Mecistocephalus diversisternus ( Silvestri, 1919 )

Published, First, 2007, The Mecistocephalidae of the Japanese and Taiwanese islands (Chilopoda: Geophilomorpha), Zootaxa 1396, pp. 1-84 : 56-59

Mecistocephalus diversisternus ( Silvestri, 1919)

[1] Lamnonyx diversisternus Silvestri 1919 — Rec. Ind. Mus. 16: 81; fig. 23 (original description, key)

[2] Lamnonyx smithi [sic]: Silvestri 1919 — Rec. Ind. Mus. 16: 79 (redescription, key); fig. 22 [pars] Mecistocephalus diversisternus: Chamberlin 1920a — Can. Ent. 52: 185 Mecistocephalus smithi [sic]: Chamberlin 1920a — Can. Ent. 52: 186 [pars] Mecistocephalus (Mecistocephalus) diversisternus: Attems 1929 — Tierreich 52: 138 (key)

[3] Mecistocephalus (Mecistocephalus) smithi [sic]: Attems 1929 — Tierreich 52: 139 (key) [pars] Mecistocephalus diversisternus: Takakuwa 1934a — Annot. Zool. Japon. 14: 363

[ 4] Mecistocephalus diversisternus: Takakuwa 1934b — Bot. & Zool. Tokyo 2: 710 (redescription, key); fig. 7 Mecistocephalus diversisternus: Takakuwa 1934c — Bot. & Zool. Tokyo 2: 884

[5] Mecistocephalus (Mecistocephalus) takakuwai: Verhoeff 1934 — Zool. Jahrb. Syst. 66: 36 (original description, key); pl. 4: fig. 58–60 new synonymy Mecistocephalus takakuwai: Takakuwa 1934a — Annot. Zool. Japon. 14: 363

[6] Mecistocephalus takakuwai: Takakuwa 1934b — Bot. & Zool. Tokyo 2: 710 (redescription, key); fig. 1–2, 8–10 Mecistocephalus takakuwai: Takakuwa 1934c — Bot. & Zool. Tokyo 2: 884 Mecistocephalus smithii: Takakuwa 1934a — Annot. Zool. Japon. 14: 363 [pars] Mecistocephalus smithi [sic]: Takakuwa 1934b — Bot. & Zool. Tokyo 2: 711 [pars] Mecistocephalus smithii: Takakuwa 1934c — Bot. & Zool. Tokyo 2: 884 [pars] Mecistocephalus smithi [sic]: Verhoeff 1934 — Zool. Jahrb. Syst. 66: 36, 37 [pars] Mecistocephalus smithi [sic]: Fahlander 1938 — Zool. Bidr. Uppsala 17: 5 [pars] Mecistocephalus (Mecistocephalus) diversisternus: Takakuwa 1938a — Annot. Zool. Japon. 17: 354 Mecistocephalus diversisternus: Takakuwa 1938b — Bot. & Zool. Tokyo 6: 2030 (key)

[7] Mecistocephalus takakuwai: Takakuwa 1938 — Bot. & Zool. Tokyo 6: 2030; fig. 0 Mecistocephalus (Mecistocephalus) smithii: Takakuwa 1938a — Annot. Zool. Japon. 17: 355 [pars] Mecistocephalus smithii: Takakuwa 1938b — Bot. & Zool. Tokyo 6: 2030 (key) [pars]

[8] Mecistocephalus takakuwai: Takakuwa 1939 — Trans. Biogeogr. Soc. Japan 3: 123 Mecistocephalus (Mecistocephalus) diversisternus: Takakuwa 1940 — Fauna Nippon. 9: 56 (key); fig. 51

