Four new Mouse Spider species (Araneae, Mygalomorphae, Actinopodidae, Missulena) from Western Australia

Abstract Four new species of the Mouse Spider genus Missulena Walckenaer, 1805 (family Actinopodidae) are described from Western Australia based on morphological features of adult males. Missulena leniae sp. n.(from the Carnarvon and Yalgoo biogeographic regions), Missulena mainae sp. n. (Carnarvon), Missulena melissae sp. n. (Pilbara) and Missulena pinguipes sp. n. (Mallee) represent a broad spectrum of morphological diversity found in this genus and differ from other congeners by details of the male copulatory bulb, colour patterns, eye sizes, leg morphology and leg spination. Two of the species, M. pinguipes sp. n. and M. mainae sp. n., are characterised by swollen metatarsi of the fourth legs in males, a feature not previously recorded in the family. A key to males of all named Missulena species from Australia is presented and allows their identification based on external morphology.


Introduction
The mygalomorph spider family Actinopodidae Simon, 1892 has a southern Gondwanan distribution with species found in the Neotropical and Australasian regions, specifically the tropical and temperate zones of Australia, South and Central America. The family includes 42 described species in three genera: the Neotropical Actinopus Perty, 1833 (27 described species), Missulena Walckenaer, 1805 from Australia and Chile (13 species), and the exclusively Chilean genus Plesiolena Goloboff & Platnick, 1987 (2 species) (Platnick 2014).
Species belonging to Missulena, commonly referred to as Mouse Spiders, are amongst the most recognisable Australian arachnids, with males of M. insignis (O. Pickard-Cambridge, 1877), M. langlandsi Harms & Framenau, 2013, M. occatoria Walckenaer, 1805and M. reflexa Rainbow & Pulleine, 1918 displaying conspicuous red fangs and cephalic areas. Adult males wander during the day, adding to their prominent status amongst naturalists and resulting in their frequent illustration in field guides (e.g. Brunet 1994;Brunet 2000;Mascord 1970). Not all species are colourful and the red markings can be reduced, e.g. in M. hoggi Womersley, 1943, or entirely absent as in M. dipsaca Faulder, 1955, M. granulosa (O. Pickard-Cambridge, 1869, M. faulderi Harms & Framenau, 2013, M. rutraspina Faulder, 1995and M. torbayensis Main, 1996. Mouse spiders have also received attention due to the toxicity of their venom that appears to be similar in composition to that of Australian funnel-web spiders (family Hexathelidae); however, severe cases of envenomation are rare and not all species appear equally harmful (Herzig et al. 2008;Isbister 2004;Rash et al. 2000).
Several species, namely the type species M. occatoria, but also M. granulosa and M. insignis, were amongst the first spiders to be collected and described from Australia, resulting in a confusing taxonomic history because early type localities were not recorded (e.g. "New Holland" for the nominate species M. occatoria), old taxonomic descriptions were poor by modern standards, and some type specimens appear to be lost (Main 1985).
The first attempt towards a more integrated taxonomy (Womersley 1943) recognised six species, only four of which are known from both male and female specimens. Little taxonomic work was undertaken subsequently, with the description of M. pruinosa from the Northern Territory by Levitt-Gregg (1966). Main (1985) catalogued all species, summarised the taxonomic literature and provided preliminary distribution data. Her contribution stimulated several subsequent taxonomic papers, all adding additional species from Western Australia: M. dipsaca, M. rutraspina (both Faulder 1995b), M. torbayensis (Main 1996), and more recently M. faulderi and M. langlandsi (both Harms and Framenau 2013). It was also after the publication of Main's (1985) catalogue that that the first Chilean representative, M. tussulena Goloboff, 1994, was described. In addition to taxonomic advances, the major phylogenetic treatises of Raven (1985) and Goloboff and Platnick (1987) developed a diagnosis of Missulena against other mygalomorph spiders: the anterior row of eyes is almost straight, the posterior median eyes are closer to the anterior lateral eyes than the posterior lateral eyes, the male pedipalps are shorter than the first leg, the patella of the first leg has robust spines, the sternum is rebordered, and the male pedipalp embolus is almost straight and thinner than that of other Actinopodidae.
Missulena currently has the highest species diversity in Western Australia where ten of the 12 Australian species occur, six of which are endemic to the state (Table 1). Recent large-scale environmental surveys conducted in Western Australia (e.g. Durrant et al. 2010;Main et al. 2000) have discovered additional morphospecies and confirm the previous notion that the diversity of this genus is underrepresented by the current taxonomy (Harms and Framenau 2013;Main 1985). It is clear, that the species of Australian Missulena known to date represent merely a fraction of the actual species diversity in this region.
The aim of this paper is twofold. Firstly, we add four new species of Missulena to the currently described Australian fauna, resulting in a total of 16 species (Table 1). These new species have very distinctive male morphologies and differ clearly from all other named species although the taxonomic status of some of these remains poorly resolved. Secondly, we provide a key that aids in the identification of males of all de-  rutraspina Faulder, 1995WA, SA, Vic Faulder (1995b M. torbayensis Main, 1996WA Main (1996 1 published literature and university theses only scribed species. A comprehensive key has not been published since Womersley (1943), although most species were described since then. A comprehensive revision of Missulena, which includes a considerable undocumented fauna is beyond the scope of this study as it would require substantial funding and full-time commitment.

