Blakistonia bassi, 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 : 27-28

Blakistonia bassi sp. n.

( Fig. 7 A–I)

Type material. AUSTRALIA: South Australia: Holotype female, off Pound Road, Ashton, Mount Lofty Ranges ,, 34°55’55.608”S, 138°44’49.667”E, 22 December 2014, hand collected from mossy roadside bank, S.E. Harrison, M. Harrison (SAM NN29619 DNA). Paratypes: 2 females, same data as holotype except 13 May 2016, S.E. Harrison, N. Birks ( SAM NN28529 , NN28530 ) .

Diagnosis. Females of B. bassi can be distinguished from all other species of Blakistonia by the fine, golden hairs that cover the carapace ( Fig. 7A, D ). Males are unknown.

All life stages of B. bassi can also be distinguished from those of other species with sequence data by the following nucleotide substitutions (n = 1 specimen): G(3), C(87), C(102), T(111), G(199), C(205), T(207), T(255), C(339), A(390), C(462), C(479), C(481), G(546), G(573), G(591); and by the following unique molecular motifs: TT(30–31), GAC(66–68), GCT(367–369), AAG(372–374), GG(432–433), TGC(456–458), TGGA (468–471).

Description. Holotype female (SAM NN29619): Medium-sized idiopid spider (total length 18.5).

Colour (in ethanol; Fig. 7 A–C): Carapace, legs and pedipalp dark red-brown, darker around fovea and lateral margins of caput, with darkened line from fovea to eye group ( Fig. 7A ); sternum, labium and maxillae uniformly golden-brown, chelicerae dark red-brown ( Fig. 7E, F ); abdomen dark brown with indistinct mottled chevron pattern ( Fig. 7A, C ).

Cephalothorax: Carapace 7.8 long, 7.2 wide, 6.3 high, 1.1 times longer than wide; oval ( Fig. 7A ), caput high, ocular area flat ( Fig. 7C ); cuticle smooth, with pits outward from fovea and both sides of caput, and also two diagonally inward-facing indentations posteriorly; fovea procurved; two indistinct parallel rows of setae from fovea to eye group, less noticeabe both sideson both sides of caput; smaller fine setae also scattered across carapace, concentrated and form fringe around lateral margins; one long seta in fovea; median clump of thickened setae on clypeus ( Fig. 7D ); carapace with fine cover of thin golden hairs ( Fig. 7A, D ). Length of median clypeus less than 1.0; anterior margin slightly convex. Eye group 1.6 wide, 1.1 long, 0.2 of carapace width; anterior eye row strongly procurved; PLE–PLE/ALE–ALE ratio 1.1; posterior eye row slightly recurved; AME about equal in size to ALE and separated by twice diameter of ALE/AME; ALE and PLE separated by just over ALE diameter; PME similar in size to ALE/AME and about half size of PLE, and separated from PLE by about its own diameter ( Fig. 7D ). Labium without cuspules ( Fig. 7F ). Sternum 5.0 long, 3.3 wide, evenly setose with setae becoming longer towards anterior margin. Maxillae with ca. 35 cuspules on both sides ( Fig. 7E, F ).

Legs: moderately setose and diffusely spinose; distinct upright setae on distal metatarsi I, II; femora I, II, and pedipalp laterally bowed; tarsi and metatarsi I, II and palpal tarsi scopulate ( Fig. 7 G–I). Paired tarsal claws with 1 row of ventral teeth: leg I p2 (1 large, 1 small) r1 (1 large, 1 small); leg II p2 (1 large, 1 small), r2 (1 large, 2 small); right leg III p2 (2 large), r1 (1 large); right leg IV p2 (1 large, 1 small), r1 (1 large); median tarsal claw without teeth. Pedipalp claw with 1 large and 1 small tooth.

Spination: Leg I: tibia p3, r4; metatarsus p2, r5; tarsus with patch of 5 short spines scattered over ventral surface ( Fig. 7G, H ). Leg II: tibia p4, r4; metatarsus p4, r5; tarsus with patch of 3 short spines ventrally. Right leg III: patella p3; tibia p3, r3; metatarsus p12, r8; tarsus with patch of 8 spines scattered ventrally. Right leg IV: metatarsus p10, r6; tarsus with ca. 20 short spines scattered ventrally. Palp: patella p1, tibia p8, r6; tarsus p1, r1.

Leg and pedipalp measurements: Length of legs IV> II> I> III. Leg I: femur 4.3, patella 3.1, tibia 2.7, metatarsus 2.1, tarsus 1.7, total = 13.9. Leg II: femur 4.2, patella 3.1, tibia 2.6, metatarsus 1.9, total = 14.9. Leg IV (right): femur 5.5, patella 3.9, tibia 4.0, metatarsus 3.7, tarsus 2.2, total = 19.3. Pedipalp: femur 4, patella 2.2, tibia 2.1, tarsus 2.5, total = 10.8.

Abdomen: Setose, oval, one pair of very small, faint, unsclerotised dorsal sigilla; 10.7 long, 7.3 wide ( Fig. 7A ).

Genitalia: Spermathecae paired, simple, unbranched, stout and outward facing, oval-shaped with lobe on anterior end, covered in opaque, mottled brown nodules ( Fig. 7I ).

Variation (n=3): Carapace 7.8–9.0 long, 6.0–8.0 wide, no labial cuspules. Spination: Leg I: tibia p3–4, r4; metatarsus p2–3, r3–5; tarsus with 3–6 spines ventrally. Leg II: tibia p3–4, r4; metatarsus p4, r4–5; tarsus with 3–4 spines ventrally. Leg III: patella p2–3; tibia p0–3; r2–3; metatarsus p6–13, r6–8; tarsus with 8–13 spines ventrally. Leg IV: metatarsus p8–12, r3–6; tarsus with 10–20 spines ventrally. Pedipalp patella p1–2; tibia p7–8, r4–6; tarsus p1, r1–2.

Etymology. This species is named in honour of Daniel Bass, for his unwavering support of this research.

Distribution. Blakistonia bassi is known from only a single roadside cutting at Ashton in the Mount Lofty Ranges, ( Fig. 31 ). A number of active burrows were found in 2017; however, the species has not been found elsewhere in the Mount Lofty Range despite extensive historical collection, and was not discovered anywhere else as part of this project.

Remarks. The burrow ( Fig. 2D, E ) is similar to that of Idiosoma in its thin, cryptic, flap-like nature, and certainly different to the D-shaped, plug-like burrow typical of B. aurea . All burrows found were adorned with moss and cryptic in appearance ( Fig. 2D, E ).

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 7. Blakistonia bassi sp. n., holotype female (SAM NN29619): 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 31. Distributions of Blakistonia species: B. bassi sp. n. (black circle), B. hortoni sp. n. (white squares), B. bella sp. n. (white circles), and B. gemmelli sp. n. (black square).