Ischnothyreus velox Jackson, 1908

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 : 230-232

Ischnothyreus velox Jackson, 1908

[New Japanese Name: Ajia-Yoroi-Danigumo]

Fig. 7I–P

Ischnothyreus velox Jackson, 1908: 51 , pl. 4, fig. 9–13, male and female syntypes from Chester , England; not examined.

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

Materials examined. Shimoji Is. (Okimawa Pref): 4 males 5 females (one male and one female: NSMT-Ar 21919; 3 males and 4 females: NSMT-Ar 21920), Bushes at coastal forest beside Shimoji Airport (24°50'08.4"N, 125°08'13.5"E), Irabu, Miyakojima City, 19-XI-2021, Y. Suzuki leg. Irabu Is. (Okimawa Pref) : 1 female, humid rainforest litter in a small valley, near Otake Naka Cave (24°50'57.5"N 125°11'05.3"E), Irabu, Miyakojima City, 14-XI-2020, F. Ballarin leg. Miyako Is. (Okimawa Pref) : 1 female, grassland at Ueno-nobaru (24°46'05.9"N, 125°19'23.2"E), Miyakojima City, 17-XI-2021, Y. Suzuki leg.

Diagnosis. This species resembles with I. peltifer but can be distinguished by lacking protrusion on the base of male fang, having a thin appendix on the distal part of palp ( Fig. 7L–M , arrows vs. triangular lobe in I. peltifer ; Fig. 7E , arrow) and having a distinctive, laterally wide, procurved ridge on epigastric region ( Fig. 7P ).

Description. Based on a male and a female specimens from Shimoji Island.

Male (NSMT-Ar 21919). Carapace almost oval, dorsum smooth. Palp ( Fig. 7K–M ): thin, membranous and short appendix on distal end. Abdomen oval, with scutum covering over half of dorsum. Coloration ( Figs. 7I, J ): carapace, chelicerae, labium and endites yellowish brown, palp dark brown, legs yellow, abdomen pale yellowish white, dorsum scutum dark brown.

Measurements. BL 1.50, CL 0.77, CW 0.63, CH 0.32. Eye size: ALE 0.085, PME 0.076, PLE 0.077. Leg length: leg I, 0.51 + 0.23 + 0.43 + 0.41 + 0.17 = 1.75; leg II, 0.51 + 0.23 + 0.38 + 0.39 + 0.17 = 1.69; leg III, 0.47 + 0.21 + 0.29 + 0.28 + 0.17 = 1.41; leg IV, 0.62 + 0.26 + 0.46 + 0.53 + 0.27 = 2.15. AL 0.70, AW 0.52, AH 0.46.

Female (NSMT-Ar 21919). Carapace and abdomen as same as those of the male. Portion of non-sclerotized area in dorsum of abdomen wider than male. Epigastric region ( Fig. 7P ): winding tube visible, moderately complicated, slightly sclerotized, procurved ridge on center of the region, a row of hairs arranged semi-circularly, a pair of apodemes developed; Coloration ( Figs. 7N, O ): same as the male.

Measurements. BL 2.79, CL 1.06, CW 0.91, CH 0.45. Eye size: ALE 0.113, PME 0.119, PLE 0.090. Leg length: leg I, 0.92 + 0.39 + 0.88 + 0.70 + 0.30 = 3.19; leg II, 0.90 + 0.37 + 0.75 + 0.63 + 0.27 = 2.93; leg III, 0.62 + 0.36 + 0.48 + 0.53 + 0.29 = 2.28; leg IV, 0.97 + 0.53 + 0.86 + 0.59 + 0.33 = 3.27. AL 1.61, AW 1.13, AH 1.12.

See Saaristo (2001, 2010) and Brescovit et al. (2019) for further details.

Distribution. Tropical Asia, Japan (Miyako Islands). Introduced to North, Central, South America, Brazil, Britain, Netherlands, Germany, Egypt, Seychelles, Madagascar, Hawaii. Also see Fig. 11 and Table 2 for details of distribution in the Nansei Islands.

Habitat. This species was collected from litter layers in bushes at coastal forest beside airport in Shimoji Island.

Remarks. The new Japanese name indicates an “Asian armored tick-like spider” and derived from its native distribution range and the presence of a scutum on the dorsum of the abdomen.

Figures

FIGURE 7. Ischnothyreus peltifer (Simon, 1891) (A–E male and F–H female: NSMT-Ar 21918 from Iriomote Island) and Ischnothyreus velox Jackson, 1908 (I–M male and N–P female: NSMT-Ar 21919 from Shimoji Island).A, F, I, N Habitus, dorsal view. B, G, J, O Habitus, lateral view. C Carapace and chelicerae, frontal view. D Carapace and chelicerae, lateral view. E, K Left palp, retrolateral view. L Left palp, dorsal view, M Left palp, prolateral view. H, P Epigastric region, ventral view. Arrows in Fig. 7E and 7L–M indicate a triangular lobe and a thin appendix, respectively. Scale bars: 1.0 mm (A, B, F, G, N, O); 0.5 mm (I, J), 0.2 mm (C, D); 0.1 mm (E, H, K–M, P).

FIGURE 11. Geographic localities of the Nansei Islands examined in this study.