Ischnothyreus lucidus Richard

Richard, Miguel, Graber, Werner & Kropf, Christian, 2016, The goblin spider genus Ischnothyreus (Araneae, Oonopidae) in Java and Sumatra, Zootaxa 4151 (1), pp. 1-99 : 60-67

Ischnothyreus lucidus Richard , sp. nov.

( Figs. 47–52 )

Type material. Holotype: male (PBI_OON00052395), SUMATRA: Kerinci, N. Park, 800m, nr. river, leaflitter, July 21–30, 1988, leg. Suh. Djojosudharmo, Coll. Deeleman, NNM Leiden.

Paratypes: 3 males, 6 females (PBI_OON00031904), collected with holotype.

Additional material examined. 1 male, 1 female (PBI_OON00031904), collected with holotype.

Etymology. The species epithet is an adjective meaning “light” in Latin and refers to the overall light coloration of this species.

Diagnosis. Males and females of I. lucidus sp. nov. show a light body coloration and a very small and weakly sclerotized dorsal abdominal scutum ( Figs. 47 A, F, 51A, E).

Males of I. lucidus sp. nov. slightly resemble males of I. falcatus Tong & Li, 2008 in palpal morphology. I. lucidus sp. nov. males can be distinguished from them by the shape of the tip of the bulb with its prolateral membrane and the distal appendage which is pointed and longer than in I. falcatus (pm, da, Figs. 48 E, F, 50B–E). The prominent process on the retrolateral side of the paturon of I. falcatus is missing in I. lucidus sp. nov. Males of I. lucidus sp. nov. possess a characteristic flat but strongly sclerotized cheliceral fang process, similar to I. rex Kranz-Baltensperger 2011 (p, Figs. 49 B–E, 50F, G).

Females of I. lucidus sp. nov. can be identified by their genitalia: The winding tube reminds of I. ligulatus sp. nov. with the roundish appearance but I. lucidus sp. nov. can be distinguished from I. ligulatus sp. nov. by the surface of the postepigastric scutum which appears anchor-shaped in the area of the winding tube (wt, a, ass, Figs. 52 A–D). Also the dorsal abdominal scutum is much smaller and less sclerotized in I. lucidus sp. nov..

Description. Male: (PBI_OON00052395). Total length 1.43; carapace length: 0.71; carapace width: 0.56; abdomen length; 0.64.

CEPHALOTHORAX: Carapace yellow, without any pattern, broadly oval in dorsal view, pars cephalica strongly elevated in lateral view, anteriorly narrowed to 0.49 times its maximum width or less, surface of elevated portion of pars cephalica smooth, sides smooth; lateral margin straight, smooth; non-marginal pars thoracica setae dark, needle-like. Clypeus margin unmodified, straight in front view, sloping forward in lateral view, high, ALE separated from edge of carapace by their radius or more. Eyes six, well developed, ALE largest, all eyes oval; posterior eye row straight from above, procurved from front; ALE touching, ALE-PLE separated by less than ALE radius, PME touching for less than half their length, PLE-PME touching. Sternum as long as wide, yellow, uniform, not fused to carapace, median concavity absent, surface smooth, microsculpture absent, lateral margin without infra-coxal grooves, distance between coxae approximately equal, extensions of pre-coxal triangles absent, lateral margins unmodified; setae dark, needle-like, evenly scattered, originating from surface. Mouthparts: Chelicerae, endites and labium yellow. Chelicerae straight, anterior face unmodified; directed medially, shape normal, tip unmodified; setae dark, needle-like, evenly scattered. Fang base with strongly sclerotized process (p, Figs. 49 B–E, 50F, G). Labium elongated hexagon, not fused to sternum, anterior margin not indented at middle, same as sternum in sclerotization; subdistal portion with unmodified setae. Endites distally not excavated, anteromedian tip with one strong, tooth-like projection, posteromedian part unmodified, much more heavily sclerotized than sternum.

ABDOMEN: ovoid, pointed posteriorly; dorsum soft portions white, without color pattern. Posterior spiracles not connected by groove. Scutum extending far dorsal of pedicel. Dorsal scutum weakly sclerotized, yellow, without color pattern, covering 1/2 to 3/4 of abdomen, between 1/4 and 1/2 abdomen width, fused to epigastric scutum, middle surface smooth, sides smooth. Epigastric scutum weakly sclerotized, surrounding pedicel, not protruding, small lateral sclerites absent. Postepigastric scutum weakly sclerotized, yellow, short, almost rectangular, covering about 1/3 of the abdominal length, fused to epigastric scutum, anterior margin unmodified. Dorsum setae present, dark, needle-like. Spinneret scutum with fringe of needle-like setae. Dense patch of setae anterior to spinnerets absent. Interscutal membrane with setae.

