Bull. Natl. Mus. Nat. Sci., Ser. A, 37(1), pp. 15–26, March 22, 2011 New Spiders of the Families Tetragnathidae, Nephilidae and Clubionidae (Arachnida, Araneae) from Izu and Ogasawara Islands, Tokyo Hirotsugu Ono Department of Zoology, National Museum of Nature and Science, 3–23–1, Hyakunin-cho, Shinjuku-ku, Tokyo, 169–0073 Japan E-mail: [email protected] (Received 29 October 2010; accepted 9 February 2011) Abstract Three new spiders of the families Tetragnathidae, Nephilidae and Clubionidae (Arach- nida, Araneae) from Hachijojima and Mikurajima Islands of the Izu Islands, and Chichijima Island of the Ogasawara Islands are described under the names, Leucauge nagashimai sp. nov. (Tetra- gnathidae), Nephila clavata caerulescens subsp. nov. (Nephilidae) and Clubiona oceanica sp. nov. (Clubionidae). Leucauge nagashimai resembles Chinese Leucauge bimaculata and liui, both de- scribed by Zhu, Song et Zhang (2003), but differs from the two species by the details of female genitalia, especially in the shape of spermathecae. Clubiona oceanica belongs to the species group of Clubiona hystrix defined by Deeleman-Reinhold (2001) and stands close to Clubiona maipai Jäger et Dankittipakul, 2010 from Thailand, Clubiona kuu Jäger et Dankittipakul, 2010 from Laos, Clubiona damirkovaci Deeleman-Reinhold, 2001 from Peninsular Malaysia and Clubiona hitchinsi Saaristo, 2002 from Seychelles Islands, but is distinguishable from these known species by the structure of female genitalia, especially the position of intromittent orifices and the condition of in- tromittent canals and in details of tibial apophysis and embolus of male palpal organ. Nephila clavata caerulescens is described for the populations of Nephila clavata on Hachijojima and Mikurajima Islands, which show a remarkable variation on the coloration of the body not mimic to the color pattern of vespid wasps. Key words: Taxonomy, Araneae, Nephilidae, Tetragnathidae, Clubionidae, Izu Islands, Oga- sawara Islands. In the course of these projects the present Introduction author concentrated his efforts on field research- Under a long-term project of the “Studies on es on Mikurajima and Hachijojima Islands of the the Origin of Biodiversity of the Sagami Sea, the Izu Islands, and Chichijima and Hahajima Is- Fossa Magna Element and the Izu-Ogasawara lands of the Ogasawara Islands. Although some Island Arc” organized by the National Museum papers were published on the basis of results of of Nature and Science, Tokyo, the present author the study during these projects (Ono, 2008, 2009, continued inventory studies of spiders of these 2010, 2011), several spider specimens have been areas in the period from 2006 through 2010. At left undetermined. On the basis of a part of this the same time, he was appointed a committee unstudied material, three new and interesting spi- member of an assessment of threatened species ders are described in the present paper. (Red Data) of spiders of the Izu and Ogasawara The Izu Islands are composed of seven main Islands, Tokyo, which was provided by the Japan islands and some smaller islands stretching to the Wildlife Research Center, Tokyo, under commis- south from the Bay of Tokyo and occupy a wide sion of the Environment Bureau of the Tokyo range between 32 and 35 degrees north latitude. Metropolitan Government in the years 2009 and Of these, Mikurajima Island (20.55 km2 in size) 2010. and Hachijojima Island (62.52 km2) are situated 16 Hirotsugu Ono in the southern part. All the islands of Izu are vember 2010 and on Chichijima Island between volcanic formed by Pleistocene activity, and their 18th and 30th May and between 19th and 24th spider fauna seems to be poor in the total number October 2010 by the present author using sweep- of species (Ono, 2001). However, Mikurajima ing and beating methods in the forest as well as and Hachijojima have developed evergreen collecting by hand, that is, two females of Nephi- broad-leaved forests well preserved and various la clavata, seven females, four males and four aspects of arachnology are expected, for instance juveniles of a leucaugine species, and six fe- a phase of isolation. males, four males and two juveniles of a clubion- From Mikurajima Island, 86 species were id species. Other than the above material, some recorded (Ono, 2010), while 91 species were specimens (17 immature females and 7 adult known from Hachijojima Island (Sasaoka, 2010). males) of Nephila clavata collected by Mr. M. A new subspecies of well-known Nephila clavata Tanaka on Mikurajima Island on 3rd October L. Koch, 1878, is reported, which shows a geo- 2009 were provided for this study. Comparative graphic variation presumably caused by the isola- material was also used, which were selected from tion in these islands. the specimens preserved in the Arachnid Collec- On the other