Australian Journal of
Taxonomy
Open-access, online, rapid taxonomy
This is a page from an unpublished manuscript
Please do not distribute it without express permission of the lead author
Holotype: AUSTRALIA: Western Australia: ♂, Mt Meharry, Karijini National Park, 22°58′46.86″S, 118°35′20.29″E, 31 May–1 June 2021, under Ptilotus obovatus, B. Durrant, N. Gunawardene, M.S. Harvey, M.K. Curran (WAM T157112).
Paratypes: AUSTRALIA: Western Australia: 6 ♂, 2 ♀, 3 tritonymphs, collected with holotype (WAM T153976–153979, T157113–157118).
Figures 1–2. 1, The type locality of Nesidiochernes fissuricola, sp. nov. near the summit of Mt Meharry, Western Australia. 2, a female specimen of Nesidiochernes fissuricola, sp. nov. (image courtesy of Bradley Durrant).
Figures 3–8. Nesidiochernes fissuricola, sp. nov.: 3–5, male paratype (WAM T157115): 3, dorsal view; 4, ventral view; 5, cephalothorax, dorsal view; 6–8, female paratype (WAM T157117): 6, dorsal view; 7, ventral view; 8, cephalothorax, dorsal view. Scale lines = 1 mm (Figures 3, 4, 6, 7), 0.2 mm (Figures 5, 8).
Figures 9–18. Nesidiochernes fissuricola, sp. nov., male holotype (WAM T157112), unless stated otherwise: 9, carapace, dorsal view; 10, right chelicera, dorsal view; 11, left galea, lateral view; 12, left galea, lateral view, female paratype (WAM T157113); 13, left rallum, lateral view; 14, right pedipalp, dorsal view; 15, left chela, lateral view; 16, left chelal teeth, lateral view; 17, left chela, lateral view, tritonymph paratype (WAM T157118); 18, left leg IV, lateral view. Scale lines = 0.5 mm (Figure 14), 0.2 mm (Figures 9, 10, 15, 17, 18), 0.05 mm (Figures 11–13).
Figures 19–21. Nesidiochernes fissuricola, sp. nov.: 19, genital sternites, ventral view, male holotype (WAM T157112); 20, genital sternites, ventral view, female paratype (WAM T157113); 21, spermathecae, ventral view, female paratype (WAM T157118). Scale lines = 0.1 mm.
Diagnosis
Nesidiochernes fissuricola can be differentiated from other species of the genus as follows: from N. australicus, N. carolinensis, N. carolinensis dybasi, N. kuscheli, N. maculatus, N. palauensis, N. tumidimanus and N. zealandicus by the position of trichobothrium st which is situated midway between sb and t (st closer to t in the other species) and from N. robustus which has st situated much closer to sb than to t; from N. insociabilis by the presence of trichobothrium st (absent in N. insociabilis); from N. australicus, N. caledonicus, N. carolinensis, N. palauensis, N. plurisetosus and N. tumidimanus by trichobothrium isb being situated midway between it and ist (Figures 14, 15) (isb closer to it than ist in other species); from N. carolinensis, N. insociabilis, N. novaeguineae, N. palauensis, N. plurisetosus, N. robustus, N. scutulatus and N. tumidimanus by trichobothrium est being situated midway between it and ist (Figures 14, 15) (est closer to esb than et in other species); and from N. slateri by the shape of chelal hand which is broadened posteriorly in N. fissuricola (Figure 14) but is uniformly oval in N. slateri.
Adults
Colour: most cuticular surfaces dark red-brown; legs yellow-brown (Figures 2–8).
Chelicera: with 6 setae on hand and 1 subdistal seta on movable finger (Figure 10); setae es, ls, bs and is acuminate, sbs′ and sbs″ dentate; with 2 dorsal lyrifissures and 1 ventral lyrifissure; galea stout with 3 (♂), 5 (♀) distal to subdistal rami (Figures 11, 12); rallum composed of 3 blades, anterior blade dentate, 2 posterior blades smooth (Figure 13); serrula exterior with 14 (♂), 14 (♀) blades; lamina exterior present.
