Ischnothyreus pome, Tong & Bian & Li, 2023

Tong, Yanfeng, Bian, Dongju & Li, Shuqiang, 2023, Three new species of the genus Ischnothyreus Simon, 1893 and the discovery of the male of I. linzhiensis Hu, 2001 from Tibet, China (Araneae, Oonopidae), ZooKeys 1152, pp. 119-131 : 119

Ischnothyreus pome sp. nov.

Figs 4D-F , 6A-L , 7A-I

Type material.

Holotype ♂ (SYNU-526): China, Tibet, Nyingchi, Pome County, road to Metok County, 80 K; 29°39.897'N, 95°29.963'E; 2140 ± 5 m; 10.VIII.2013; Qi Cao leg. Paratypes 2♂, 3♀ (SYNU-527-531): same data as for holotype.

Diagnosis.

Females of the new species are similar to those of I. jianglangi Tong & Li, 2020 in having the large, chestnut-shaped structure of the endogyne, but can be distinguished by the simple winding duct of the endogyne (Fig. 7H, I ) vs. the complex winding duct (see Tong et al. 2020: fig. 17B). Males of the new species are similar to those of I. yunlong Tong & Li, 2021 in having the large flag-like sclerotized process of the cheliceral fang, but can be distinguished by the fused abdominal dorsal and epigastric scuta (Fig. 6C ) vs. unfused (see Huang et al. 2021: fig. 1E), and by lacking the dorsal protuberance on the distal end of the bulb (Fig. 4D, E ) vs. with dorsal protuberance (see Huang et al. 2021: fig. 2J).

Description.

Male (holotype). Body: habitus as in Fig. 6A-C ; body length 1.58. Carapace: 0.84 long, 0.69 wide; yellow, oval in dorsal view, with brown egg-shaped patches behind eyes, pars cephalica strongly elevated in lateral view, surface of elevated portion of pars cephalica smooth, sides finely reticulate, lateral margin straight, smooth (Fig. 6D ). Clypeus: straight in frontal view, ALE separated from edge of carapace by 1.4 × of their diameter (Fig. 6F ). Eyes: ALE largest, ALE circular, PME squared, PLE oval; posterior eye row recurved from above; ALE touching, ALE-PLE touching (Fig. 6D, F ). Sternum: as long as wide, pale orange (Fig. 6E ). Mouthparts: chelicerae, endites, and labium yellow; chelicerae straight, with ridge-like protuberance at anterior face, base of fangs with large flag-like sclerotized process, fang groove with a few small and two larger denticles (Figs 4F , 6G-I ); anteromedian tip of endites with one strong, tooth-like projection (Fig. 6E ). Abdomen: 0.74 long, 0.46 wide; dorsal scutum well sclerotized, dark brown, covering 3/5 of abdomen width and approximately 2/3 of abdomen length, fused to epigastric scutum (arrow in Fig. 6C ); postgastric scutum covering ~ 5/6 of abdomen length. Legs: pale orange, femur I with two prolateral spines, tibia I with four pairs, metatarsus I with two pairs of long ventral spines. Leg II spination similar to leg I, except femur with only one prolateral spine. Legs III and IV spineless. Palp: trochanter with ventral projection; bulb without small ventral protuberance, distal end of bulb stout, with needle-like membrane and broad leaf-like projection (Figs 4D, E , 6J-L ).

Female (paratype, SYNU-529). Same as male except as noted. Body: habitus as in Fig. 7A-C ; body length 1.64. Carapace: 0.77 long, 0.67 wide. Mouthparts: chelicerae and endites unmodified. Abdomen: 0.88 long, 0.65 wide; dorsal scutum very small; epigastric scutum well sclerotized, orange; postgastric scutum widely hexagonal, only around epigastric furrow. Endogyne: winding duct simple, with anterior portion straight, strongly convoluted only in posterior section, ending in large, chestnut-shaped structure (Fig. 7H, I ).

Etymology.

The specific name is a noun in apposition taken from the type locality.

Distribution.

Known only from the type locality.

Figures

Figure 4. Ischnothyreus linzhiensis Hu, 2001, male A-C SEM; Ischnothyreus pome sp. nov., male holotype D-F SEM A, E left palp, prolateral view B, D distal end of bulb, prolateral view C, F left chelicerae, anterior and posterior views. Abbreviations: ca = conical apophysis; dm = dorsal membrane; flp = flag-like process; llp = leaf-like projection; nlm = needle-like membrane. Scale bars: 0.1 mm (A, C, E, F); 0.05 mm (B, D).

Figure 6. Ischnothyreus pome sp. nov., male holotype A-C habitus in dorsal, ventral and lateral views (arrow shows the fused scuta) D-F prosoma, dorsal, ventral and anterior views G-I left chelicera, anterior, lateral and posterior views J-L left palp, prolateral, dorsal and retrolateral views. Abbreviations: flp = flag-like process; rlp = ridge-like protuberance; stp = strong, tooth-like projection; vp = ventral projection. Scale bars: 0.4 mm (A-F); 0.1 mm (G-L).

Figure 7. Ischnothyreus pome sp. nov., female paratype A-C habitus in dorsal, ventral and lateral views D epigastric region, ventral view E-G prosoma, dorsal, ventral and anterior views H, I endogyne, ventral and dorsal views (cleared in lactic acid). Abbreviations: a = apodeme; css = chestnut-shaped structure; wd = winding duct. Scale bars: 0.4 mm (A-C, E-G); 0.2 mm (D, H, I).