Blakistonia mainae, Harrison & Rix & Harvey & Austin, 2018

Harrison, Sophie E., Rix, Michael G., Harvey, Mark S. & Austin, Andrew D., 2018, Systematics of the Australian spiny trapdoor spiders of the genus Blakistonia Hogg (Araneae: Idiopidae), Zootaxa 4518 (1), pp. 1-76 : 42-45

Blakistonia mainae , sp. n.

( Figs 15 A–I, 16A–F)

Type material. AUSTRALIA: Western Australia: Holotype female, Mount Ragged, Cape Arid National Park , 33°26’47”S, 123°28’15”E, 27 August 2014, hand collected from burrows, S.E. Harrison, M.S. Harvey (WAM T 141137 DNA). Paratypes: 1 female, same data except 33°26’43”S, 123°28’07”E ( WAM T 141136 DNA) ; 1 female, same data except 33°26’44”S, 123°28’08”E ( WAM T 141138 DNA) .

Other material examined. AUSTRALIA: Western Australia: 1 male (in fragments), Mount Ragged, Cape Arid National Park , 33°27’S, 123°28’E, 2 November 1986, hand collected from redback spider web, B. Main (WAM T 141143 ).

Diagnosis. Males of B. mainae can be distinguished from those of B. maryae , B. plata , B birksi , B. newtoni , B. hortoni , B. parva , B. olea , B. tariae , B. carnarvon and B. raveni , by the prolateral clasping spurs on tibia I, each with raised cuticular bases and bearing multiple terminal peg-like macrosetae ( Fig. 16 B–C); and from those of B. bella , B. pidax , B. tunstilli , B. emmottorum , B. gemmelli , and B. aurea by the presence of four thick, evenly spaced setae between the eye group and the fovea (16A). Females of B. mainae can be distinguished from those of other species by the book lungs being brown or dark brown, in contrast to the paler abdomen ( Fig. 15C ), and also by the presence of four thick, evenly spaced setae between the eye group and fovea ( Fig. 15A, D ).

All life stages of B. mainae can also be distinguished from those of other species with sequence data by the following nucleotide substitutions (n = 3 specimens): G(132), A(216), C(300), A(453), A(482), T(507); and by the following unique motifs: TG(42–43), TA(66–67), AT(90–91).

Description. Holotype female (WAM T 141137) Medium-sized idiopid spider (total length 14.6).

Colour (in ethanol; Fig. 15 A–C): Carapace, legs and pedipalp medium to dark golden-brown, carapace slightly darker around fovea ( Fig. 15A ); sternum medium golden-brown, darker towards anterior and lateral margins; labium and maxillae golden-brown, chelicerae dark brown ( Fig. 15E, F ); abdomen grey-brown with 7 chevrons of uniform width spaced over length of abdomen, becoming more closely spaced towards posterior abdomen; anterior-most chevrons connected by medial patch ( Fig. 15A, C ).

Cephalothorax: Carapace 6.7 long, 4.9 wide, 5.5 high, 1.1 times longer than wide; oval ( Fig. 15A ), caput high, ocular area very slightly raised ( Fig. 15C ); cuticle uniformly smooth; fovea procurved; four prominent, evenly spaced setae located between fovea and eye area, cluster of setae directly posterior to eye areas, and very small, fine setae also scattered across carapace, forming indistinct fringe around lateral margins; median clump of thickened setae on clypeus. Length of median clypeus less than 1.0; anterior margin slightly convex. Eye group 1.1 wide, 1 long, 0.2 of carapace width; anterior eye row strongly procurved, PLE–PLE/ALE–ALE ratio 1.0; posterior eye row straight; AME ca. half size of ALE and separated by about diameter of ALE; ALE equal in size to PLE, and separated by their diameter; PME pale, ca. 0.25 of PLE, and separated from PLE by less than its own diameter ( Fig. 15D ). Labium with two cuspules ( Fig. 15F ). Sternum 4.1 long, 2.9 wide, moderately setose with setae becoming denser and longer around margins; one pair of sigilla located ca. halfway down abdomen, and separated from lateral margins of abdomen by about their own diameter ( Fig. 15E ). Maxillae with ca. 30 cuspules on both sides ( Fig. 15E, F ).

Legs: moderately setose and spinose, with exception of retrolateral leg IV, which is mostly asetose; distinct erect setae on metatarsi and distal tibiae I, II; femora I, II, and pedipalp laterally bowed; tarsi and metatarsi I, II, and palpal tarsus heavily scopulate ( Fig. 15G, H ). Paired tarsal claws: p2 (2 large) r3 (1 large, 2 small); leg II p3 (2 large, 1 small), r2 (1 large, 1 small); right leg III p2 (2 large), r2 (1 large, 1 small); leg IV p2 (2 large) r3 (3 large); median claw without teeth. Pedipalp with 2 (1 large, 1 small) teeth.

Spination: Leg I: tibia p4, r3; metatarsus p4, r4; tarsus r2. Leg II: tibia p2, r3; metatarsus p4, r7; tarsus p1, r5. Right leg III: patella p3, metatarsus p5, r4; tarsus with 7 short spines ventrally. Leg IV: metatarsus p4, r1, tarsus with 7 short spines ventrally. Pedipalp: tibia p7, r6; tarsus p3, r3.

Leg and pedipalp measurements: Length of legs IV> I> II> III. Leg I: femur 3.7, patella 2.8, tibia 2.4, metatarsus 1.6, tarsus 1.3, total = 11.8. Leg II: femur 3.7, patella 2.5, tibia 2.2, metatarsus 1.7, tarsus 1.3, total = 11.4. Leg III: femur 3.1, patella 2.4, tibia 2.1, metatarsus 1.9, tarsus 1.4, total = 10.9. Leg IV (right): femur 4.2, patella 3.4, tibia 3.8, metatarsus 3.5, tarsus 1.8, total = 16.7. Pedipalp: femur 3.7, patella 2.2, tibia 2.3, tarsus 2.3, total = 10.4.