Pedipalp (Figure 14): all surfaces granulate, except for smooth chelal fingers; all segments robust, trochanter 0.30–0.34 (♂, ♀), femur 0.41–0.53 (♂), 0.51–0.54 (♀), patella 0.48–0.54 (♂), 0.51–0.53 (♀), chela (with pedicel) 0.88–0.96 (♂), 0.92–0.97 (♀), chela (without pedicel) 0.89–0.90 (♂), 0.83–0.92 (♀), hand (without pedicel) 1.25–1.42 (♂), 1.46–1.59 (♀) × longer than broad, movable finger 0.38–0.45 (♂), 0.38–0.40 (♀) × longer than hand (without pedicel). Fixed chelal finger with 8 trichobothria, movable chelal finger with 4 trichobothria (Figure 14): eb and esb situated basally; est midway between esb and et (especially in lateral view); ib and ist subbasally; it situated midway between et and est; isb situated midway between ist and it; t situated subdistally; st situated midway between sb and t; and sb situated much closer to b than to st. Fixed and movable fingers without pseudotactile setae (Figure 15). Venom apparatus only present in movable chelal finger, venom duct long, terminating in nodus ramosus adjacent to st. Fingers not gaping (Figure 15). Chelal teeth juxtadentate, rounded (Figure 16); fixed finger with 30 (♂), 35 (♀) teeth, plus 4 (♂), 7 (♀) retrolateral and 4 (♂), 1 (♀) prolateral accessory teeth; movable finger with 33 (♂), 34 (♀) teeth, with 5 (♂), 7 (♀) retrolateral and 1 (♂), 0 (♀) prolateral accessory teeth; sense spots: fixed chelal finger with 6 (♂), 3 (♀) retrolateral and 7 (♂), 5 (♀) prolateral; movable chelal finger with 5 (♂), 2 (♀) retrolateral and 4 (♂), 1 (♀) prolateral.
Carapace (Figure 8): evenly granulate; 0.59–0.69 (♂), 0.68–0.74 (♀) × longer than broad; with 1 pair of small, very faint eye-spots; with setae arranged: 4 (♂), 4 (♀) near anterior margin; 29 (♂), 24 (♀) in prozone; 18 (♂), 24 (♀) in mesozone; and 8 (♂, ♀) in metazone; with 2 distinct furrows, posterior furrow situated closer to posterior margin of carapace than to anterior furrow; posterior margin straight.
Coxal region: maxillae granulate; dorsolateral region of coxae I–IV granulate, other surfaces smooth; manducatory process somewhat pointed, with 2 apical to sub-apical acuminate setae, 1 small sub-oral seta, and 20 (♂, ♀) additional setae; median maxillary lyrifissure rounded and situated submedially; posterior maxillary lyrifissure rounded. Chaetotaxy of coxae I–IV: ♂, 12: 11: 13: 23; ♀, 12: 13: 13: 34.
Legs: junction between femora and patellae I and II strongly oblique to long axis; junction between femora and patellae III and IV very angulate; femora III and IV much smaller than patellae III and IV (Figure 18); femur + patella of leg IV 3.54 (♂), 4.72 (♀) × longer than deep (Figure 18); patella and tibia III and IV without pseudotactile setae; tarsi III and IV without tactile seta (Figure 18); tarsi with single raised slit sensillum; subterminal tarsal setae arcuate and acute; claws not modified; arolium slightly shorter than claws.
