Nuliodon, Raven, Robert J., 2009

Raven, Robert J., 2009, Revisions of Australian ground-hunting spiders: IV. The spider subfamily Diaprograptinae subfam. nov. (Araneomorphae: Miturgidae), Zootaxa 2035, pp. 1-40 : 31-32

Nuliodon gen. nov.

Type species. Nuliodon fishburni sp. nov.

Diagnosis. Differs from Miturga in the presence of claw tufts ( Fig. 24 a), from Mituliodon in the absence of strong scopulae on metatarsi and tarsi I–IV, the form of the male palp ( Fig. 21 a, b), viz., short embolus, absence of cymbial groove and small conductor. Resembles Mitzoruga gen. nov. in the distodorsal crest of thick curved setae on cymbium ( Fig. 21 a), and the carapace shape but males differ in the stout RTA ( Figs 21 c, d), the absence of dark stripes on the carapace ( Fig. 22 e) and the large median apophysis is not in the same line as the embolus origin ( Fig. 21 a).

Etymology. Based on the zoropsid genus name Uliodon which it somatically resembles; the gender is feminine.

Description. Carapace brown with irregular darker flecks along striae ( Figs 22 b, e); abdomen dorsally fawn with irregular mottling forming weak internested “V”s; ventrally with irregular darker mottling; legs brown with weak paler bands ( Figs 22 a, e, g). Carapace pear-shaped with gentle anterior constriction; caput low; fovea present reaching to edge of posterior declivity; caput slightly elevated, distinct; other striae indistinct; lightly hirsute. Clypeus ca. one AME diameter high. Eight eyes in two rows: anterior narrower, recurved; posterior more recurved ( Fig. 22 b). All eyes of similar size with anterior row eyes slightly larger. Group occupies two-thirds of headwidth. AME on common tubercle on clypeal edge, look forward, to side and up; ALE less than 1 diameter away look more up and to side, PME paler look up, ca. 1 diameter apart; PLE look to side. Chelicerae small, vertical with small boss; fangs short, diaxial; dentition 3 small P, 2 R, of short furrow; long pallid ovoid area prolaterally above fangs. Maxillae ( Fig. 22 f) roughly diamond-shaped with rounded corners and shallow basal diagonal groove; serrula long. Labium ( Fig. 22 f) short, shield-like.

Sternum ( Fig. 22 f) almost lenticular; converges in front, rounded margins, strong setae along marginal band, marginal setae outward, central setae radially directed inward. Legs. Coxae with rounded inner edges, anterior corner of basal strial attachment triangular, smaller process on posterior corner. RCH raised, pallid. Coxae IV of male cluster of ca. 10–20 long thick setae on ventral inner corner ( Fig. 22 d). Trochanters short, with small but distinct deep notches ca. 1.5 times wider than deep ( Fig. 22 g). Tarsi slightly curved. Female palpal tarsus tapered conical, unmodified; claw clearly evident. Scopula : on male weak, thin on tarsi I, II, not obscuring cuticle reduced to distal group of setae on III, IV, weak, thin, lateral group of scattered hairs on metatarsi I, II, absent on III, IV and tibiae. Scopula slightly denser in females than males, for ca. 0.8 of metatarsal length, full length of tarsus. Trichobothria in 2 rows on tibiae, an irregular line on metatarsi, two bands on tarsi, distal most trichobothria on each segment very long. Trichobothrial base collariform ( Fig. 24 a). Tarsal organ ovoid with ovoid aperture ( Fig. 24 b). Spines. Male (female): proventral spine on femora I, II weak; patellae aspinose; tibiae I, II with 3 pairs of weak spines (only 3–4 thicker bristles) ventrally, much weaker than on metatarsi; 2 (1) pairs on ventral metatarsi I, II. Female palp: fe p1; pa d1 elongate; ti p3d2 all strong; ta p3d1r 2 v 2 subdistally. Preening combs absent. Claws. 2 claws with 3–6 teeth; claw tufts dense, fused, as high as claws but not obscuring teeth. Female palpal claw with 3–4 teeth. Spinnerets ( Fig. 22 g). Colulus small. Female: ALS ca. 2x diameter of PLS and longer, PLS slightly longer than PMS with conical apical segment; PMS long, cylindrical with no enlarged spigots on tip or dorsally. Male Palp ( Fig. 21 ). Tibia short, with retrodistal RTA with inner keel and outer flange with unsclerotised crescent between them. Cymbium short with ovoid apical scopula and long thick recurved setae apically; apical cone wide, short, retromargin with wide flattened area with medial groove for basal third; light cage of long bristles on promargin ( Fig. 21 a). Bulb: tegulum with several processes and lobes apart from prominent distal bifid median apophysis and short embolus originating on mid-prolateral edge; small conductor below median apophysis. Epigyne ( Figs 22 c, g, 23a, b). Externally a pair of anterior crescentic ridges set diagonally; medially forming shallow trough posteriorly; vulva simple, copulatory fossae funnel-shaped with short twisted duct leading to enlarged distal spermatheca and fertilisation duct.

Distribution and habitat ( Fig 25 a, 26b). Known only from leaf litter in open eucalypt, wet sclerophyll, semi-evergreen vine thicket, Blackbutt close forest and heath mixed with eucalypt forest from Rockhampton to Ipswich, southeast Queensland.

Remarks. Nuliodon gen. nov. includes the smallest miturgids known (total length about 5 mm); the spiders are common in open forest, but not rainforest, leaf litter. Perhaps as a result of limited spider surveys in the Brisbane area prior to 1990, records of these spiders prior to 1978 are lacking. Despite this, these spiders were taken very close to long-occupied suburbs and in bushland on the Griffith University campus. Hence, this new species has literally long been in the backyards of Brisbane dwellers.

Figures

FIGURE 21. Nuliodon fishburni sp. nov., male: a, palpal tibia, cymbium and bulb, ventral view; b, median apophysis, ventral view; c, d, RTA, ventral (c) and retrolateral view (d).

FIGURE 22. Nuliodon fishburni sp. nov., female: a, habitus; b, carapace, dorsal view; c, epigyne, external view; d, coxae IV, ventral view; e, carapace, abdomen and legs, dorsal view; f, sternum, maxillae and labium, ventral view; g, abdomen, ventral view. Scale lines: 5 mm for a, e; 1 mm for b, f; d, f, g to same scale; 0.2 mm for c.

FIGURE 24. Nuliodon fishburni sp. nov., female, scanning electron micrographs: a, tarsal trichobothria and cuticle, dorsal view; b, tarsal organ, dorsal view; c, claw tufts.

FIGURE 25. Distribution records of Miturgidae in Australia: a, Diaprograpta, Eupograpta, Mitzoruga and Nuliodon; b, all records of Miturgidae for Australia.