Austrarchaea smithae Blue Mountains Assassin Spider Rix & Harvey

Rix, Michael G. & Harvey, Mark S., 2011, Australian Assassins, Part I: A review of the Assassin Spiders (Araneae, Archaeidae) of mid-eastern Australia, ZooKeys 123, pp. 1-100 : 34-36

Austrarchaea smithae Blue Mountains Assassin Spider Rix & Harvey sp. n. Figs 7N9G2543

Type material.

Holotype male: Blue Mountains National Park, Mount Wilson, off Mount Wilson Road, New South Wales, Australia, 33°30'56"S, 150°21'54"E, sifting elevated leaf litter under Xanthorrhoea , complex eucalypt forest with thick understory bordering rainforest, 948 m, 9.IV.2010, M. Rix, D. Harms (AMS KS114978).

Paratypes: Allotype female, same data as holotype (AMS KS114979); 2 females and 2 juveniles, same data as holotype (WAM T112576DNA: Ar32-116-F/Ar32-117-J/Ar32-118-J).

Additional material examined (of tentative identification).

AUSTRALIA. New South Wales: Kanangra-Boyd National Park: Kanangra Walls, near lookout, 33°59'08"S, 150°06'40"E, sifting elevated leaf litter under Xanthorrhoea , montane sclerophyll forest/heathland with thick understory, 1091 m, 10.IV.2010, M. Rix, D. Harms, 4 juveniles (WAM T112578DNA: Ar33-119-J/Ar33-120-J/Ar33-121-J); Kanangra Waterfall, near Kanangra Walls, 33°59'04"S, 150°06'33"E, sifting elevated leaf litter under ferns, streamside vegetation next to Kanangra Brook, 1069 m, 10.IV.2010, M. Rix, D. Harms, 2 juveniles (WAM T112579DNA: Ar34-122-J/Ar34-123-J).

Additional material (not examined).

AUSTRALIA: New South Wales: Kanangra-Boyd National Park: Kanangra Walls, near lookout, 33°59'08"S, 150°06'40"E, sifting elevated leaf litter under Xanthorrhoea , montane sclerophyll forest/heathland with thick understory, 6.XI.2008, H. Smith, 2 juveniles (AMS KS110500).

Etymology.

The specific epithet is a patronym in honour of Dr Helen Smith, for first discovering archaeids in the Blue Mountains region west of Sydney.

Diagnosis.

Austrarchaea smithae can be distinguished from all other Archaeidae from mid-eastern Australia by the unique shape of the male ‘head’ (Fig. 9G), which is strongly elevated dorsally (post-ocular ratio 0.39), with the highest point of the pars cephalica (HPC) closer to the middle of the ‘head’ than to the posterior margin of the carapace (ratio of HPC to post-ocular length <0.75).

This species can also be distinguished from other genotyped taxa from mid-eastern Australia (see Fig. 3B) by the following 12 unique nucleotide substitutions for COI and COII (n = 3): C(42), A(45), A(81), G(120), G(288), G(456), A(708), G(758), G(1269), A(1346), C(1368), C(1590).

Description.

Holotype male: Total length 2.97; leg I femur 2.79; F1/CL ratio 2.48. Cephalothorax dark reddish-brown; legs tan-brown with darker annulations; abdomen mottled grey-brown and beige, with darker reddish-brown dorsal scute and sclerites (Fig. 25B). Carapace tall (CH/CL ratio 2.14); 1.13 long, 2.41 high, 1.05 wide; ‘neck’ 0.51 wide; bearing two pairs of rudimentary horns; highest point of pars cephalica (HPC) approaching posterior quarter of ‘head’ (ratio of HPC to post-ocular length 0.71), carapace gently sloping posterior to HPC; ‘head’ strongly elevated dorsally (post-ocular ratio 0.39) (Fig. 9G). Chelicerae with short brush of accessory setae on anterior face of paturon (Fig. 25C). Abdomen 1.59 long, 1.27 wide; with three pairs of dorsal hump-like tubercles (HT 1-6); dorsal scute fused anteriorly to epigastric sclerites, extending posteriorly to first pair of hump-like tubercles; HT 3-6 each covered by separate dorsal sclerites. Unexpanded pedipalp (Figs 25D-F) with thin, slightly-tapered, rectangular conductor; tegular sclerite 1 (TS 1) long, spiniform, obscured by conductor in retrolateral view; TS 2 spur-like, shorter than TS 1; TS 2a sinuous, largely obscured by TS 2; TS 3 embedded proximally within distal haematodocha, with arched dorsal margin and bluntly-pointed apex projecting ventrally beyond retro-distal rim of tegulum.

Allotype female: Total length 4.00; leg I femur 3.09; F1/CL ratio 2.30. Cephalothorax dark reddish-brown; legs tan-brown with darker annulations; abdomen mottled grey-brown and beige (Fig. 25A). Carapace tall (CH/CL ratio 2.13); 1.35 long, 2.87 high, 1.23 wide; ‘neck’ 0.65 wide; bearing two pairs of rudimentary horns; highest point of pars cephalica (HPC) near posterior third of ‘head’ (ratio of HPC to post-ocular length 0.66), carapace gently sloping posterior to HPC; ‘head’ moderately elevated dorsally (post-ocular ratio 0.34) (Fig. 7N). Chelicerae without accessory setae on anterior face of paturon. Abdomen 2.56 long, 1.96 wide; with three pairs of dorsal hump-like tubercles (HT 1-6). Internal genitalia with cluster of ≤ 12 variably shaped spermathecae on either side of gonopore, clusters meeting near midline of genital plate (Fig. 25G); innermost (anterior) spermathecae longest, sausage-shaped, curved antero-laterally; outermost (posterior) spermathecae bulbous; other spermathecae variably pyriform, straight, directed antero-laterally.

Variation: Females (n=3): total length 3.74-4.00; carapace length 1.28-1.35; carapace height 2.62-2.92; CH/CL ratio 2.04-2.19.

Distribution and habitat.

Austrarchaea smithae is known only from wet eucalypt forest habitats in the Blue Mountains National Park west of Sydney, New South Wales (Fig. 43). Numerous juvenile specimens from the Kanangra Walls Plateau (Kanangra-Boyd National Park) may also belong to this species, but possess divergent mtDNA sequences indicative of possible speciation (Fig. 3B).

Conservation status.

This species has an imperfectly known distribution, and although potentially restricted, appears to be relatively abundant within the World Heritage-listed Blue Mountains National Park near Mount Wilson (M. Rix, pers. obs.). It is not considered to be of conservation concern.