Ischnothyreus dactylinus Tong & Li

Tong, Yanfeng, Koh, Joseph K. H., Tong, Xiujiao & Li, Shuqiang, 2016, Five new species of the genus Ischnothyreus Simon, 1893 from Singapore, ZooKeys 618, pp. 39-66 : 44-45

Taxon classification Animalia Araneae Oonopidae

Ischnothyreus dactylinus Tong & Li sp. n. Figs 7, 8, 9

Type material.

Holotype: male (LKCNHM), Singapore: Central Catchment Nature Reserve, near Singapore Zoo, Alt. 50 m, 1°24'22.3"N, 103°47'7.4"E, August 30, 2015, S. Li and Y. Tong leg. Paratypes: 5 males, 8 females (LKCNHM), same data as holotype.

Other material studied.

1 male, 1 female (SYNU-85), Singapore: Bukit Timah Nature Reserve, Alt. 86 m, 1°21'37.4"N, 103°46'30.0"E, August 24, 2015, S. Li and Y. Tong leg.; 7 males, 9 females (SYNU-86), Singapore: Central Catchment Nature Reserve, near Singapore Zoo, Alt. 50 m, 1°24'22.3"N, 103°47'7.4"E, August 30, 2015, S. Li and Y. Tong leg.; 1 male, 8 females (SYNU-87), Singapore: Central Catchment Nature Reserve (off Mandai Lake Road), Alt. 39 m, 1°24'30.7"N, 103°46'51.3"E, August 31, 2015, S. Li and Y. Tong leg.; 1 female (SYNU-88), Singapore: Central Catchment Nature Reserve, near Mandai Agrotechnology Park, Alt. 46 m, 1°24'53.7"N, 103°47'56.2"E, Sep 1, 2015, S. Li and Y. Tong leg.; 1 male, 1 female (SYNU-89), Singapore: Central Catchment Nature Reserve, Alt. 46 m, 1°21'13.3"N, 103°48'29.4"E, August 27, 2015, S. Li and Y. Tong leg.; 1 male, 1 female (SYNU-91), Singapore: Central Catchment Nature Reserve, Alt. 39 m, 1°21'17.9"N, 103°47'50.7"E, August 25, 2015, S. Li and Y. Tong leg.; 1 male (SYNU-92), Singapore: Central Catchment Nature Reserve, Alt. 60 m, 1°21'21.7"N, 103°48'3.8"E, August 26, 2015, S. Li and Y. Tong leg.; 2 females (SYNU-93), Singapore: Bukit Timah Nature Reserve, Bukit Timah Summit, Alt. 163 m, 1°21'16.65"N, 103°46'34.95"E, August 19, 2015, S. Li and Y. Tong leg.; 1 male, 1 female (SYNU-94), Singapore: Bukit Timah Nature Reserve, Bukit Timah Summit, Alt. 163 m, 1°21'16.65"N, 103°46'34.95"E, August 19, 2015, S. Li and Y. Tong leg.; 4 females (SYNU-95), Singapore: Bukit Timah Nature Reserve, Catchment Path, Alt. 107 m, 1°21'12.5"N, 103°46'50.6"E, August 20, 2015, S. Li and Y. Tong leg.; 1 male, 1 female (SYNU-96), Singapore: Bukit Timah Nature Reserve, Bukit Timah Summit, Alt. 163 m, 1°21'16.65"N, 103°46'34.95"E, August 19, 2015, S. Li and Y. Tong leg.; 2 males, 5 females (SYNU-97), Singapore: Central Catchment Nature Reserve, near Singapore Zoo, Alt. 50 m, 1°24'22.3"N, 103°47'7.4"E, August 30, 2015, S. Li and Y. Tong leg.; 1 male, 3 females (SYNU-98), Singapore: Bukit Timah Nature Reserve, Seraya Loop, Alt. 118 m, 1°21'25.4"N, 103°46'25.3"E, August 17, 2015, S. Li and Y. Tong leg.

Etymology.

The specific epithet means “finger-like” in Greek, and refers to the long apophysis on the distal part of the male papal bulb (Fig. 9D, E); adjective.

Diagnosis.

