Male (Holotype). Body: habitus as in Fig. 1A–C; body length 1.64. Carapace: 0.88 long, 0.65 wide; yellow, oval in dorsal view, pars cephalica strongly elevated in lateral view, sur­face of elevated portion of pars cephalica reticulate, sides finely reticulate, lateral margin straight, smooth (Fig. 1C). Clypeus: straight in frontal view, ALE separated from edge of carapace by 1.5 times of their diameter (Fig. 1F). Eyes: ALE largest, ALE circular, PME circular, PLE oval; posterior eye row recurved from above; ALE separated by less than their radius, ALE and PLE touching. Sternum: as long as wide, pale orange (Fig. 1E). Mouthparts: chelicerae, endites and labium yellow; chelicerae straight, base of fangs with flag-like process, fang groove with a few small and one larger denticles (Fig. 2J–L); an­teromedian tip of endites with one strong, tooth-like projection (Fig. 1G). Abdomen: 0.76 long, 0.44 wide; dorsal scutum well sclerotised, dark brown, covering 4/5 of the abdomen width and approximately 5/6 of the abdomen length, not fused to epigastric scutum; epigastric and postepigastric scutum pale orange, fused, covering 3/4 of the abdomen length. 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 without ventral projection; bulb with 1 ven­tral protuberance, distal end of bulb stout (Fig. 2A–I).

Figure 1.  

Ischnothyreus daheling sp. nov., male holotype. A habitus, dorsal view; B habitus, ventral view; C habitus, lateral view; D prosoma, dorsal view; E prosoma, ventral view; F prosoma, anterior view; G left chelicera, anterior view; H left chelicera, lateral view; I left chelicera, posterior view. Abbreviation: stp = strong, tooth-like projection. Scale bars: A–F = 0.4 mm; G–I = 0.1 mm.

Figure 2.  

Ischnothyreus daheling sp. nov., male holotype, light (A–C) and SEM (D–L) images. A left palp, prolateral view; B left palp, retrolateral view; C left palp, dorsal view; D left palp, prolateral view; E left palp, retrolateral view; F left palp, dorsal view; G distal part of palpal bulb, prolateral view; H distal part of palpal bulb, retrolateral view; I distal part of palpal bulb, dorsal view; J left chelicera, anterior view; K left chelicera, posterior view; L left chelicera, lateral view. Abbreviation: fp = flag-shaped process. Scale bars: A–F = 0.4 mm; G–L = 0.1 mm.

Female (paratype, SYNU-708). Same as male, except as noted. Habitus as in Fig. 3A–C. Body: 1.82 long. Carapace: 0.81 long, 0.66 wide. Mouthparts: chelicerae and endites unmodified. Abdomen: 1.24 long, 0.79 wide; dorsal scutum approximately 1/3 of the abdomen length. Epigastric area: postepigastric scutum with inverted bell-shaped structure (Fig. 3G and H). Endogyne: winding tube simple, strongly convoluted; lateral apodemes present (Fig. 3I).

Figure 3.  

Ischnothyreus daheling sp. nov., female paratype. A habitus, dorsal view; B habitus, ventral view; C habitus, lateral view; D prosoma, dorsal view; E prosoma, ventral view; F prosoma, anterior view; G epigastric region, ventral view H endogyne, ventral view; I endogyne, dorsal view. Abbreviation: bss = bell-shaped structure. Scale bars: A–F = 0.4 mm; G–I = 0.1 mm.

This species is similar to Ischnothyreus yueluensis Yin & Wang, 1984 in the size of the abdominal scuta, but can be distinguished by the flag-shaped sclerotised process of cheliceral fang (Fig. 2J) vs. small stick-shaped sclerotised process (Huang et al. 2021: fig. 4G), the stout distal end of bulb (Fig. 2G and H) vs. elongated distal end, with several leaf-shaped membranes (Huang et al. 2021: figs. 5G and H) and the inverted bell-shaped structure of postepigastric scutum of female (Fig. 3G) vs. small, narrow bowl-shaped structure (Huang et al. 2021: fig. 6H).

