Zephyrarchaea Rix & Harvey

Rix, Michael G. & Harvey, Mark S., 2012, Australian Assassins, Part II: A review of the new assassin spider genus Zephyrarchaea (Araneae, Archaeidae) from southern Australia, ZooKeys 191, pp. 1-62 : 3-8

Genus Zephyrarchaea Rix & Harvey gen. n.

Type species.

Austrarchaea mainae Platnick, 1991b.

Etymology.

The generic name is derived from the Latin ‘zephyrus’, meaning 'west wind’ ( Brown 1956), in reference to the diversity of this genus in south-western Australia, and the windy, coastal habitats occupied by several species, including the type species.

Diagnosis.

Species of Zephyrarchaea can be distinguished from all eastern Australian species of Austrarchaea by the significantly shorter carapace (CH/CL ratio << 2.0) (Fig. 4B cf. Fig. 4A, 7), by the presence of accessory setae on or adjacent to the proximal (rather than the distal) bulge of the male cheliceral paturon (Fig. 4B cf. Fig. 4A), and by the shape of the two conductor sclerites on the male pedipalp, which are hinged, unfused and moveable (Fig. 4D cf. Fig. 4C), together forming a fully articulated cradle for the unexpanded embolus (Fig. 10E). Like species of Austrarchaea , the genus can be further distinguished from Malagasy and African species of Eriauchenius and Afrarchaea by the presence of numerous, clustered spermathecae in females (Fig. 16G) and by the presence of a long, wiry embolus on the pedipalp of males (Figs 10E, 16E) ( Forster and Platnick 1984, Wood 2008, Rix and Harvey 2011).

Description.

Small, haplogyne, araneomorph spiders; total length 2.5 to 4.5.

Colouration: Body colouration cryptic and relatively uniform across species, usually with only subtle intraspecific variation in abdominal patterning; carapace, sternum and chelicerae tan brown to reddish-brown in males, interspersed with darker regions of granulate cuticle (Figs 5 F–G), covered in highly reflective setae; legs tan-brown to darker reddish-brown, with pattern of darker annulations on distal segments; abdomen mottled with beige and variable hues of grey-brown (Fig. 6), with reddish-brown sclerites, scutes and sclerotic spots (Fig. 6); paler beige markings due to reflective, subcuticular guanine crystals; antero-lateral face of abdomen always with large, humeral patch of reflective guanine crystals (Figs 6 A–B, 17 A–B).

Cephalothorax: Carapace elevated anteriorly (CH/CL ratio usually 1.55-1.75; Fig. 7), with raised, highly modified pars cephalica forming ‘neck’ and bulbous ‘head’ (see Wood 2008; Rix and Harvey 2011) (Figs 5 A–D); ‘neck’ with concomitantly long diastema (see Schütt 2002) between cheliceral bases and anterior margin of carapace, fused along entire length with sclerotised cuticle; cheliceral bases emanating from broad, fully-enclosed cheliceral foramen situated at front of ‘head’ (Figs 5B, 5D). Carapace with densely granulate cuticular microstructure, covered in larger setose tubercles arranged in clusters or distinct rows (Figs 5 F–G); each tubercle bearing single densely plumose or ciliate seta; setose tubercles largest on ‘neck’ and pars thoracica (Figs 5C, 5 F–G). Eight eyes present on anterior margin of ‘head’, in four widely separated d iads (Figs 5 A–D); AME largest, widely separated, directed antero-laterally on rounded ocular bulge (Fig. 5B); PME situated closely posterior to AME, directed obliquely on postero-lateral side of ocular bulge; lateral eyes contiguous, with shared raised bases, directed ventro-laterally on widest lateral margin of ‘head’ (Figs 5 A–D). Sternum longer than wide, covered in setose tubercles; lateral margins separated from dorsal pleural sclerite extending between coxae I–IV. Labium subtriangular, not fused to sternum, directed antero-ventrally at oblique angle to sternum; labrum with pair of divergent projections on anterior surface. Maxillae large, straddling labium and labrum, converging distally; serrula a single row of teeth. Chelicerae very long, spear-like, distally divergent (Figs 5 C–E), usually with proximal bulging projection in males (Figs 5A, 5E); both sexes with oval, ectal stridulatory file adjacent to pedipalps (Fig. 5E); males also with tuft (Figs 4B, 5A, 5E, 18B), brush (Figs 14C, 15C) and/or comb (Figs 5C, 16C, 17C) of accessory setae on anterior face of paturon. Chelicerae armed with three rows of peg teeth; anterior (prolateral) row with two peg teeth near tip of fang; posterior (retrolateral) row with single peg tooth near tip of fang; median (prolateral) row with more than 15 peg teeth extending along inner prolateral margin of paturon to near base of fang; median row with approximately eight porrect, comb-like peg teeth adjacent to fang, several larger, flattened, spiniform peg teeth near tip of fang, and additional progressively shorter, spiniform peg teeth along inner paturon; cheliceral retromargin also with four or five true teeth and prominent cheliceral gland mound.

