Studies on the Japanese Harvesters. IV. Notes on the Two Harvesters from Yaku-shima and Tane-$a-shima, Islands of Southwest Japan BY Seisho SUZUKI Reprinted from the JOURNAL of SCIENCE of the HIROSHIMA UNIVERSITY Series B, Div. 1, Vol. 11, Art. 6 HIROSHIMA, JAPAN MARCH, 1950
Studies on the Japanese Harvesters. IV. Notes on the Two Harvesters from Yakushima and Tane-ga-shima, Islands of Southwest Japan Seisho SUZUKI Zoological Laboraloty, Faculty of Science, Hiroshima Unjtersity, Hiroshrma (With 2 Text-figures) Not a single reference has been reported concerning the Opilio-" nes fauna of Yaku-shima and Tane-ga-shima, islands of southwest Japan, which are interesting as far as the biogeographical point of view is concerned. I have received recently some specimens of harvesters from Prof. Y. HORIKAWA and Mr. H. SUZUKI, which had been collected in those islands by them. The materials include two species, Nelima gem f usca pumilio n. subsp. (Subfam. Liobuninae) and Gagrella cyanea ROEWER (Subfam. Gagrellinae). Of these the former inhabits only in the island Yaku-shima, but the latter was collected in both Yaku-shima and Tane-ga-shima islands. The allied species of Nelima gengfusca pumilio distribute widely in Kyushu, Shikoku (Nelima nigriccxa SATO et SUZUKI), Japan proper, Hokkaido, Southern Saghali en, Corea and so forth (N elima genufusca genzcf usca (ROZWER)). Many other species of this genus are known from several Eurasiatic continents including Japan proper, s'o this new subspecies seem; to be the northern-element. On the contrary, Gagrella cyalzea ROEWER has been reported hitherto to be living in Formosa and the island Amami-ohshims in Liu-Kiu Archipelago and never to be found in Kyushu nor in Japan proper. I believe it indicates that this species belongs to the oriental element. The description of a new subspecies and some notes on these two harvesters are given below. 1. Nelima genufusca pumilio n, subsp. Body extremely small (3.0 mm) in size and a little upheaved (Text-figs. 1-2A). Frontal margin of cephalothorax waved twice. Carapace totally smooth, without any armaments. Two thoracic segments distinct and each forms a hard chitinous plate in the (1) Ricardo Pinto-da-Rocha
middle. I-V tergites completely unite and form a hard chitinous dorsal scutum. Other dorsal segments free and bent to the ventral side. All the dorsal segments smooth, without armaments. Ocular tubercle normal in structure and smooth, without spines nor teeth (Text-fig. 2C). Chelicerae and palpi are quite normal; these structure nearly equal to that of Nelima genufusca genufusca (ROEWER). Palpal tarsus alone ventrally armed with small number of fine teeth, arranged in a longitudinal line (Text-fig. 2B). Text-fig. 1. Nelima genufusca pumilio n, subsp. 6. Lateral view of th3 bobdy, legs removed. x18. Ventral surface of abdomen including I-IV coxae and genital plate smooth, only with fine hairs. Other than these hairs, some fine (granules are seen on the I-IV coxae and genital plate. Legs conspicuously slender and comparatively long to its body size, beset with fine hairs. Color: Ground color of cephalothorax rusty brownish black; rings of odoriferous glands and small area between frontal margin and ocular tubercle brownish. In this area exist two linear black stripes, which run from median towards ocular tubercle, but they do not reach the latter. Ocular tubercle brownish black to black. Soft skin of two thoracic segments light yellowish brown, but their hard chitinous plates and all the dorsal scutum segments deep black with splendid bluis:~ or greenish metallic lustre. First cheliceral segment light yellow, but dorsally brownish; second segment yellowish whi~e; arical end of cheliceral chelae and teeth black. Palpal femur, patella and tibia mostly black or rusty brownish black; ventral surface of femur and tibia brownish. Tarsus light yellowish, but proximal half of this segment brownish; end claw black. Ground color of I-IV
Studies on the.7apanese Harvesters. ZV 5 1 coxae and genital plate greyish yellow, but sternites almost dark brown and proximal half or coxae brown to blackish brown. Other leg joints uniformly dark brown. Text-fig. 2. Nelima genu f usca pumilio n. subsp. 8. A. Body, dorsal.xl8; B. Inner-side view of palpus. x27; C. Ocular tubercle, lateral. x40. Locality: 18. 19 Oct., 1945. Island Yaku-shima, Kagoshima Pref. (H. SUZUKI). Measurements (in mm.): Length of body 3.0; breadth of cephalothorax 2.2; breadth of abdomen 2.0; length of femur I 9.0: I1 17.7: 111 8.6: IV 11.7; length of leg I 43.0: I1 92.6: 111 44.5: IV 66.0. The type-specimen is preserved in the Zoological Laboratory of the Hiroshima University. Remzrks: As above mentioned Nelirna genu f usca ROEWER is one of the mgst common harvesters in Japan and distributes widely throughout the Japan proper, Hokkaido, Southern Saghalien, Corea and so forth. In Kyushu and Shikoku districts inhabits an allied species, Nelirna nigricoxa SATO et Suzu~r. These two species are distinguished mainly by the color of the ventral surface in mature individuals; namely in N. nigricoxa, when it is fully developed in
