Blakistonia hortoni, 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: 40-42

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Blakistonia hortoni

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Blakistonia hortoni   , sp. n.

( Fig. 14 View FIGURE 14 A–L)

Type material. AUSTRALIA: South Australia: GoogleMaps   Holotype male, Mount Crawford Forest Reserve, Mount Lofty Ranges   GoogleMaps , 34°42’S, 138°58’E, 27 May–9 September 1988, pitfall, R. Tuckwell (SAM NN20090). Paratypes: 8 males, same data ( SAM NN20089 View Materials , NN20091 View Materials , NN20092 View Materials , NN20095 View Materials , NN20100 View Materials , NN20101 View Materials , NN20102 View Materials , NN20103 View Materials ) GoogleMaps   .

Other material examined. AUSTRALIA: South Australia: GoogleMaps   1 male, Padthaway Conservation Park   GoogleMaps , 36°36’S, 140°31’E, May 1982, pitfall, B. Guerin (SAM NN20076).

Diagnosis. Males of B. hortoni   can be distinguished from B. bella   , B. pidax   , B. tunstilli   , B. emmottorum   , B. gemmelli   , and B. aurea   by the absence of prolateral clasping spurs on tibia I ( Fig. 14 View FIGURE 14 G–I); from B. parva   , B. maryae   , B. olea   , B. tariae   , B. carnarvon   and B. raveni   by the presence of one, rather than two, prolateral macroseta on tibia I ( Fig. 14 View FIGURE 14 G–I); from those of B. birksi   and B. plata   by the square eye group ( Fig. 14D View FIGURE 14 ); and from those of B. newtoni   and B. maryae   by the field of spinules on the palpal tibia being broad and not in a rounded crescentshape ( Fig. 14J View FIGURE 14 ). Females are unknown.

Description. Holotype male (SAM NN20090). Medium idiopid spider (total length 10.0).

Colour (in ethanol; Fig. 14 View FIGURE 14 A–C): Carapace uniform pale golden orange-brown ( Fig. 14A View FIGURE 14 ); sternum, labium and maxillae very similar, chelicerae slightly darker red-brown ( Fig. 14E, F View FIGURE 14 ); abdomen same golden orange-brown with pattern of seven mottled chevrons, dark, with darker mottling also between chevrons ( Fig. 14A, C View FIGURE 14 ); legs and pedipalp same colour as cephalothorax ( Fig. 14 View FIGURE 14 G–L).

Cephalothorax: Carapace 4.9 long, 3.9 wide, 3.3 high, 1.3 times longer than wide; oval ( Fig. 14A View FIGURE 14 ), caput moderately raised, ocular area raised ( Fig. 14C View FIGURE 14 ); cuticle smooth, with pits outward from fovea and both sides of caput; fovea straight; row of thick setae between fovea and eye group; carapace quite setose, with smaller fine setae distributed evenly across carapace, concentrated and forming fringe around lateral margins; clump of thickened setae on clypeus ( Fig. 14D View FIGURE 14 ). Length of median clypeus less than 1.0; anterior margin slightly convex. Eye group 0.9 wide, 0.8 long, 0.2 of carapace width; anterior eye row strongly procurved, PLE–APLE/ALE–ALE ratio 1.0; posterior eye row slightly procurved; AME approximately half the size of ALE and separated by about the diameter of AME; ALE and PLE separated by about twice the diameter of PLE; PME pale, similar in size to AME and about two-thirds size of PLE, and separated from PLE by about its own diameter ( Fig. 14D View FIGURE 14 ). Labium with 5 cuspules ( Fig. 14F View FIGURE 14 ). Sternum 2.8 long, 2.1 wide, evenly setose ( Fig. 14E View FIGURE 14 ). Maxillae with ca. 20 cuspules on both sides ( Fig. 14E, F View FIGURE 14 ).

Legs: setose and spinose; tarsi I, II ventrally swollen; tarsi and distal metatarsi I, II weakly scopulate ( Fig. 14 View FIGURE 14 G–I). Paired tarsal claws: leg I p7 (7 large) r6 (6 large); leg II p6 (6 large), r6 (6 large); leg III p6 (2 large, 4 small), r4 (1 large, 3 small); leg IV p5 (2 large, 3 small), r5 (2 large, 3 small).

Spination: Tibia I with single prolateral macroseta ( Fig. 14 View FIGURE 14 G–I). All other legs heavily 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 4.6, patella 2.3, tibia 3.3, metatarsus 3.3, tarsus 2.1, total = 15.6. Leg II: femur 4.4, patella 2.0, tibia 3.2, metatarsus 3.4, tarsus 2.1, total = 15.1. Leg III: femur 3.6, patella 1.8, tibia 2.6, metatarsus 3.2, tarsus 2.2, total = 13.4. Leg IV: femur 4.4, patella 2.2, tibia 4.5, metatarsus 4.4, tarsus 2.6, total = 18.1. Pedipalp: femur 2.7, patella 1.3, tibia 2.5, tarsus 1.1, total = 7.6.

Pedipalp: Patella with thickened ventral setae; tibia short and swollen, RTA short, pointed, with thick clump of setae on tip, and covered in short, dense spinules for two-thirds distance between base of apophysis and distal tibia, becoming only slightly sparser towards distal dibia; long, erect setae on ventral tibia; bulb uniform, globular; embolus simple, slender, tapering, tip slightly twisted, just under twice the length of bulb; cymbium covered in rows of short spinules, becoming longer closer to distal edge ( Fig. 14 View FIGURE 14 J–L).

Abdomen: Setose, oval, dorsal sigilla not evident; 5.1 long, 3.2 wide ( Fig. 14A View FIGURE 14 ).

Variation (n=10): Carapace 3.0–5.0 long, 3.0–3.3 wide, 5 labial cuspules.

Etymology. This species is named in honour of Benjamin Horton, for his commitment to wildlife education and conservation, and for his efforts in saving the lives of countless animals during the Sampson Flat bushfires of 2015.

Distribution. Blakistonia hortoni   is known only from Mount Crawford Conservation Park and Padthaway Conservation Park in the Mount Lofty Ranges ( Fig. 31 View FIGURE 31 ).

Remarks. Further specimens of this species, including females, could not be located at the type locality by one of the authors (SEH). Mount Crawford is now mostly covered in plantation forests and is quite sandy, which is an unusual habitat for Blakistonia   . Blakistonia aurea   is also found in roadside banks just outside the forest reserve, but has not been found within the reserve itself.


South African Museum