Legs and female pedipalp: Legs (longest to shortest) 1 –4–2– 3, covered with short plumose setae; spines absent; patella I long, greater than one-third length of femur I. Trichobothria present on tibiae and metatarsi of legs; tibiae I–IV each with two trichobothria; metatarsi I–IV each with single trichobothrium. Tarsi shorter than metatarsi, with three claws; tarsi, metatarsi and distal tibiae of legs I–II usually with ventral and pro-ventral rows of moveable, spatulate setae. Female pedipalp with long, porrect trochanter and small tarsal claw; tibia with two dorsal trichobothria.

Abdomen: Abdomen arched anteriorly, rounded-subtriangular or spherical in lateral view (Figs 6 A–B), sometimes with six large hump-like tubercles on dorsal surface (Figs 6A, 10 A–B, 11 A–B); cuticle covered with short plumose setae and numerous sclerotic spots (Figs 6 C–F). Epigastric region with sclerotised (setose) book lung covers and dorsal and ventral plates surrounding pedicel (Figs 6 C–D) (plates fused in males); dorsal pedicel plate with transverse ridges; females with median genital plate and sclerotised lateral sigillae (Fig. 6C); males with broad dorsal scute fused anteriorly to epigastric sclerites, with (Fig. 6A) or usually without (Fig. 6B) additional paired sclerites associated with hump-like tubercles. Six spinnerets, surrounded by thickened cuticle (Fig. 6F); ALS largest, PMS smallest; colulus absent. Posterior pair of divided tracheal spiracles situated closely anterior to spinnerets; males also with epiandrous gland spigots situated closely anterior to epigastric furrow.

Genitalia: Female genitalia haplogyne, with sclerotised, subtriangular genital plate anterior to epigastric furrow (Fig. 6C); internally with gonopore leading to large, membranous bursa (Figs 13 B–C; see also Harvey 2002a, fig. 2) overlying two separate, radiating clusters of sclerotised, sausage-shaped anterior spermathecae (Figs 13 B–D, 15G, 16 G). Male pedipalp with complex, expandable spherical or pyriform bulb (Figs 4D, 10E, 16E, 18D), consisting of smooth tegulum, proximal ‘subtegulum’ and associated tegular groove with basal haematodocha (Fig. 4D); distal tegulum with excavate, rimmed cavity surrounding massive, inflatable haematodochal complex, incorporating distal embolus, basal embolic sclerite, two articulating conductor sclerites and three additional tegular sclerites (Figs 4D, 10E, 18D) (see below). Unexpanded pedipalp with folded, curved embolus abutting paired conductor sclerites (Fig. 10E); other tegular sclerites embedded pro-distally (Fig. 10F); pedipalpal expansion and haematodochal inflation (e.g. see Figs 4D, 18D) resulting in significant conformational changes to length and orientation of embolus, and relative position of tegular sclerites.

