Ideoblothrus nesotymbus, Harvey & Edward, 2007

Harvey, Mark S. & Edward, Karen L., 2007, A review of the pseudoscorpion genus Ideoblothrus (Pseudoscorpiones, Syarinidae) from western and northern Australia, Journal of Natural History 41 (5 - 8), pp. 445-472 : 457-462

Ideoblothrus nesotymbus sp. nov.

( Figures 4 , 22–28 )

Material examined

Holotype: „, Australia: Western Australia: Barrow Island , 5.8 km NW of Chevron Texaco Camp, borehole S2, 20 ° 469330S, 115 ° 269530E, 8 March to 20 April 2006, litter trap, 7 m depth, L. Mould and L. Beesley ( WAM T 75203) . Paratypes: Australia: Western Australia: Barrow Island : 1♀, 5.8 km NW of Chevron Texaco Camp , borehole S2, 20 ° 469330S, 115 ° 269530E, 31 April to 18 July 2006, litter trap, 14 m depth, L. Mould and K. Edward ( WAM T 75213) ; 1♀, 4.3 km N of Chevron Texaco Camp , borehole B19, 20 ° 479230S, 115 ° 269540E, 28 February to 18 April 2005, litter trap, 6 m depth, G. Humphreys and L. Mould ( WAM T 66019) ; 1♀, Barrow Island , 7.1 km NW of Chevron Texaco Camp, borehole BMW4, 20 ° 479020S, 115 ° 239390E, 7 March 2006, litter trap, L. Mould and L. Beesley ( WAM T 71969) .

Etymology

The specific epithet refers to the occurrence of this subterranean species on Barrow Island (nesos, Greek, island; and tymbos, Greek, tomb).

Diagnosis

Ideoblothrus nesotymbus is substantially larger than most other Australasian species [e.g. pedipalpal patella length 0.45–0.50 mm („), 0.53–0.56 mm (♀)], including I. descartes , I. aeesti , I. milikapiti , I. pugil , I. ceylonicus , I. palauensis , and I. bipectinatus which are all substantially smaller (e.g. pedipalpal patella length less than 0.33 mm). Ideoblothrus nesotymbus differs from I. pisolitus in the shape of the pedipalpal chela which is noticeably more slender in I. pisolitus . It differs from I. pugil robustus in being slightly larger [e.g. pedipalpal patella length 0.42 mm (♀)]. It differs from I. aeoodi by the length of the male galea, which is relatively long in I. nesotymbus and much reduced in I. aeoodi . It differs from I. papillon by the slightly less slender pedipalpal chela, which is 2.59 („), 2.69–2.92 (♀) times longer than broad in I. nesotymbus and 2.83 („), 3.00 (♀) times longer than broad in I. papillon .

Description

Adults. Colour: carapace and pedipalps reddish brown, chelicera and coxae orange, legs and abdomen pale tan.

Chelicera: five setae on hand, all setae acuminate, is, ls, sbs, and bs long, es very short; movable finger with one sub-distal seta; fixed finger with ca 7 („), 9–14 (♀) teeth; movable finger with ca 8 („), 7–8 (♀) teeth; with two dorsal lyrifissures and one ventral lyrifissure; galea of male straight, extending to tip of fixed finger; galea of female slightly curved, extending past tip of finger but not to tip of galeal seta; flagellum of five blades, distal blade broadened and finely denticulate; serrula exterior with 30 blades.

Pedipalp ( Figure 23 ): mostly smooth, with only the internal margins of trochanter and femur sparsely granulate; setae on internal margins long and acicular; trochanter without tubercles; trochanter 1.64 („), 1.49–2.09 (♀), femur 2.89 („), 2.84–3.06 (♀), patella 2.00 („), 1.93–2.06 (♀), chela (with pedicel) 2.81 („), 2.83–3.11 (♀), chela (without pedicel) 2.59 („), 2.69–2.93 (♀), hand 1.38 („), 1.49–1.58 (♀) times longer than broad; movable finger 0.90 („), 0.78–0.91 (♀) times longer than hand. Femur without tactile setae; without basal projection. Patella with three lyrifissures, two situated dorsally near pedicel, and one situated distally. Fixed chelal finger with eight trichobothria, movable chelal finger with four trichobothria ( Figure 24 ): eb, esb, ib, and isb forming an oblique row on baso-lateral margin of fixed finger; est situated near ist; it situated medially, distal to est and ist; et subdistal; seven small lanceolate setae present on fixed chelal finger; microsetae (chemosensory setae) absent on both fingers; trichobothria b of movable finger situated basally; sb, st, and t situated medially, very close to each other; t slightly shortened, lanceolate, and bent backward. Venom apparatus present only in fixed chelal finger, venom duct very short, nodus ramosus inflated. Fixed finger with 43 („), 36–48 (♀) slightly retrorse teeth, tooth row terminating basally to est ( Figure 25 ); movable finger with 50 („), 48–52 (♀) rounded teeth, extending nearly to full length of finger ( Figure 26 ); accessory teeth absent. External and internal chelal condyles small and rounded.

