Arrup ishiianus, Published, 2007

Published, First, 2007, The Mecistocephalidae of the Japanese and Taiwanese islands (Chilopoda: Geophilomorpha), Zootaxa 1396, pp. 1-84 : 17-19

Arrup ishiianus n. sp.

Figs. 14–17

Diagnosis. An Arrup species with body length reaching at least 4 cm in adult males and 5 cm in adult females. Frontal line curved. Distal article of the telopodite of the second maxillae without claw. Tooth of the forcipular article I well developed, but poorly projecting and rounded; tooth of the tarsungulum shallow and rounded in larger specimens, slightly pointed in smaller specimens. Poison calyx almost reaching the base of the forcipular article I in males, only the mid­length of the forcipular article I in females. Sternum of the last legbearing segment wider than long.

Type material. Holotype: male, 40 mm long, adult. Paratype: female, 48 mm long, subadult.

Type locality. Hon­noo , Mobara City, Chiba Pref., Honshu, Japan .

Depository of type material. National Science Museum , Tokyo (holotype); coll. A. Minelli, University of Padova (paratype).

Material examined. 5 specimens. Type series: 1 male, adult (40 mm), and 1 female, subadult (48 mm), from Hon­noo, Mobara City, Chiba Pref., Honshu , 3.XII.1997, K. Ishii leg. (holotype and paratype respectively), coll. NSMT (holotype) and AM (paratype). Other specimens : 1 male, adult (29 mm), and 2 males, subadult (both 28 mm), from Imperial Palace, Tokyo, Honshu , 3 IX.1997, K. Ishii leg., coll. AM .

Description of the holotype. Male, adult, body length 40 mm (both telopodites of the last leg­bearing segment lacking some distal segments). Body colour brownish­yellow, without dark patches. Head 1.5 times as long as wide; frontal line present, uniformly curved. Antennae 3.6 times as long as the head width. Apical sensilla about 8 µm long. Clypeal setae: a median pair anterior to the plagulae and a group on each side of the clypeus, reaching the anterior corner. Clypeal ratio about 3.2. Labrum: anterior ala triangular, with medial margin reduced to a vertex; internal margins of side­pieces convergent posteriorly, not touching each other; posterior margin of each side­piece sinuous, slightly convex close to the internal and external ends. First maxillae: anterior corners of coxosternum not projecting; medial projection about 2.0 times as long as wide, the internal margin with few spines and deeply sinuate at the base, distal lobe about 1.8 times as long as wide, aligned to the external margin of the projection, only slightly clavate; dorsal side of medial projections with hyaline scales, very abundant near the basal sinus; telopodite about 3.6 times as long as wide, distal lobe attenuated. Second maxillae: article I of telopodite about 2.4 times as long as wide; article III about 2.8 times as long as wide, with few setae at the tip, on the internal side; apical claw absent, replaced by about 4 small tubercles. Forcipular segment: width to length ratio of exposed part of coxosternum about 1.2; cerrus absent; dorsal ridge of pleura not developed, but marked by areolation; scapular point of pleura not reaching the anterior margin of coxosternum. Forcipules: article I about 1.9 times as long as wide, with a well developed, rounded distal tooth; article II untoothed; article III with a tubercle; tarsungulum with a rounded basal tooth; poison calyx extending backwards to the proximal quarter of the forcipular segment I; poison gland almost reaching the base of the same segment. A total of 41 leg­bearing segments. Last leg­bearing segment: sternum sub­triangular, about 1.2 times as wide as long; about 35 pores on each coxopleuron; telopodites with dense and short additional setae on the ventral side.

Description of paratype (only differences with holotype are reported). Female, subadult, body length 48 mm. Clypeal ratio about 3.0. First maxillae: medial projection about 2.2 times as long as wide. Second maxillae: article I of telopodite about 2.9 times as long as wide; article III about 3.5 times as long as wide, with rudimental apical claw. Forcipules: article I about 1.8 times as long as wide; poison calyx almost reaching the mid­length of the first forcipular segment. Telopodites of the legs of the last pair without additional dense short setae.

Interindividual variation (based on 5 specimens). Head 1.4–1.5 times as long as wide. Ratio between antennal length and head width 3.4–3.7. Clypeal ratio 3.0–3.3. Medial projection of first maxillae: basal deep sinus absent in two males (28 and 29 mm long). Forcipular article I 1.6–1.9 times as long as wide. Tooth of the forcipular article I smaller and less projecting in smaller males; basal tooth of tarsungulum small­sized but sharper in smaller males. Coxal pores from 30 (male 29 mm long) to 35 (both holotype and paratype) on each coxopleuron. Dense, short additional setae on the last legs absent from all other specimens except holotype.

Distribution in the considered area.

Honshu: Hon­noo, Mobara City (type locality); Imperial Palace , Tokyo .

General distribution. Honshu.

Derivatio nominis. Dedicated to our friend K. Ishii (Dokkyo Medical University, Mibu, Tochigi), the collector of this new species, for his valuable help to our research.

Remarks. Arrup ishiianus is very similar to A. obtusus , particularly in the shape of forcipular teeth ( Fig. 17); moreover, the two species are sympatric. Anyway, we recognise the two species as distinct because of the different number of coxal pores at corresponding body size (see also remarks under A. obtusus ).