Blakistonia olea, 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 : 53-55

Blakistonia olea , sp. n.

( Fig. 21 A–L)

Type material. AUSTRALIA: Western Australia: Holotype male, Peak Charles National Park , site LH9, 32°54’34.3”S, 121°10’19.3”E, 26 March 2012, Allocasuarina woodland, S. Comer, E. Adams (WAM T127864 ).

Diagnosis. Males of B. olea can be distinguished from those of all other Blakistonia species by the AME being significantly larger than the ALE ( Fig. 21D ). Females are unknown.

Description. Holotype male (WAM T127864). Small idiopid spider (total length 11.6).

Colour (in ethanol; Fig. 21 A–C): Carapace and chelicerae olive-brown, darker around lateral margins ( Fig. 21A ); sternum, labium and maxillae uniformly yellow; abdomen darker mottled olive-brown with lighter pattern of four thin chevrons, joined by pale, oblong medial patch ( Fig. 20A, C ); legs and pedipalp lighter than carapace, with dorsal femora the darkest ( Fig. 21 G–L).

Cephalothorax: Carapace 5.4 long, 4.2 wide, 3.9 high, 1.3 times longer than wide; oval ( Fig. 21A ), caput moderately raised, ocular area raised ( Fig. 21C ); cuticle smooth, with pits outward from fovea and each side of caput; fovea straight; row of four thick setae between fovea and eye group, culminating in several longer, thickened setae directly posterior to eye group; carapace sparsely setose, with indistinct lines of setae radiating outwards from fovea, slightly more concentrated on lateral margins; median clump of thickened setae on clypeus ( Fig. 21D ). Length of median clypeus less than 1.0; anterior margin slightly convex. Eye group 1.0 wide, 0.6 long, 0.2 of carapace width; anterior eye row strongly procurved, PLE–PLE/ALE–ALE ratio 1.0; posterior eye row slightly recurved; AME ca. twice the size of ALE and separated by about half of ALE; PLE ca. half of ALE and separated by about ALE diameter; PME pale, about half of PLE, and separated from PLE by less than its own diameter ( Fig. 21D ). Labium without cuspules ( Fig. 21F ). Sternum 2.9 long, 2.4 wide, evenly setose; sigilla indistinct ( Fig. 21E ). Maxillae with 8 (left) and 4 (right) cuspules ( Fig. 21E, F ).

Legs: diffusely setose and spinose; tarsi I, II ventrally swollen; tarsi I, II weakly scopulate ( Fig. 21 G–I). Paired tarsal claws: leg I p2 (2 large) r6 (6 large); leg II p5 (5 large), r5 (2 large, 3 small); leg III p3 (1 large, 2 small), r3 (3 large); leg IV prolateral claw missing, r3.

Spination: Tibia I with two prolateral macrosetae ( Fig. 21 G–I). All other 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 5.3, patella 2.4, tibia 3.8, metatarsus 4.0, tarsus 2.2, total = 17.7. Leg II: femur 4.8, patella 2.2, tibia 3.5, metatarsus 3.9, tarsus 2.2, total = 16.6. Leg III: femur 3.9, patella 2.0, tibia 2.9, metatarsus 3.8, tarsus 2.5, total = 15.1. Leg IV: femur 5.1, patella 2.5, tibia 4.9, metatarsus 5.6, tarsus 3.0, total = 21.1. Pedipalp: femur 2.9, patella 1.5, tibia 2.6, tarsus 1.2, total = 8.2.

Pedipalp: Femur with dorsal spines, patella with thickened ventral setae; tibia short and swollen, RTA short and pointed, with thick clump of setae on tip, and covered in short, dense spinules for ca. half of distance between base of apophysis and distal tibia; long, erect setae on ventral tibia; bulb uniform, globular; embolus simple, slightly longer than bulb, slender, tapering, tip slightly twisted; cymbium covered in fine setae ( Fig. 21 J–L).

Abdomen: Setose, oval, three pairs of indistinct, unsclerotised dorsal sigilla; 6.2 long, 3.4 wide ( Fig. 21A ).

Variation: None.

Etymology. The specific name is taken from the Latin olea (meaning ‘olive’), in reference to the olive-green the colour of this species. Distribution. Blakistonia olea is known only from Peak Charles National Park, in Western Australia ( Fig. 33 ).

Remarks. Although females of Blakistonia have been found from this location, we cannot link them with certainty to this male due to lack of genetic data from the male and females, the conservative morphology of female specimens and the significantly larger size of females compared to the male.

Figures

FIGURE 20. Blakistonia nullarborensis sp. n., holotype female (WAM T141142): 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 21. Blakistonia olea sp. n., holotype male (WAM T127864): 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), 1 mm (J).

FIGURE 33. Distribution of Blakistonia species: B. mainae sp. n. (white circle), B. wingellina sp. n. (white triangle), B. olea sp. n. (white square), B. nullarborensis sp. n. (black squares), Blakistonia ‘sp. 1’ (black circle), and B. tariae sp. n. (black triangles).