Cephalothorax: carapace ( Figure 22 ) 1.21 („), 1.27–1.35 (♀) times longer than broad; sub-rectangular; without any traces of eyes; epistome small; with 25 („), 21–25 (♀) setae arranged 4: 4: 4: 6: 7 („), 4: 4: 4: 4–7: 5–6 (♀); without furrows; with five pairs of small lyrifissures, first and second pairs placed near anterior margin, third pair placed sub-medially, fourth and fifth pairs placed near setae on posterior row. Manducatory process with one long distal and one long sub-distal seta, without sub-oral seta ( Figure 27 ); remainder of maxilla with eight setae. Chaetotaxy of coxae I–IV: 6: 5: 4: 5 („), 6: 6: 4: 6 (♀). Posterior section of coxae II slightly overlapping anterior section of coxae III ( Figure 27 ).

Abdomen: pleural membrane granulo-striate near cephalothorax, remainder longitudinally striate, without setae. Tergites and sternites undivided. Tergal chaetotaxy: holotype „, 6: 6: 8: 9: 9: 9: 9: 9: 9: 7: 4: 2; paratype ♀ ( WAM T 66019), 6: 6: 8: 8: 9: 8: 8: 8: 8: 7: 4: 2; setae uniseriate and acuminate. Sternal chaetotaxy: holotype „, 9: (?) 10 [4+3] (2): (?) 7 (3): 9: 9: 9: 9: 10: 9: 4: 2; paratype ♀ ( WAM T 66019), 9: (3) 8 (3): (2) 7 (2): 9: 11: 11: 11: 11: 9: 6: 2; setae on sternite II of ♀ small; setae uniseriate and acuminate; without median glandular setae; anus not surrounded by sternite XI .

Genitalia: male genitalia, identical to I. pisolitus , apart from internal genital setae arranged in a triangular group of three setae and a group of four setae: pair of setae on edge of sternite III surrounding the antero-median notch of posterior genital operculum. Female genitalia with single, broad median cribriform plate, and one pair of small lateral median cribriform plates ( Figure 28 ).

Legs: femora I and II longer than patellae I and II; femora I and II with one transverse lyrifissure situated sub-distally; femur + patella of leg IV 2.68 („), 2.98 (♀) times longer than broad; legs III and IV with articulation between femur and patella segments slightly oblique; tibiae III and IV with medial tactile seta; metatarsi III and IV with sub-basal tactile seta; diplotarsate, all legs with tarsus longer than metatarsus; subterminal tarsal setae distally serrate; arolia same length as claws, not divided; claws simple.

Dimensions (mm) of „ holotype WAM T 75203: body length 1.35. Pedipalps : trochanter 0.263 / 0.160 , femur 0.474 / 0.164, patella 0.448 / 0.224, chela (with pedicel) 0.805 / 0.287, chela (without pedicel) 0.744, hand length 0.397, movable finger length 0.358. Chelicera 0.278 / 0.133 , movable finger length 0.221. Carapace 0.512 / 0.422 . Leg I: femur 0.176 / 0.093, patella 0.175 / 0.088, tibia 0.213 / 0.058, metatarsus 0.079 / 0.037, tarsus 0.128 / 0.032. Leg IV: femur + patella 0.429 / 0.160, tibia 0.351 / 0.080, metatarsus 0.109 / 0.056, tarsus 0.180 / 0.056.

Dimensions (mm) of ♀ paratype WAM T 66019 (with other females in parentheses where relevant): body length ca 1.79 (2.31). Pedipalps : trochanter 0.307 / 0.147 (0.281– 0.346/0.189) , femur 0.528 / 0.186 (0.563–0.627/0.192–0.205), patella 0.499 / 0.250 (0.525–0.557/0.255–0.288), chela (with pedicel) 0.923 / 0.326 (0.946–1.075/0.322– 0.346), chela (without pedicel) 0.877 (0.894 –1.011), hand length 0.486 (0.510 – 0.544), movable finger length 0.391 (0.395 –0.493). Chelicera 0.318 / 0.147 , movable finger length 0.247. Carapace ca 0.595 / 0.442 (0.593 / 0.458). Leg I: femur 0.211 / 0.106, patella 0.182 / 0.099, tibia 0.262 / 0.059, metatarsus 0.100 / 0.039, tarsus 0.181 / 0.032. Leg IV: femur + patella 0.477 / 0.160, tibia 0.384 / 0.081, metatarsus 0.111 / 0.056, tarsus 0.202 / 0.048.

Remarks

Ideoblothrus nesotymbus has only been found at three locations within limestone karst on Barrow Island. One male and three females were collected from boreholes using leaf-litter baited traps placed at depths of 5– 46 m.

Figures

Figures 3, 4. (3) Ideoblothrus pisolitus sp. nov., paratype ♀ (WAM T65785). (4) I. nesotymbus sp. nov., paratype ♀ (WAM T75213).

Figures 22–28. Ideoblothrus nesotymbus sp. nov., holotype „ unless otherwise stated. (22) Carapace, paratype ♀ (WAM T66019). (23) Right pedipalp, dorsal. (24) Left chela, lateral. (25) Detail of left fixed chelal finger, lateral. (26) Detail of left movable chelal finger, lateral. (27) Coxal region, ventral, paratype ♀ (WAM T66019). (28) Female genitalia, paratype ♀ (WAM T75213). Scale bars: 0.2 mm (22, 24); 0.5 mm (23, 27); 0.1 mm (25, 26, 28).