Missulena melissae, Miglio, Laura Tavares, Harms, Danilo, Framenau, Volker Wilhelm & Harvey, Mark Stephen, 2014

Miglio, Laura Tavares, Harms, Danilo, Framenau, Volker Wilhelm & Harvey, Mark Stephen, 2014, Four new Mouse Spider species (Araneae, Mygalomorphae, Actinopodidae, Missulena) from Western Australia, ZooKeys 410, pp. 121-148 : 124-127

Missulena melissae sp. n. Figs 1A, 2 A–J, 3 A–J

Type material.

AUSTRALIA: Western Australia: holotype male, Millstream-Chichester National Park, 6 km N. of Millstream Homestead, site PW11, 21°32'24.8"S, 117°03'25.2"E, 15 July 2003−11 October 2004, wet pitfall trap, Department of CALM staff (WAM T97323). Paratypes: 2 males, same data as holotype, except Corunna Downs, 52.5 km N. of Nullagine, Pilbara Biological Survey site NW11, 21°24'27.7"S, 120°04'16.7"E, 3 August 2003−20 October 2004, Department of CALM staff (WAM T120931).

Etymology.

The specific epithet is a patronym in honour of Melissa Thomas, the third author’s partner, for her continuing support of late-night arachnological endeavours.

Diagnosis.

Males of Missulena melissae sp. n. differ from the two other species with a brown body colour, strongly-sclerotised rastellum with thick spines, smooth and glabrous chelicerae with prominent horizontal ridges and short claws (i.e. Missulena faulderi and Missulena rutraspina ) by details of the bulb and somatic morphology: embolus short and with a distal tooth (exceeding length of the bulb and without distal tooth in Missulena faulderi ), carapace length ca. 4 cm (3.5 cm in Missulena rutraspina ), patella I-III with rasps (patella III only in Missulena faulderi ), rastellum on a low mound (mound distinct in Missulena faulderi ), inner row of cheliceral teeth divided (first six teeth fused in Missulena faulderi ), and pedipalp patella and tibia swollen (much more slender in Missulena faulderi ). Males of Missulena rutraspina differ in having a simple embolus tip without processes, a straight embolus, rasps on patella III only, rastellum on a distinct mound, inner row of cheliceral teeth with six spaced teeth, and pedipalp tibia and patella more slender. The female of Missulena melissae sp. n. is unknown.

Description.

Adult male, based on holotype (WAM T97323). Medium-sized mygalomorph spider (total length 8.00).

Colour: carapace (Fig. 1A) dark reddish-brown, margins dark brown; eye region (Fig. 2B) dark brown, anterior median eyes on black tubercle; chelicerae (Fig. 3I) dark reddish-brown, fangs reddish-brown; abdomen (Fig. 1A) pale brown with a grey metallic spot in dorsal region; sternum (Fig. 3H) yellowish-brown, margins contoured dark yellowish-brown, sigillae yellowish-brown; labium (Fig. 3G) and maxillae (Fig. 3C) dark reddish-brown; legs (Figs 1A, 3 A–B) yellowish brown, tarsi and metatarsi ventrally yellow; spinnerets (Fig. 3J) pale gray, spigots white.

Carapace: 3.81 long, 4.0 wide; clypeus 0.13; fovea 2.18; caput and eye region (Fig. 2 A–C) laterally elevated, strongly arched; fovea (Fig. 2A, C) very deep, wide and strongly procurved, medially extending as triangular depression, pars cephalica smooth around the eyes and between the eyes and fovea, pars thoracica rugose with bands of fine, random fissures centered around fovea (Fig. 2C).

Eyes: OQ 3.61 times wider than long, occupying 1.12 of cephalic width; OAW 3.54; OAL 2.68; IPF 0.40; width of anterior eye group 2.95, with of posterior group 2.36, OQ length 0.81; PME 0.19; PLE 0.22; ALE 0.26; AME 0.22, AME on tubercle, 0.27 long, 0.62 wide; AME inter-distance 0.65; AME to ALE 1; AME to PME 0.40; PLE to ALE 0.55; PLE to PME 0.41; PME inter-distance 1.41; PME to ALE 0.55; eye region (Fig. 2B) with reduced setation although some setae present anterior to AME and between posterior eyes and fovea.

Chelicerae: 2.95 long, 1.54 wide; distally broad, diagonal, slightly conical; edges smoothly rounded; with weak transverse ridges which distally extend over entire length (Fig. 3I), without setae in area of transverse ridges but with ca. 60 short setae along inner margin of chelicera; rastellum developed, slightly pronounced, consisting of a sclerotised process with 3 strong conical spines and 12−14 disordered setae (Fig. 3I), 12−13 long setae extend forward from anterior margin of each chelicera and cover base of fang, setae largest on latero-ventral side; inner margin of cheliceral furrow with 3 rows of teeth (Fig. 3E); prolateral (inner) row with ca. 12 teeth, 3 proximal teeth fused together and the rest spaced; intermediate row with 9 proximal, spaced teeth; retrolateral (outer) row with 3 proximal, spaced teeth.

Maxillae: 1.86 long; 1.31 wide, longer than wide (Fig. 3C, D), with ca. 57 pointed cuspules along entire anterior margin, distally pointed and extended into a prominent heel.