The new species is similar to Ischnothyreus browni Chickering, 1968 ( Platnick et al. 2012), but can be distinguished from it by the dark brown body color, the flake-like dorsal process (fdp) on the male chelicerae (Fig. 9F, G), the finger-like apophysis on the distal part of the male papal bulb (Fig. 9D, E) and the fan-shaped atrium (fsa) in the female epigastric region (Fig. 8H). The female epigastric region of the new species is also similar to that of Ischnothyreus balu Kranz-Baltensperger, 2011, but can be distinguished from it by the larger abdominal scutum and the color patterns on legs and abdomen.

Description.

Male (holotype). Total length 1.43; carapace 0.78 length, 0.57 width; abdomen 0.65 length, 0.39 width. Habitus as in Fig. 7A, C, E. Carapace: yellow, dark brown on lateral and posterior surfaces, with brown egg-shaped patches behind eyes, ovoid in dorsal view, slightly elevated in lateral view, surface of elevated portion of pars cephalica smooth, sides strongly reticulate, fovea absent, lateral margin straight, smooth (Fig. 7B, D). Clypeus: straight in frontal view, vertical in lateral view, high, ALE separated from edge of carapace by more than twice of their diameter. Eyes: six, very small, ALE largest, ALE circular, PME and PLE oval, posterior eye row procurved from both above and front, ALE separated by less than their radius, ALE-PLE separated by less than ALE radius, PME touching, PLE-PME touching (Fig. 7I). Sternum: longer than wide, pale yellow, uniform, not fused to carapace, surface smooth, setae sparse. Mouthparts: chelicerae, endites and labium yellow. Chelicerae straight, base of fangs with a flake-like dorsal process (fdp) (Fig. 9F, G), fang groove with a few small and one larger denticles. Labium rectangular, fused to sternum, anterior margin not indented at middle. Anteromedian tip of endites with one strong, tooth-like projection (Fig. 7E, F). Abdomen: ovoid, rounded posteriorly. Posterior spiracles not connected by groove. Pedicel tube short, ribbed, scutum not extending far dorsal of pedicel. Dorsal scutum well sclerotized, yellow, except dark brown on posterior part, covering, whole abdomen width and approximately 5/6 of abdomen length, not fused to epigastric scutum, middle surface and sides smooth. Epigastric and postepigastric scutum well sclerotized, fused, the upper part of the pedicel tube is dark brown, the other part pale yellow, without posteriorly directed lateral apodemes. Dorsum setae present, light, needle-like. Legs: yellow, with dark brown pattern on subbasal part of femur, trochanter and basal half part of tibia of leg IV, femur I with two prolateral and two small retrolateral spines, tibia I with four pairs, metatarsus I with two pairs of long ventral spines. Leg II spination is similar to leg I except femur with only one prolateral and one retrolateral spine. Legs III and IV spineless. Genitalia: epigastric region with sperm pore large, circular, situated at level of anterior spiracles. Palp strongly sclerotized, right and left palps symmetrical, proximal segments brown, trochanter with ventral projection (vp) (Fig. 9A), cymbium brown, fused with bulb, bulb brown, more than two times as long as cymbium, tapering apically, with one large ventral protuberance (vpr) (Fig. 9B, C), distal part elongated, with two long apophyses, one sclerotized, finger-like (sfa), one membranous, triangle-shaped (mta) (Fig. 9D, E).

Female (paratype). Total length 1.51; carapace 0.73 length, 0.58 width; abdomen 0.76 length, 0.49 width. Habitus as in Fig. 8A, C, E. As in male except as noted. Carapace: without any pattern. Mouthparts: endites unmodified. Abdomen: dorsal scutum covering less than 5/6 of abdomen length, 2/3 of abdomen width. Postepigastric scutum widely hexagonal. Genitalia: the posterior margin of the epigastric scutum is lined with numerous needle-like setae. The epigastric groove is narrow. From the middle of the slightly thickened margin of the postepigastric scutum runs a dark, winding tube posteriorly (wt) (Fig. 8G, J), ending in a fan-shaped atrium (fsa) (Fig. 8H).

Distribution.

Singapore.