[9] Mecistocephalus (Mecistocephalus) takakuwai: Takakuwa 1940 — Fauna Nippon. 9: 62 (key); fig. 1–11, 56 Mecistocephalus (Mecistocephalus) smithi [sic]: Takakuwa 1940 — Fauna Nippon. 9: 61 (key) [pars] Mecistocephalus (Mecistocephalus) diversisternus: Takakuwa 1943 — Bull. Biogeogr. Soc. Japan 13: 170 (also as Mecistocephalus diversistens [sic] on page 170) Mecistocephalus takakuwai: Takakuwa 1943 — Bull. Biogeogr. Soc. Japan 13: 170 Mecistocephalus smithi [sic]: Takakuwa 1943 — Bull. Biogeogr. Soc. Japan 13: 170 [pars] Mecistocephalus takakuwai: Attems 1947 — Ann. Naturhistor. Mus. Wien 55: 102 (key) Mecistocephalus smithii: Attems 1947 — Ann. Naturhistor. Mus. Wien 55: 102 (key) [pars] Mecistocephalus (Mecistocephalus) diversisternus: Takashima 1949 — Acta Arachn. 11: 12 Mecistocephalus (Mecistocephalus) takakuwai: Takashima 1949 — Acta Arachn. 11: 12 Mecistocephalus (Mecistocephalus) smithi [sic]: Takashima 1949 — Acta Arachn. 11: 12 [pars]

[10] Mecistocephalus (Mecistocephalus) diversisternus: Takashima & Shinohara 1952 — Acta Arachn. 13: 6 (key)

[11] Mecistocephalus takakuwai: Chamberlin & Wang 1952 — Proc. Biol. Soc. Washington 65: 177 Mecistocephalus smithi [sic]: Chamberlin & Wang 1952 — Proc. Biol. Soc. Washington 65: 178 [pars] Mecistocephalus (Mecistocephalus) takakuwai: Takashima & Shinohara 1952 — Acta Arachn. 13: 7 (key); fig. 1

[12] Mecistocephalus (Mecistocephalus) smithii: Takashima & Shinohara 1952 — Acta Arachn. 13: 7 (key); fig. 1: B, B', B'' [pars]

[13] Mecistocephalus takakuwai: Miyosi 1955a — Misc. Rep. Res. Inst. Nat. Resources Tokyo 38: 152

[14] Mecistocephalus smithi [sic]: Miyosi 1955a — Misc. Rep. Res. Inst. Nat. Resources Tokyo 38: 152 [pars] Mecistocephalus (Mecistocephalus) smithi [sic]: Wang 1955 — Quart. J. Taiwan Mus. 8: 15 [pars]

[15] Mecistocephalus smithi [sic]: Wang 1956 — Quart. J. Taiwan Mus. 9: 158 [pars]

[16] Mecistocephalus diversisternalis [sic]: Wang 1957 — Quart. J. Taiwan Mus. 10: 27 Mecistocephalus smithi [sic]: Wang 1958 — Proc. X Intern. Congr. Ent.: 881 [pars]

[17] Mecistocephalus smithi [sic]: Wang 1959 — Quart. J. Taiwan Mus. 12: 195 [pars] Mecistocephalus takakuwai: Ogawa 1961 — Zool. Mag. Tokyo 70: 204; fig. 10–13

[18] Mecistocephalus diversisternus: Shinohara 1961a — Sc. Rep. Yokosuka City Mus. 6: 76

[19] Mecistocephalus smithi [sic]: Wang 1963 — Quart. J. Taiwan Mus. 16: 93 [pars]

[20] Mecistocephalus takakuwai: Shinohara 1966 — Ecol. St. Biotic Comm. Nat. Park Nat. St. Tokyo 1: 124 Mecistocephalus takakuwai: Shinohara 1970 — J. Biol. Teach. Ass. Tokyo 6: 16 Mecistocephalus takakuwai: Murakami 1975a — Bull. natn. Sci. Mus. Paris, ser. A Zool. 1: 86

[21] Mecistocephalus takakuwai: Murakami 1975b — Bull. natn. Sci. Mus. Paris, ser. A Zool. 1: 157 (redescription) Mecistocephalus takakuwai: Moritz & Fischer 1979 — Mitt. Zool. Mus. Berlin 55: 350 Mecistocephalus takakuwai: White 1979 — Myriapod Biol.: 6

