Blakistonia tunstilli, 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 : 64-66

Blakistonia tunstilli , sp. n.

( Fig. 27 A–L)

Type material. AUSTRALIA: South Australia: Holotype male, Relief Bore, Tallaringa Conservation Park, Great Victoria Desert , 28°13’S, 133°22’E, 2–7 October 1993, pitfall, Australian and New Zealand Scientific Exploration Society (SAM NN20068 ). Paratype: 1 male, same data ( SAM NN20069 ) ; 1 male, same data except 28°14’S, 133°20’E ( SAM NN20080 ) .

Diagnosis. Males of B. tunstilli can be distinguished from those of B. maryae , B. plata , B birksi , B. newtoni , B. hortoni , B. parva , B. maryae , B. olea , B. tariae , B. carnarvon and B. raveni by the presence of prolateral clasping spurs on tibia I, each with raised cuticular bases and bearing multiple terminal peg-like macrosetae ( Fig. 27 G–I); from those of B. bella by the absence of a dark dorsal cardiac stripe ( Fig. 27A ); from those of B. pidax by the presence of spinules on the cymbium ( Fig. 27 J–L); and from those of B. emmottorum , B. gemmelli , and B. aurea by the spinules on the palpal tibia being much shorter than those on the RTA ( Fig. 27A ). Females are unknown.

Description. Holotype male (SAM NN20080). Medium-sized idiopid spider (total length 11.6).

Colour (in ethanol; Fig. 27 A–C): Carapace, legs and pedipalp uniform pale golden orange-brown ( Fig. 27A ); sternum, labium and maxillae very similar colour, chelicerae slightly darker orange-brown ( Fig. 27E, F ); abdomen same golden orange-brown, covered by seven greyish brown mottled chevrons along entire dorsum ( Fig. 27A, C .

Cephalothorax: Carapace 5.5 long, 4.4 wide, 3.4 high, 1.3 times longer than wide; oval ( Fig. 27A ), caput low, ocular area slightly raised ( Fig. 27C ); cuticle smooth, with pits outward from fovea and both sides of caput; fovea straight; defined row of setae from behind eye group to about one-third of distance between fovea and eye group; two lines of setae also diagonally backwards and outwards from fovea, with setae concentrated and forming fringe around lateral margins; median clump of thickened setae on clypeus ( Fig. 27D ). Length of median clypeus less than 1.0; anterior margin slightly convex. Eye group 0.9 wide, 0.7 long, 0.2 of carapace width; anterior eye row strongly procurved, PLE–PLE/ALE–ALE ratio 1.2; posterior eye row straight; AME ca. two-thirds of ALE and separated by about half ALE; ALE and PLE separated by about ALE diameter; PME about two-thirds of AME and about half of PLE. PLE and PME both pale and directly adjacent ( Fig. 27D ). Labium without cuspules ( Fig. 27F ). Sternum 3.2 long, 2.0 wide, evenly setose ( Fig. 27E ). Maxillae without cuspules ( Fig. 27E, F ).

Legs: moderately setose; I and II without macrosetae or spines, legs III and IV with few spines; tarsi I, II ventrally swollen; tarsi I, II weakly scopulate ( Fig. 27 G–I). Paired tarsal claws: leg I p7 (7 large) r5 (5 large); leg II p5 (5 large), r5 (5 large); leg III p5 (5 large), r5 (4 large, 1 small); leg IV p4 (4 large), r5 (5 large).

Spination: Spination: Tibia I with prolateral clasping spurs, distal-most spur with 2 terminal peg-like macrosetae, proximal-most with 4 terminal peg-like macrosetae ( Fig. 27 G–I). Leg II without spines. Leg III: patella p5; metatarsus p1, r3. Leg IV: metatarsus p4, r1.

Leg and pedipalp measurements: Length of legs IV> I> II> III. Leg I: femur 5.2, patella 2.4, tibia 3.5, metatarsus 3.5, tarsus 2.2, total = 16.6. Leg II: femur 4.5, patella 2.3, tibia 3.3, metatarsus 3.4, tarsus 2.0, total = 15.5. Leg III: femur 4.0, patella 1.8, tibia 2.9, metatarsus 3.7, tarsus 2.2, total = 14.6. Leg IV (right): femur 5.5, patella 2.7, tibia 4.9, metatarsus 5.4, tarsus 2.2, total = 20.6. Pedipalp: femur 3.2, patella 1.6, tibia 2.6, tarsus 1.3, total = 10.2.

Pedipalp: All segments without spines; patella with thickened ventral setae; tibia short and swollen, RTA short and pointed, covered in short, dense spinules almost to distal tibia, becoming sparser towards distal tibia; long, erect setae on ventral tibia; bulb uniform, globular; embolus simple, slender, tapering, slightly twisted with flanged tip, slightly longer than length of bulb; cymbium covered in rows of short spinules, becoming longer closer to distal edge ( Fig. 27 J–L).

Abdomen: Setose, oval, dorsal sigilla not evident; 6.1 long, 3.5 wide ( Fig. 27A ).

Variation (n=3): Carapace 5.3–6.1 long, 4.3–4.8 wide, no labial cuspules. Spination: leg III: patella p4–6, metatarsus p0–1, r3–4. Leg IV: metatarsus p3–4, r0–1, tarsus p0–1.

Etymology. This species is named in honour of Guy Tunstill, for his dedication to preserving and teaching indigenous languages, as well as for his knowledge of Australian wildlife.

Distribution. Blakistonia tunstilli is known only from Tallaringa Conservation Park, south-west of Lake Eyre in central South Australia ( Fig. 32 ).

Remarks. The specimens of this species were pitfall trapped in vegetation including Acacia aneura , Eucalyptus , Waitzia and Eremophila .

Figures

FIGURE 27. Blakistonia tunstilli sp. n., holotype male (SAM NN20068): 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, clasping spurs, prolateral view; I, left leg I, ventral view; J, left pedipalp, prolateral view; K, left pedipalp, retrolateral view; L, left pedipalp, proventral view. Scale bars = 2 mm (A, G), 1 mm (J).

FIGURE 32. Distributions of Blakistonia species: B. birksi sp. n. (black circles), B. maryae sp. n. (white circles), B. tunstilli sp. n. (white triangle), B. newtoni sp. n. (black square), B. pidax sp. n. (black triangle) and B. parva sp. n. (white square).