point.
Eyes (Fig. 2B) set on low tubercle, ocular area 1.00 long,
2.43 wide anteriorly, 2.43 wide posteriorly, occupying two
fifths of carapace width at that point. Clypeus height 1.46.
Anterior eye row straight and posterior eye row recurved,
both rows almost equal in length. Ratio of eyes, ALE: AME:
PLE: PME (0.53: 0.45: 0.40: 0.25). ALE-AME 0.30, AME-
AME 0.20, PLE-PME 0.08, PME-PME 1.18. MOA 0.91 long,
1.10 wide in front, 1.68 wide at back.
Chelicerae red-brown, inner margin with 11 teeth, outer
margin with nine teeth and 15 denticles between them.
Rastellum raised on prominent angled projection and
consisting of many short black teeth. Labium yellow-brown,
1.56 long, 2.28 wide, with three black cuspules anteriorly.
Maxilla yellow-brown, 4.50 long, 2.61 wide, armed with 15
black cuspules at base. Sternum yellow-brown, 6.75 long,
6.30 wide, with numerous long black setae, two pairs of small
round sigilla near margin opposite coxae I and II, and a pair
of large, irregularly outlined posterior sigilla. Palpal patella
with one proventral distal spine.
Legs yellow-brown, with tibiae, metatarsi and tarsi darker in
color, short and stout, with erect setae ventrally. Tibiae and
tarsi of pedipalps, and tibiae, metatarsi and tarsi of legs I and
II with numerous horn-like spines, metatarsus III with a few
short dorsal and two ventral spines, tarsus III with a few dark
spines prolaterally and ventrally, metatarsus IV with four short
spines. Paired claws with a single large tooth, unpaired claw
lacking tooth. Pedipalp with single claw bearing one tooth.
Measurements of legs: I 21.15 (7.20, 4.14, 4.23, 3.60, 1.98),
II 18.09 (5.85, 4.05, 3.15, 3.06, 1.98), III 17.46 (5.58, 4.23,
2.52, 2.97, 2.16), IV 22.32 (6.21, 5.40, 4.23, 4.14, 2.43). Leg
formula: 3214. Tibia I 1.98 wide, tibia II 1.98 wide, tibia III
2.25 wide, tibia IV 2.25 wide.
Abdomen (Fig. 2C-D) funnel-shaped and dark yellow-brown.
Caudal disc slightly concave, 13.95 in transversal diameter
and 15.30 in longitudinal diameter, with two ribs running
dorsoventrally and 32/33 radiating ribs on each side; each
rib angle with 25 or more bristles. Abdominal disc with six
well-marked muscle impressions. Four spinnerets, with inner
pair small and one-segmented, and outer pair much longer
and three-segmented. Two spermathecae (Fig. 2E), sack-like,
parallel-sided, each one with a length less than one and a
half times its width.
Male. Unknown.
Distribution. – China (Fujian, Hunan, Zhejiang, Sichuan).
Remarks. – Song et al. (1999: 36, Figs. 16H, K-L, pl. 1A-B)
provided the illustrations of Cyclocosmia ricketti basing on
a female specimen collected from Zhangjiajie, Hunan
Province, China (drawn by Mr. J. F. Wang). However, the
drawing of the disc (Song et al., 1999: Fig. 16L) was copied
from Gertsch & Platnick, 1975: Fig. 29, and it showed to be
C. siamensis.
Cyclocosmia latusicosta, new species
(Figs. 3-6)
Holotype. – Female, Aidian Village (21°49'N 107°18'E), Ningming
County, Guangxi, China, coll. M. S. Zhu, J. X. Zhang and F. Zhang,
25 Aug.2004.
Paratypes. – 4 females, same data as for the holotype.
Diagnosis. – The new species is similar to Cyclocosmia
ricketti, especially in the shape of its spermathecae, but differs
from the latter by the spermathecae being two times longer
than wide (Figs. 6F-J), abdominal disc with 20/23 ribs on
each side, and each upper muscle impression with an elevated
central zone (Fig. 6B). It is also similar to Cyclocosmia
siamensis Schwendinger, 2005 (Schwendinger, 2005: 231,
figs. 9-30, pl. 1C) in the shape of spermathecae, but differs
Fig. 3. Burrow entrance and trapdoor of Cyclocosmia latusicosta,
new species.
