Ischnothyreus xui, Tong, Yanfeng & Li, Shuqiang, 2012

Tong, Yanfeng & Li, Shuqiang, 2012, Four new species of the genus Ischnothyreus from Hainan Island, China (Araneae, Oonopidae), Zootaxa 3352, pp. 25-39 : 29-35

Ischnothyreus xui sp. nov.

( Figs 6–8 , 11 )

Type material: 1 male Holotype ( IZCAS Ar 19320), canopy fogging, China: Hainan, Ledong, Jianfengling Natural Reserve, Alt. 997 m, 18°44.658´N, 108°50.435´E, August 18, 2010, leg. Guo Zheng; 2 males and 1 female paratypes ( IZCAS Ar 19320), same data as holotype; 1 female paratype ( IZCAS Ar 19321), canopy fogging, China: Hainan, Ledong, Jianfengling Natural Reserve, on the road to Fifth subarea, Alt. 975 m, 18°44.026´N, 108°52.460´E, August 15, 2010, leg. Guo Zheng; 1 female paratype ( IZCAS Ar 19322), canopy fogging, China: Hainan, Ledong, Jianfengling Natural Reserve, on the road to Fifth subarea, August 14, 2010, leg. Guo Zheng; 1 female paratype ( IZCAS Ar 19335), canopy fogging, Diaoluoshan Natural Reserve, on the road to waterfall, August 10, 2010, leg. Guo Zheng.

Etymology: The specific name is a patronym honoring Professor Yajun Xu, who worked on the Oonopidae of China.

Diagnosis: The new species is similar to I. falcatus Tong & Li, 2008 , but can be distinguished by the larger dorsal scutum, the membranous outgrowth on the male palpal bulb, the modifications on the male chelicerae and the shape of the atrium.

Description: Male (holotype). Total length 1.45 mm. Carapace: orange-brown, with brown egg-shaped patches behind eyes, oval in dorsal view, pars cephalica strongly elevated in lateral view, surface and sides strongly reticulate. Eyes: six, in one group, well developed, ALE largest, PME and PLE nearly equal sized; posterior eye row straight from above, procurved from front. Mouthparts: chelicerae slightly divergent, with slightly sclerotized process at base of fangs (ssp); fang groove with a few small and two larger denticles ( Figs 6 G, 8C). Anterior margin of labium not indented at middle. Anteromedian tip of endites with one strong, tooth-like projection. Abdomen: ovoid, rounded posteriorly. Posterior spiracles not connected by groove. Pedicel tube short, unmodified, scutum extending far dorsal of pedicel. Dorsal scutum covering about 4/5 of abdomen, about equal to the abdomen width, not fused to epigastric scutum. Epigastric and postepigastric scutum well sclerotized, pale orange, fused. Leg spine formula: femur I with 2 prolateral and 1 small retrolateral spine, tibia I with 4 pairs, metatarsus I with 2 pairs of long ventral spines. Spination of leg II similar to leg I except femur with only one prolateral spine. Legs III and IV spineless. Genitalia: Sperm pore situated at level of anterior spiracles. Palp strongly sclerotized, trochanter with ventral projection (vp); patella as long as femur; cymbium brown, not fused with bulb, bulb brown, about 1.5 times as long as cymbium, stout, tapering apically, with two ventral protuberances (vpr), at the bending site with a small lobe (l), distal part of bulb with membranous outgrowth (mo) ( Figs 6 E, F, 8A, B)

Female (paratype). Total length 1.79 mm. As in male except as noted. Carapace broadly oval in dorsal view. Mouthparts: chelicerae and endites unmodified. Abdomen: dorsal scutum covering about 1/2 of abdomen, about 2/ 3 of abdomen width. Postepigastric scutum not fused to epigastric scutum, with short posteriorly directed lateral apodemes. Genitalia: in the middle of the postepigastric scutum is a sclerotized ridge visible (sr), underneath runs a strongly winding tube (wt), ending in a small atrium (atr). A curved sclerotized ridge (csr) is visible in the middle of the epigastric scutum when viewed from dorsal ( Figs 7 G, 8E, F).

Distribution: Known only from Hainan Island.

Figures

FIGURE 6. Ischnothyreus xui sp. nov., male. A, habitus, dorsal view; B, habitus, ventral view; C, habitus, lateral view; D, prosoma, frontal view; E, left palp, prolateral view; F, left palp, retrolateral view; G, left chelicera, posterior view. mo, membranous outgrowth; ssp, slightly sclerotized process; vp, ventral projection; vpr, ventral protuberance. Scales: A – C = 0.4 mm; D = 0.2 mm; E – G = 0.1 mm.

FIGURE 7. Ischnothyreus xui sp. nov., female. A, habitus, dorsal view; B, habitus, lateral view; C, habitus, ventral view; D, prosoma, ventral view; E, prosoma, frontal view; F, genital area, ventral view; G, genital area, dorsal view. a, apodeme; atr, atrium; csr, curved sclerotized ridge; sr, sclerotized ridge; wt, winding tube. Scales: A – C = 0.4 mm; D, E = 0.2 mm; F, G = 0.05 mm.

FIGURE 8. Ischnothyreus xui sp. nov. A, left male palp, prolateral view; B, left male palp, retrolateral view; C, left male chelicera, posterior view; D, female genital area, ventral view (not cleared in lactic acid); E, female genital area, ventral view; F, female genital area, dorsal view. a, apodeme; atr, atrium; csr, curved sclerotized ridge; l, lobe; mo, membranous outgrowth; sr, sclerotized ridge; ssp, slightly sclerotized process; vp, ventral projection; vpr, ventral protuberance; wt, winding tube. Scales: A – C, E, F = 0.1 mm; D = 0.2 mm.

FIGURE 11. Localities of four new Ischnothyreus species from Hainan Island, China.