Abdomen: tergites granulate; tergites I–X and sternites IV–X with medial suture line (Figures 3, 4, 6, 7). Tergal chaetotaxy: ♂, 10: 10: 10: 11: 11: 12: 12: 12: 12: 10: 6: 2; ♀, 12: 11: 12: 14: 14: 12: 12: 13: 14: 10: 5: 2; setae short and dentate. Sternal chaetotaxy: ♂, 25: 13: (2) 8 (2): (2) 12 (2): 14: 12: 11: 11: 12: 7: 2; ♀, 21: (3) 10 (3): (3) 9 (3): 13: 13: 13: 13: 12: 10: 5: 2: 2. Male with setae broadly arranged over sternite II and with setae widely scattered over sternite III (Figure 19); female with setae arranged in inverted-U on sternite II, but without setae on posterior margin, and with setae on posterior margin of sternite III (Figure 20). Pleural membrane wrinkled; without setae.
Genitalia: male of typical chernetid morphology; female with paired spermathecae with a pair of anteriorly directed receptacula and smaller pair of posterior receptacula (Figure 21).
Dimensions (mm): holotype male (WAM T157112), followed by 6 other paratype males (when measured) in parentheses: Body length 2.22 (1.58–2.06). Pedipalps: trochanter 0.340/0.185 (0.300–0.320/0.170–0.210), femur 0.410/0.210 (0.480–0.530/0.205–0.280), patella 0.510/0.290 (0.480–0.520/0.245–0.380), chela (with pedicel) 0.960/0.345 (0.880–0.940/0.360–0.400), chela (without pedicel) 0.880 (0.855–0.900), hand (without pedicel) length 0.490 (0.430–0.500), movable finger length 0.385 (0.380–0.450). Carapace 0.690/0.580 (0.585–0.660/0.525–0.550); anterior eye 0.110. Leg IV: femur + patella 0.495/0.140, tibia 0.385/0.095, tarsus 0.300/0.060.
Dimensions (mm): paratype female (WAM T157113), followed by one other paratype female (when measured) in parentheses: Body length 3.18 (2.90). Pedipalps: trochanter 0.300/0.175 (0.340/0.190), femur 0.510/0.200 (0.540/0.225), patella 0.510/0.235 (0.530/0.280), chela (with pedicel) 0.915/0.290 (0.970/0.335), chela (without pedicel) 0.825 (0.920), hand (without pedicel) length 0.460 (0.520), movable finger length 0.380 (0.400). Carapace 0.680/0.530 (0.735/0.580); eye diameter 0.065. Leg IV: femur + patella 0.470/0.100, tibia 0.485/0.080, tarsus 0.295/0.060.
Tritonymph
Colour: most cuticular surfaces pale red-brown; legs yellow-brown.
Chelicera: with 6 setae on hand and 1 subdistal seta on movable finger; setae es, ls and is acuminate, bs and sbs dentate; galea with 5 distal to subdistal rami; rallum composed of 3 blades, anterior blade dentate, 2 posterior blades smooth.
Pedipalp: all surfaces granulate except fingers; trochanter 2.73, femur 2.42, patella 1.78, chela (with pedicel) 2.71, chela (without pedicel) 2.54, hand (without pedicel) 1.24 × longer than broad, movable finger 0.95 × longer than hand (without pedicel). Fixed chelal finger with 7 trichobothria, movable chelal finger with 3 trichobothria (Figure 16): eb and esb situated basally; est situated midway between esb and et; ib and ist subbasally; it situated midway between et and est; st situated midway between b and t. Venom duct long, terminating in nodus ramosus near t. Chelal teeth juxtadentate; fixed finger with 28 teeth, plus 2 retrolateral and 1 prolateral accessory teeth; movable finger with 31 teeth, plus 2 retrolateral and 1 prolateral accessory teeth; sense spots absent on both fingers.
Carapace: evenly granulate; 1.41 × longer than broad; with 1 pair of small, very faint eye-spots; with setae arranged: 4 near anterior margin; 26 in prozone; 18 in mesozone; and 8 in metazone; with 2 furrows, posterior furrow situated closer to posterior margin of carapace than to anterior furrow; posterior margin straight.