[22] Mecistocephalus takakuwai: Takano 1980 — Atypus 76: 53 Mecistocephalus diversisternum [sic]: Demange 1981 — Rev. Zool. Afr. 95: 639

[23] Mecistocephalus takakuwai: Shinohara 1981b — Misc. Rep. Nat. Park Nat. St. Tokyo 12: 89 Mecistocephalus smithi [sic]: Shinohara 1981b — Misc. Rep. Nat. Park Nat. St. Tokyo 12: 89 [pars] Mecistocephalus takakuwai: Colmagro et al. 1986 — Caryologia 39: 310 Mecistocephalus diversisternus: Murakami 1993 — List Species Anim. Japan 5: 104 Mecistocephalus takakuwai: Murakami 1993 — List Species Anim. Japan 5: 105 Mecistocephalus smithi [sic]: Murakami 1993 — List Species Anim. Japan 5: 105 [pars] Mecistocephalus diversisternus: Wang & Mauriès 1996 — Mém. Mus. natn. Hist. Nat. Paris 169: 89 Mecistocephalus takakuwai: Wang & Mauriès 1996 — Mém. Mus. natn. Hist. Nat. Paris 169: 89 Mecistocephalus smithi [sic]: Wang & Mauriès 1996 — Mém. Mus. natn. Hist. Nat. Paris 169: 89 [pars] Mecistocephalus diversisternus: Shinohara 1999 — Pictorial Keys Soil Anim. Japan: 709 Mecistocephalus takakuwai: Shinohara 1999 — Pictorial Keys Soil Anim. Japan: 709; fig. 5 (703) Mecistocephalus smithi: Shinohara 1999 — Pictorial Keys Soil Anim. Japan: 709 [pars]

[24] Mecistocephalus takakuwai: Ishii 2000 — Mem. natn. Sci. Mus. Tokyo 35: 106 Mecistocephalus diversisternus: Bonato et al. 2003 — Syst. Entom. 28: 550, 551 Mecistocephalus takakuwai: Bonato et al. 2003 — Syst. Entom. 28: 550, 551

Diagnosis. A Mecistocephalus species with 57 or 59 leg­bearing segments. Body length of adults between 2.5 and 5.5 cm. Trunk without dark patches. Head 1.7–2.0 times as long as wide. Clypeus about 1.6–1.9 times wider than long; clypeal ratio about 1.2–1.6. Areolate part of the clypeus without insulae, each side with 3–4 setae. Plagulae with pore­like sensilla. Buccae without setae. Sternal sulcus not furcate.

Type material. Number of specimens not stated, probably only one specimen (holotype), male, 34 mm long, adult ( Silvestri, 1919).

Type locality. ‘Japonia: Kamatura’, Honshu ( Silvestri, 1919).

Depository of type material. Coll. F. Silvestri ( Viggiani, 1973), Museo Civico di Storia Naturale "G. Doria", Genova.

