Mangrovia occidentalis, Framenau & Castanheira, 2022

Framenau, Volker W. & Castanheira, Pedro de S., 2022, A new genus of Australian orb-weaving spider with extreme sexual size dimorphism (Araneae, Araneidae), Zoosystematics and Evolution 98 (1), pp. 137-149 : 137

Mangrovia occidentalis sp. nov.

Figs 4B , 6A-D , 7A, B , 8A-E , 9

Type material.

Holotype male, Cape Range National Park, Yardie Creek (22°20'S, 113°48'E, Western Australia, Australia), 7 July 1987, B. Y. Main ( WAM T77397).

Etymology.

The specific epithet is a Latin adjective in apposition - Mangrovia occidentalis - meaning western, and it refers to its distribution that is limited to coastal Western Australia.

Other material examined.

Australia: Western Australia: 1 female, Bay of Rest , 22°18'S, 114°08'E ( WAM T75793 ) ; 1 female, same locality ( WAM T75827 ) ; 1 female, 1 juv., Cape Range , 22°10'S, 114°E ( AM KS.62723) ; 3 juv., Cape Range National Park, Yardie Creek , 22°20'S, 113°48'E ( WAM T157108) ; 1 female, same locality ( WAM T75322 ) ; 1 female, same locality ( WAM T75326 ) ; 1 female with eggsac, same locality ( WAM T115115) ; 1 female, same locality ( WAM T75327 ) ; 1 female, Cooke Point, Port Headland , 20°19'S, 118°36'E ( WAM T75325 ) ; 2 females, Faure Island, North , 25°48'S, 113°53'E ( WAM T67857 ) ; 3 females, Faure Island, West , 25°52'S, 113°53'E ( WAM T67854 ) ; 1 female, same locality ( WAM T67855 ) ; 1 female, same locality ( WAM T67856 ) ; 1 female, Karratha , NW airport, 20°44'S, 116°51'E ( WAM T75840 ) ; 1 female, King Sound, Derby Jetty , 16°49'S, 123°28'E ( WAM T75777 ) .

Diagnosis.

See above for Mangrovia albida comb. nov.

Description.

Male (based on holotype, WAM T77397): Total length 2.2. Carapace (Fig. 6A ) 1.0 long, 0.9 wide; light brown with darker lateral flanks; few white setae. Eyes diameter AME 0.09, ALE 0.05, PME 0.08, PLE 0.05; row of eyes: AME 0.29, PME 0.22, PLE 0.50. Chelicerae paturon dark grey; two promarginal teeth, the apical slightly larger, three retromarginal teeth of similar size. Legs (Fig. 6A, B ) beige with distal parts of femora, tibiae and patellae brown. Leg formula I > II > IV > III; length of segments (femur + patella + tibia + metatarsus + tarsus = total length): I - 1.0 + 0.4 + 0.8 + 0.7 + 0.4 = 3.3, II - 0.9 + 0.3 + 0.6 + 0.9 + 0.4 = 3.1, III - 0.6 + 0.2 + 0.3 + 0.3 + 0.3 = 1.7, IV - 0.8 + 0.3 + 0.5 + 0.5 + 0.4 = 2.5. Labium and endites beige. Sternum (Fig. 6B ) heart-shaped, yellowish brown, with darker contour. Abdomen (Fig. 6A, B ) 1.1 long, 1.2 wide; olive-grey with indistinct darker folium pattern; laterally yellowish-brown; ventral olive-brown, four irregular white guanine spots. Pedipalp (Figs 6C, D , 7A, B ) length of segments (femur + patella + tibia + cymbium = total length): 0.2 + 0.1 + 0.2 + 0.4 = 0.9; cymbium broad, tegulum and subtegulum well-developed; conductor broadly elongate, basally slightly sclerotised, otherwise fleshy; median apophysis oval with an apical, slightly curved spine-like prong; radix elongate; terminal apophysis well-developed, with rounded distal portion, bent apically; subterminal apophysis originating near the basis of terminal apophysis, thin and sclerotized; embolus basally inflated, otherwise thin, straight and with small subterminal branch.

