Ischnothyreus brunneus 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 : 41-44

Taxon classification Animalia Araneae Oonopidae

Ischnothyreus brunneus Tong & Li sp. n. Figs 4, 5, 6

Type material.

Holotype: male (LKCNHM), 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. Paratypes: 7 males, 8 females (LKCNHM), same data as holotype.

Other material studied.

8 males, 14 females (SYNU-65), 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.; 3 females (SYNU-66), Singapore: Pulau Ubin, Alt. 2 m, 1°25'18.0"N, 103°56'25.4"E, August 22, 2015, S. Li and Y. Tong leg.;1 female (SYNU-67), 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.

Etymology.

The specific epithet means “brown” in Latin, and refers to the body color of this species; adjective.

Diagnosis.

Males of the new species is similar to those of Ischnothyreus dactylinus sp. n., but can be distinguished from it by the larger eyes and the unmodified chelicerae. Furthermore the distal part of the male palpal bulb lacks the finger-like apophyses present in Ischnothyreus dactylinus (Fig. 6 A–F). Females of the new species is similar to those of Ischnothyreus barus Kranz-Baltensperger, 2011, but can be distinguished from it by the brown body color and the dark brown pattern on leg IV, and the small bell-shaped atrium (bsa) in the epigastric region (Fig. 5J).

Description.

Male (holotype). Total length 1.36; carapace 0.73 length, 0.57 width; abdomen 0.67 length, 0.48 width. Habitus as in Fig. 4A, 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 finely reticulate, fovea absent, lateral margin straight, smooth (Fig. 4B, D). Clypeus: straight in frontal view, vertical in lateral view, high, ALE separated from edge of carapace by more than their radius. Eyes: six, well developed, ALE largest, ALE circular, PME and PLE oval, posterior eye row straight from above, procurved from front, ALE separated by less than their radius, ALE-PLE separated by less than ALE radius, PME touching, PLE-PME touching (Fig. 4J). 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 unmodified, fang groove with many small denticles (Fig. 6G, H). Labium rectangular, fused to sternum, anterior margin not indented at middle. Anteromedian tip of endites with one strong, tooth-like projection (Fig. 4E, 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, dark brown, covering whole abdomen width and approximately 5/6 of abdomen length, fused to epigastric scutum, middle surface and sides smooth. Epigastric and postepigastric scutum well sclerotized, fused, upper pedicel tube region dark brown, the other part yellow, without posteriorly directed lateral apodemes. Dorsum setae present, light, needle-like. Legs: yellow, with dark brown pattern on distal part of femur IV and middle part of tibia IV (Fig. 4G), 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, trochanter with ventral projection (vp) (Fig. 6A, D), cymbium brown, fused with bulb, bulb brown, more than two times as long as cymbium, tapering apically, with two small ventral protuberances (vpr) (Fig. 6E), distal part elongated, with membranous outgrowth (Fig. 6B, C).

Female (paratype). Total length 1.47; carapace 0.76 length, 0.56 width; abdomen 0.79 length, 0.52 width. Habitus as in Fig. 5A, C, E. As in male except as noted. Carapace: dark brown, without any pattern. Mouthparts: endites unmodified. Abdomen: dorsal scutum covering approximately 2/3 of abdomen length, 1/2 of abdomen width. Genitalia: from the middle of the slightly thickened margin of the postepigastric scutum runs a dark, winding tube posteriorly (wt) (Fig. 5G, H), ending in a small bell-shaped atrium (bsa) (Fig. 5J).

Distribution.

Singapore.