Missulena harewoodi, Framenau, Volker W. & Harms, Danilo, 2017

Framenau, Volker W. & Harms, Danilo, 2017, A new species of Mouse Spider (Actinopodidae, Missulena) from the Goldfields region of Western Australia, Evolutionary Systematics 1 (1), pp. 39-46 : 39

Missulena harewoodi sp. n. Figs 1 A–G, 2 A–F, 4

Type material.

AUSTRALIA: Western Australia: holotype male, 20 km East of Kalgoorlie, 30°44 ’41” S, 121°34 ’01” E, 14-16 April 2015, Greg Harewood, dry pitfall trap, Goldfields Blackbutt low woodland over open scrub on loam (WAM T142820).

Etymology.

The specific epithet is a patronym in honour of Greg Harewood, the collector of the type specimen.

Diagnosis.

The colouration of the holotype of M. harewoodi sp. n. is most similar to M. pruinosa due to the light dorsal discolouration of the abdomen, but the species differs in the lower number of spines of the rastellum (three vs ten), smaller size (male body length 8.0 mm vs 12.5 mm) (measurements from Faulder 1995a) and narrower pedipalp tibia. Male Missulena bradleyi also have a light pattern on the dorsal side of the abdomen, but it is restricted to an anterior light blue patch and the species is also larger (male body length 8.0 mm vs 10.9 mm) (measurements from Faulder 1995a). Otherwise, somatic morphology most closely resembles three species with a brown carapace, M. melissae Miglio, Harms, Framenau & Harvey, 2014, M. faulderi Harms & Framenau, 2013 and M. rutraspina Faulder, 1995, but M. harewoodi sp. n. differs considerably in the colour pattern of the abdomen of both live and preserved specimens (brown in M. melissae , grey-brown in M. faulderi and blue-grey in M. rutraspina ) and the much smoother carapace ( Faulder 1995b; Harms and Framenau 2013; Miglio et al. 2014).

Description.

Adult male, based on holotype (WAM T142820). Small mygalomorph spider (total length 8.0).

Colour: Carapace glabrous brown to dark brown (Fig. 1A); dark brown around PME (Fig. 1C); chelicerae and fangs glabrous, brown to reddish-brown (Figs 1D, G); abdomen dorsally pale whitish laterally, medially light grey (Figs 1A, F); ventrally pale yellowish-brown (Fig. 1B); sternum yellowish-brown, darker towards margins, sigilla light brown (Fig. 1B, E); labium and maxillae light brown, with yellow-brown spots (Fig. 1G); legs glabrous brown, ventrally with olive tinge (Figs 1A, B); spinnerets olive gray (Fig. 2F).

Carapace: 3.52 long, 3.74 wide; clypeus 0.19; caput and eye region elevated (Fig. 1D); pars cephalica smooth, pars thoracica with bands of fine, radial fissures.

Eyes: OQ 3.28 times wider than long, OAW 2.13; OAL 0.65; width of posterior eye group 1.85; PME 0.178; PLE 0.18; ALE 0.23; AME 0.30; AME inter-distance 0.15; AME to ALE 0.83; AME to PME 0.21; PLE to ALE 0.40; PLE to PME 0.42; PME inter-distance 1.20; PME to ALE 0.49; two black setae anterior of AME (Fig. 1C).

Chelicerae: 1.62 long, 1.03 wide; with few short silvery setae medially; rastellum developed, slightly pronounced, consisting of a sclerotised process with 3 (left 4) strong conical spines and 12−14 disordered setae (Fig. 2E), 10-14 long setae extend forward from anterior margin of each chelicera and cover base of fang; inner margin of cheliceral furrow with 3 rows of teeth (Fig. 1G); prolateral (inner) row with ca. 9 teeth; intermediate row with 6 proximal, small spaced teeth; retrolateral (outer) row with 2 proximal teeth.

Maxillae : 1.56 long; 1.10 wide (Fig. 1G), with ca. 40 pointed cuspules along entire anterior margin.

Labium: ca. 0.82 long, 0.70 wide; conical, 11 pointed cuspules anteriorly (Figs 1G); labiosternal suture poorly developed; a pair of sigilla near labiosternal suture (Fig. 1E).

Sternum: 2.17 long, 2.00 wide; pear-shaped and rebordered (Fig. 1E), with dark setae of varying length, arranged irregularly but denser laterally and towards labium; 4 pairs of sigilla located more than three times their length from the border of the sternum, anterior and second pair (anterior-posterior) smallest and poorly defined, third pair bigger than 2 anterior pairs and poorly defined; posterior pair biggest, roughly oval and well defined, 3 posterior sigilla slightly depressed.

Abdomen: 3.58 long, 3.23 wide; roughly oval (but collapsed through preservation) (Fig. 1A, F); 4 spinnerets (Fig. 2F), PLS 0.52 long, 0.43 wide, apical segment domed; PMS 0.35 long, 0.16 wide at base.

Pedipalp: Length of trochanter 0.76, femur 1.62, patella 1.08, tibia 2.12, tarsus 0.86; tibia with irregular black setae, densest ventrally (Fig. 2 A–C); bulb pyriform (Fig. 2 A–C), two strongly sclerotised sections connected by a velar median structure ( “haematodocha”, Fig. 2C); embolus very slightly curved, reaches to half tibia length, with an intumescence in proximal region (BEI), a strong curvature in the duct in prolateral view, tapering and slightly twisted medially (Fig. 2C); embolus tip rounded triangular, with a lamella (EL) poorly developed and no prominent tooth (DET) (Fig. 2D).

