Ischnothyreus namo, Kranz-Baltensperger, Yvonne, 2012

Kranz-Baltensperger, Yvonne, 2012, Three new species of the oonopid spider genus Ischnothyreus (Araneae: Oonopidae) from Tioman Island (Malaysia), Zootaxa 3161 (1), pp. 37-47 : 43-46

Ischnothyreus namo sp. nov.

( Figs 5–6 , 7 )

Type material. Holotype: male ( PBI_OON 00012688 ), MALAYSIA: Tioman Island (= Pulau Tioman ), Gunung Kajang , 900–1000m, 2°46’0”N, 104°09’4”E, 29.IV.2005, leg. A. Schulz, MHNG . Paratypes: 1 female ( PBI_OON 00032382 ), collected with holotype, MHNG . 1 female ( PBI_OON 00015670 ), Tioman Island, westside, 2 km SE of Kampung Genting , 100m, 2°47’N, 104°8’E, 27.VI.2001, leg. A. Schulz & K. Vock, MHNG . 1 male ( PBI_OON 00012604 ), Tioman Island, Gunung Kajang , 500–600m, 2°46’0”N, 104°09’4”E, 25.IV.2005, leg. A.Schulz, MHNG . 2 females ( PBI_OON 00012646 ), same data as holotype, but 27.IV.2005, MHNG . 1 female ( PBI_OON 00032352 ), Tioman Island, path from Kampung Paya to Gunung Kajang , 200–600m, 02°46’84”N, 104°07’63”E, 6.–7.VI.2007. leg. A. Schulz, MHNG . 1 female ( PBI_OON 00032353 ), Tioman Island, westside of Gunung Kajang, 2 km E of Kampung Genting , 400m, 2°47’N, 104°8’E, 2.VII.2001, leg. A. Schulz & K. Vock, MHNG . 1 female ( PBI_OON 00015672 ), same data as PBI_OON 0 0 0 32353, but 300–400m, 3.VII.2001, MHNG .

Etymology. The specific name is an arbitrary combination of letters.

Diagnosis. The male of I. namo can be distinguished from males of I. tioman and I. tekek by the lack of the cheliceral apophyses and the simple palp. I. namo resembles I. aculeatus ( Simon 1893) from Sumatra and the Philippines but can be distinguished from this species by the abdominal scuta, which cover almost the whole abdomen ( Fig. 5 A–F), while they are short in I. aculeatus . The female of I. namo shows a very distinct epigastric conformation with strongly sclerotized apodemes and a strongly winding tube ( Fig. 6 C–E).

Description. Male. Total length 1.49 mm. Carapace: slightly elevated in lateral view, fovea present, lateral margin rebordered. Eyes: ALE separated by less than their radius. Mouthparts: Chelicerae slightly divergent, base of fang slightly enlarged, ridges (r) and three trichobothria-like setae present on the anterior face of the paturon (arrows) ( Fig. 5 D). Anterior margin of labium indented at middle. Anteromedian tip of endites with one strong, tooth-like projection (stp) ( Fig. 5 B). Abdomen: Scutum extending far dorsal of pedicel. Dorsal scutum covering more than 3/4 of abdomen, more than 1/2 to most of abdomen width, not fused to epigastric scutum. Legs: spine formula: femora: I p0-1-1; II p0-0-1; tibiae: I, II p2-1-1; r2-1-1; metatarsi: I, II p1-1-0; r1-1-0. Trichobothria not examined. Genitalia: Trochanter with small ventral projection (vp) ( Fig. 5 B); tibia with three trichobothria, distal part of bulb simple, with small prolateral membrane (mo) and retrolateral lobe (l), embolus (e) thin and short, directed backwards ( Fig. 5 E–F).

Female: Total length 1.39 mm. As in male except as noted. Carapace: without any pattern, broadly oval in dorsal view, pars cephalica strongly elevated in lateral view, fovea absent. Eyes: ALE separated from edge of carapace by less than their radius. ALE touching. Mouthparts: Labium not fused to sternum, anterior margin not indented at middle. Anteromedian tip of endites unmodified. Palpal femur with four spines, palpal tibia with three trichobothria. Abdomen: Pedicel scutum not extending far dorsal of pedicel. Dorsal scutum covering less than 1/2 of abdomen, between 1/4 and 1/2 abdomen width. Epigastric scutum slightly protruding. Postepigastric scutum widely hexagonal, only around epigastric furrow, not fused to epigastric scutum, with short posteriorly directed lateral apodemes. Dense patch of setae anterior to spinnerets present. Legs: spine formula: femora: I p0-1-1; r0-1-0; II p0- 0-1; r0-0-1; tibiae: I, II p2-1-1; r2-1-1; metatarsi: I, II p1-1-0; r1-1-0. Genitalia: The posterior margin of the epigastric scutum is lined with numerous needle-like setae. Postepigastric scutum with strongly sclerotized apodemes (a), connected by transverse ridge (tr). Dark, winding tube running posteriorly (wt) ( Fig. 6 D–F).

Distribution. Tioman Island.

Figures

FIGURE 5. Ischnothyreus namo sp. nov. male. A, habitus, dorsal view; B, habitus, ventral view; C, carapace, frontal view; D, left chelicera, anterior view; E, right palp, retrolateral view; F, right palp, prolateral view. Stp, strong tooth-like projection; vp, ventral projection; r, ribbed; l, lobe; mo, membranous outgrowth; e, embolus. Scale bars A, B = 0.5 mm; C = 0.25 mm; D, E, F = 0.1 mm.

FIGURE 6. Ischnothyreus namo sp. nov. female. A, habitus, dorsal view; B, habitus, ventral view; C, abdomen, ventral view; D, genital area, ventral view; E, genital area, dorsal view. Wt, winding tube; a, apodemes; tr, transverse ridge. Scale bars A, B = 0.5 mm; C = 0.25 mm; D, E = 0.1 mm.

FIGURE 7. A. Overview map of Southeast Asia. B. Detailed map of Tioman Island with localities of Ischnothyreus species treated in the present study.