Flavarchaea humboldti, Rix, Michael G. & Harvey, Mark S., 2010

Rix, Michael G. & Harvey, Mark S., 2010, The first pararchaeid spider (Araneae: Pararchaeidae) from New Caledonia, with a discussion on spinneret spigots and egg sac morphology in Ozarchaea, Zootaxa 2414, pp. 27-40 : 28-31

Flavarchaea humboldti n. sp.

Figs 1–11

Type material. NOUVELLE CALÉDONIE: Province Sud: holotype female, Mont Humboldt, 21º53’S, 166º24’E, 1400 m, pyrethrum fogging trees and logs in moss forest, 6–7 November 2002, G. Monteith, C. Burwell ( MNHN). Paratypes: 2 females, same data as holotype ( QMB S88155 ); 1 female, same data as holotype ( WAM T99064).

Etymology. The specific epithet is a patronym in honour of the German naturalist, geologist and explorer Alexander von Humboldt (1769–1859) – one of the founding figures of modern geography – after whom the type locality of ‘Mont Humboldt’ is named.

Phylogenetic affinities. Although male specimens are required to definitively diagnose the pararchaeid genera ( Rix 2006), this species is extremely similar to Australian species of Flavarchaea (e.g. F. anzac Rix, 2006 ) in possessing numerous rows of setae on the dorsal pars cephalica ( Figs 1, 3 ), receptacula with ‘noselike’ inner lobes ( Figs 9–10 ), a row of curved, peg-like setae on femur I (e.g. see Fig. 31 ), and a uniformly pale body colouration ( Figs 1–8 ).

Diagnosis. Females of Flavarchaea humboldti n. sp. can be distinguished from all described Australian species of Flavarchaea by the profile of the external epigyne ( Fig. 8 ) and the shape of the receptacula, which are strongly arched and bear oval, anteriorly-directed, ‘nose-like’ inner lobes ( Figs 9–10 ) (see also Rix 2006, figs 58–64, for a comparison with other described species). Males are unknown.

Description. Female (holotype): Dimensions: total length 2.11; carapace 0.85 long, 0.52 wide; abdomen 1.31 long, 1.07 wide; leg I femur 0.52 long. Colour: carapace, chelicerae, sternum dark tan-yellow; legs dark tan-yellow with lighter cream patellae and distal tibiae; abdomen cream with light brown sigillae and setal sclerotic spots. Carapace: rhomboidal in lateral profile, with pars cephalica steeply elevated anterior to coxa III; dorsal surface of pars cephalica convex, sloping down to anterior median eyes from posterior margin ( Fig. 5 ); numerous curved setae present on dorsal pars cephalica and around eyes and clypeus ( Fig. 3 ). Eyes: eight present on antero-dorsal aspect of pars cephalica; AME, lateral eyes paired; PME separated by slightly more than twice their own diameter ( Figs 1, 3 ). Sternum: longer than wide, posteriorly obtuse ( Fig. 4 ); fused to lateral margins of carapace around petiole and anterior to coxa III, IV. Labium: wider than long, fused to anterior margin of sternum; not rebordered. Maxillae: directed across labium, distally convergent; serrula a single row of teeth. Chelicerae: rectangular, 2x longer than wide, constricted proximally ( Fig. 6 ), protruding from oval foramen in cephalothorax, with pronounced keel extending along pro-ventral margin; peg tooth group A (PTA) with five peg teeth adjacent to fang; peg tooth group B (PTB) with three peg teeth near tip of fang; peg tooth group C (PTC) with three larger peg teeth on pro-dorsal margin adjacent to PTB; paturon also with numerous moveable setae on ventral surface. Abdomen: globose, broadly oval in dorsal profile, with two pairs of sigillae dorsally and ventrally ( Figs 1–2 ); two, small, square post-epigastric sclerites situated slightly posterior to epigastric furrow ( Figs 7–8 ). Spinnerets: six, posterior to colulus; surrounded dorsally and ventrally by separate, weakly sclerotised strips; posterior tracheal spiracle surrounded by small, oval sclerite. Legs: leg formula IV, I, II, III; short (leg I femur-carapace ratio 0.61), three-clawed, covered in short setae; retrolateral femur I with proximal, dorsally-curved row of five stout, peg-like setae; tibiae each with two long trichobothria; metatarsi each with single trichobothrium; tarsal organ capsulate. Pedipalp: five-segmented, without claw; tibia with single trichobothrium. Epigyne: entelegyne, relatively small, only slightly broader than petiole ( Figs 8–10 ); receptacula ‘comma-shaped’, strongly arched, with complex internal chambers; each receptaculum with bulbous distal portion bearing oval, anteriorly-directed, ‘nose-like’ inner lobe ( Figs 9–10 ); fertilisation ducts short, strongly-curved ( Fig. 10 ).

Male: Unknown.

Distribution and habitat. This species is known only from montane rainforest near the summit of Mont Humboldt, 46 km north of Nouméa, New Caledonia ( Fig. 11 ). The type specimens were collected by pyrethrum fogging trees and logs in a moss forest at 1400 m altitude.

Figures

FIGURE 11. Distribution map showing the type locality of Flavarchaea humboldti n. sp. north of Nouméa, New Caledonia.

FIGURES 1 – 4. Holotype female Flavarchaea humboldti n. sp. from Mont Humboldt, New Caledonia: 1, habitus, dorsal view; 2, habitus, ventral view; 3, carapace, dorsal view; 4, sternum, ventral view, showing strongly reticulate cuticle.

FIGURES 5 – 8. Holotype female Flavarchaea humboldti n. sp. from Mont Humboldt, New Caledonia: 5, habitus, antero-lateral view; 6, cephalothorax, frontal view; 7, abdomen, ventral view; 8, epigyne, ventral view.

FIGURES 9 – 10. Cleared, dissected epigyne of paratype female Flavarchaea humboldti n. sp. from Mont Humboldt, New Caledonia: 9, receptacula, dorsal view; 10, detail of receptacula, showing ducts. Arrows denote the trajectory of insemination ducts. cR, internal chamber of receptaculum; EF, epigastric furrow; FD, fertilisation duct; ID, insemination duct; ilR, ‘ nose-like’ inner lobe of receptaculum.

FIGURES 28 – 31. Scanning electron micrographs of Ozarchaea harveyi Rix from near Banksiadale Dam, Western Australia: 28, female cephalothorax, dorsal view; 29, female splayed chelicerae, ventral view; 30, female leg IV claws; 31, male leg I femur, retrolateral view, showing curved row of peg-like setae. Fe 1 — femur I; iC—inferior claw; ps—peglike seta; Ta 4 — tarsus IV; Tr 1 — trochanter I.