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Zhu et al.: Chinese Cyclocosmia
Fig. 4. Abdomen of Cyclocosmia latusicosta, new species, paratype,
caudal view.
from the latter in the upper and median pair of muscle
impressions on opisthosomal disc separated by one transversal
rib, all ribs lacking hairs with dark, short, cylindrical, upright
proximal portion and light, long, flat, reclining distal portion,
abdominal disc with 20-23 ribs on each side, and each upper
muscle impression with an elevated central zone (Fig. 6B).
Description. – Female. Holotype total length, including
chelicerae, 33.56; chelicerae 4.50 long; carapace 12.78 long,
11.25 wide; abdomen 17.20 long, 16.38 wide.
Carapace black-brown and smooth, with a few hairs and four
long bent bristles in longitudinal row running through ocular
area. Carapace curved in front and straight behind, widest at
coxae III. Ocular area darker in color. Cervical groove and
radial furrows distinct. Fovea deep and procurved, U-shaped,
its greatest width occupying one fifth of carapace width at
that point.
Eyes (Fig. 6A) set on low tubercle, ocular area 1.25 long,
3.06 wide anteriorly, 3.09 wide posteriorly, occupying one
third of carapace width at that point. Clypeus height 1.80.
Anterior eye row straight and posterior eye row slightly
recurved, both rows subequal in width. Ratio of eyes, ALE:
AME: PLE: PME (0.75: 0.51: 0.54: 0.37). ALE-AME 0.40,
AME-AME 0.27, PLE-PME 0.08, PME-PME 1.39. MOA
1.05 long, 1.29 wide at front, 2.19 wide at back.
Chelicerae (Fig. 6E) black-brown, inner margin with 10-12
teeth of different size, outer margin with eight or nine large
teeth and 23 denticles between them. Rastellum raised on
prominent angled projection and consisting of many short
black teeth. Labium dark red-brown, 2.16 long, 2.52 wide,
with three black cuspules anteriorly. Maxilla dark red-brown,
5.40 long, 3.15 wide, armed with 12-17 cuspules at base and
many small cuspules in anterior part. Sternum red-brown,
7.47 long, 7.56 wide, with numerous long black setae, two
pairs of small round sigilla near margin opposite coxae I and
II, and a pair of large indistinctly outlined posterior sigilla.
Palpal patella with one proventral distal spine.
Legs black-brown, short and stout, with erect setae and hairs
ventrally. Legs III and IV distinctly thicker and stronger than
legs I and II. Tibiae and tarsi of pedipalps and tibiae, metatarsi
and tarsi of legs I and II with numerous horn-like spines,
metatarsus and tarsus III with a few scattered spines dorsally
and ventrally, metatarsus IV with several small spines at tip.
Paired claws with a single large tooth, occasionally
accompanied by a denticle, unpaired claw lacking tooth.
Pedipalp with single claw bearing one tooth. Measurements
of legs:I 22.95 (8.55, 4.95, 4.14, 3.60, 1.71), II 21.60 (7.65,
4.50, 3.51, 3.69, 2.25), III 20.88 (6.03, 4.95, 3.42, 3.78, 2.70),
IV 27.27 (7.29, 5.58, 4.50, 6.93, 2.97). Leg formula: 3214.
Tibia I 2.52 wide, tibia II 2.25 wide, tibia III 2.97 wide, tibia
IV 2.88 wide.
