Blakistonia pidax, 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 : 57-58

publication ID	https://doi.org/ 10.11646/zootaxa.4518.1.1
publication LSID	lsid:zoobank.org:pub:708981EF-21DC-4DC2-B1CD-8CFF4373DA8C
DOI	https://doi.org/10.5281/zenodo.5967827
persistent identifier	https://treatment.plazi.org/id/03C10411-556F-FFFF-E1E8-FF66FD79FF46
treatment provided by	Plazi
scientific name	Blakistonia pidax
status	sp. nov.

Treatment

Blakistonia pidax View in CoL , sp. n.

( Fig. 23 View FIGURE 23 A–L)

Type material. AUSTRALIA: South Australia: GoogleMaps Holotype male, Strangways Springs GoogleMaps , 29°08’14”S, 136°34’00”E, 25–30 September 1995, pitfall trap, D.E.L.M. Stony Deserts Survey (SAM NN20064 View Materials DNA). Paratype: 1 male, same data ( SAM NN20065 ) GoogleMaps .

Diagnosis. Males of B. pidax 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. 23 View FIGURE 23 G–I); and from those of B. bella , B. tunstilli , B. emmottorum , B. gemmelli and B. aurea by the absence of spinules on the cymbium ( Fig. 23 View FIGURE 23 J–L). Females are unknown.

All life stages of B. pidax can also be distinguished from those of other species with sequence data by the following nucleotide substitutions (n = 1 specimen): G(128), T(198), T(327), T(378), C(459), T(519), A(538) and the following unique motif: TA(321–322).

Description. Holotype male (SAM NN20064). Medium idiopid spider (total length 10.2).

Colour (in ethanol; Fig. 23 View FIGURE 23 A–C): Carapace, legs and pedipalp uniform pale golden orange-brown ( Fig. 23A View FIGURE 23 ); sternum, labium and maxillae very similar, sternum darker towards anterior margins; chelicerae slightly darker than carapace ( Fig. 23E, F View FIGURE 23 ); abdomen golden orange-brown with distinctive pattern of seven mottled dark chevrons dorsally not laterally ( Fig. 23A, C View FIGURE 23 ).

Cephalothorax: Carapace 4.6 long, 3.9 wide, 3.3 high,1.2 times longer than wide; oval ( Fig. 23A View FIGURE 23 ), caput low, ocular area raised ( Fig. 23C View FIGURE 23 ); cuticle smooth, with pits outward from fovea and both sides of caput; fovea straight; distinct row of setae from halfway between fovea and eye group to eye group, culminating in a group of longer, thickened setae directly posterior to eye group; smaller fine setae also scattered very sparsely across the carapace, concentrated and form fringe around lateral margins; median clump of thickened setae on clypeus ( Fig. 23D View FIGURE 23 ). Length of median clypeus less than 1.0; anterior margin slightly convex. Eye group 0.8 wide, 0.7 long, 0.2 of carapace width; anterior eye row strongly procurved, PLE–PLE/ALE–ALE ratio 1.1; posterior eye row straight; AME ca. two-thirds of ALE and separated by about AME diameter; ALE and PLE separated by about twice ALE diameter; PME about two-thirds of the size of AME and only slightly smaller than PLE, and separated from PLE by about its own diameter ( Fig. 23D View FIGURE 23 ). Labium without cuspules ( Fig. 23F View FIGURE 23 ). Sternum 2.9 long, 2.2 wide, evenly setose; three pairs of small sigilla ( Fig. 23E View FIGURE 23 ). Maxillae without cuspules ( Fig. 23E, F View FIGURE 23 ).

Legs: moderately setose and very sparsely spinose; tarsi I, II ventrally swollen; tarsi I II weakly scopulate ( Fig. 23 View FIGURE 23 G–I). Paired tarsal claws: leg I p8 (8 large) 75 (6 large, 1 small); leg II p8 (8 large), r5 (4 large, 1 small); leg III p4 (3 large, 1 small), r5 (4 large, 1 small); leg IV p5 (4 large, 1 small), r5 (2 large, 3 small).

Spination: Tibia I with prolateral clasping spurs, distal-most spur with 2 terminal peg-like macrosetae, proximal-most with 3 terminal peg-like macrosetae ( Fig. 23 View FIGURE 23 G–I). Leg II without spines. Leg III: patella p4; metatarsus p2, r2; tarsus p4, r1. Leg IV: metatarsus p5, r2.

Leg and pedipalp measurements: Length of legs IV> I> II> III. Leg I: femur 4.3 patella 2.0, tibia 3.1, metatarsus 3.1, tarsus 1.7, total = 14.2. Leg II: femur 4.3, patella 2.1, tibia 3.0, metatarsus 3.0, tarsus 1.7, total = 14.1. Leg III: femur 3.7, patella 1.6, tibia 2.1, metatarsus 1.9, tarsus 1.9, total = 13.0. Leg IV: femur 4.2, patella 2.3, tibia 4.1, metatarsus 4.9, tarsus 2.4, total = 18.1. Pedipalp: femur 2.3, patella 1.0, tibia 2.2, tarsus 1.1, total = 6.6.

Pedipalp: All segments without spines; patella with thickened ventral setae distally; tibia short and swollen, RTA short, thin and pointed, covered in dense spinules in line ca. as wide as apophysis halfway to distal tibia, becoming only slightly sparser; long, erect setae ventrally; bulb uniform, globular; embolus simple, slender, tapering, slightly twisted with a flanged tip, slightly longer than length of bulb; cymbium covered in rows of sparse, thickened setae, becoming longer closer to distal edge ( Fig. 23 View FIGURE 23 J–L).

Abdomen: Setose, oval, dorsal sigilla not evident; 5.6 long, 3.2 wide ( Fig. 23A View FIGURE 23 ).

Variation (n=2): Carapace 4.4–4.6 long, 3.5–3.9 wide, no labial cuspules. Spination: leg III patella p4, metatarsus p2, r1-3. Leg IV: metatarsus p4-5, r1-2.

Etymology. The specific name is taken from the Greek pidax (meaning ‘spring’), and refers to the location where the species was found.

Distribution. Blakistonia pidax is known only from Strangways Springs, south-west of Lake Eyre in central South Australia ( Fig. 32 View FIGURE 32 ).

Remarks. This male was collected in a pitfall trap during the ‘Stony Deserts Biological Survey’, which was conducted between 1994 and 1997 (see Brandle 1998).