Ischnothyreus Simon, 1893,

Richard, Miguel, Graber, Werner & Kropf, Christian, 2016, The goblin spider genus Ischnothyreus (Araneae, Oonopidae) in Java and Sumatra, Zootaxa 4151 (1), pp. 1-99: 5-6

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Ischnothyreus Simon, 1893


Genus Ischnothyreus Simon, 1893 

Type species Ischnothyreus peltifer ( Simon) 1891 

Diagnosis. Ischnothyreus  synapomorphies: Males possess heavily sclerotized “burnt” palps (e. g. Figs. 1View FIGURE 1 D –G) which are associated with an elaborate internal skeletomuscular system in the anterior part of the elevated carapace ( Dumitrescu and Georgescu 1983). These endoskeletal elements are visible through the carapace cuticle and appear as egg-shaped patches that are somewhat darker than the rest of the carapace (e. g. Figs. 31View FIGURE 31 E, 32C). The resting position of the male palps is characteristic, as they are held twisted retrolaterally, lying flat at the sides of the endites and sternum (e. g Figs. 1View FIGURE 1 D –G). Male palps of Ischnothyreus  show a fusion of cymbium and bulb but with a visible seam (se, Fig. IC). Males of most species of Ischnothyreus  possess conspicuous processes on the base of the cheliceral fang (p, e. g. Figs. 19View FIGURE 19 C, D). Females of Ischnothyreus  show an elongated, asymmetrically curved and highly sclerotized convoluted duct (winding tube) in their genital area underneath the centre of the postepigastric scutum (wt, e. g. Fig. 15View FIGURE 15 E) (Burger 2010). The winding tube is laterally flanked by two apodemes (a, e. g. Fig. 15View FIGURE 15 E) in most species of Ischnothyreus  . Females also show very diverse and species-specific modifications of the postepigastric scutum (e. g. nsp Fig. 16View FIGURE 16 G). The postepigastric scutum bears a row or field of pores (po, e. g. Fig. 16View FIGURE 16 F) connected to the winding tube (Burger 2010).

General morphology of the male pedipalp:

Male pedipalps of Ischnothyreus  show several conspicious features: Besides the fusion of cymbium and bulb there is also a partial fusion of trochanter, femur and patella (pfj, Figs. IC, D). The trochanter is strongly modified, with ventral projections (tvp, Figs. IC, D). The bulb shows one or two protuberances on the ventral side (vp, Fig. ID) and a retrolateral lobe distally close to the embolic region (rl, Fig. ID) (e. g. Kranz-Baltensperger 2011, Saaristo 2001). The embolic opening is often on the prolateral side (eo, Fig. IC) and there are often lesssclerotized processes in the embolic region (ssa, Figs. IC, D). Three trichobothria are situated on the dorsal side of the tibia (t, Figs IA, B). Three strings of unknown function (str, Figs. IE, F) pass through the segments of male pedipalps from the endite to the bulb.

Description of the genus Ischnothyreus  : see e. g. Edward and Harvey 2014.

FIGURE I. Ischnothyreus  male left pedipalp: 1, 3, prolateral view; 2, 4, retrolateral view; 5, bulb, lateral view; 6, femurtrochanter. eo, embolic opening; pfj, partially fused joints; rl, retrolateral lobe; se, seam; ssa, slightly sclerotized appendage; str, strings; t, trichobothria; tvp, trochanter ventral projection; vp, ventral protuberance.