Female (based on WAM T75326): Total length 10.8. Carapace (Fig. 8A ) 3.8 long, 3.6 wide; pear-shaped, uniformly reddish-brown; few white setae. Eyes diameter AME 0.25, ALE 0.16, PME 0.18, PLE 0.16; row of eyes: AME 0.65, PME 0.47, PLE 1.64. Chelicerae reddish-brown; four promarginal teeth, second basal largest; three retromarginal teeth of similar size. Legs (Fig. 8A, B ) reddish-brown. Pedipalp length (femur + patella + tibia + tarsus = total length): 1.2 + 0.6 + 0.9 + 1.5 = 4.2. Leg formula I > IV > II > III; length of segments (femur + patella + tibia + metatarsus + tarsus = total length): I - 4.6 + 2.1 + 3.5 + 3.4 + 1.1 = 14.7, II - 4.0 + 1.8 + 3.1 + 0.9 + 1.0 = 10.8, III - 2.5 + 1.2 + 1.5 + 1.6 + 0.8 = 7.6, IV - 3.8 + 1.6 + 2.3 + 2.9 + 0.9 = 11.5. Labium and endites reddish-browns. Sternum (Fig. 8B ) heart-shaped, reddish-brown with two small lighter patches along the median line. Abdomen (Fig. 8A, B ) 6.5 long, 6.3 wide; dorsally beige, with a black band along anterior margin; four pairs of dark brown sigillae; venter olive-brown, with transverse guanine band posterior of epigastric furrow, somewhat lighter anterior of spinnerets and two small white spot antero-lateral of spinnerets. Epigyne (Figs 4B , 8C-E ) almost twice as wide as long, copulatory openings laterally of scape; scape almost twice as long as epigyne plate, narrow, basally and apically wider, and with terminal pocket. Spermathecae ovoid; fertilisation ducts basally convoluted and attaching posteriorly to spermathecae (Fig. 4B ).

Variation.

Male only known from holotype; the spine on the median apophysis of the left pedipalp was broken off, therefore the right pedipalp is illustrated here. Female total length 8.7-10.6 (n = 8); there was little colour variation in females although the abdomen venter showed distinct white guanine spots in most specimens.

Habitat preferences and life history.

Collection data on labels with museum specimens of M. occidentalis sp. nov. exclusively lists ‘mangroves’ as habitat, where, similar to M. albida comb. nov., spiders were collected mainly from rolled leaves near the orb-web. Mature spiders were mainly collected in May, July and September with a single record in February.

Distribution.

This species is only known from coastal Western Australia (Fig. 9 ).

Figures

Figure 4. Mangrovia albida comb. nov. (AM KS. 98754) and M. occidentalis sp. nov. (WAM T 75326), cleared female epigynes, posterior view. A. Mangrovia albida comb. nov.; B. M. occidentalis sp. nov. Scale bar: 0.2 mm (A, B).

Figure 6. Mangrovia occidentalis sp. nov., male (WAM T 77397). A. Habitus, dorsal view; B. Habitus, ventral view; C. Right pedipalp, ventral view; D. Right pedipalp, dorsal view. Scale bars: 1 mm (A, B); 0.1 mm (C, D).

Figure 7. Mangrovia occidentalis sp. nov., expanded right left pedipalp (WAM T 77397). A. Apico-dorsal view; B. Mesal view. Scale bars: 0.1 mm (A, B).

Figure 8. Mangrovia occidentalis sp. nov., female (WAM T 75326). A. Habitus, dorsal view; B. Habitus, ventral view; C. Epigyne, ventral view; D. Epigyne, lateral view; E. Epigyne, posterior view. Scale bars: 2 mm (A, B); 0.2 mm (C-E).

Figure 9. Distribution records of Mangrovia occidentalis sp. nov.