Material examined. 37 specimens. Specimens with 57 leg­bearing segments: 1 female, adult (38 mm), from Aono , Minami­izu­machi, Shizuoka pref., Japan, 26.VIII.1978, K. Ishii leg., coll AM . Specimens with 59 leg­bearing segments: 2 males, adult (35 and 39 mm), 3 males, subadult (20, 25 and 26 mm), 11 females, adult (25, 29, 42, 45, 45, 46, 46, 50, 50, 50 and 55 mm), and 6 females, subadult (20, 20, 21, 21 22 and 22 mm) from Miyake Id., Ooji­ike, Tokyo, Honshu, 18. III .1980, K. Ishii leg., coll. AM; 2 males, adult (40 and 43 mm), and 1 female, subadult (40 mm), from the Imperial Palace, Tokyo, Honshu , 3.IX.1997, K. Ishii leg., coll. AM ; 1 female, adult (43 mm) from Kanegususku, SDF Base, 2.2 km from prefectural road, Gushikawa­son, Kumejima Id. Okinawa Pref., Ryukyu Ids, 23. II .1992, T . Tanabe leg., coll. TT; 2 males, adult (35 and 42 mm), from Alishan, Taiwan, 28. II .2001, H.W. Chang leg., coll. AM and HWC; 2 males, adult (36 and 38 mm), from Shoushan , Taiwan, 30.IX.1999, H.W. Chang leg., coll. AM and HWC ; 1 male, adult (45 mm), and 1 female, adult (52 mm), from Dahanshan , H.W. Chang leg., coll. HWC ; 2 females, adult (48 an 55 mm), from Beililungshan , Taiwan, H.W. Chang leg., coll. AM and HWC ; 1 male, adult (38 mm) from Fangshan , Taiwan, (collecting date unknown), H.W. Chang leg., coll. HWC ; 1 female, subadult (21 mm), from Mt. Nanren ( South Cape ), Taiwan, 20.X.1996, collector unknown, coll. HWC .

Description. Body length of adults between about 2.5 and 5.5 cm. Body colour orange, without dark patches; head and forcipular segment darker. Head 1.7–2.0 times as long as wide; frontal line angled, with the vertex pointing backwards. Antennae 4.2–5.0 times as long as the head width. Apical sensilla about 8–10 µm long. Clypeus: width to length of the clypeus about 1.6–1.9; clypeal ratio 1.2–1.6; a central area with smaller, less evident scutes; smooth insulae absent; 3–4 patterned setae on each side, other short setae sometimes present in larger specimens; up to 10–15 pore­like sensilla in the antero­external corner of each plagula, some pore­like sensilla sometimes also in the adjacent areolate part; each plagula about 1.5–1.9 times as wide as long. Labrum: anterior ala subtrapezoidal, medial margin short to reduced to a vertex; internal margins of side­pieces convergent backwards, usually projecting into a tooth and touching each other; posterior margin of each side­piece slightly sinuous to straight. Spiculum present; buccae without setae. Mandible: about 9–10 lamellae; first lamella with 5 teeth; average intermediate lamella with about 15–18 teeth; basal tooth with small scales on the edge and on the apex. First maxillae: anterior corners of coxosternum slightly projecting; each medial projection about 2.6–2.9 times as long as wide, internal margin with long setae, distal lobe 1.9– 2.6 times as long as wide, clavate, subtriangular, without hyaline scales; each telopodite about 4.0–4.6 times as long as wide, with some basal setae, external margin slightly sinuate, sinus without hyaline scales, distal lobe attenuated. Second maxillae: article I of telopodite about 3.5–4.3 times as long as wide; article III about 2.0–2.7 times as long as wide, densely covered with setae; apical claw present. Forcipular segment: width to length ratio of exposed part of the coxosternum about 1.1–1.4; cerrus composed of lateral groups of setae only; dorsal ridge of each pleuron evident, scapular point elongate; condylar process elongate, projecting in a spine. Forcipules: article I about 1.9–2.2 times as long as wide, basal tooth subequal to the distal tooth; articles II and III each with a tooth; tarsungulum with two small basal teeth, one dorsal to the other; poison calyx extending to the distal part of the forcipular article I. A total of 57 or 59 leg­bearing segments. Sternal sulcus apparently not furcate. Last leg­bearing segment: sternum subtriangular, 1.1–1.3 times as long as wide, the posterior part much narrow, with parallel sides; telopodites with dense short setae on the ventral side in both sexes; apical spine absent.

Distribution in the considered area.