As noted by Wood (2008) and Rix and Harvey (2011), the homology of the tegular sclerites among archaeid genera remains unclear. Rix and Harvey (2011) used a numbering system for comparing the moveable tegular sclerites among species of Austrarchaea from mid-eastern Australia, identifying four separate sclerites (TS 1, 2, 2a and 3) according to their relative position within the unexpanded tegular cavity (see Fig. 4C). These four sclerites can be broadly homologised with the tegular sclerites of species of Zephyrarchaea , although at least one sclerite appears to be absent or otherwise highly modified in the latter, with no evidence for an interlocking, differentiated TS 2-2a complex (as in Austrarchaea ; Fig. 4C cf. Fig. 4D). Tegular sclerite 1 (TS 1) is a prominent and strongly developed process in all species of Zephyrarchaea (Figs 4D, 10F, 16F), originating proventrally adjacent to the base of conductor sclerite 1. Two additional tegular sclerites (here labelled collectively TS 2-3) are closely contiguous and not easily distinguished in the unexpanded state, usually embedded pro-distally adjacent to the retro-distal rim of the tegulum. The larger of these two sclerites, presumably homologous to tegular sclerite 3 (TS 3) in species of Austrarchaea , has a shorter and broader, more plate-like morphology relative to TS 1, and is usually (but not always) visible as a pointed projection beyond the retro-distal rim of the tegulum (Figs 10E, 16E).

Distribution.

Species of Zephyrarchaea occur in mesic habitats throughout southern Western Australia, South Australia and Victoria (Fig. 2), usually in coastal (Figs 20C, 22C), sub-coastal or montane (Figs 23C, 24C) temperate heathlands, but also in wet eucalypt forests (Figs 21C, 29C) and temperate rainforests (Figs 26C, 27C). In Victoria they occur along the Great Dividing Range, from Grampians National Park and the Otway Range in south-western Victoria east to the Yarra and Strzelecki Ranges east of Melbourne (Figs 26-29). In South Australia they occur on Kangaroo Island, at a single known locality north of Flinders Chase (Fig. 30). In south-western Western Australia they occur in the southern high rainfall and south-eastern coastal provinces (see Hopper and Gioia 2004; Figs 20-25), from the Wellington and Leeuwin-Naturaliste National Parks (near Bunbury) east to Cape Le Grand National Park, with outlying populations in the Porongurup and Stirling Range National Parks.

Composition.

Two described species - Zephyrarchaea mainae (Platnick, 1991b) and Zephyrarchaea robinsi (Harvey, 2002a) - and the nine new species from southern Australia: Zephyrarchaea austini sp. n., Zephyrarchaea barrettae sp. n., Zephyrarchaea grayi sp. n., Zephyrarchaea janineae sp. n., Zephyrarchaea marae sp. n., Zephyrarchaea marki sp. n., Zephyrarchaea melindae sp. n., Zephyrarchaea porchi sp. n. and Zephyrarchaea vichickmani sp. n. The previously described species Archaea hickmani Butler, 1929 is here recognised as a nomen dubium.

Remarks.

The genus Zephyrarchaea forms a monophyletic and highly divergent clade sister to all other Archaeidae from mid-eastern and north-eastern Australia (see Rix and Harvey 2011, 2012; Fig. 3). Three main lineages have been recognised within the genus, for species from south-eastern Australia (South Australia and Victoria), from the Stirling Range National Park and from elsewhere in south-western Western Australia (see Rix and Harvey 2012; Fig. 3). The genus is not known to occur north or east of the Australian Alps, which may be a vicariant biogeographic barrier between populations of Zephyrarchaea and Austrarchaea .

Key to the Australian species of

Zephyrarchaea

Note that males of Zephyrarchaea austini sp. n., Zephyrarchaea grayi sp. n. and Zephyrarchaea robinsi are unknown; females of Zephyrarchaea marki sp. n. and Zephyrarchaea porchi sp. n. are unknown.

* Females of Zephyrarchaea mainae and Zephyrarchaea janineae sp. n. are very similar morphologically, with only subtle morphometric differences in the shape of the carapace; male specimens or nucleotide sequences are recommended to accurately identify these closely related species.

** Females of Zephyrarchaea vichickmani sp. n. and Zephyrarchaea marae sp. n. are essentially indistinguishable morphologically, with male specimens or nucleotide sequences required to identify these closely related sister-species.