Mecistocephalus karasawai, Published, 2007

Published, First, 2007, The Mecistocephalidae of the Japanese and Taiwanese islands (Chilopoda: Geophilomorpha), Zootaxa 1396, pp. 1-84 : 53-54

Mecistocephalus karasawai n. sp.

Figs. 66–70

Diagnosis. A Mecistocephalus species with 49 leg­bearing segments. Body length of adults between about 30 and 55 mm. Trunk with or without dark patches. Head 1.6–2.0 times as long as wide. Areolate part of the clypeus with about 4 smooth insulae on each side, each insula with a seta; clypeal ratio about 1.1–1.4. Anterior ala of the labrum subtrapezoidal, with the medial margin not reduced to a vertex. Basal tooth of the mandible slightly longer than the teeth of the first lamella, with entire margin; intermediate lamellae with about 20 teeth. Buccae with setae in the posterior half only. Forcipular article I with two teeth, one distal to the other, the distal tooth larger than the basal one. Sternal sulcus apparently not furcate.

Type material. Holotype: male, 36 mm long, adult (one mandible mounted on a microscope slide). Paratypes: 61 specimens (see Material examined for further detail).

Type locality. Mt. Nishime, Okinawa, Ryukyu Ids .

Depository of type material. National Science Museum , Tokyo, (holotype and 10 paratypes); Coll. A. Minelli, University of Padova (51 paratypes).

Material examined. 82 specimens. Type series: 1 male, adult (36 mm), from Mt. Nishime, about 350 m, Okinawa, Ryukyu Islands , 13.XI.2001 (holotype), S. Karasawa leg., coll. NSMT ; 7 males, adult (23–34 mm), 9 males, subadult (17–34 mm), 10 females, adult (24–55 mm), 20 females, subadult (15–33 mm), and 15 juveniles (11–16 mm), same locality of holotype, between 20.VI.2001 and 27.II.2003, S. Karasawa leg., coll. NSMT and AM . Other specimens: 4 broken specimens (missing some posterior segments), same locality of holotype, between 20.VI.2001 and 27.II.2003, S. Karasawa leg., coll. AM ; 1 female, subadult (24 mm), from Hirakiki­jinja Shrine, Kaimon­cho, Ibusuki­gun , Kagoshima Pref., Kyushu , 16.IV.1986, A. Moroto leg., coll. TT ; 1 juvenile (17 mm) from Maeda, Kuchinoerabu Id., Kamiyaku­cho, Kumage­gun , Kagoshima Pref., Ryukyu Ids , 16.XI.1985, T . Tanabe leg., coll. TT; 1 male, subadult (25 mm), 1 female, subadult (23 mm), 1 juvenile (22 mm), and 1 partial specimen, from Osaki, Nishinoomote­shi, Tanegashima Id., Kumage­gun, Kagoshima Pref., Ryukyu Ids , 14.XI.1986, A. Moroto leg., coll. AM and TT ; 1 male, adult (48 mm), 1 male, subadult (20 mm), 1 female, subadult (26 mm) and 1 juvenile (20 mm), from Sumiyoshi, Nakatane­cho, Tanegashima Id., Kagoshima Pref., Ryukyu Ids , 15.XI.1986, A. Moroto leg., coll AM and TT ; 1 female, subadult (27 mm) from Onoaida, 760 m, Yaku­cho, Yakushima Id., Kumage­gun, Kagoshima Pref., Ryukyu Ids , 21.X.1986, A. Moroto leg., coll. AM ; 2 juveniles (21 and 22 mm), from Kurio, 50 m, Yaku­cho, Yakushima Id., Kumage­gun, Kagoshima Pref., Ryukyu Ids , 26.X.1986, A. Moroto leg., coll. TT ; 2 juveniles (11 and 15 mm), from along Hanayama­hodo, 500 m, Yakushima Id., Kumage­gun, Kagoshima Pref., Ryukyu Ids , 18.XI.1985, T . Tanabe leg., coll. AM and TT; 1 male, adult (47 mm), from Kanegusuku – SDF base, 2.2 km from Prefectural Road, Gushikawa­son, Kumejima Id., Okinawa Pref., Ryukyu Ids, 23. II .1992, T . Tanabe leg., coll TT.

