Maratus cranius sp. nov.

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Figure x:

Maratus cranius is placed in the Maratus flavus group (Otto & Hill 2021) with respect to the five longitudinal tracts of red setae marking the ocular quadrangle region of the carapace, and by its courtship display by which the male extends legs III in a relatively vertical position and waves them in a bilaterally symmetrical manner without raising the opisthosoma. Males of M. cranius can be readily separated from all members of the M. flavus group by the lack of any vibrantly coloured scales covering the dorsal opisthosoma. Females of M. cranius are similar to other females in the M. flavus clade and identification may not be possible without association with a male or the aid of molecular data. The structures of the external male and female genitalia of M. cranius are of little use in distinguishing them from other Southwestern Australia endemic Maratusspecies.

Holotype male (REG NUMBER).

Cephalothorax. Ocular quadrangle region of carapace covered with dense mat of red setae. Medial thoracic tract comprised of off-white setae extends from posterior slope of carapace towards the fovea. Lateral slopes of carapace covered with white setae. Carapace otherwise dark brown to black. Clypeus with dense cover of grey setae. Chelicerae black and glabrous. Coxae, labium, and endites pale and glabrous. Sternum dark brown with light covering of fine, white setae.

Opisthosoma. Dorsal opisthosoma covered with dark brown scales laterally suffused with white scales posteriorly. Distinctive pyriform marking comprised of white scales extends from anterior margin of dorsal opisthosoma to ~2/3 the length of the opisthosomal plate. Scales above opisthosomal apodemes lighter, revealing dark brown cuticle below. Opisthosoma laterally covered with white setae. Stout, white setae project anteriorly at the anterior margin of the opisthosoma. Anal tuft of white setae present above black spinnerets.

Legs. Legs I and II subequal in length, legs III and IV longer, legs III by far longest. Legs uniformly covered in white setae (but see variation section), cuticular surface below dark brown.

Pedipalps. Pedipalp covered dorsally with long white setae. Relatively large male palpal bulb with retrolateral sperm duct loop, large, angular retrobasal tegular lobe, finger-like RTA. Embolic disc with anticlockwise coiled embolus (left pedipalp). Distal embolus with two apices when viewed laterally; heavily sclerotized cuticle on tegulum prolaterally below embolic disc.

Paratype female (REG NUMBER).

Cephalothorax. Ocular quadrangle region with dense cover of brown-orange and off-white setae, darker near PMEs and PLEs. Posterior slope of carapace posterior to ocular quadrangle dark brown and interrupted by median thoracic tract comprised of white setae. Lateral tracts of white setae extend from behind each AME to rear margin of carapace. Lateral slopes of carapace light brown and mostly glabrous. Carapace rim lacking marginal band of setae. PME closer to PLE than to ALE. Anterior eyes ringed with brown-orange and white setae or scales. Long white setae project downwards from below AME forming triangular shape. Clypeus lightly covered with short, white setae. Chelicerae dark brown and glabrous. Coxae, endites, and labium dark brown, translucent and mostly glabrous. Sternum dark brown with light covering of fine, white setae.

Opisthosoma. Opisthosoma marked with dark brown dorsum, lighter anteriorly, darker and slightly tapering posteriorly. Lateral opisthosoma flanked by broad, light brown to off-white tracts of setae extending to posterior margin of dorsal opisthosoma. Colular tuft of white setae situated above spinnerets. Lateral and ventral opisthosoma light brown with irregular dark spots.

Legs. Legs I and II subequal in length, legs III and IV longer, legs III longest. Each leg with incomplete cover of off white and brown setae, integument below light brown and translucent. Pedipalps light brown and translucent with incomplete cover of white setae.

Epigynum. Epigynum with pair of large ovate fossae separated by septum. Ovate posterior spermatheca behind each fossa. Sclerotized ducts present anterior to each spermatheca.

Figure x:

Variation. Like several other Southwest Australian endemic Maratus species, two distinct colour forms of M. cranius are known – a ‘light’ morph with mostly white setae covering the legs, pedipalps, and carapace, and a ‘dark’ morph with mostly light brown setae covering the legs, pedipalps, and carapace.

The former of which, shown in Figure x bears much wider longitudinal tracts of red scales situated behind each anterior eye. Additionally, the dorsal opisthosoma is more lightly coloured. The colour and shape of the brown tracts of setae on the lateral margins of the dorsal opisthosoma vary between individuals of both colour forms, but generally follow the same structure.

An individual which we consider to be M. cranius was photographed in Nambeelup Nature Reserve, Western Australia with slightly varied markings on the ocular region (see Figure x), however, a specimen from this population has not been examined. It is not uncommon for markings of the ocular region to vary to some degree between distant populations of conspecific Maratus individuals.

Courtship display.

Males do not raise their opisthosoma during courtship display, but they rapidly bob it up and down in a nearly horizontal position. Males elevate and hold their extended legs III in a

In one display (Figure 14) they hold their extended legs III in a variably elevated, bilaterally symmetric V-shaped position, and wave this pair of legs up and down (bilaterally symmetric movement; both legs up then both legs down) at a similar rate (~11 cycles/s). In a second display (Figure 16) they tend to hold both legs III in position as they bob the opisthosoma, but intermittently rotate both extended legs III in the same direction. This movement may be accompanied by slight movement of the body in the same direction

Habitat and distribution.

In leaf litter on edges of sandy track in an open x woodland. Known from x, x, and x. See variation section for blah blah.