Ideoblothrus descartes, Harvey & Edward, 2007

Ideoblothrus descartes View in CoL sp. nov.

( Figures 36–41 View Figures 36–41 )

Material examined

Holotype: „, Australia: Western Australia: Descartes Island , site DERT01 , 14 ° 099500S, 125 ° 409470E, near freshwater seep, under rocks, 30 August 2002, M. S. Harvey and R. J. Teale ( WAM T 70785). Paratypes: Australia: Western Australia: 1 „, 2♀, same data as holotype ( WAM T 70787– T 70789).

Etymology

The specific epithet is a noun in apposition taken from the type locality, Descartes Island. This island was originally named for the famed French philosopher, mathematician and scientist, René Descartes (1596–1650).

Diagnosis

Ideoblothrus descartes is a medium-sized species of the genus [e.g. pedipalpal patella 0.31– 0.32 mm ( „), 0.30–0.31 ( ♀)], notably larger than I. bipectinatus , I. palauensis , and I. milikapiti (patella 0.20–0.22 mm), and smaller than I. aeoodi , I. papillon , I. pisolitus , I. nesotymbus , and I. pugil robustus (patella greater than 0.40 mm). It is approximately the same size as I. pugil [patella 0.33 mm ( „)], I. ceylonicus (patella 0.28–0.36 mm), and I. aeesti [patella 0.30 mm ( ♀)], differing from I. pugil by the longer chelal hand versus movable finger ratio ( 0.94–0.99 in I. descartes and 0.71 in I. pugil ), from I. ceylonicus by the slightly stouter chela [chela (with pedicel) 2.61–2.68 ( „), 2.60–2.64 ( ♀) in I. descartes and 2.7–3.0 in I. ceylonicus ] and from I. aeesti by the lack of a strongly angulate externo-basal margin of the chelal hand.

Description

Adults. Colour: pedipalps red orange, carapace, chelicera, and coxae yellow orange, rest of body pale yellow.

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 10 teeth; movable finger with six teeth; with two dorsal lyrifissures and one ventral lyrifissure; male galea short, only very slightly curved and not extending to tip of galeal seta; female galea long, curved and extends to tip of galeal seta; flagellum of five blades, distal blade broadened and finely denticulate; serrula exterior with 21–23 ( „), 22 ( ♀) blades.

Pedipalp ( Figure 37 View Figures 36–41 ): internal margins of trochanter, femur, patella and chela with fine granulations; setae on internal margins long and acicular; trochanter without tubercles; trochanter 1.77–1.93 ( „), 1.85–1.91 ( ♀), femur 2.43–2.60 ( „), 2.54–2.58 ( ♀), patella 1.80– 1.83 ( „), 1.78–1.89 ( ♀), chela (with pedicel) 2.61–2.68 ( „), 2.60–2.64 ( ♀), chela (without pedicel) 2.41–2.48 ( „), 2.46–2.50 ( ♀), hand 1.25–1.29 ( „), 1.26–1.28 ( ♀) times longer than broad; movable finger 0.94–0.99 ( „), 0.94–0.95 ( ♀) times longer than hand. Femur without tactile setae; without basal projection. Patella with four lyrifissures, two situated dorsally near pedicel, and two situated distally. Fixed chelal finger with eight trichobothria, movable chelal finger with four trichobothria ( Figure 38 View Figures 36–41 ): eb, esb, isb, and ib forming an oblique row on basolateral margin of fixed finger; ist, est, and it situated close together forming a triangle; est situated adjacent to ist; et sub-distal; six small lanceolate setae present on fixed chelal finger; 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. Fixed finger with 23 ( „), 25 ( ♀) slightly retrorse teeth, only extending to level of est ( Figure 40 View Figures 36–41 ); movable finger with 32 ( „), 37 ( ♀) rounded teeth, extending nearly to full length of finger ( Figure 41 View Figures 36–41 ); accessory teeth absent. External and internal chelal condyles small and rounded.

