Blakistonia raveni, 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 : 60-62

Blakistonia raveni sp. n.

( Fig. 25 A–L)

Type material. AUSTRALIA: Queensland: Holotype male, Drummond Ranges Summit , 23°32’00”S, 147°18’00”E, 25 October–17 December 2000, open forest, pitfall trap, D. Cook, G. Monteith (QMB S57760 ).

Diagnosis. Males of B. raveni 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. 25 G–I); from those of B. plata , B birksi , B. newtoni , and B. hortoni by the presence of two, rather than one, prolateral macrosetae on tibia I ( Fig. 25 G–I); from those of B. parva and B. maryae by an eye group that is wider than long ( Fig. 25D ), and from those of B. olea , B. tariae and B. carnarvon by the AME that are not significantly larger than the ALE ( Fig. 25D ), a distinctive ring of dark colour around the carapace edge ( Fig. 25A ), and an embolus that narrows/ tapers before its midpoint ( Fig. 25L ). Females are unknown.

Description. Holotype male (QMB S57760 ). Small idiopid spider (total length 9.2).

Colour (in ethanol; Fig. 25 A–C): legs, pedipalp and carapace yellow-brown, darker around lateral margins ( Fig. 25A ); sternum yellow-brown, paling towards margins; labium and maxillae same medium brown as sternum; chelicerae slightly darker yellow-brown ( Fig. 25E ); abdomen grey-brown with a distinct pattern of seven dark brown chevrons, anterior two chevrons connected by dark brown median patch, posterior three chevrons separated by pale medial patch ( Fig. 25A, C ).

Cephalothorax: Carapace 3.6 long, 2.8 wide, 2.8 high, 1.3 times longer than wide; oval ( Fig. 25A ), caput moderately raised, ocular area raised ( Fig. 25C ); cuticle smooth, with pits outward from fovea and both sides of caput; fovea straight; row of setae between fovea and eye group, culminating in clump of setae directly posterior to eye group; setae radiating outwards in lines from fovea, concentrated and form fringe on lateral margins; median clump of thickened setae on clypeus ( Fig. 25D ). Length of median clypeus less than 1.0; anterior margin slightly convex. Eye group 0.8 wide, 0.5 long, 0.3 of carapace width; anterior eye row strongly procurved, PLE–PLE/ALE– ALE ratio 1.0; posterior eye row slightly recurved; AME slightly smaller than ALE and separated by less than AME diameter; PLE about one-third 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. 25D ). Labium without ( Fig. 25F ). Sternum 1.9 long, 1.7 wide, evenly setose; sigilla indistinct ( Fig. 25E ). Maxillae without cuspules ( Fig. 25E, F ).

Legs: diffusely setose and spinose; tarsi I and II ventrally slightly swollen; tarsi and distal metatarsi I, II scopulate. Paired tarsal claws: leg I p5 (5 large) r6 (5 large, 1 small); leg II p5 (5 large), r5 (5 large); leg III p5 (5 large), r5 (5 large); leg IV p6 (5 large, 1 small, r6 5 large, 1 small).

Spination: Tibia I with two prolateral macrosetae ( Fig. 15 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 3.6, patella 1.8, tibia 2.6, metatarsus 2.3, tarsus 1.6, total = 11.9. Leg II: femur 3.2, patella 1.5, tibia 2.4, metatarsus 2.1, tarsus 1.7, total = 9.2. Leg III: femur 2.8, patella 1.3, tibia 2.1, metatarsus 2.3, tarsus 1.7, total = 8.5. Leg IV: femur 3.7, patella 1.8, tibia 3.4, metatarsus 3.4, tarsus 1.9, total = 14.2. Pedipalp: femur 2.0, patella 1.0, tibia 1.7, tarsus 0.9, total = 8.0.

Pedipalp: Femur with dorsal spines, patella with thickened ventral setae; tibia short and swollen, RTA very short and stout, covered in short, dense spinules for more than half distance between base of apophysis and distal tibia, becoming more sparse towards distal end; 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 long spinules, becoming longer and denser distally ( Fig. 25 J–L).

Abdomen: Abdomen setose, oval, dorsal sigilla not evident; 3.5 long, 2.4 wide ( Fig. 25A ).

Variation: None.

Etymology. This species is named in honour of Dr Robert Raven, for his unparalleled contributions to arachnid taxonomy.

Distribution. Blakistonia raveni is known only from the Drummond Ranges, Queensland ( Fig. 34 ).

Remarks. This specimen was caught in a pitfall trap in open forest.

Figures

FIGURE 15. Blakistonia mainae sp. n., holotype female (WAM T141137): 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 25. Blakistonia raveni sp. n., holotype male (QMB S57760).): 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), 1 mm (J).

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).