Missulena iugum

Description. MALE (based on holotype; WAM T 123110). Total length 9.89. Colour: pars cephalica and chelicerae orange (Fig. 8 C); a slim, black ring surrounding the PME (Fig. 8 G); pars thoracica brown with a light, metallic blue sheen (Fig. 8 C); abdomen greyish with a very strong, metallic blue and green sheen on the dorsal side (Fig. 8 D), ventrally more brownish with a faint hint of purple (Fig. 8 E); sternum orange, slightly fading into olive with 8 sigilla in different shades of orange (Fig. 9 C); labium and maxillae orange with a slightly darker reddish-orange spot on the base of labium (Fig. 8 F); legs olive fading into light brown ventrally, dorsally brown (Fig. 8 A-B); spinnerets beige-coloured (Fig. 8 E). Carapace: 3.87 long, 4.98 wide and 1.67 high; clypeus 0.34; pars cephalica covers 2.34 of its length, is highly elevated and faintly granulated with very few setae (Fig. 9 H); pars thoracica also granulated with bands of faint, radial fissures and with two notches close to the abdomen (Fig. 8 C). Eyes: OQ 3.7 times wider than long; outer width of each eye pair AME 0.53, ALE 2.54, PME 1.66 and PLE 2.2; diameter of AME 0.2, ALE 0.21, PME 0.11, PLE 0.19; anterior eyes slightly recurved; posterior eyes strongly recurved (Fig. 8 G). Chelicerae: 2.28 long and 1.55 wide on the base; edges rounded and curved with the widest point being 1.57 very close to the chelicerae base (Fig. 8 C); few setae along the inner margin and slightly more evenly spread setae along the anterior part of the chelicerae; rastellum present, slightly pronounced, consisting of a sclerotized process with 8 strong, conical spines (Fig. 8 H); approx. 20 setae cover the anterior base of fang of each chelicera; inner margin of cheliceral furrow with 2 rows of teeth with each a ridge along the row and a general cheliceral teeth area in between those 2 clear rows (Fig. 9 G, I); prolateral row with approx. 10 teeth; retrolateral row with 3 teeth (paratype has 4 teeth); intermediate area with 8 small teeth. Maxillae: 2.24 long and 1.52 wide; at least 85 - 100 weakly developed cuspules along entire anterior margin (Fig. 8 F). Labium: 0.94 long and 0.91 wide on the base; conical; at least 35 weakly developed cuspules anteriorly (Fig. 8 F); labiosternal junction visible (Fig. 9 C). Sternum: 2.84 long and 2.77 wide; ovoid (Fig. 9 C); setae of various length somewhat densely but disordered along the margin and a smaller amount of setae spread unevenly over the sternum; 4 pairs of sigilla, anterior pair small and hardly visible, second pair smallest (roughly half the size of the first pair) and circular, third pair larger than first and second pair (roughly 2 times bigger than first pair) in the shape of a drop, and posterior pair biggest (roughly 2.5 times the size of the third pair) in the shape of an elongated drop, all sigilla slightly depressed. Abdomen: 3.7 long and 3.41 wide; shape of a rounded trapezoid (Fig. 8 D); 4 spinnerets, PLS 0.88 long, 0.55 wide; PMS 0.45 long, 0.19 wide (Fig. 8 E). Pedipalp: length of trochanter 1.37, femur 4.17, patella 1.88, tibia 4.22, tarsus 0.75; all segments with setae, tibia ventrally densely covered with comparably long setae (Fig. 9 D-F); tibia rather thin and slightly recurved from lateral view, 1.00 wide on the widest point from prolateral and 1.08 from dorsal view (Fig. 9 D-F); bulb roughly pyriform, two strongly sclerotized sections connected by a velar median structure (" haematodocha "); embolus rather short with an intumescence in proximal region; tip of embolus triangular with a small lamella and a tooth best visible from prolateral view (paratype, Fig. 9 J, K). Legs: brown setae of various sizes on all sides of the legs and bent towards the exterior; some comparably long setae dorsally on most segments double the length of the other setae; ventral preening comb on tarsi and metatarsi III and IV. Leg spination: leg I: tibia rl 1, v 13, pl 0, d 0; metatarsus rl 2, v 10, pl 1, d 0; tarsus rl 2, v 7, pl 5, d 0; leg II: tibia rl 1, v 11, pl 1, d 0; metatarsus rl 2, v 11, pl 0, d 0; tarsus rl 5, v 9, pl 1, d 0; leg III: tibia rl 6, v 5, pl 5, d 6; metatarsus rl 5, v 7, pl 5, d 9; tarsus rl 10, v 9, pl 2, d 6; leg IV: tibia rl 1, v 10, pl 1, d 1; metatarsus rl 1, v 9, pl 3, d 2; tarsus rl 14, v 13, pl 5, d 5; patella I with 9 spines spread out prolaterally and three spine ventrally in a vertical row; patella II two spines ventrally in a vertical row; patella III with 27 spines spread out dorsally and prolaterally, 4 spines retrolaterally (Fig. 9 A) and 3 spines ventrally in a vertical row; patella IV with approx. 7 spines on the dorsal side (Fig. 9 B), approx. 6 spines on the prolateral side, all very small, and 3 spines ventrally in a vertical row. Leg measurement: Leg I: femur 4.2, patella 1.63, tibia 3.06, metatarsus 2.76, tarsus 1.58, total 13.23. Leg II: femur 3.47, patella 1.53, tibia 2.66, metatarsus 2.24, tarsus 1.48, total 11.38. Leg III: femur 3.07, patella 1.35, tibia 1.88, metatarsus 2.37, tarsus 1.52, total 10.19. Leg IV: femur 3.91, patella 1.59, tibia 2.99, metatarsus 2.78, tarsus 1.64, total 12.91. Formula: 1> 4> 2> 3.

Figs 8, 9, 10

Diagnosis. Males of Missulena iugum sp. nov. share the red chelicerae and pars cephalica with M. davidi sp. nov., M. manningensis sp. nov., M. langlandsi, M. occataria and M. insignis that are morphologically most similar. They differ from M. langlandsi by a longer carapace (> 3.00 mm; M. langlandsi up to 2.8 mm) and a rastellum with strong, conical spines (simple in M. langlandsi). Rastellum and cuspules on labium and maxillae stronger than in M. insignis (rastellum: 8 - 9 spines; M. insignis 2 - 5; cuspules: M. insignis none). Pars cephalica lower than in M. occatoria (up to 1.69; M. occataria approx. 3.0) and carapace shorter (3.87 long, 4.98 wide; M. occataria approx. 5.0 long, 7.0 wide). Differs from M. davidi sp. nov. and M. manningensis sp. nov. by the presence of a ridge in the cheliceral groove (Fig. 9 G, I).

Distribution. Known only from the Mt Ida region approximately 16 km east of Ularring in the Goldfields region of Western Australia (Fig. 10). The habitat of the holotype comprises Acacia shrubland.

Etymology. The specific epithet is a Latin noun (Missulena iugum = ridge) in apposition, referring to the strongly developed ridges along the cheliceral groove of the males.