Difference between revisions of "Austrarchaea griswoldi"

Latest revision as of 12:29, 30 August 2012

Taxonavigation

Ordo: Araneae
Familia: Archaeidae
Genus: Austrarchaea

Name

Austrarchaea griswoldi Rix & Harvey sp. n. – Wikispecies link – ZooBank link – Pensoft Profile

• Austrarchaea sp. n. ‘(NEQ-2)’ Rix and Harvey 2012b^[1]: 379, figs 3, 6.

Vernacular name

Eungella Assassin Spider

Type material

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).

Etymology

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.

Diagnosis

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).

Description

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.).

Natural history

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.

Conservation status

This species appears to be a short-range endemic taxon (Harvey 2002b^[2], Harvey et al. 2011^[3]), 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.

Original Description

• 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

Other References

1. ↑ 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
2. ↑ 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
3. ↑ 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

Images

'Figure 1. Habitus and habitat images of species Archaeidae from north-eastern Queensland. A–D, Habitus images of live paratype specimens of Austrarchaea griswoldi sp. n. from Eungella National Park: A newly-moulted female with recently cast cuticle; B–C, female, lateral view; D, female carrying egg-sac. E–F, Habitat images: E, tropical rainforest at Broken River, Eungella National Park – type locality of Austrarchaea griswoldi sp. n.; F, dense tropical rainforest at Malaan National Park, Atherton Tableland – locality of Austrarchaea daviesae Forster & Platnick.  Figure 6. Morphological differences between the five pedipalp types (Types A-E) identified for species of Austrarchaea from north-eastern Queensland, with left bulbs illustrated in ventral view at scale-identical sizes. Type A pedipalps are shared among at least five species from the Wet Tropics bioregion; Types B-E are autapomorphic for single species. Note especially the variation in the size and shape of the bulb, and the shape and orientation of the conductor. C = conductor; E = embolus; ESp = embolic spur; (TS)1-3 = tegular sclerites 1-3. Scale bar = 0.2 mm.  Figure 15. Austrarchaea griswoldi sp. n. A–B, Cephalothorax and abdomen, lateral view: A, allotype female (QMB S92213) from Broken River, Eungella National Park, NE. Queensland; B, holotype male (QMB S92212) from Broken River, Eungella National Park, NE. Queensland. C, Holotype male chelicerae, lateral view, showing accessory setae. D–F, Holotype male pedipalp: D–E, bulb, ventral view; F, detail of distal tegular sclerites, retrolateral view. G, Allotype female internal genitalia, postero-ventral view (genital plate removed). C = conductor; E = embolus; Es = embolic sclerite; T = tegulum; (TS)1-3 = tegular sclerites 1-3. Scale bars: A-B = 1.0 mm; E = 0.2 mm.  Figure 24. Distribution of Austrarchaea griswoldi sp. n.: A, topographic map showing the known distribution of Archaeidae in the north-eastern Queensland Mackay and Whitsundays Hinterland, with collection localities for Austrarchaea griswoldi highlighted in yellow; B–C, topographic and satellite maps showing detail of inset (A). Small circles in (B–C) denote unidentified female specimens; large circles denote described species of Austrarchaea.  ' Figure 25. Summary distribution of the Austrarchaea daviesae species-group in tropical north-eastern Queensland, showing collections records for described species (labelled, with black circles) and unidentified juveniles or females (yellow circles) (see Table 1). Note the high proportion of unidentified specimens, especially within the Wet Tropics bioregion between Cooktown and Ingham.