Blakistonia newtoni, 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 : 49-51

Blakistonia newtoni , sp. n.

( Fig. 19 A–L)

Type material. AUSTRALIA: South Australia: Holotype male, Hiltaba, Gawler Ranges National Park , 32°09’51”S, 135°03’09”E, 13–22 November 2012, pitfall, N. Birks, BushBlitz survey (SAM NN28064 ).

Diagnosis. Males of B. newtoni can be distinguished from those of B. bella , B. pidax , B. tunstilli , B. emmottorum , B. gemmelli , B. aurea , B. parva , B. olea , B. tariae , B. carnarvon and B. raveni by the presence of one, rather than two, prolateral macroseta on tibia I, and by the absence of prolateral clasping spurs on tibia I ( Fig. 19 G– I); from those of B. plata and B. birksi by the square eye group ( Fig. 19D ); and from those of B. maryae and B. hortoni by the field of spinules on the palpal tibia being in a rounded crescent shape, and by the ventral margin of the palpal tibia distal to the RTA being strongly concave in prolateral view ( Fig. 19 J–L). Females are unknown.

Description. Holotype male (SAM NN28064). Medium-sized idiopid spider (total length 10.4).

Colour (in ethanol; Fig. 19 A–C): Carapace bright golden orange-brown, with darker, indistinct lines of colour both sideson both sides of caput, and between fovea and eye group ( Fig. 19A ); sternum, labium and maxillae very similar colour, chelicerae darker red-brown ( Fig. 19E, F ); abdomen same golden orange-brown as sternum and carapace with pattern of seven dark, broad, mottled chevrons, down entire side of abdomen ( Fig. 19A, C ); legs and pedipalp same colour as of carapace ( Fig. 19 G–L).

Cephalothorax: Carapace 5.1 long, 4.4 wide, 3.8 high, 1.2 times longer than wide; oval ( Fig. 19A ), caput low, ocular area raised ( Fig. 19C ); cuticle smooth, with pits outward from fovea and both sides of caput; fovea slightly procurved; carapace very sparsely setose, slightly more concentrated behind and both sides of eye group, and forming fringe around edge of carapace; median clump of thickened setae on clypeus ( Fig. 19D ). Length of median clypeus less than 1.0; anterior margin slightly convex. Eye group 0.8 wide, 8.9 long, 0.2 of carapace width; anterior eye row strongly procurved, PLE–PLE/ALE–ALE ratio 1.0; posterior eye row straight; AME only slightly smaller than ALE and separated by about one and a half times the distance of AME; ALE and PLE separated by about three times the diameter of ALE; PME pale, less than half the size of AME and about half the size of PLE, and separated from PLE by about its own diameter ( Fig. 19D ). Labium with five cuspules ( Fig 19F ). Sternum 2.8 long, 2.1 wide, evenly setose ( Fig. 19E ). Maxillae with 25 (left) and 19 (right) cuspules ( Fig. 19E, F ).

Legs: Moderately setose and sparsely spinose; tarsi I, II ventrally flattened; tarsi and distal metatarsi I, II weakly scopulate. Paired tarsal claws: leg I p9 (3 large, 3 small) r8 (6 large, 2 small); leg II p9 (8 large, 1 small), r8 (6 large, 2 small); leg III p7 (6 large, 1 small), r6 (3 large, 3 small); leg IV p6 (6 large), r8 (7 large, 1 small).

Spination: Leg I: Tibia with single prolateral macroseta ( Fig. 19 G–I), r1; metatarsus p1 r1. Leg II: tibia r1; metatarsus p2, r3. Leg III: tibia p1, r3; tibia p1, r3; metatarsus p7, r10; tarsus p7, r6. Leg IV: moderately setose and sparsely spinose, with no clear demarcation between lanceolate setae and smaller spine-like setae.

Leg and pedipalp measurements: Length of legs IV> II> I> III. Leg I: femur 5.0, patella 2.5, tibia 3.8, metatarsus 3.2, tarsus 2.0, total = 16.5. Leg II: femur 4.9, patella 2.5, tibia 3.6, metatarsus 3.0, tarsus 2.3, total = 16.3. Leg III: femur 4.2, patella 2.2, tibia 3.2, metatarsus 3.4, tarsus 2.2, total = 15.2. Leg IV (right): femur 5.0, patella 2.3, tibia 5.3, metatarsus 5.4, tarsus 2.7, total = 20.7. Pedipalp: femur 2.8, patella 1.3, tibia 2.2, tarsus 1.2, total = 7.5.

Pedipalp: Femur spinose on dorsal surface; patella with thickened ventral setae; tibia short and swollen, RTA short, pointed, densely covered in short, stout spinules in narrow line to just over two-thirds of distance between base of apophysis and distal tibia, becoming more sparse towards distal tibia; long, erect setae on ventral tibia; bulb uniform, globular; embolus simple, slender, tapering, curved but not twisted, only slightly longer than bulb; cymbium covered in rows of short spinules, becoming longer distally ( Fig. 19 J–L).

Abdomen: Setose, oval, dorsal sigilla not evident; 5.3 long, 3.2 wide ( Fig. 19A ).

Variation: None.

Etymology. This species is named in honour of Mark Newton, for his work in making South Australia’s invertebrate fauna more readily identifiable to the general public, and for supplying specimens and images for this study.

Distribution. Blakistonia newtoni is known only from Hiltaba Reserve in the Gawler Ranges ( Fig. 32 ).

Remarks. Specimens of this species were collected in a pitfall trap, 1.8 km WSW. of Hiltaba Station, under Triodia vegetation on a rocky hill slope.

Figures

FIGURE 19. Blakistonia newtoni sp. n., holotype male (SAM NN28064): 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, macroseta, 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, 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).