Description of the holotype. Male, adult, 36 mm long. Body colour yellow, with faint dark patches along the trunk; head and forcipular segment darker. Head 1.9 times as long as wide; frontal line rounded. Antennae 6.2 times as long as the head width. Apical sensilla about 10 µm long. Clypeus: clypeal ratio about 1.2; areolate part with 4 small, smooth insulae on each side (two of them coalescent), 4 setae on each side of the clypeus, one inside each insula; plagulae without evident sensilla. Labrum: anterior ala subtrapezoidal, the medial margin about one third of the medial margin of the posterior ala; posterior margin of each side­piece sinuous, slightly convex close to the internal and external ends, the medial end projecting into a tooth. Spiculum present; buccae with about 10 setae in the posterior half only. Mandible: 6 well­developed lamellae; first lamella with 5 teeth; average intermediate lamella with about 18 teeth, basal teeth about as long as the distal teeth; basal tooth of the mandible, slightly longer than the first tooth of the first lamella, with entire margin. First maxillae: anterior corners of coxosternum projecting; each medial projection about 2.0 times as long as wide, internal margin with 4–6 long setae, distal lobe about 2.0 times as long as wide, clavate; each telopodite about 3.8 times as long as wide, distal lobe slightly clavate. Second maxillae: article I of telopodite about 4.3 times as long as wide; article III about 2.8 times as long as wide, with many setae; apical claw present. Forcipular segment: width to length ratio of exposed part of coxosternum 1.0; cerrus composed of two convergent rows of setae and a pair of setae on each side; dorsal ridge of each pleuron evident. Forcipules: article I about 2.2 times as long as wide, with two teeth, the basal tooth smaller than the distal one; articles II and III each with a tooth, the tooth on article III slightly larger than the tooth on article II; tarsungulum with two basal teeth, one dorsal to the other; poison calyx extending backwards to the distal part of the forcipular article I. A total of 49 leg­bearing segments. Sternal sulcus apparently not furcate. Last legbearing segment: sternum subtrapezoidal, as long as wide; about 25 pores on each coxopleuron; telopodites without dense, short setae on ventral side, and with one short apical spine.

Interindividual variation (based on the 62 specimens of the type series). Body length of adults 23–34 mm in males (n = 7), 24–55 mm in females (n = 10). Dark patches present more frequently in full­grown specimens, often absent in smaller specimens. Head ratio 1.7–2.0 in adult males (n = 8), 1.4–1.9 in adult females (n = 10), 1.4–1.7 in juvenile specimens without visible gonopods (n = 14). Clypeus: sometimes with spine­like sensilla aligned along the anterior margin of each plagula in largest specimens (up to 3 in each plagula); clypeal ratio 1.1–1.4 (n = 10); number of insulae from none in juveniles to 6 on each side in fullgrown specimens. Mandible: average intermediate lamella with up to 22 teeth in largest specimens. Forcipules: article I 1.6–2.1 times as long as wide, teeth variable in size, the basal one sometimes reduced to a tubercle or apparently absent in juveniles. Coxal pores: none in specimens 10–15 mm long to about 45 in fullgrown specimens.

Distribution in the considered area.

Kyushu: Hirakiki­jinja Shrine, Kaimon­cho, Ibusuki­gun, Kagoshima Pref.

Ryukyu Islands: Maeda, Kuchinoerabu Id.; Osaki, Tanegashima Id.; Sumiyoshi, Tanegashima Id.; Onaida, Yakushima Id.; Kurio, Yakushima Id.; Hanayama­hodo, Yakushima Id.; Kanegusuku Kumejima Id.; Mt. Nishime , Okinawa Id. (type locality) (all localities new) .

General distribution. Kyushu and Ryukyu Islands.

Derivatio nominis. Dedicated to Shigenori Karasawa (Tropical Biosphere Research Center, University of the Ryukyus, Taketomi, Japan), who collected the type material of this new species.

Remarks. M. karasawai is easily distinguished from other Mecistocephalus species with smooth insulae on the clypeus occurring in the Ryukyu Islands by the lack of pore­like sensilla or setae in the anterior half of the buccae and by the structure of the mandible. It differs from M. yamashinai and M. pauroporus , both described from Okinawa, mainly by the presence of clypeal insulae, which are absent from both of these species. As the evidence of clypeal insulae increases during growth, worth notice is that both M. yamashinai and M. pauroporus were described on specimens measuring about 25 mm and lacking clypeal insulae, whereas in M. karasawai the clypeal insulae are present in all specimens 20 to 25 mm long (n = 16). The longest specimen of M. karasawai lacking insulae is only 17 mm long, but a few insulae are recognizable also in some 15–16 mm specimens. Furthermore, size measurements of M. karasawai may be exaggerated in comparison to those given by Takakuwa for the other species due to lactophenol treatment (see Material and methods).