Morphology
Specimens used for morphological examination were preserved in 75% ethanol. Material was examined using a Leica MZ16A stereomicroscope. Digital images were taken using a Leica DFC 500 digital camera attached to a Leica MZ16A stereomicroscope controlled by the Leica Application Suite Version 3.7. This program allows the alignment of images taken at different focal planes (here ca. 20-40 images) and combines them into a single image. The images were edited and formatted in Adobe Photoshop, version CS5.
The specimens examined for this study are lodged in the Western Australian Museum, Perth, Australia (WAM). We also examined type material of all Australian Missulena that was available to us ( Table 2).
The distribution data for species is described within the context of the Interim Biogeographic Regionalisation for Australia (IBRA) (Department of the Environment 2013).
All measurements are expressed in millimetres. The format of the descriptions and measurements follows Griswold and Ledford (2001), except for the spination pattern of the legs that is described according to Harms and Framenau (2013). Spine counts were taken from the right legs. The number of teeth on the claws is given as the formula "leg number: number of teeth of lateral claws/number of teeth of median claw". The leg formula is given as the order of the leg lengths from longest to shortest. The leg "index" is given here as the leg length divided by carapace length and indicates the ratio of leg lengths versus carapace. The term "rasps" refers to the presence of short but strong conical spines on the patellae of all legs. The presence of such rasps on patella I is a potential synapomorphy for Missulena species (Goloboff and Platnick 1987).
The following abbreviations were used: Morphology: (EL) embolar lamella, (DET) distal embolar tooth, (BEI) basal embolar intumescence, (d) dorsal, (v) ventral, (p) prolateral, (r) retrolateral, (PME) posterior median eyes, (PLE) posterior lateral eyes, (ALE) anterior lateral eyes, (AME) anterior median eyes, (MOQ) median ocular quadrangle, (OAL) ocular area length, The taxonomic key is based on a complete inventory of the available literature and examination of type material of many species. We have restricted this key to males because nine of the now 16 Australian described species are known from the male gender only; females remain unknown and are morphologically less distinct. We note that this key is preliminary because many additional unnamed species are present in collections, at least from Western Australia.  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.

Family Actinopodidae Simon, 1892
Diagnosis. Males of M. 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. M. faulderi and M. 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 M. faulderi), carapace length ca. 4 cm (3.5 cm in M. rutraspina), patella I-III with rasps (patella III only in M. faulderi), rastellum on a low mound (mound distinct in M. faulderi), inner row of cheliceral teeth divided (first six teeth fused in M. faulderi), and pedipalp patella and tibia swollen (much more slender in M. faulderi). Males of M. 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 M. melissae sp. n. is unknown. 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.
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.
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. 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 retrolaterodorsal 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 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).
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). Etymology. The specific epithet is a Latin adjective referring to the swollen metatarsi IV of males (pinguis, fat; pes, foot).