Coxal region: maxillae with 2 apical to sub-apical acuminate setae, 1 small sub-oral seta, and 15 additional setae. Chaetotaxy of coxae I–IV: 9: 9: 10: 13.
Legs: very similar to adults.
Abdomen: tergites granulate; tergites I–X and sternites II–X with median suture line. Tergal chaetotaxy: 8: 9: 10: 9: 12: 11: 10: 11: 10: 9: 6: 2. Sternal chaetotaxy: 5: (2) 7 (2): (2) 8 (2): 10: 11: 10: 10: 10: 9: 5: 2.
Dimensions (mm): paratype (WAM T157118): Body length 0.99. Pedipalps: trochanter 0.300/0.110, femur 0.435/0.180, patella 0.410/0.230, chela (with pedicel) 0.800/0.295, chela (without pedicel) 0.750, hand (without pedicel) length 0.385, movable finger length 0.365. Carapace 0.620/0.440; anterior eye 0.010.
Figures 1–2. 1, The type locality of Nesidiochernes fissuricola, sp. nov. near the summit of Mt Meharry, Western Australia. 2, a female specimen of Nesidiochernes fissuricola, sp. nov. (image courtesy of Bradley Durrant).
Figures 3–8. Nesidiochernes fissuricola, sp. nov.: 3–5, male paratype (WAM T157115): 3, dorsal view; 4, ventral view; 5, cephalothorax, dorsal view; 6–8, female paratype (WAM T157117): 6, dorsal view; 7, ventral view; 8, cephalothorax, dorsal view. Scale lines = 1 mm (Figures 3, 4, 6, 7), 0.2 mm (Figures 5, 8).
Figures 9–18. Nesidiochernes fissuricola, sp. nov., male holotype (WAM T157112), unless stated otherwise: 9, carapace, dorsal view; 10, right chelicera, dorsal view; 11, left galea, lateral view; 12, left galea, lateral view, female paratype (WAM T157113); 13, left rallum, lateral view; 14, right pedipalp, dorsal view; 15, left chela, lateral view; 16, left chelal teeth, lateral view; 17, left chela, lateral view, tritonymph paratype (WAM T157118); 18, left leg IV, lateral view. Scale lines = 0.5 mm (Figure 14), 0.2 mm (Figures 9, 10, 15, 17, 18), 0.05 mm (Figures 11–13).
Figures 19–21. Nesidiochernes fissuricola, sp. nov.: 19, genital sternites, ventral view, male holotype (WAM T157112); 20, genital sternites, ventral view, female paratype (WAM T157113); 21, spermathecae, ventral view, female paratype (WAM T157118). Scale lines = 0.1 mm.
Remarks
Nesidiochernes fissuricola was collected from leaf litter under cotton bush [Ptilotus obovatus (Gaudich.) F.Muell.] in a deep, sheltered cleft situated within 100 m of the summit of Mt Meharry (the tallest mountain in Western Australia at 1,249 m a.s.l.).
Specimens of the genus Nesidiochernes have been collected from a wide variety of localities and habitats throughout mainland Australia (see Atlas of Living Australia website, https://bie.ala.org.au/species/https://biodiversity.org.au/afd/taxa/a22eaaee-3e7a-49fc-8b34-837468f97b6b, accessed 13 July 2024). We have compared the specimens of N. fissuricola from Mt Meharry with museum samples from other parts of Australia and could not locate any conspecific specimens. Most importantly, this was true for four other collections from the Pilbara region (near Pannawonica, near Mt Sheila, Marillana Creek, and Roy Hill) which comprised at least two different species, highlighting the unrecorded diversity of Nesidiochernes in the Pilbara region of Western Australia.
Sequence data
We obtained sequence data for a single specimen (WAM T157117, female) of N. fissuricola, which is available under the GenBank accession number: OR653650.
Etymology
The species epithet is an adjective that refers to this species preference for living in fissures or clefts (fissura, Latin, crack, cleft, chink; colus, Latin, dwelling in, living among) (Brown 1956).