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

Known only from the type locality.

Male (holotype). Body: habitus as in Fig. 4A–C; body length 1.91. Carapace: 0.91 long, 0.73 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. 4C and D). Clypeus: straight in frontal view, ALE separated from edge of carapace less than their diameter (Fig. 4F). Eyes: ALE largest, ALE circular, PME circular, PLE oval; posterior eye row straight from above; ALE touching, ALE-PLE touching. Sternum: longer than wide, pale orange (Fig. 4E). Mouthparts: chelicerae, endites and labium yellow; chelicerae straight, base of fangs with flag-like process, fang groove with a few small and two larger denticles (Fig. 5K and L); an­teromedian tip of endites with one strong, tooth-like projection (Fig. 4E). Abdomen: 1.00 long, 0.61 wide; dorsal scutum well sclerotised, dark brown, covering 1/2 of the abdomen width and approximately 1/2 of the abdomen length, not fused to epigastric scutum; epigastric and postepigastric scutum well sclerotised, yellow, fused; postepigastric scutum covering about 2/3 of the abdomen length. 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 without ventral projection; bulb with 1 ven­tral protuberance, distal end of bulb stout, with a retrolateral broad lobe (Fig. 5A–I).

Figure 4.  

Ischnothyreus longyang sp. nov., male holotype. A habitus, dorsal view; B habitus, ventral view; C habitus, lateral view; D prosoma, dorsal view; E prosoma, ventral view; F prosoma, anterior view; G left chelicera, anterior view; H left chelicera, lateral view; I left chelicera, posterior view. Abbreviation: stp = strong, tooth-like projection. Scale bars: A–F = 0.4 mm; G–I = 0.1 mm.

Figure 5.  

Ischnothyreus longyang sp. nov., male holotype, light (A–C) and SEM (D–L) images. A left palp, prolateral view; B left palp, retrolateral view; C left palp, dorsal view; D left palp, prolateral view; E left palp, retrolateral view; F left palp, dorsal view; G palpal bulb, prolateral view; H distal part of palpal bulb, retrolateral view; I distal part of palpal bulb, dorsal view; J left chelicera, anterior view; K distal part of left chelicera, anterior view; L distal part of left chelicera, posterior view. Abbreviation: fp = flag-shaped process; rl = retrolateral lobe. Scale bars: A–F, J–L = 0.1 mm; G–I = 0.05 mm.

Female. Unknown.

The new species is similar to Ischnothyreus qiuxing Tong & Li, 2021 in the size of the abdominal scuta, but can be distinguished by the flag-shaped sclerotised process of cheliceral fang (Fig. 5K) vs. finger-shaped process (Tong et al. 2021: figs. 13H–J, 21F and G) and the broad retrolateral lobe of palpal bulb (Fig. 5H) vs. lack the lobe, but has a tuber-like projection (Tong et al. 2021: fig. 14H).

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

Known only from the type locality.

See Platnick et al. (2012).

Males differ from those of Ischnothyreus peltifer (Simon, 1892) in lacking a protuberance on the base of the fang; palp with rounded bulb and sperm pore larger (Platnick et al. 2012: figs. 104 and 107; Brescovit et al. 2019: figs. 26–30). Females can be recognised by the boat-shaped structure on the postepigastric scutum (Fig. 6G).

Figure 6.  

Ischnothyreus velox Jackson, 1908, female. A habitus, dorsal view; B prosoma, dorsal view; C habitus, ventral view; D prosoma, ventral view; E habitus, lateral view; F prosoma, anterior view; G endogyne, ventral view; H endogyne, dorsal view. Scale bars: A–F = 0.4 mm; G, H = 0.1 mm.

Pantropical; newly recorded from China.