Miturgopelma brachychiton, Raven & Hebron & Williams, 2023

Raven, Robert J., Hebron, Wendy & Williams, Kylie, 2023, Revisions of Australian ground-hunting spiders VI: five new stripe-less miturgid genera and 48 new species (Miturgidae: Miturginae), Zootaxa 5358 (1), pp. 1-117 : 27-30

Miturgopelma brachychiton sp. nov.

Figs 16–17

Diagnosis. Males resemble those of Miturgopelma watarrka sp. nov. in the recurved outer corner of the lower edge of the RTA, and differ in the much shorter median apophysis with retrobasal circular “well” ( Fig. 17a ). Female unknown.

Etymology. The species epithet is a noun in apposition from the genus name of the Queensland Bottle trees, genus Brachychiton , which is common at the type locality.

Type material. Queensland: male holotype, Forty Mile Scrub National Park , 18°05’S, 144°51’E, rainforest, pitfall, Oct 93– Jan 1994, J. Hasenpusch, QM S31439 .

Paratype. Queensland: 1 ma., Davies Ck National Park , 17°00’S, 145°34’E, pitfall, 26 Nov 1992 – 15 Apr 1993, R., J. & S. Raven, P. & E. Lawless, QM S19774 .

Description. Male, holotype QM S31439.

Carapace 2.71 long, 2.16 wide. Opisthosoma 2.34 long, 1.46 wide. Total, 4.1.

I: 3.00, 1.07, 2.86, 2.74, 1.07, 10.74. II: 2.80, 1.13, 2.54, 2.54, 1.13, 10.14. III: 2.69, 1.00, 2.40, 2.80, -.-, -.-. IV: 3.60, 1.13, 3.27, 3.94, 2.27, 14.21. Palp, 0.67, 0.60, 0.54, 0.00, 0.01, 1.82.

Colour. Carapace yellow brown with dark reticulations on caput and centrally; chelicerae dark gray with yellow brown boss; opisthosoma dorsally with dark gray medial sash edged in black; laterally densely grouped longitudinal striations; venter entirely pallid. Femora lightly mottled. Carapace almost glabrous.

Eyes: Eight in 2 recurved rows; front edge of ALE in base of back edge of AME, likewise in back row. ALE smallest, other eyes of similar size. Group front width: back width: length, 30:36:24. Sizes: AME 7, ALE 6, PME 8, PLE 6. Interspaces: AME–AME 3, AME–ALE 1, PME–PME 3, PME–PLE 6. Chelicerae: 3p, 2r. Sternum. Thick pallid hairs on margin, finer black centrally. Trochanteral notches ca. x 2–2.5 wider than deep. STC with 3–4 long teeth.

Legs: Scopula: Difficult to determine on metatarsi because of damage; very thin for 1/2–2/3 of metatarsi I–IV; denser but still very thin on tarsi I–IV; pseudotufts weak, indication of true tuft on I, not elsewhere. Trichobothria: in 2 lengthening rows on tarsi; one long trichobothrium on metatarsi; 2 rows on tibiae.

Spines. I: fe pv1p2d3 3; pa 0; ti p2d2r2v2.2.2; me p1.2r1v2.2. II: fe pv1p2d3r3; pa 0; ti p2d3r2v2.2.2; me p1.2r1v2.2. III: fe p4d3r4; pa 0; ti p2d2.1r2v2.2.2; me p1.2.1r2.1.1v2.2.1. IV: fe p4d3r3; pa 0; ti p2d2.1r2v2.2.2; me p1.1.1.2r2.1.1.2v2.2.1. Palp: fe p1d1.1.2d4; pa d1.1 (incl. 1 apical); ti p3.

Spinnerets. PLS and ALS long cylindrical; PLS ca. 0.5 x diameter of ALS with conical apical article; PMS smaller cylinders.

Palp. Tibia short with large trianguloid bipartite RTA, lower face with convex sclerotised with strong blunt hook anteriorly; upper face a conical process basally two meet in point ventrally which is narrowest part of deep trough. Cymbium leaf-like, no scopula; no thickened setae; apical cone small; lateral margins prolaterally narrow, retrolaterally concealed by tegulum. Median apophysis a small triangular process basally surrounded partially by circular well. Embolus arises mid-prolaterally with angular turn around and under median apophysis to very small conductor. Tegulum large, gourd-shaped, retrolateral; subtegulum dumbbell-shaped with larger lobe basally.

Distribution. Known only from Forty Mile Scrub, an area of vine thicket, west of Mt Garnet, and Davies Ck National Park, northeastern Queensland.

Figures

FIGURE 16. Miturgopelma brachychiton sp. nov., male holotype, QM S31439: a, habitus, dorsal view; b, male palpal patella to cymbium, dorsal view, showing chelate-like RTA.

FIGURE 17. Miturgopelma brachychiton sp. nov., male palpal bulb, cymbium and tibia, scanning electron micrographs: a, ventral view; b, proventral view; c, d, RTA, two slightly different retrolateral views.