LEGS: yellow, without color pattern; patella plus tibia I near as long as carapace, tibia I unmodified. Leg spination: femora: I p0-1-1; II p0-0-1; tibiae: I, II p2-2-0; r2-2-0; metatarsi: I, II p1-1-0; r1-1-0.

GENITALIA: Bulb with two small ventral protuberances, retrolateral lobe simple (rl, Figs. g, h). Tip of bulb short, blunt, with prolateral membrane and distal appendage (pm, da, Figs. 48 E, F, 50B–E).

Female: (PBI_OON31904). Total length 1.68; carapace length: 0.73; carapace width: 0.59; abdomen length; 1.06.

CEPHALOTHORAX: Carapace pale orange, pars cephalica slightly elevated in lateral view. Clypeus vertical in lateral view, low, ALE separated from edge of carapace by less than their radius. Eyes six, well developed, ALE largest, ALE oval, PME squared, PLE oval; posterior eye row straight from above, procurved from front; ALE touching, ALE-PLE separated by less than ALE radius, PME touching throughout most of their length, PLE-PME touching. Sternum pale orange. Mouthparts: Chelicerae, endites and labium pale orange, without prominent basal process; paturon distal region unmodified. Labium with setae. Female palp claws absent; spines absent; tarsus unmodified.

ABDOMEN: Scutum not extending far dorsal of pedicel. Dorsal scutum covering less than 1/2 of abdomen, less than 1/4 abdomen width, not fused to epigastric scutum. 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: Leg spination: femora: I p0-1-1; II p0-0-1; tibiae: I, II p2-2-0; r2-2-0; metatarsi: I, II p1-1-0; r1-1-0.

GENITALIA: Winding tube large, apodemes lateral of winding tube with openings to surface of postepigastric scutum, postepigastric scutum with central anchor-shaped structure and row of pores (wt, a, ass, po Figs. 52 A–D).

Distribution. Known only from Kerinci National Park in middle Sumatra.

Figures

FIGURE 47. Ischnothyreus lucidus sp. nov. Male: A, habitus, dorsal view; B, habitus, lateral view; C, habitus, ventral view; D, carapace, frontal view; E, opisthosoma, lateral view; F, opisthosoma, dorsal view; G, opisthosoma, ventral view. Scale bar: A = 1 mm.

FIGURE 48. Ischnothyreus lucidus sp. nov. Male: A, G, left palp, prolateral view; B, H, left palp, retrolateral view; C, E, left embolus, prolateral view; D, F, left embolus, retrolateral view. da, distal appendage; pm, prolateral membrane; rl, retrolateral lobe. Scale bars: B, H = 0.1 mm.

FIGURE 49. Ischnothyreus lucidus sp. nov. Male: A, chelicera, anterior view; B, fang of right chelicera, posterior view; C, fang of right chelicera, anterior view; D, right chelicera, posterior view; E, right chelicera, anterior view. p, process. Scale bars: A, D = 0.1 mm; B, C = 20 µm.

FIGURE 50. Ischnothyreus lucidus sp. nov. Male, SEM images: A, left palp with gnathocoxa and endoskeletal element, prolateral view; B, left palp, prolateral view; C, left bulbus, posterior view; D, left embolus, prolateral view; E, left embolus, posterior view; F, left chelicera, posterior view; G, left chelicera, ventral view. da, distal appendage; ee, endoskeletal element; eo, embolic opening; p, process. Scale bars: A = 0.2 mm; B = 0.1 mm; C, G = 50 mm; D, F = 20 µm; E = 10 µm.

FIGURE 51. Ischnothyreus lucidus sp. nov. Female: A, habitus, dorsal view; B, habitus, lateral view; C habitus, ventral view; D, carapace, frontal view; E, opisthosoma, dorsal view; F, opisthosoma, ventral view; G, opisthosoma, lateral view. H, opisthosoma, frontal view. Scale bar: A = 1 mm.

FIGURE 52. Ischnothyreus lucidus sp. nov. Female: A, genital area, dorsal view; B, C, D, genital area, ventral view; E, surface of postepigastric scutum with row of pores and scratch marks, ventral view. a, apodeme; ass, anchor-shaped structure; po, pores; s, stigma; sm, scratch marks; wt, winding tube. Scale bars: A, B = 0.15 mm; C, D = 0.1 mm; E = 20 µm.