hand, the Ogasawara Islands (ϭ tion of the National Museum of Nature and Sci- the Bonin and Volcano Islands) are situated in a ence, Tokyo. much southern area surrounded by the latitude All the specimens were preserved in 76% or between 23° and 28° N and the longitude be- absolute ethanol on location, examined under tween 141° and 143° E in the northwestern Pacif- Leica MZ16 stereomicroscope, and taxonomical- ic (see Ono, 2011, figs. 1–4). The islands have ly studied at the Department of Zoology of the volcanic origin came into existence forty-eight above museum. Some individuals were pho- million years ago and were uninhabited up to the tographed while alive at the field to record natur- 19th Century. Being more than 1,000 km apart al coloration (Figs. 32–38). Body, legs and eyes from a land, such islands should perform a typi- were measured, and pro- and opisthosomata, che- cal oceanic fauna composed of many endemics licerae and details of female genitalia and male explosively evolved from small number of ances- palpal organ of the specified specimens were tral species. However, human activities after first illustrated. Thus, a new subspecies of Nephila immigration in 1830 influenced actually the na- clavata L. Koch, 1878 (Nephilidae), and two new ture of Ogasawara, and gave a serious damage on species of the genera Leucauge White, 1841 the spider fauna. Of 81 species known from the (Tetragnathidae) and Clubiona Latreille, 1804 Ogasawara Islands, two thirds are regarded as (Clubionidae) are recognized and described as artificial immigrants (Ono, 2011). Chichijima Is- follows. land (24 km2) is the largest and administratively The type specimens of the new species and main island in Ogasawara, having a population of subspecies are deposited in the Department of about 2,000. Two new species of the families Zoology, National Museum of Nature and Sci- Tetragnathidae and Clubionidae are herein de- ence, Tokyo (NSMT). scribed from this island, both of which seem to Following abbreviations are used for the be endemic to the islands. descriptions: AME, anterior median eye, ALE, anterior lateral eye, PME, posterior median eye and PLE, posterior lateral eye. Material and Methods The specimens used for this study were col- lected during research trips on Hachijojima be- tween 23rd and 26th November 2007 and between 6th and 8th March and between 7th and 11th No- New Spiders from Izu and Ogasawara Islands 17 ϩ ϩ ϩ ϩ Descriptions of New Taxa IV 8.69 mm (2.94 0.53 1.91 2.48 0.83), male, I 13.10 mm (3.39ϩ0.64ϩ3.56ϩ4.31ϩ1.20), Family Tetragnathidae II 9.01 mm (2.63ϩ0.56ϩ2.36ϩ2.63ϩ0.83), Leucauge nagashimai sp. nov. III 4.13 mm (1.35ϩ0.36ϩ0.83ϩ1.06ϩ0.53), [Japanese name: Hime-shirokanegumo] IV 7.24 mm (2.40ϩ0.47ϩ1.58ϩ2.06ϩ0.73). (Figs. 1–16, 36–38) Prosoma: Carapace flat, longer than wide (length/width female 1.23, male 1.25), median Diagnosis. This new species resembles some furrow distinct. Eyes almost same in size, ALE Chinese species as Leucauge bimaculata Zhu, and PME of female slightly larger, the anterior Song et Zhang, 2003 from Yunnan and Leucauge eye row slightly recurved and the posterior row liui Zhu, Song et Zhang, 2003 from Hainan Is- straight in both the sexes, AME-AMEՅAME- land in the structure of female genitalia, but is ALE (5 : 6 in female, 1:1 in male), PME-PMEϽ distinguishable from these species by the details ME-PLE (1 : 2 in female, 2 : 3 in male), median of female genitalia, especially the shape of sper- ocular area almost square (length/width 0.94 in mathecae (Figs. 10–11). The structure of male female, 1.08 in male; anterior width/posterior palpal organ of this new species is also peculiar width 0.88 in female, 1.00 in male), clypeus nar- (Figs. 3–6) and the horn-like dorsal apophysis on row. Chelicera of female with three strong teeth cymbium is absent. The opisthosoma of this new on the promargin of fang furrow and one large species is cylindrical and without posterior pro- and four small teeth on retromargin (Fig. 8), that jection, while that of the other species is fusiform of the male with retromarginal teeth reduced and the posterior end is more or less narrowed (Fig. 2). Labium wider than long (length/width and expanded over the spinnerets. 0.60 in female, 0.66 in male), sternum longer Type specimens. Holotype: male and allotype: than wide (length/width 1.11 in female, 1.09 in female from Mt. Yoakeyama, Chichijima Island, male), female palp without a long claw. Legs Ogasawara Islands, Tokyo, Japan, 28-V-2010, H. long and slender, with long spines on femora Ono leg. (NSMT-Ar 9451-9452); paratypes: one dorsally and laterally, patellae dorsally, tibia lat- female from the same locality as for the holotype, erally and metatarsi dorsally; femora with a low 22-X-2010, one female from Omura, 1-IV-1974, of trichobothria [twelve pairs in female, ten pairs Mt.