Nucastia, Raven, 2015

Nucastia View in CoL gen. nov.

Diagnosis. Differs from Poecilipta in having a distinctly raised caput or cephalic region ( Fig. 1e, f View FIGURE 1 ); males have a weak dorsal scute, a very thin ventral scute, if present, no paracymbial spine, and in females, the dorsal scute is very small to absent, other scutes absent. Both males and females have the anterior eye row set on the roundly projected clypeal edge ( Figs 1e, f View FIGURE 1 , 68a View FIGURE 68 ), extending the extent of the carapace. Differs from Castianeira in having only bristles or lacking spines on tibiae I and II and 0–2 on metatarsi I and II. Females and males are also unusual in having a distinct retrobasal spinose ridge on the chelicerae ( Fig. 1f View FIGURE 1 ).

Etymology. Based on Castianeira , with bare (spine-free) tibiae I and II. The gender is masculine.

Type Species: Nucastia virewoods View in CoL sp. nov.

Description. Carapace elongate, with long raised caput; almost glabrous, cuticle smooth; usually narrow dark margin and pattern-less orange brown centre; fovea long, over edge of shallow posterior slope. Lateral profile of carapace ( Fig. 1e, f View FIGURE 1 ): caput distinctly domed with eyes on projecting lobe, domed slightly less behind fovea but shallow slope from fovea along posterior declivity; highest point at midpoint of fovea and eye group. Feathery hairs sparse on femora, usually absent on carapace and abdomen. Eyes: eight in two rows in small tight group; front row recurved; back row slightly procurved; front eyes larger, with AME set forward on common tubercle; small PME ca. 1.5 times apart. Retrolateral face of moderately large chelicerae with distinct multicusped ridge ( Fig. 1f View FIGURE 1 ); chelicerae long with distinct gap to maxillae most noticeable in ♀ ( Fig. 1f View FIGURE 1 ); fang short, groove oblique with two teeth on both margins; enlarged fang setae absent in ♀. Labium as wide as long; maxillae rhomboidal, convergent at base with broad diagonal mounded edge; inner edge concave. Sternum roughly triangular with small intercoxal extensions. Coxal bases with extensions. RCH present; femur IV without predistal constriction. Legs slender, tibiae I and II and sometimes III weakly spinose or aspinose. Patellar spine sometimes on III. Scopula on metatarsi and tarsi I and II, and weaker on tarsi III and IV. Claw tufts dense, short. Lateral spinnerets of similar size. Colulus hirsute, triangular. Abdominal pattern of males often absent or a pair of spots mid-dorsally with bars or spots posteriorly; dorsal scute narrow in male, absent in females; ventral scute very thin to absent in males, absent in females; tracheal scute not strongly sclerotised in males or females; genital scute weak. Male palp without retrolateral tibial apophysis but with shallow ventral groove ( Fig. 70b View FIGURE 70 ); cymbium simple, tapering with pallid tip but no enlarged pseudoclaw; paracymbial spine absent; bulb simple with sinuous embolus; subtegular notches small. Epigyne ( Fig. 70c View FIGURE 70 ) a broad triangular plate with two small round fossae.

Species Included: N. culburra sp. nov., N. eneabba sp. nov., N. muncoonie sp. nov., N. supunnoides sp. nov., Nucastia virewoods sp. nov., and Medmassa fusca Hogg, 1900 , a nomen dubium.

Remarks. Some Nucastia species seem to be a mimic of Nyssus or Storena ( Zodariidae ), both in the pattern and Storena also in the elevated shiny caput. The most diagnostic interspecific character is the abdominal pattern. Data with females from South Australia (AM KS32069) report that the spiders were mimicking the ant Iridomyrmex purpureus (Smith, 1858).

Key to species of Nucastia View in CoL

Males (of N. eneabba View in CoL unknown)

1. Dorsal abdominal scute for almost length of abdomen ( Fig. 65c View FIGURE 65 )...................................... N. virewoods View in CoL Dorsal abdominal scute for at most two-thirds the length of abdomen............................................ 2

2(1). Dorsal abdominal scute for two-thirds the length of abdomen........................................... N. culburra View in CoL Dorsal abdominal scute for about half length of abdomen...................................................... 3

3(2). Ventral “scute” thin but glossy, glabrous; dorsal abdomen with two pallid spots ( Fig. 69a View FIGURE 69 ).................. N. muncoonie Ventral View in CoL abdomen of similar pilosity and hardness; dorsal abdomen with long bell-shaped pallid zone ( Fig. 71e View FIGURE 71 )...................................................................................................... N. supunnoides View in CoL

Females 1. Dorsal abdomen with 3–5 or more pallid spots evident anteriorly ( Fig. 69b View FIGURE 69 )....................................... 2

Dorsal abdomen with only two pallid spots evident anteriorly, if any ( Fig. 68a View FIGURE 68 )..................................... 4 2(1). Carapace dark brown ( Fig. 71e View FIGURE 71 ); patella IV not strongly contrasting with femur and tibia IV.......................... 3

Carapace jet black ( Fig. 69b View FIGURE 69 ); patella IV strongly contrasts with femur and tibia IV....................... N. muncoonie View in CoL 3(2). Abdomen dorsally with two pallid small spots and posterior chevron ( Fig. 66d View FIGURE 66 )............................ N. culburra View in CoL

Abdomen with anterior and posterior pallid bars and medially c-shaped pallid spots laterally ( Fig. 71e View FIGURE 71 )....... N. supunnoides View in CoL 4(1). Dorsal abdomen with two large paired fused irregular spots medially and laterally ( Fig. 68a View FIGURE 68 ).................. N. eneabba View in CoL

Dorsal abdomen with few, if any, spots ( Fig. 65c View FIGURE 65 ).................................................. N. virewoods View in CoL