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Eungella Assassin Spider
Holotype male: Eungella National Park (Broken River Section), Broken River Rainforest Discovery Circuit and Granite Bend Circuit, Queensland, Australia, 21°10'07"S, 148°30'22"E, sifting elevated leaf litter under palms (especially fan palms), tropical rainforest, 684 m, 23.III.2012, M. & A. Rix (QMB S92212).
Paratypes: Allotype female, same data as holotype (QMB S92213); 2 males, 1 female and 2 juveniles, same data as holotype (WAM T125630); 1 female, same data as holotype except Broken River Rainforest Discovery Circuit, hand collecting at night, 24.III.2012 (QMB S92214).
Other material examined
AUSTRALIA: Queensland: Eungella National Park: Broken River Rainforest Walk, 21°10'02"S, 148°30'23"E, litter, night collection, 720 m, 30.XI.2008, H. Smith, 1 juvenile (AMS KS106561); off Crediton Road Loop, 21°11'09"S, 148°31'43"E, sifting elevated leaf litter under fan palms, tropical rainforest, 673 m, 24.III.2012, M. & A. Rix, 1 juvenile (WAM T125631). Eungella: Schoolhouse rainforest general collection, 21°08'S, 148°29'E, 11–15.II.1986, R. Raven, J. Gallon, 1 juvenile (QMB S7039).
The specific epithet is a patronym in honour of Dr Charles Griswold, for his outstanding contributions to arachnology, and for his contributions to the study of Archaeidae and other basal Araneomorphae.
Austrarchaea griswoldi can be distinguished from all other Archaeidae from north-eastern Queensland by the presence of a unique Type E pedipalp (Fig. 6), with a very large bulb (width >> 0.30 mm) (Figs 6, 15E), modified ventro-distal rim of the tegulum forming rectangular opercular plate (Figs 6, 15E), and very large, flattened tegular sclerite 3 (TS 3), the latter extending along the entire retrolateral edge of the conductor (Fig. 15F). This species can be further distinguished by the very short, barely differentiated comb of accessory setae on the male chelicerae (Fig. 15C), and by the presence of only two pairs of female spermathecae (Fig. 15G).
Holotype male: Total length 3.08; leg I femur 2.99; F1/CL ratio 2.62. Cephalothorax dark reddish-brown; legs dark tan-brown with darker annulations; abdomen mottled dark grey-brown and beige, with darker brown dorsal scute and sclerites (Fig. 15B). Carapace tall (CH/CL ratio 2.17); 1.14 long, 2.47 high, 1.11 wide, ‘neck’ 0.58 wide; bearing two pairs of rudimentary horns; highest point of pars cephalica (HPC) near middle of ‘head’ (ratio of HPC to post-ocular length 0.56), carapace sloping in straight plane posterior to HPC; ‘head’ not strongly elevated dorsally (post-ocular ratio 0.27). Chelicerae with very short, barely differentiated comb of accessory setae on anterior face of paturon (Fig. 15C). Abdomen 1.47 long, 1.05 wide; with two pairs of dorsal hump-like tubercles (HT 1-4); dorsal scute fused anteriorly to epigastric sclerites, extending posteriorly to first pair of hump-like tubercles; HT 3-4 each covered by separate dorsal sclerites. Unexpanded pedipalp (Figs 15D-F) of Type E morphology (Fig. 6), very large in size (width of bulb >> 0.30), with retrolaterally directed, arched conductor; ventro-distal rim of tegulum distally extended to form rectangular opercular plate; embolus distally directed, curved, without spur, projecting only slightly beyond distal rim of conductor; tegular sclerite 3 (TS 3) very large, flattened, extending along entire retrolateral edge of conductor; TS 2-2a largely obscured by rectangular opercular plate, TS 2a projecting beyond distal rim of conductor to just past tip of embolus; TS 1 deeply embedded in bulb, obscured by opercular plate, not visible in ventral view.
Allotype female: Total length 3.68; leg I femur 2.87; F1/CL ratio 2.29. Cephalothorax dark reddish-brown; legs tan-brown with darker annulations; abdomen mottled dark grey-brown and beige (Fig. 15A). Carapace tall (CH/CL ratio 2.20); 1.26 long, 2.77 high, 1.21 wide; ‘neck’ 0.70 wide; bearing two pairs of rudimentary horns; highest point of pars cephalica (HPC) near middle of ‘head’ (ratio of HPC to post-ocular length 0.55), carapace sloping in straight plane posterior to HPC; ‘head’ not strongly elevated dorsally (post-ocular ratio 0.28). Chelicerae without accessory setae on anterior face of paturon. Abdomen 1.92 long, 1.59 wide; with four pairs of dorsal hump-like tubercles (HT 1-4). Internal genitalia (Fig. 15G) with pair of pyriform spermathecae on either side of gonopore, clusters widely separated along midline of genital plate.
Variation: Males (n = 3): total length 2.87–3.08; carapace length 1.10–1.14; carapace height 2.37–2.51; CH/CL ratio 2.15–2.22. Females (n = 3): total length 3.03–3.68; carapace length 1.24–1.26; carapace height 2.72–2.77; CH/CL ratio 2.16–2.23.
Distribution and habitat
Austrarchaea griswoldi is known only from Eungella National Park, 70 km west of Mackay (Figs 24–25). Specimens have been collected by beating and sifting elevated leaf litter in tropical rainforest (Fig. 1E), especially under the dead fronds of Eungella Fan Palms (Livistona sp.).
A single female specimen was collected by MGR during night collecting in March 2012, suspended with her egg-sac in a tangled maternal web decorated with hanging debris, at the base of a large standing rainforest tree trunk. This egg-sac (Fig. 1D) was carried with both legs IV, positioned behind and against the posterior face of the abdomen, and was composed of soft brown silk. The shape of the egg-sac was irregular, with two large projections, and 18 spiderlings hatched out of the egg-sac on 3-4 April 2012.
This species appears to be a short-range endemic taxon (Harvey 2002b, Harvey et al. 2011), which although potentially restricted in distribution, is abundant within the Eungella National Park (MGR, pers. obs.). It is not considered to be of conservation concern.
- Rix, M; Harvey, M; 2012: Australian Assassins, Part III: A review of the Assassin Spiders (Araneae, Archaeidae) of tropical north-eastern Queensland ZooKeys, 218: 1-50. doi
- Rix M, Harvey M (2012b) Phylogeny and historical biogeography of ancient assassin spiders (Araneae: Archaeidae) in the Australian mesic zone: evidence for Miocene speciation within Tertiary refugia. Molecular Phylogenetics and Evolution 62: 375-396. doi: 10.1016/j.ympev.2011.10.009
- Harvey M (2002b) Short-range endemism among the Australian fauna: some examples from non-marine environments. Invertebrate Systematics 16: 555-570. doi: 10.1071/IS02009
- Harvey M, Rix M, Framenau V, Hamilton Z, Johnson M, Teale R, Humphreys G, Humphreys W (2011) Protecting the innocent: studying short-range endemic taxa enhances conservation outcomes. Invertebrate Systematics 25: 1-10. doi: 10.1071/IS11011