Ischnothyreus xiaolongha Tong & Li, 2021

Tong, Yanfeng, Sun, Xiaochen, Li, Shuqiang & Bian, Dongju, 2021, Taxonomic study of the genus Ischnothyreus (Araneae, Oonopidae) from Xishuangbanna Rainforest, southwestern China, ZooKeys 1034, pp. 165-197 : 165

Ischnothyreus xiaolongha Tong & Li sp. nov. Figures 17 , 18 , 19 , 21A-E , 24C, D

Type material.

Holotype ♂: China, Yunnan, Mengla County, Xiaolongha, Xishuangbanna Biodiversity Conservation Corridor, Qidaoban, valley forest; 21°24.832'N, 101°37.906'E; 721 m; 18.VI.2013; Q. Zhao and Z. Chen leg. (SYNU-428). Paratypes 1♀: same data as for holotype (SYNU-429); 1♂3♀: same data as for holotype; 21°24.253'N, 101°36.324'E; 761 m; 15.VI.2013; Q. Zhao and Z. Chen leg. (SYNU-430-433).

Diagnosis.

The new species is similar to I. cristiformis sp. nov. and I. mangun sp. nov. in the lamella-like membrane of the male palp and the short dorsal scutum of the abdomen, but can be distinguished by the tongue-shaped sclerotized process (Fig. 17H-J ) of the cheliceral fang (vs large cockscomb-shaped sclerotized process (Fig. 1H-J ) in I. cristiformis sp. nov. and the unmodified male cheliceral fang (Fig. 4H, I ) in I. mangun sp. nov.), the broad leaf-shaped retrolateral lobe of the male palp (Fig. 18F ) (vs broad rectangular-shaped (Fig. 2F ) in I. cristiformis sp. nov. and narrow leaf-shaped (Fig. 5F ) in I. mangun sp. nov.) and the small bell-shaped atrium (Fig. 19H ) of the female (vs the large bowl-shaped atrium (Fig. 3H ) in I. cristiformis sp. nov. and the small rectangular shaped atrium (Fig. 6F ) in I. mangun sp. nov.).

Description.

Male (holotype). Body: habitus as in Fig. 17A-C ; body length 1.48. Carapace: 0.80 long, 0.61 wide; yellow, with egg-shaped patches behind eyes, surface of elevated portion of pars cephalica smooth, sides finely reticulate, fovea absent, lateral margin straight, smooth (Fig. 17D, E ). Clypeus: height about equal to ALE diameter (Fig. 17G ). Eyes: see Fig. 17D, G . Sternum: pale orange (Fig. 17F ). Mouthparts: chelicerae, endites and labium orange; chelicerae straight, base of fangs with tongue-shaped sclerotized process, fang groove with a few small denticles (Figs 17H-J , 21D, E ); anteromedian tip of endites with one strong, tooth-like projection (Fig. 17F ). Abdomen: 0.64 long, 0.48 wide; dorsal scutum pale orange, very small, covering approximately 1/4 of the abdomen width and 1/3 of the abdomen length, not fused to epigastric scutum; epigastric and postgastric scutum well sclerotized, pale orange, fused, postgastric scutum covering about 1/2 of the abdomen length (Fig. 17A-C ). Legs: pale orange, femur I with 2 prolateral spines, tibia I with 4 pairs, metatarsus I with 2 pairs of long ventral spines. Leg II spination similar to leg I except femur with only 1 prolateral spine. Legs III and IV spineless. Palp: trochanter with ventral projection, cymbium brown; bulb with 2 ventral protuberances, one large and another very small, distal end of bulb stout, with one narrow needle-shaped prolateral projection and a lamella-like membrane, retrolateral lobe broad leaf-shaped (Figs 18 , 21A-C ).

Female (paratype, SYNU-429). Same as male except as noted. Body: habitus as in Fig. 19A-C ; body length 1.70. Carapace: 0.76 long, 0.63 wide. Mouthparts: chelicerae and endites unmodified. Abdomen: 0.95 long, 0.64 wide. Epigastric area: surface without external features (Fig. 19H ). Endogyne: from the middle of the slightly thickened margin of the postgastric scutum runs a dark, simple winding tube posteriorly, ending in a small bell-shaped atrium (Fig. 24C, D ).

