Blakistonia carnarvon, 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 : 34-36

Blakistonia carnarvon , sp. n.

( Fig. 11 A–L)

Type material. AUSTRALIA: Queensland: Holotype male, Carnarvon Station , 24°49’12.00”S, 147°44’31.20”E, 24 November–13 December 2010, malaise trap, A. Zwick (QMB S96934 ).

Diagnosis. Males of B. carnarvon can be distinguished from those of B. bella , B. pidax , B. tunstilli , B. emmottorum , B. gemmelli , and B. aurea by the absence of prolateral clasping spurs on tibia I ( Fig. 11 G–I); from those of B. hortoni , B. plata , B. birksi , and B. newtoni by the presence of two, rather than one, prolateral macrosetae on tibia I ( Fig. 11 G–I); from those of B. parva and B. maryae by an eye group that is wider than long ( Fig. 11D ); from those of B. olea and B. tariae by the combined presence of a distinctive ring of dark colour around the edge of the carapace ( Fig. 11A ) and the AME with a similar or smaller diameter to the ALE ( Fig. 11D ); and from those of B. raveni by an embolus that narrows and tapers before the midpoint ( Fig. 11 J–L). Females are unknown.

Description. Holotype male (QMB S96934 ). Small idiopid spider (total length 9.2).

Colour (in ethanol; Fig. 11 A–C): Legs, pedipalp and carapace medium chestnut-brown, distinctly darker around lateral margins ( Fig. 11A ); labium, maxillae and sternum lighter medium brown, paler towards margins; chelicerae slightly darker ( Fig. 11E, F ); abdomen greyish-brown with distinct pattern of seven dark brown chevrons ( Fig. 11A, C ).

Cephalothorax: Carapace 4.7 long, 4.2 wide, 3.4 high, 1.1 times longer than wide; oval ( Fig. 11A ), caput low, ocular area raised ( Fig. 11C ); cuticle smooth, with pits outward from fovea and both sides of caput; fovea straight; row of setae between fovea and eye group, and radiating outwards from fovea, with two distinctive patches of short, fine setae on sides of caput, carapace setae concentrated and form fringe on lateral margins; median clump of thickened setae on clypeus ( Fig. 11D ). Length of median clypeus less than 1.0; anterior margin slightly convex. Eye group 1.3 wide, 2.2 long, 0.3 of carapace width; anterior eye row strongly procurved, PLE–PLE/ALE–ALE ratio 0.9; posterior eye row slightly recurved; AME slightly smaller than ALE and separated by less than AME; PLE about one-third the size of ALE and separated by about ALE diameter; PME pale, about two-thirds of PLE, and separated from PLE by less than its own diameter ( Fig. 11D ). Labium without cuspules ( Fig. 11F ). Sternum 2.2 long, 3.3 wide, evenly setose. Maxillae without cuspules ( Fig. 11E, F ).

Legs: diffusely setose and spinose; tarsi I, II slightly ventrally swollen; tarsi and distal metatarsi I, II scopulate ( Fig. 11 G–I). Paired tarsal claws: leg I p5 (5 large) r5 (5 large); leg II p4 (4 large), r6 (5 large, 1 small); leg III p3 (3 large), r2 (2 large); leg IV p5 (2 large, 3 small, r3 2 large, 3 small).

Spination: Tibia I with two prolateral macrosetae ( Fig. 11 G–I). All legs diffusely setose and spinose, with no clear demarcation between lanceolate setae and smaller spine-like setae.

Leg and pedipalp measurements: Length of legs IV> I> II> III. Leg I: femur 5.2, patella 2.4, tibia 4.1, metatarsus 5.3, tarsus 2.2, total = 19.2. Leg II: femur 5.0, patella 2.4, tibia 3.6, metatarsus 3.2, tarsus 2.2, total = 16.4. Leg III: femur 4.1, patella 1.9, tibia 3.0, metatarsus 3.7, tarsus 2.3, total = 15.0. Leg IV: femur 5.5, patella 2.3, tibia 4.8, metatarsus 5.1, tarsus 2.9, total = 20.6. Pedipalp: femur 2.8, patella 1.5, tibia 2.5, tarsus 1.2, total = 8.0.

Pedipalp: Femur with dorsal spines, patella with thickened ventral setae; tibia short and swollen, RTA short and pointed, covered in short, dense spinules for ca. half of distance between base of apophysis and distal tibia, becoming more sparse toward distal tibia; long, erect setae on ventral tibia; bulb uniform, globular; embolus simple, slender, tapering, tip slightly twisted, just over length of bulb; cymbium with rows of spnules, becoming longer and denser distally ( Fig. 11 J–L).

Abdomen: Setose, oval, dorsal sigilla not evident; 4.5 long, 3.2 wide ( Fig. 11A ).

Variation: None.

Etymology. The specific name is a noun in apposition that refers to the type locality at Carnarvon Station Reserve, Queensland.

Distribution. This species is known only from Carnarvon Station, in central Queensland ( Fig. 34 ).

Remarks. The specimen was caught in a Malaise trap in brigalow ( Acacia harpophylla ) woodland on a grassy hillside at Carnarvon Station Reserve, which is one of the largest remnants of native vegetation in inland Queensland.

Figures

FIGURE 11. Blakistonia carnarvon sp. n., holotype male (QMB S96934). 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, macrosetae, 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).

FIGURE 34. Distribution of Blakistonia species: B. emmottorum sp. n. (black square), B. raveni sp. n. (black triangle), B. carnarvon sp. n. (black circle), and B. plata sp. n. (white circle).