Ideoblothrus aeesti, 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 : 462-465

Ideoblothrus aeesti sp. nov.

( Figures 29–35 )

Material examined

Holotype: ♀, Australia: Western Australia: Fortescue River , borehole B7, in the alluvials, 21 ° 039170S, 116 ° 099350E, 29 March 2001, P. L. West ( WAM T 71319).

Etymology

This species is named for Paul West, collector of the holotype.

Diagnosis

Ideoblothrus aeesti is amongst the smallest species of the genus [e.g. pedipalpal patella 0.30 mm (♀)] and, amongst the Australasian species, is of similar size to I. descartes and I. pugil (e.g. pedipalpal patella 0.30–0.32 mm). It is larger than I. milikapiti , I. palauensis , and I. bipectinatus (e.g. pedipalpal patella 0.20–0.22 mm). Ideoblothrus aeesti differs from similarly sized species of the genus by the shape of the pedipalpal chela, which is rather stout and the externo-basal margin of the chelal hand is distinctly angulate.

Description

Adult female. Colour: pedipalps reddish brown, legs pale yellow brown, rest of body pale yellow.

Chelicera ( Figure 32 ): five setae on hand, all setae acuminate, is very long, ls, sbs, bs, and es short; movable finger with one sub-distal seta; fixed finger with ca eight teeth; movable finger with ca four teeth; with two dorsal lyrifissures and one ventral lyrifissure; galea long, slightly curved and extends to tip of galeal seta; flagellum of five blades, distal blade broadened and finely denticulate; serrula exterior with ca 15 blades.

Pedipalp ( Figure 30 ): mostly smooth, with only the internal margins of patella and chela with sparse fine granulations; setae on internal margins very long and acicular; trochanter without tubercles; trochanter 1.80, femur 2.69, patella 2.00, chela (with pedicel) 2.60, chela (without pedicel) 2.50, hand 1.35 times longer than broad, movable finger 0.82 times longer than hand. Femur without tactile setae; without basal projection. Patella with one lyrifissure situated dorsally near pedicel. Fixed chelal finger with eight trichobothria, movable chelal finger with four trichobothria ( Figure 31 ): eb and esb situated close together on lateral margin of hand, isb situated medially at base of finger, slightly basal to ib; est situated near ist and it; et sub-distal; single sensory pit between sb and st; microsetae (chemosensory setae) absent on both fingers; trichobothrium b of movable finger situated sub-basally; sb, st, and t situated medially, close to each other; t lanceolate, slightly shortened, and bent backward. Venom apparatus present only in fixed chelal finger, venom duct very short, nodus ramosus inflated. Chelal teeth of both fingers with flattened edges; fixed finger with 13 teeth, tooth row terminating slightly basal to et; movable finger with ca 27 teeth; accessory teeth absent. External and internal chelal condyles small and rounded.

Cephalothorax: carapace ( Figure 29 ) 1.22 times longer than broad; sub-rectangular; without any traces of eyes; epistome very small; with 25 setae arranged 4: 4: 4: 6: 7; without furrows; with four pairs of small lyrifissures, first and second pairs placed near anterior margin, third pair placed sub-medially, and fourth pair placed near edge of posterior row. Manducatory process with one long distal and one long sub-distal seta, without sub-oral seta ( Figure 35 ); remainder of maxilla with six setae. Chaetotaxy of coxae I–IV: 5: 4: 5: 5.

Abdomen: pleural membrane granulo-striate near cephalothorax, remainder longitudinally striate, without setae. Tergites and sternites undivided. Tergal chaetotaxy: 6: 9: 8: 8: 9: 9: 9: 9: 9: 9: 7: 2; setae uniseriate and acuminate. Sternal chaetotaxy: 4: (1) 4 (1): (2) 6 (2): 9: 11: 11: 11: 9: 9: 4: 2; setae on sternite II of ♀ small; setae uniseriate and acuminate, without medial glandular setae; anus not surrounded by sternite XI.

Genitalia: female genitalia not visible in preparation.

Legs ( Figures 33, 34 ): 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 2.92 times longer than broad; legs III and IV with articulation between femur and patella segments slightly oblique; tibiae III and IV with one medial and one sub-distal tactile seta; metatarsi III and IV with subbasal tactile seta; diplotarsate, all legs with tarsus longer than metatarsus; subterminal tarsal setae distally serrate; arolia slightly longer than claws, not divided; claws simple.

Dimensions (mm) of ♀ holotype WAM T 71319: body length 1.883. Pedipalps : trochanter 0.167 / 0.093 , femur 0.293 / 0.109, patella 0.300 / 0.150, chela (with pedicel) 0.492 / 0.189, chela (without pedicel) 0.472, hand length 0.255, movable finger length 0.208. Chelicera 0.177 / 0.086 , movable finger length 0.137. Carapace 0.339 / 0.278 . Leg I: femur 0.110 / 0.060, patella 0.096 / 0.058, tibia 0.130 / 0.040, metatarsus 0.054 / 0.027, tarsus 0.061 / 0.022. Leg IV: femur + patella 0.228 / 0.078, tibia 0.171 / 0.045, metatarsus 0.063 / 0.033, tarsus 0.075 / 0.031.

Remarks

Ideoblothrus aeesti is known from a single location situated in the Fortescue River in the Pilbara region of Western Australia ( Figure 2 ).

Figures

Figures 29–35. Ideoblothrus aeesti sp. nov., holotype ♀. (29) Carapace. (30) Right pedipalp, dorsal. (31) Left chela, lateral. (32) Left chelicera, dorsal. (33) Leg I. (34) Leg IV. (35) Coxal region, ventral. Scale bars: 0.2 mm (29–31, 35); 0.1 mm (32–34).

Figures 1, 2. Known distributions of Ideoblothrus species in Western Australia and Northern Territory.