Etymology.

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

Distribution.

Known only from the type locality.

Figures

Figure 1. Ischnothyreus cristiformis sp. nov., male holotype A-C habitus, dorsal, lateral and ventral views D-G prosoma, dorsal, lateral, ventral and anterior views H-J left chelicerae, anterior, posterior and lateral views. Abbreviation: stp = strong, tooth-like projection. Scale bars: 0.4 mm (A-G); 0.1 mm (H-J).

Figure 2. Ischnothyreus cristiformis sp. nov., male holotype, left palp, SEM A-C prolateral, retrolateral and dorsal views D, E palpal bulb, prolateral and retrolateral views F-H distal part of palpal bulb, dorsal, prolateral and retrolateral views. Abbreviations: llm = lamella-like membrane; rl = retrolateral lobe; rol = round lobe; tsm = thread-shaped membrane; vpr = ventral protuberance.

Figure 3. Ischnothyreus cristiformis sp. nov., female paratype A-C habitus, dorsal, lateral and ventral views D-G prosoma, dorsal, lateral, ventral and anterior views H epigastric region, ventral view. Abbreviation: css = central strongly sclerotized structure; Scale bars: 0.4 mm (A-G); 0.2 mm (H).

Figure 4. Ischnothyreus mangun sp. nov., male holotype A-C habitus, dorsal, lateral and ventral views D-G prosoma, dorsal, lateral, ventral and anterior views H, I left chelicerae, anterior and posterior views. Abbreviation: stp = strong, tooth-like projection. Scale bars: 0.4 mm (A-G); 0.1 mm (H, I).

Figure 5. Ischnothyreus mangun sp. nov., male holotype, left palp, SEM A-C prolateral, retrolateral and dorsal views D, E palpal bulb, prolateral and retrolateral views F-H distal part of palpal bulb, dorsal, prolateral and retrolateral views. Abbreviations: llm = lamella-like membrane; nsm = needle-shaped membrane; rl = retrolateral lobe; rol = round lobe; vpr = ventral protuberance.

Figure 6. Ischnothyreus mangun sp. nov., female paratype A-D prosoma, dorsal, lateral, anterior and ventral views E abdomen, dorsal view F epigastric region, ventral view. Abbreviation: css = central strongly sclerotized structure. Scale bars: 0.4 mm (A-E); 0.2 mm (F).

Figure 17. Ischnothyreus xiaolongha sp. nov., male holotype A-C habitus, dorsal, lateral and ventral views D-G prosoma, dorsal, lateral, ventral and anterior views H-J left chelicerae, anterior, posterior and lateral views. Abbreviation: stp = strong, tooth-like projection. Scale bars: 0.4 mm (A-G); 0.1 mm (H-J).

Figure 18. Ischnothyreus xiaolongha sp. nov., male holotype, left palp, SEM A-C prolateral, retrolateral and dorsal views D, E palpal bulb, prolateral and retrolateral views F-H distal part of palpal bulb, dorsal, prolateral and retrolateral views. Abbreviations: llm = lamella-like membrane; nsm = needle-shaped membrane; rl = retrolateral lobe; rol = round lobe; vpr = ventral protrusion.

Figure 19. Ischnothyreus xiaolongha sp. nov., female paratype A-C habitus, dorsal, lateral and ventral views D-G prosoma, dorsal, lateral, ventral and anterior views H epigastric region, ventral view. Scale bars: 0.4 mm (A-H).

Figure 21. A-E I. xiaolongha sp. nov. F, G I. qiuxing A left male palp, prolateral view B left male palp, dorsal view C left male palp, retrolateral view D, F left male chelicerae, anterior view E, G left male chelicerae, posterior view. Abbreviations: fsp = finger-shaped process; tsp = tongue-shaped process. Scale bars: 0.2 mm (A-C).

Figure 24. Endogyne of Ischnothyreus spp., A, B I. sijiae sp. nov. C, D I. xiaolongha sp. nov. A, C ventral view B, D dorsal view. Abbreviations: a = apodemes; bsa = bell-shaped atrium; nsa = nipple-shaped atrium; wt = winding tube. Scale bars: 0.2 mm.