Legs: With few brown setae, ventral setae of tibiae and metatarsi generally much longer and thicker than dorsal setae; dorsal; preening comb distal in tarsi, very small and plain; metatarsi and tarsi I and II ascopulate, metatarsi (along distal half) and tarsi (along whole length) of legs III and IV densely scopulate. Leg measurements: Leg I: femur 2.37, patella 1.54, tibia 1.84, metatarsus 1.46, tarsus 0.97, total 8.18. Leg II: 2.54, 1.44, 1.46, 1.59, 0.95, 7.98. Leg III: 2.68, 1.49, 1.29, 1.17, 1.28, 8.11. Leg IV: 3.14, 1.70, 2.10, 3.29, 1.16, 11.39. Formula 4123.

Trichobothria: Arranged in discontinuous rows; tibiae I–II with 2 rows of 3 in retrodorsal and prodorsal position, respectively; tibiae III with 1 rows of 2 in retrolaterodorsal; tibiae IV with 2 rows, the first row with 3 in retrolatero-dorsal and the second row with 2 in proximolateral position; metatarsi with 3 in proximo-dorsal row, tarsi I with 2 in proximo-dorsal row, tarsi II with 3, III+IV with 4 medio-dorsally, respectively.

Leg spination: Pedipalp aspinose; leg I: tibia rv1−1−0, 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 with ca. 10 rasp prolaterally, II with 2 rasp prolaterally, III with ca. 40 rasps prolaterally to dorsal, patella IV with ca. 10 rasps prolaterally and proximo-dorsally.

Phylogenetic analyses.

Our phylogenetic analyses places M. harewoodi sp. n. as sister taxon to an undescribed Missulena species from the Pilbara region in Western Australia, Missulena ‘DNA02’ (WAM T124777) (Fig. 3; Table 1), although this relationship is not well supported. Sequence divergence between both specimens is 14.5%, which is considerably larger than the current operational sequence divergence of 9.5%, employed to differentiate species in the Actinopodidae ( Castalanelli et al. 2014). Morphological comparison between both species is not possible as the Pilbara species is represented by a single juvenile specimen. Missulena harewoodi sp. n. from the Goldfields nests within a clade of three putative new species, Missulena ‘DNA02’, ‘DNA03’ and ‘MYG290’ and Missulena faulderi , that are all from the Pilbara bioregion of Western Australia, situated more than 900 km north-west of the City of Kalgoorlie-Boulder (Fig. 3). The Pilbara is geologically, floristically and climatically distinct from the Goldfields and it is unclear whether the results of our analyses are caused by taxon bias in the set of DNA sequences or reflect a true biogeographic pattern. Only more comprehensive analyses with additional representatives from southern and central Western Australia and including additional genes can clarify the phylogeographic patterns in Missulena .

Distribution.

Missulena harewoodi sp. n. is currently only known known from the type locality, ca. 20 km East of the City of Kalgoorlie-Boulder in the Goldfields region of Western Australia (Fig. 4).

Habitat.

The type specimen was collected alive in a 10-litre, dry bucket pitfall trap targeting vertebrates. The collecting site is described as Goldfields Blackbutt ( Eucalyptus lesouefii ) low woodland over open scrub on loamy soil (G. Harewood, personal communication to VWF). Similar to many other Missulena species, M. harewoodi sp. n. appears to mature in autumn (collected in April), contradicting the assumption that many mygalomorph spiders in arid and semi-arid Australia reproduce in the months with highest rainfall (e.g. January/February in the Goldfields near Kalgoorlie) ( BoM 2017; EPA 2016).

Remarks.

Missulena harewoodi sp. n. is the seventeenth named species of this genus in Australia and within a radius of about at least 100 km of its type locality, the only described species in the genus with the exception of the widespread M. occatoria (Walckenaer, 1805) (based on data of the Atlas of Living Australia; http://ala.org.au; accessed 10 April 2017). The species is yet another example of the extremely diverse invertebrate fauna of the semi-arid Goldfields region of Western Australia that is currently poorly studied in relationship to its invertebrate fauna when compared to other bioregions in Western Australia, e.g. the Pilbara ( Durrant et al. 2010; McKenzie et al. 2009; Volschenk et al. 2010). Whilst comprehensive biological studies have been conducted in the Goldfields more than two decades ago, these rarely considered invertebrates ( Biological Surveys Committee 1984; Keighery et al. 1995). Recent studies on terrestrial snails in the genus Bothriembryon Pilsbry, 1894 ( Breure and Whisson 2012), millipedes in the genus Antichiropus Attems, 1911 ( Car and Harvey 2013, 2014) and trapdoor spiders of the family Idiopidae Simon, 1892 ( Rix et al. 2017) have highlighted both extreme diversity and endemism in invertebrates within the vast woodlands of the Goldfields and numerous unpublished reports as part of environmental impact assessments have supported these general findings for other taxonomic groups. The fact that M. harewoodi sp. n. has never been sampled before near the regional centre of Kalgoorlie-Boulder and remains only known from a single specimen that was collected as by-catch during a vertebrate trapping survey, highlights the need for a comprehensive invertebrate fauna survey of this region that includes both its woodlands and isolated ranges of banded ironstone.