Abdomen (Figs. 6B-D) dark yellow-brown, with crescent-
shaped sclerite posterior to spinnerets and anus not connected
to ventral median rib angle. Caudal disc convex, with two
ribs running dorsoventrally and 20/23 radiating ribs on each
side; ribs wide and grooves deep; each rib angle distinctly
elevated carrying 46-52 long and smooth bristles and a few
bottlebrush-like bristles rising from inner surface of rib angle
and bent towards disc center. All ribs with many granular
structures in different size (Fig. 4). Abdominal disc with six
well-marked muscle impressions, the upper pair with an
elevated central zone connected to the outer rim of each of
these muscle impressions, and separated from median pair
by only one transversal rib, second (lower) transversal rib
wide, running into upper portion of ring around median
muscle impression. Disc surface with only three pairs of
bristles on the rims of muscle impressions. Four spinnerets,
with inner pair small and one-segmented, and outer pair much
longer and three-segmented. Two sack-like, parallel-sided
spermathecae (Fig. 6F), each one almost two times longer
than wide.
Male. Unknown.
Etymology. – Latin: latus = wide; Latin: costa = rib.
Variation. Measurements and rib counts (females, n=5):
Body length: 33.03-33.56, carapace length 12.78-13.50, width
11.25-12.24; rib counts 20-23 (20/21, 21/20, 21/21, 22/21,
20/23). Spination of patellae: One female possesses one
proventral spine on its right palpal patella, two proventral
spines on the other palpal patella. Another female has one
proventral spine on its right palpal patella, and none on the
other palpal patella. Other specimens are the same as holotype.
Labium with 2-3 cuspules.
Burrow. Burrows found at a sloping earth bank with moist
leaf litter were about 16 cm in depth and 22 mm in diameter,
narrowed near the bottom. The hinged entrance door was 32
mm in diameter, made of moss, earth and silks. The inside of
the burrow was lined with a thin silk layer (Fig. 3).
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THE RAFFLES BULLETIN OF ZOOLOGY 2006
Fig. 5. Cyclocosmia latusicosta, new species, paratype (SEM micrographs). A, detail of ribs; B, detail of inner side of rib angles showing
two kinds of bristles; C, detail of long and smooth bristles; D, detail of bottlebrush-like bristles.
Distribution. – Known only from the type locality in
southeastern China, near the border to Vietnam.
DISCUSSION
According to the shape of spermathecae, the two Chinese
species of the genus Cyclocosmia (C. ricketti and C.
latusicosta, new species) and one of the Thailand species (C.
siamensis) seem to be more primitive than the other Thailand
species (C. lannaensis) and the three American species (C.
truncata, C. torreya and C. loricata) because their
spermathecae are simple and parallel-sided, whereas the
spermathecae of the latter are more complex. Among the four
Asian species, C. ricketti and C. latusicosta, new species,
from China are more closely related because their ribs of disc
are smooth and lack setae. C. lannaensis is more derived than
the other three Asian species due to its medially constricted
spermathecae with knob-shaped apices, and its ribs of disc
with many knob-like tubercles. Although the shape of
spermathecae of C. lannaensis is similar to the American
species C. loricata, it seems to be more closely related to the
other Asian species than the American species, because its
apices of spermathecae are round but not “T”-shaped as C.
loricata. Among the American species, C. truncata and C.
torreya from the USA seem to be more closely related to
each other. As Gertsch & Platnick (1975) pointed out, their
spermathecae are so similar that it is very difficult to
distinguish them on the basis of genitalic characters alone.
The distribution and relationship of these seven species
suggest that this genus already existed before the splitting of
Laurasia, and that the Asian and American species were later
geographically separated.
ACKNOWLEDGEMENTS
This study was supported by grants from the NSFC
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Zhu et al.: Chinese Cyclocosmia
Fig. 6. Cyclocosmia latusicosta, new species. A, ocular area, dorsal view, holotype; B, abdomen, caudal view, holotype; C, same, lateral
view, holotype; D, posterior portion of opisthosoma, ventral view, holotype; E, left chelicera, prolateral view, holotype; F-J, spermathecae,
dorsal view: F, holotype; G-J, paratypes. Scale bars: A, F-J = 1.0 mm, B-E = 2.0 mm.
(30170118) to M. S. Zhu and in part by the NSFC (30130040)
to D. X. Song. We thank Tinghui Li (Southern Spider
Research and Breeding Institute of Nanning, Guangxi, China)
for his assistance during the expedition to Guangxi Province
in August 2004. Many thanks are also due to Dr. P. J.
Schwendinger for providing the valuable reference.
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