autumn, the color of the ventral surface becomes blackish. The new subspecies bears sjme similarities in the general structure of body with these two allied species; nevertheless, the former can be distinguis3ed from the latter in the coloration of body and in the armaments of body, legs and other appendages. Other than these differences, between these forms exist notable gaps in the size of body and leg. I have collected hundreds of specimens of N. genu fusca and N. nigricoxa from various localities of enire range and compared the new subspecies with those numerous examples. Some of the measurements were given in' the following table. TABLE I. Body size and length of leg of adult males in three forms of Japan. Species name N. genu f zlsca pumilro N. genuf usca genu usca N. nig? ~COXU. Locality No, of Breadth Length oflength of n1:n :!,,domsn I femur 1 leg IS. Yaku-shh?. 9.0 43.0 Sapporo 1 lhokkaido, N~kko (Japan proper) 8 43 4.7+0.063 2.7*0,029 8.9* 0.12346.4*0.654 Hiroshima!Japan proper) 6 25 (22) (22) 5.3+ 0.070 3.5& 0.06~ 14.2-10.095 70.0+ 0.705 Mt. Takanawa (Shikoku) 6 11 5.6k0.165 3.5zt0.050 14.0k0.31668.Szt1.831 As is shown in the table I, the body and legs of the island Yaku-shims specimen are smaller than those of other populations of allied forms. In the length of femw and :leg, both forms of Yaku-shim1 and Nikko approximztely equal, but exist remarkable differences in body size between them. Therefore the relative length of femur or leg (i. e. length of femur to body length and length of leg to body length) differs remarkably between two forms. The population of Nikko seems to be notably specialized and I think it might be a psrticular ecological type. Although the form of the island Yaka-shims bears some similarities with the case of Nikko, as above described, the former differs in various characters from the parent form. Thus we can see so much differences between the present and the allied forms that it makes us believe that the former should be a quite different species, but as the present investigation is based on a single specimen, the author wishes to think it for a while as a new subspecies of Nelima genufusca ROEWER. -Mere we must refer once mwe to the relation between the new subspecies and the two allied spxies, N. nigricoxa and N. genu fusca. As above fully stated, in the color of the ventral surface of body, the present form seem; to be nearer to N. nigricoxa than N. genufusca. 30 that if we recognize N. nigriccxa as a full species, it would
Studies on the,.japanese HaroesLers. ZV 53 be more reasonable to name the present subspecies N. nigricoxa pumilio. But because I think now N. nigricoxa may be a local variety of wide-spread N. genu f usca, I named the present form N. g~nufusca pumilio instead of N. nigricoxa pumilio. 2. Gagrella cyanea ROEWER. G. cyanea ROEWER, 1915. Arch. Naturg., 81 A, 3, P. 142. ROEWER, 1923. Die Weberknechte der Erde, Jena, P. 491. Suzu~r, 1944. Journ. Sci. Hiroshima Univ., Ser. B, Div.1, P. 250. This species was described at first by RoEwER(~~~~) based on the specimens from Rokko (Formosa), after that time SUZUKI (1944) reported that it inhabits in Mt. Niitaka (3950m. Formosa) and the island Amami-ohshima in Liu-Kiu Archipelago. The individuals of the island Tane-ga-shima bears much similarities in many characters with the type-specimen (collected in Formosa) and the examples of the island Amami-ohshima; the specimen of the island Yaku-shima also accords in the structure and coloration of body with the above mentioned populations, but in the means of measurements of body size and length of legs exist remarkable differences between them. The results of measurements in some localities are given in the following table (in mm:): TABLE 11. Body size aqd length of 1-2 of adult individuals in G. cyanea of various localities. ~ ~ of femui. ~ ~ t Length h of leg shims ML. Nlitaka It can be seen that the body size and length of femora and 1 egs in two populations of Tane-ga-shims and Amami-ohshima are nearly equal, but those of Yaku-shima are far smaller than these two populations. The differences are particularly remarkable in the length of femur and leg, namely, if we take the length of femur or leg of Yaku-shima population as 100, that of Tane-ga-shima and Amamiohshima populations is nearly twice or more times of the former specimen. The specimen of the island Yaku-shima is thus exceedingly smaller in body size and has the slenderer and shorter legs of only
half length of normal populations. The similar condition is seen ' in the case of Mt. Niitaka. It seems that such dwarf specimens as found in the island Yaku-shima and Mt. Niitaka should have been resulted by the special environmental factors of habitats; concerning this point more complete study will be published in the near future by the author. At any rate, it would be worth to notice that the two harvasters, Nelima genu fusca pumilio and Gagrella cyanaa inhabiting in the island Yaku-shima are conspicuously smaller in body size and length of legs, as compared with the same or allied 1 species of their neighboring or remote islands and main lands. Locality: 18, 19 Oct., 1948. Island Yaku~shima, Kagoshima Pref. (H. SUZ~TKI); 3 8, 19, 22-23 'Oct., 1948. Island Tane-ga-shima, Kagoshima Pref. (Y. HORIKAWA and H. SUZUKI). 3 SUMMARY 1. A new subspecies, Nelima genufusca pumilio was recorded from Yaku-shima, an island of southwest Japan. It bears the closest relationship to Nelima genu f usca genu f usca (ROEWER) and Nelima nigricoxa SATO et SUZUKI, and seema to be the northern element. 2. Gagrella cyanea ROEWER which is considered to be the oriental element, inhabits in both Yaku-shima and Tane-ga-shima islands. 3. B3th N elima genu f usca pumilio and Gagrella cyanea occurring in the island Yaku-shima, are exceedingly smaller in body size and length of legs than those of the normal forms of the same or allied species. 4. Although the island Tane-ga-shima situates more northerly than the island Yaku-shima, Gagrella cyanea occurring in the former island bears the closer relation with the same species inhabiting in the island Amsmi-ohshima and Formosa rather than in the nearest island Yaku-shima. The author wishes to thank to Prof. Y. HORIKAWA and Mr. H. ' Suzu~r for their kind presentation of the valuable materials.