Labium: 1.04 long, 0.77 wide; conical, ca. 20 pointed cuspules anteriorly (Fig. 3G); labiosternal suture developed as a shallow groove; a pair of sigilla near labiosternal suture (Fig. 3H), developed as irregular, poorly-defined patches.

Sternum: 2.27 long, 2.09 wide; oval and rebordered (Fig. 3H), with prominent setae, arranged irregularly but denser lateral to labium; 4 pairs of sigillae, anterior and second pair (anterior-posterior) smallest and poorly defined, third pair bigger than 2 anterior pairs and poorly defined, and posterior pair bigger than all others, roughly oval and well defined, 3 posterior sigillae slightly depressed.

Abdomen: 4 long, 3.54 wide; roughly oval (Fig. 3F); 4 spinnerets (Fig. 3J), PLS 0.72 long, 0.45 wide, apical segment domed; PMS 0.40 long, 0.13 wide.

Pedipalp: length of trochanter 0.85, femur 2.11, patella 0.33, tibia 0.66, tarsus 0.18; entire palp is aspinose, femur more than 3 times longer than tibia, tarsus terminally blunt (Fig. 2F); bulb pyriform and rather stout than globular (Fig. 2G, I−J), 2 strongly sclerotised sections connected by a velar median structure ( “haematodocha”, Fig. 2G, I); bulb strongly twisted proventrally (Fig. 2I); embolus short, with an intumescence in proximal region (BEI), a strong curvature in the duct in prolateral view, tapering and slightly twisted medially (Fig. 2I, J); embolus tip triangular, with a lamella (EL) well-developed and a prominent tooth (DET) in all views (Fig. 2 G–J).

Legs: with few brown setae, ventral setae of tibiae and metatarsi generally much longer and thicker than dorsal setae and bent towards the exterior; dorsal, lateral and ventral setae of tibiae and metatarsi longer than the diameter of respective segment; preening comb distal in tarsi, very small and plain; metatarsi and tarsi I and II ascopulate, metatarsi and tarsi III and IV densely scopulate but in metatarsi, the length of scopula reaches only 80% of the segment length. Metatarsi I and II with ca. 23, 33 fine ventral setae distally, respectively. Leg measurements: Leg I: femur 2.37, patella 2.00, tibia 2.00, metatarsus 2.00, tarsus 1.00, total 9.37. Leg II: 2.25, 1.87, 1.62, 2.12, 1.00, 8.87. Leg III: 2.5, 1.62, 1.5, 2.37, 1.00, 9.00. Leg IV: 3.25, 1.62, 2.00, 2.25, 1.37, 10.5. Formula 4123.

Trichobothria: arranged in discontinuous rows; tibiae I–II with 2 rows of 2 in retrodorsal and prodorsal position, respectively; tibiae III with 2 rows of 2 in retrolatero-dorsal and proximo-prodorsal position, respectively; tibiae IV with 2 rows, the first row with 2 in retrolatero-dorsal and the second row with 3 in proximolateral position; metatarsi with 5 in proximo-dorsal position, tarsi I+II with 4 and 6 medio-dorsally, respectively, III+IV with 5 and 6 medio-dorsally, respectively, all trichobothria in medio-dorsal position.

Leg spination: pedipalp aspinose; leg I: tibia rv0−0−0, v3−3−7, pv1−2−0, d0−0−0; metatarsus rv2−1−1, v2−3−5, pv0−0−0, d0−0−0; tarsus rv1−4−3, v2−7−3, pv2−2−2, d0−0−0; leg II: tibia rv0−0−0, v0−0−0, pv0−1−0, d0−0−0; metatarsus rv0−0−0, v0−0−0, pv0−0−0, d0−0−0; tarsus rv3−5−4, v1−2−2, pv1−3−2, d0−0−0; leg III: tibia rv0−0−0, v0−3−2, pv2−2−2, d2−1−3; metatarsus rv2−2−3, v0−0−0, pv3−3−4, d8−4−2; tarsus rv3−5−4, v0−0−1, pv1−3−4, d0−2−2; leg IV: tibia rv0−2−0, v2−4−4, pv1−1−2, d3−0−0; metatarsus rv1−3−2, v0−0−0, pv1−3−4, d0−0−1; tarsus rv4−9−13, v0−0−1, pv1−4−6, d0−0−2; patellae I and II with ca. 53 and 35 rasps, in 8 and 6 oblique rows prolatero-dorsally, respectively; patella III with ca. 59 rasps widespread in dorsal view (Fig. 4B); patella IV with 19 rasps, in 8 and 6 oblique rows prolatero-dorsally, median rows shorter than lateral rows and with less spines, distal spines forming an interrupted crown of spines in the border of the article (Fig. 4B).

Tarsal claws: leg I: 5−4/1; leg II: 6−6/1; leg III: 5−4/1; leg IV: 3−3/1; claws slightly shorter than spines of tarsi.

Variation in paratypes (N=2): total length 6.72−7.36; carapace 3.45 long, 3.90−4.36 wide; number of labial cuspules 14−16, maxillary cuspules 48−67; rastellum with 1−4 thick and conical spines.

Distribution.

This species is known from the type locality Millstream-Chichester National Park and Corunna Downs in the Pilbara biogeographic region of Western Australia (Fig. 4).

Habitat.

All specimens were collected in pitfall traps. The collecting sites were dominated by Acacia spp., with one site having a eucalypt over-storey ( McKenzie et al. 2009).