Ischnothyreus narutomii ( Nakatsudi, 1942 )

Suzuki, Yuya, Hidaka, Ryota & Tatsuta, Haruki, 2023, Revision of goblin spiders (Araneae: Oonopidae) in the Nansei Islands, Southwest Japan, with description of a new species, Zootaxa 5323 (2), pp. 216-242 : 229-230

Ischnothyreus narutomii ( Nakatsudi, 1942)

Fig. 6A–L

Gamasomorpha narutomii Nakatsudi, 1942: p.298 , fig. 5.1–6, male holotype from Miyake Is., Tokyo; not examined).

See the World Spider Catalog (2023) for the complete taxonomic list.

Materials examined. Kanagawa pref.: 1 male (FB, per. coll.), thick leaf litter along a creek (35°25’43.14”N, 139°14’32.38”E), Mt. Oyama, Isehara, Kanagawa, 25-VII-2021, F. Ballarin leg. 1 female (FB, per. coll.), thick leaf litter in a primary forest (35°08'38.7"N, 139°09'20.0"E), Manazuru cape, Manazuru, Ashigarashimo District , Kanagawa, 28-VII-2021, F. Ballarin leg. Yakushima Is. (Kagoshima Pref.): 1 female 1 male (FB, per. coll.), 30°17'38.2"N, 130°25'24.6"E, 25-XI-2021, F. Ballarin leg.; 1 male (FB, per. coll.), 30°17'38.2"N, 130°25'24.6"E, 24-XI-2021, F. Ballarin leg.; 2 females (FB, per. coll.), 30°17'04.5"N, 130°37'04.8"E, 24-IX-2021, F. Ballarin leg.; 1 male (FB, per. coll.), 30°16'41.7" N, 130°25'53.5"E, 25-IX-2021, F. Ballarin leg .; 1 female, Koseda, Yakushima Town, Kumage District , 24-III-2023, S. Konishi leg. ; 2 males 1 female, Miyanoura, Yakushima Town, Kumage District , 20-III-2023 (1 male), 26-III-2023 (1 female 1 male), S. Konishi leg. ; 1 female, Tabukawa, Yakushima Town, Kumage District , 19-IV-2023, S. Konishi leg. ; 1 female, Hurauchi, Yakushima Town, Kumage District , 9- II-2023, S. Konishi leg. Tanegashima Is. (Kagoshima Pref.) : 1 female, Nishino-omote, Nishino-omote City , 8-IV-2023, S. Konishi leg.

Diagnosis. Females of I. narutomii resemble those of I. sijiae Tong & Li, 2021 and I. yueluensis Yin & Wang, 1984 in the shape of atrium on epigastric region, but can be distinguished by simpler and transversely narrower course of wt ( Fig. 6K, L vs. Fig. 24A in Tong & Li 2021 and Fig. 6H, I in Huang et al. 2021). Males of I. narutomii can be distinguished from congeners by the following combination of the characteristics: clypeus, chelicerae and fangs lacking appendages, palps with a bluntly bifurcated tip ( Fig. 6 ).

Description. See Nakatsudi (1942), Ono (2009) and Tong & Li (2008) for details of description.

Distribution. Japan, China, Taiwan.

Habitat. This species was collected from litter layers at primary and secondary forests.

Remarks. In Japan, this species was recorded on Yakushima, Okinoerabu, Okinawa, and Miyagi Islands without illustrations or photographs ( Shimojana 1977). However, in our comprehensive field surveys, we were unable to collect this species from Okinawa, Miyako, and Yaeyama Islands; instead, I. petlifer and I. verox were found to be dominant on these islands. We assume that I. peltifer in the Okinawa Islands were misidentified as I. narutmoii in the previous studies. While specimens from Yakushima Island differ slightly in body size and color (smaller and paler) in comparison with those from mainland Japan ( Fig. 6 ), they may be regarded as the same species because no clear differences in genital morphology were found.

Figures

FIGURE 6. Ischnothyreus narutomii (Nakatsudi, 1942) (A, B, D–F male: FB, per. coll., from Kanagawa Prefecture; C, G male: FB, per.coll., from Yakushima Island; H, I, K female: FB, per. coll., from Kanagawa Prefecture; J, L female: FB, per. coll., from Yakushima Island). A, C, H, J Habitus, dorsal view. B, I Habitus, lateral view. D Carapace, frontal view. E Left palp, dorsal view. F, G Left palp, retrolateral view. K, L Epigastric region, ventral view. Abbreviations: 0.5 mm (A–C, H–J); 0.2 mm (D); 0.1 mm (E–G, K, L).