Cephalothorax: carapace ( Figure 36 View Figures 36–41 ) 1.26–1.29 ( „), 1.29–1.32 ( ♀) times longer than broad; sub-rectangular; without any traces of eyes; epistome present; three specimens (including holotype „) with 24 setae arranged 4: 4: 4: 6: 6, one specimen ( paratype ♀) with 25 setae arranged 4: 4: 5: 6: 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 edge of posterior row. Manducatory process with one long distal and one long sub-distal seta, without sub-oral seta; remainder of maxilla with nine setae ( Figure 41 View Figures 36–41 ). Chaetotaxy of coxae I–IV: 6: 5: 4: 7 ( „), 6–7: 5: 5–6: 6–7 ( ♀).

Abdomen: pleural membrane granulo-striate near cephalothorax, remainder longitudinally striate, without setae. Tergites and sternites undivided. Tergal chaetotaxy: holotype „, 6: 7: 9: 9: 9: 9: 9: 9: 9: 7: 6: 2; paratype ♀ ( WAM T 70789), 6: 8: 9: 9: 9: 9: 9: 9: 9: 7: 7: 2; setae uniseriate and acuminate. Sternal chaetotaxy: holotype „, 7: (2) 10 [3+3] (2): (2) 7 (2): 11: 11: 11: 11: 11: 11: 6: 2; paratype ♀ ( WAM T 70789), 6: (2) 7 (2): (2) 8 (2): 11: 12: 12: 11: 11: 11: 6: 2; setae on sternite II of ♀ small; setae uniseriate and acuminate, without medial glandular setae; anus not surrounded by sternite XI .

Genitalia: male genitalia, as far as can be discerned, identical to I. pisolitus ; internal genital glandular setae arranged in two triangular groups of three; pair of setae on edge of sternite III surrounding the antero-median notch of the posterior genital operculum. Female genitalia with single, broad median cribriform plate, and one pair of slender lateral median cribriform plates.

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 2.64 ( „), 2.73 ( ♀) 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 not distally serrate; arolia same length as claws, not divided; claws simple.

Dimensions (mm) of „ holotype WAM T 70785 (with „ paratype WAM T 70787 in parentheses, where applicable): body length 1.82 (1.34). Pedipalps: trochanter 0.188 / 0.106 ( 0.195 / 0.101), femur 0.321 / 0.089 ( 0.340 / 0.131), patella 0.311 / 0.170 ( 0.317 / 0.176), chela (with pedicel) 0.543 / 0.208 ( 0.573 / 0.214), chela (without pedicel) 0.502 (0.531), hand length 0.259 (0.275), movable finger length 0.256 (0.258). Chelicera 0.215 / 0.101 GoogleMaps , movable finger length 0.159. Carapace 0.397 / 0.314 ( 0.406 / 0.314). Leg I: femur 0.127 / 0.075, patella 0.104 / 0.068, tibia 0.148 / 0.044, metatarsus 0.058 / 0.032, tarsus 0.107 / 0.029. Leg IV: femur + patella 0.285 / 0.108, tibia 0.221 / 0.064, metatarsus 0.076 / 0.042, tarsus 0.118 / 0.038.

Dimensions (mm) of ♀ paratype WAM T 70789 (with ♀ paratype WAM T 70788 in parentheses, where applicable): body length 1.74 (0.173). Pedipalps: trochanter 0.195 / 0.102 ( 0.189 / 0.102), femur 0.330 / 0.130 ( 0.322 / 0.125), patella 0.302 / 0.170 ( 0.314 / 0.166), chela (with pedicel) 0.557 / 0.211 ( 0.554 / 0.213), chela (without pedicel) 0.518 (0.526), hand length 0.269 (0.269), movable finger length 0.256 (0.253). Chelicera 0.222 / 0.099 GoogleMaps , movable finger length 0.162. Carapace 0.422 / 0.321 ( 0.378 / 0.294). Leg I: femur 0.129 / 0.068, patella 0.100 / 0.065, tibia 0.151 / 0.045, metatarsus 0.052 / 0.032, tarsus 0.096 / 0.028. Leg IV: femur + patella 0.284 / 0.104, tibia 0.222 / 0.062, metatarsus 0.069 / 0.042, tarsus 0.118 / 0.036.

Remarks

Ideoblothrus descartes was collected from under rocks at the base of a freshwater seep in Descartes Island, in the Kimberley region of Western Australia ( Figure 1 View Figures 1, 2 ).