Missulena pinguipes
Diagnosis. Males of M. pinguipes sp. n. differ from all other named species of the genus, except M. mainae sp. n. by the swollen metatarsus IV (Fig. 6K). They differ from M. mainae sp. n. by the brown carapace and chelicerae, which are red in the latter. Females of M. pinguipes sp. n. are unknown.
Sternum: 1.37 long, 1.48 wide; oval and rebordered (Fig. 6H), with prominent setae, arranged irregularly but denser lateral to labium; 4 pairs of sigillae, anterior and second pair (anterior-posterior) smallest but well defined, third pair bigger than 2 anterior pairs and well defined, and posterior pair bigger than all others, roughly oval but not well defined, all sigillae slightly depressed.
Trichobothria: arranged in discontinuous rows; tibiae I-II with 1 row of 3 in retrolateral and dorsal position, respectively; tibiae III-IV with 2 rows of 4−5 in dorsal position, first row situated prodorsally and second row situated retrodorsally; metatarsi with 2 in medio-dorsal position, tarsi I+II with 2, III+IV with 3, all trichobothria in medio-dorsal position.    (Fig. 6A), patella III with ca. 26 rasps in 8 oblique rows dorsally, median rows shorter than lateral rows and with less spines, distal spines forming a interrupted crown of spines in the border of the article (Fig. 6B); patella IV with 6 rasps retrolaterally and 12 thick and short spines dorsally.
Distribution. This species is known only from the Mallee biogeographic region of southern Western Australia (Fig. 4).
Phenology and habitat preferences. The specimens were collected in pitfall traps in woodland habitats in either April or November. Description. Adult male, based on holotype (WAM T96784). Medium-sized mygalomorph spider (total length 6.81).
Chelicerae: 2.04 long, 0.95 wide; distally broad, diagonal, slightly conical; edges smoothly rounded; with transverse ridges which distally extend over entire length and many strong granulations widespread in dorsal view (Fig. 8I), with ca. 22 long setae widespread in inner area of transverse ridges and with more than 70 short setae along inner margin of chelicera; rastellum (Fig. 7D) poorly developed, weakly pronounced, consisting of a sclerotised process with 2 strong conical spines and 9−10 disordered setae, 9 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. 8E); prolateral (inner) row with ca. 9 teeth, all teeth spaced; intermediate row with 4 proximal, spaced teeth; retrolateral (outer) row with 3 proximal, spaced teeth.
Sternum: 1.95 long, 1.72 wide; oval and rebordered (Fig. 8H), with prominent setae, arranged irregularly but denser lateral to labium; 4 pairs of sigillae, anterior pair very small, irregular and undefined; second pair (anterior-posterior) smallest but well defined; third pair bigger than 2 anterior pairs and well defined; and posterior pair bigger than all others, roughly oval but not well defined; 3 posterior sigillae slightly depressed.
Distribution. This species is currently known from two sites located in the Carnarvon and Yalgoo biogeographic regions of Western Australia (Fig. 4).
Phenology and habitat preferences. The two specimens were collected in pitfall traps between May and August. They were listed as Missulena sp. 4 in a survey of mygalomorph spiders of the southern Carnarvon Basin by Main et al. (2000). The two sites are dominated by Banksia and eucalypt mallee woodland (site NA3), or Acacia aneura (site MR2) over stable but sandy substrates (Burbidge et al. 2000, Appendix A;Wyrwoll et al. 2000). Etymology. This species is named in honour of Barbara York Main in recognition of her substantial contributions to arachnology. She also was the first to recognize this taxon as a distinctive new species (Main et al. 2000).
Diagnosis. Males of Missulena mainae sp. n. differ from all other species by the uniformly red dorsal coloration of the carapace (pars cephalica and thoracica red; Figs 2D, 10C). Males share with M. pinguipes sp. n. the presence of a swollen metatarsus IV, but the character is less pronounced in M. mainae (Fig. 10K).
Colour: carapace (Fig. 9C) 9C) very deep and strongly procurved, medially extending as triangular depression, pars cephalica with few granulations around the eyes, behind the eyes and between the eyes and fovea, pars thoracica with bands of fine, random fissures centered around fovea (Fig. 9C).
Sternum: 1.82 long, 1.71 wide; oval and rebordered (Fig. 10H), with prominent setae, arranged irregularly but denser lateral to labium; 4 pairs of sigillae, anterior pair smallest than others and undefined, second pair (anterior-posterior) smallest but well defined, third pair bigger than 2 anterior pairs and well defined, and posterior pair bigger than all others, roughly oval but not well defined, all sigillae slightly depressed.
Distribution. This species is known only from Quobba Station in the Carnarvon biogeographic region of Western Australia (Fig. 4).
Phenology and habitat preferences. All specimens were collected in pitfall traps in a period between May and October. They were listed as Missulena sp. 2 in a survey of mygalomorph spiders of the southern Carnarvon Basin (Main et al. 2000). The two sites are dominated by Acacia over dune substrates (Burbidge et al. 2000, Appendix A;Wyrwoll et al. 2000).

Key to the described males of Missulena from Australia
(Distribution indicative as in Table 1; some species may have a wider occurrence.)  Faulder (1995a), in an unpublished thesis, considers M. hoggi and M. granulosa, mainly differentiated by the colour pattern of carapace and chelicerae, conspecific.