Arrup obtusus (Takakuwa, 1934)

Published, First, 2007, The Mecistocephalidae of the Japanese and Taiwanese islands (Chilopoda: Geophilomorpha), Zootaxa 1396, pp. 1-84 : 15-16

Arrup obtusus (Takakuwa, 1934)

[1] Prolamnonyx obtusus Takakuwa 1934a — Annot. Zool. Japon. 14: 358; fig. 6 (original description)

Prolamnonyx obutusus [ sic]: Takakuwa 1934b — Bot. & Zool. Tokyo 2: 707 (key)

Prolamnonyx obtusus: Takakuwa 1934c — Bot. & Zool. Tokyo 2: 882; fig. 23–26

Prolamnonyx obstusus [sic]: Takakuwa 1938a — Annot. Zool. Japon. 17: 355

Prolamnonyx obtusus: Takakuwa 1938b — Bot. & Zool. Tokyo 6: 2030 (key)

Prolamnonyx obtusus: Takakuwa 1940 — Fauna Nippon. 9: 93 (key); fig. 97 (also cited as Prolamnonyx obstusus [sic])

Prolamnonyx obstusus [sic]: Takakuwa 1943 — Bull. Biogeogr. Soc. Japan 13: 195

Prolamnonyx obtusus: Attems 1947 — Ann. Naturhistor. Mus. Wien 55: 105 (key)

Prolamnonyx obtusus: Takashima 1949 — Acta Arachn. 11: 13

Prolamnonyx obtusus: Takashima & Shinohara 1952 — Acta Arachn. 13: 9 (key)

Prolamnonyx obtusus: Titova 1975 — Zool. Zh. 54: 45

Prolamnonyx obtusus: Murakami 1993 — List Species Anim. Japan 5: 105

Arrup obtusus: Foddai et al. 2003 — J. Nat. Hist. 37: 1261

Diagnosis. An Arrup species with a body length reaching at least 2 cm. Tooth of the forcipular tarsungulum shallow and rounded. A high number of coxal pores in a small sized specimen. Sternum of the last leg­bearing segment wider than long.

Type material. Holotype: sex unknown, 20 mm long ( Takakuwa, 1934a), probably adult (based on the high number of coxal pores).

Type locality. ‘Tokyo’, Honshu ( Takakuwa, 1934a) [cited as ‘Otemon of the Imperial Palace, Koji­machi, Chiyoda­ku, Tokyo’ by Takakuwa (1940)].

Depository of type material. The holotype is probably lost (see Discussion).

Material examined. None.

Description. Body length reaching at least about 2 cm. Body colour brownish­deep yellow, without dark patches. Head 1.4 times as long as wide. Mandible with about 6 lamellae; first lamella with 6 teeth; average intermediate lamella with about 11 teeth; margin of basal tooth entire. Forcipules: article I with a well developed distal tooth; articles II and III almost without teeth, tarsungulum with one shallow, rounded tooth. Last leg­bearing segment: sternum sub­triangular, about 1.3 times as wide as long; about 40 pores on each coxopleuron.

Distribution in the considered area.

Honshu: ‘Tokyo’ [1] (type locality).

General distribution. Only known from the type locality.

Remarks. This species was described on a single specimen and no further records were published later. The only available description is rather incomplete and poorly illustrated and the apparent loss of the holotype does not allow us to recognize properly the identity of this nominal species. The original diagnosis of A. obtusus was based on a very unusual character, i.e. the particular shape of the leg claws, which were described and illustrated as stout and rounded ( Takakuwa, 1934a: fig. 6). We suspect this could be only an aberrant character of one specimen, as similar claws have never been recorded in other centipedes. Crabill (1964) already claimed the invalidity of this species, and proposed A. obtusus as a synonym of A. holstii , without any further comment. Even though we are not able to evaluate properly the taxonomic status of this nominal species, we reject this synonymy, because A. obtusus and A holstii apparently differ in the number of coxal pores (about 40 in the 20 mm long holotype of A. obtusus , about 12 in the 20 mm long holotype of A. holstii ) and in the shape of the tarsungular tooth (shallow and rounded in A. obtusus , more developed and pointed in A. holstii ). A. obtusus seems actually to agree with Arrup ishiianus n. sp. in the shape of the tarsungular tooth, but these two species are different in the size and number of coxal pores, the smallest specimen of A. ishiianus being a 28 mm long male with only about 30 pores on each coxopleuron.