Maratus occasus Schubert 2019, sp. nov.

Maratus occasus sp. nov.

Type specimens. Holotype: Male. Australia, Queensland: Lake Broadwater, 27°20'21.12''S, 151°5' 49.595''E, 30 September 2016 (Coll. P. W. Price, deposited in the Queensland Museum, QMS 110414). Paratypes: 4 male, 1 female. Australia, Queensland: Lake Broadwater, 27°20'25.89''S, 151°5’48.231’’E, 6 October 2017 (Coll. P. W. Price, deposited in the Queensland Museum, QMS 110415).

Etymology. The specific name (occasus, Latin m., noun in apposition, English translation: sunset) refers to the colours of the scale patterns on the dorsal opisthosomal plate of the male.

Diagnosis. This species belongs to the Maratus tasmanicus group (Otto & Hill, 2017) with respect to the large triangular fan with lobate opisthosomal flaps, each flap bearing with a large black spot. The dorsal opisthosomal surface of the male M. occasus is marked with two longitudinal tracts of orange scales whereas males of M. tasmanicus and M. australis bear three (the middle stripe bifurcated in M. australis). Females of M. occasus are similar to other female Maratus species and identification may be problematic without association with a male.

Description of male (Figures 1:1-6, 2:1-3, 3:1-4, 6:1-5, 7:2). In life: Carapace dark brown, almost black and mostly glabrous; ocular quadrangle region covered thickly in grey scales and interrupted by stripes of red-orange scales which extend from behind each anterior eye to rear margin of ocular quadrangle (Figure 1:4); median thoracic tract comprised of white scales extends from rear slope of carapace to rear margin of ocular quadrangle region (may be worn in some specimens, see Figure 6); lateral tracts of white scales situated behind each PLE (Figure 3:3).

AME ringed with short, white scales; ALE ringed with short, red-orange scales on upper perimeter and short, white scales on lower perimeter; long white setae project downwards from below AME forming triangular shape (Figure 3:1); clypeus covered with short, white setae; chelicerae dark brown and glabrous; coxae, labium, and endites dark brown and glabrous; sternum dark brown with light covering of fine, white setae (Figure 3:4).

Dorsal opisthosoma patterned with complex figure comprised of orange scales on background of light blue scales by which two orange longitudinal tracts extend from anterior margin of opisthosoma meeting an orange oblong-like figure; transverse, curved band of orange scales runs parallel to posterior margin of opisthosoma; anterolateral edges of opisthosoma marked with tracts of orange/tan-orange scales (Figure 1:2-3); lateral opisthosomal lobes marked with two large black spots, upper perimeter encircled by orange scales; lateral opisthosomal lobes otherwise densely covered with dull blue-purple scales; opisthosomal plate thinly fringed with long, white setae, lateral lobes more thickly so (Figure 7:2); colular tuft of white setae situated above grey spinnerets (Figure 1:2-3); ventral opisthosoma dark brown and scattered with short, creamy coloured setae.

Legs I and II subequal in length; legs III and IV longer; legs III by far longest; legs I and II ringed with alternating white and brown/orange setae; legs IV similarly ringed but less distinctively so; femora and patellae of legs III lightly covered with white setae; tarsi of legs III white (Figure 1:1-6).

Pedipalp covered dorsally with long, off-white setae (Figure 1:1); relatively large male palpal bulb with retrolateral sperm duct loop, large retrobasal tegular lobe, finger-like retrolateral tibial apophysis, anticlockwise coiled embolus; distal embolus with two apices when viewed laterally; heavily sclerotized cuticle on tegulum, proximomedial to ring of embolus (Figure 2:1-3).

Female (Figures 4:1-6, 5:1-4). Ocular quadrangle region dark brown with incomplete cover of red-brown and white setae; area posterior to ocular quadrangle light brown and lightly scattered with short, white scales, otherwise mostly glabrous; rim of carapace glabrous and lacking marginal band (Figure 4:4-6); anterior eyes bordered with red-brown and white scales (Figure 4:1); PME closer to PLE than to ALE; long white setae project downwards from below AME forming triangular shape; clypeus covered with short, white setae (Figure 4:1); chelicerae light brown and glabrous; coxae, endites, and labium dark brown, translucent and mostly glabrous; sternum medium-dark brown with light covering of fine, white setae.

Dorsal opisthosomal surface dark brown and scattered with long, dark setae; anterior and lateral edges of opisthosoma light brown and covered with broad tracts of white setae (Figure 4:2-6); spinnerets dark brown; lateral and ventral opisthosoma light brown and mottled with small dark spots (Figure 5:2).

Legs I and II subequal in length; legs III and IV longer; legs III longest; all legs light brown and translucent with light covering of dark brown and white setae, legs III and IV slightly more heavily so; ventral femoral surface of legs I and II with distinct dark markings on cuticle (Figure 4:5-6); tarsi of each leg tipped with dark brown setae; pedipalps light brown and translucent with incomplete cover of dark brown and white setae (Figure 4:1).

Epigynum with pair of large ovate fossae separated by septum; ovate posterior spermatheca behind each fossa; sclerotized ducts present anterior to each spermatheca (Figure 5:4).

1, Dorsal view. 2, Ventral view. 3, Lateral view. 4, Epigyne.

Variation. In males, the median thoracic tract and lateral tracts of white scales on the carapace may be more distinct or indistinct between specimens due to rubbing and loss of scales. The longitudinal tracts of orange scales on the dorsal opisthosoma of the male vary in thickness between specimens (Figure 6) and the colours of these tracts and the background of blue/blue-green scales may be duller or more vibrant.

Dimensions of male (mm). Total length: 3.41‒3.85 (3.68±0.19, n=5). Carapace length 1.98‒2.08 (2.00±0.05, n=5). Opisthosoma length 1.42‒1.86 (1.65±0.15, n=5). Leg I length: 2.81‒2.85 (2.84±0.02, n=5). Leg II length: 2.82‒2.85 (2.83±0.01, n=5). Leg III length: 4.15‒4.24 (4.19±0.04, n=5). Leg IV length: 3.77‒3.84 (3.80±0.03, n=5).

Dimensions of female (mm). Total length: 4.23. Carapace length 2.15. Opisthosoma length 2.08. Leg I length 2.49. Leg II length: 2.51. Leg III length: 4.18. Leg IV length: 3.78.

Courtship display (Figure 7:2). During the courtship display, the male Maratus occasus sp. nov. raises and waves legs III, elevates the opisthosoma and extends the opisthosomal flaps. In many respects the courtship display strongly resembles that of M. tasmanicus (Otto & Hill 2013) and M. australis (Otto & Hill 2016).