Abdomen: Setose, oval, one pair of unsclerotised dorsal sigilla evident; book lungs dark brownish-grey, distinctly darker than lateral abdomen; 8.2 long, 5.9 wide ( Fig. 15A ).

Genitalia: Spermathecae paired, simple, unbranched, stout and outward facing, circular, covered in opaque mottled brown nodules, becoming more concentrated towards distal spermathecae ( Fig. 15I ).

Variation (n=3): Carapace 6.4–7.1 long, carapace 5.4–5.9 wide, 2–4 labial cuspules. Spination: leg I tibia p4, r3–4; metatarsus p4, r4–5; tarsus p0–1, r2–4. Leg II tibia p2, r2–3; metatarsus p3–4, r6–7; tarsus p1, r5–7. Leg III patella p3; metatarsus p3–5, r3–5; tarsus with 5–8 short spines ventrally. Leg IV metatarsus p4–6, r1; tarsus with 7– 12 short spines ventrally. Pedipalp: tibia p7–9, tarsus r3–6.

Male (WAM T 141143). Total size unknown.

Colour (in ethanol; Fig. 16 A–F): Carapace, legs and pedipalp uniform pale golden orange-brown.

Cephalothorax: Carapace 5.8 long, 4.3 wide, 1.3 times longer than wide; oval ( Fig. 16A ), caput low, ocular area slightly raised; cuticle smooth, with pits outward from fovea and both sides of caput; fovea straight; four prominent setae located between fovea and eye area, cluster of setae also directly posterior to eye areas, and very small, fine setae also scattered across carapace, forming indistinct fringe around lateral margins; median clump of thickened setae on clypeus ( Fig. 16A ). Eye group 0.8 wide, 1.0 long, 0.2 of carapace width; anterior eye row strongly procurved, PLE–PLE/ALE–ALE ratio 1.0; posterior eye row slightly procurved; AME similar in size to ALE and separated by less than the diameter of AME; ALE and PLE separated by just over the diameter of PLE; PME oval, 0.75 of PLE, and separated from PLE by less than its own diameter ( Fig. 16A ).

Spination: Tibia I with prolateral clasping spurs, both spurs with 2 terminal peg-like macrosetae ( Fig. 16B, C ).

Pedipalp: Tibia short, swollen, RTA short and pointed, with thick clump of setae on tip, and covered in short, dense spinules almost to distal tibia, becoming sparser; long, erect setae on ventral tibia; bulb uniform, globular; embolus simple, slender, tapering, twisted, and just under twice the length of bulb; cymbium covered in rows of short spinules, becoming longer distally ( Fig. 16 D–F).

Variation: None.

Etymology. This species is named in honour of Dr Barbara York Main, for first collecting Blakistonia specimens from Mount Ragged in 1986, and for her lifelong commitment to improving our knowledge of Australian trapdoor spiders.

Distribution. Blakistonia mainae is known only from Mount Ragged, Cape Arid National Park, Western Australia ( Fig. 33 ).

Remarks. The burrows of B. mainae are round with a narrow hinge, and slightly indented ( Fig. 2G ). The male specimen on which this description was based was collected dead from a Latrodectus web and is incomplete. The female description is based on a complete specimen (WAM T 141137) and also has molecular data available thus it has been designated as the holotype.

Figures

FIGURE 2. Images of Blakistonia burrows. A, B. aurea Hogg, 1902 burrow with scalloped edge from Humbug Scrub, South Australia; B, B. aurea burrow from Parra Wirra Recreation Park, South Australia; C, B. aurea burrow, Mount Lofty Ranges, South Australia; D–E, B. bassi sp. n. burrow from Ashton, Mount Lofty Ranges, South Australia; F, B. birksi sp. n. burrow from Mark Oliphant Conservation Park, Mount Lofty Ranges, South Australia; G, B. mainae sp. n. burrow from Mount Ragged, Cape Arid National Park, Western Australia; H–I, B. maryae sp. n. burrow showing twig-lining from Scrubby Peak, Gawler Ranges, South Australia; J, B. maryae sp. n. burrow showing twig-lining from Tumby Bay, Eyre Peninsula, South Australia; K, B. maryae sp. n. burrow from Gawler Ranges, South Australia; L, B. nullarborensis sp. n. burrow from Cocklebiddy, Western Australia. All images by S. Harrison except: C by N. Birks; H, by N. Birks; I, by N. Birks; all used with permission.

FIGURE 15. Blakistonia mainae sp. n., holotype female (WAM T141137): A, habitus, dorsal view; B, habitus, ventral view; C, habitus, lateral view; D, eye group, dorsal view; E, sternum, ventral view; F, maxillae and labium, ventral view; G, left leg I, prolateral view; H, left leg I, retrolateral view; J, spermathecae. Scale bars = 5 mm (A), 2 mm (G).

FIGURE 16. Blakistonia mainae sp. n., male (WAM T141143): A, carapace, dorsal view; B, left leg I, clasping spurs, prolateral view; C, left leg I, dorsal view; D, right pedipalp, prolateral view; E, left pedipalp, retrolateral view; F, left pedipalp, proventral view. Scale bars = 2 mm (A, B), 1 mm (D).

FIGURE 33. Distribution of Blakistonia species: B. mainae sp. n. (white circle), B. wingellina sp. n. (white triangle), B. olea sp. n. (white square), B. nullarborensis sp. n. (black squares), Blakistonia ‘sp. 1’ (black circle), and B. tariae sp. n. (black triangles).