Honshu: ‘Kamatura’ [1]; ‘Kanagawa’ [3]; Ajiro (Akiruno, Tokyo); Yokosuka naval port (Yokosuka, Kanagawa pref.); Shimoda (Shizuoka pref.); Shimo­Kamo (Kamo­gun, Minami­Izu­cho, Shizuoka pref.) [4] (transcribed from Japanese); Tokyo and surrounding area [5, 6, 10, 11, 12, 20, 23, 24]; Akita (Akita pref.), Sanda (Hyogo pref.), O­shima (Tokyo, Izu­shoto), Hiroshima (Hiroshima pref.) [6] (transcribed from Japanese); Kanazawa (Ishikawa pref.), Mita (Hyogo pref.) [9] (transcribed from Japanese); Izu­shoto, Hachijo­jima [13, 14] (transcribed from Japanese); ‘Manazuru Seashore’ [18]; Saru­shima, Yokosuka, Kanagawa pref. [22] (transcribed from Japanese); Miyake Id. (new) .

Shikoku: Imabari (Ehime pref.) [6] (transcribed from Japanese).

Kyushu: Shibushi (Soo­gun, Kagoshima pref.) [4] (transcribed from Japanese); ‘Toshita (Choyo­mura, Asogun, Kumamoto pref.), Oita (Oita pref.)’ [6].

Ryukyu Islands: ‘Ryukyu Islands’ [7, 8]; Kanegosuku, Kumejima Id (new).

Taiwan: ‘Kosempo’ [2]; Hualian (Hualian­xian, Taiwan), Zhunan (Miaoli­xian, Taiwan), Huwei (Yunlinxian, Taiwan), Yilan (Yilan­xian, Taiwan) and Wanli (?­xian, Taiwan) [9] (transcribed from Japanese); ‘Tsu­ Yin, Hualien [...] Shih­Tou Mountain, Hsin­Cho’ [15]; ‘Changhua’ [16]; ‘Shirin, Taipei, Taichung, Kwan­Tze Ling and Nan­Tou’ [17]; ‘Ta Ping Shan’ [19]; Alishan (new); Shoushan (new); Dahanshan (new); Beililungshan (new); Fanghshan (new); Mt. Nanren (new) .

Also reported from ‘Nishibûmabaru­dô cave Bûma, Nago­shi’ [21] (location unknown).

General distribution. From Honshu to Taiwan, including Shikoku, Kyushu, and Ryukyu Islands.

Remarks. Mecistocephalus takakuwai Verhoeff, 1934 , described upon 10 specimens from ‘Tokyo’ (Honshu), is here recognised as a junior synonym of Mecistocephalus diversisternus ( Silvestri, 1919) . These two species have been regarded so far as distinct species, mainly based on the different number of leg­bearing segments (57 in M. diversisternus and 59 in M. takakuwai ). The interindividual invariance of this number, within a given species, has long been considered a common feature of all mecistocephalid species, and therefore it has been widely used as a diagnostic character. However, evidence of interindividual variation in the number of trunk segments has been recently documented for a Mecistocephalus species in the Philippines ( Bonato et al., 2001), thus prompting a critical evaluation of the diagnostic value of this character in other mecistocephalids. Our comparison of one specimen with 57 leg pairs with several representative specimens with 59 leg pairs from different localities did not reveal any diagnostic character between the two putative species M. diversisternus and M. takakuwai other than the number of leg­bearing segments, nor did any other emerge from the literature. Consequently, we regard this specific distinction as unwarranted. Further support comes from the fact that the two putative species have been recorded from largerly overlapping geographical ranges: specimens with 59 leg­bearing segments, which have been collected more frequently that those with 57, have been recorded from central Honshu, Shikoku, Kyushu, Ryukyu Islands and Taiwan, whereas specimens with 57 leg­bearing segments have been recorded from Honshu, Ryukyu Islands and Taiwan.

All published records for M. smithii Pocock, 1895 from the considered area are here referred to M. diversisternus , as we found no reliable the presence of this species in the Japanese Archipelago and Taiwan. Consequently, most citations for M. smithii after that of Silvestri (1919) should be referred to a composite concept of this species, encompassing both M. smithii and M. diversisternus . See ‘Species erroneously recorded from Japan and Taiwan’ for further detail about M. smithii .