Corasoides occidentalis, Humphrey, 2017

Humphrey, Margaret, 2017, A Revision and Cladistic Analysis of the Genus Corasoides Butler (Araneae: Desidae) with Descriptions of Nine New Species, Records of the Australian Museum 69 (1), pp. 15-64 : 48-53

Corasoides occidentalis sp. nov.

Figs 19a , 26–29

Holotype ♂, Yallingup , Western Australia, 33°42'S 115°02'E, 02 Oct. 1993, M. Humphrey, KS.71658 ( AM) . Paratypes as follows, all Western Australia : 6♂♂, Yallingup , 33°42'S 115°02'E, 02 Oct. 1993, M. Humphrey, KS.71674 ( AM) ; 1♂, Yallingup , 33°42'S 115°02'E, 02 Oct. 1993, M. Humphrey ; 1♂, 2♀♀, Yallingup , 33°42'S 115°02'E, 02 Oct. 1993, M. Humphrey, KS.71670 ( AM) ; 1♂, Cervantes , 30°30'S 115°04'E, 06 Oct. 1993, M. Moulds, KS.71675 ; 1♂, 1♀, Nannup , 33°59'S 115°45'E, 02 Oct. 1993, MM, KS.71672 ; 1♂, 1♀, Fitzgerald River NP, 33°55'S 120°10'E, 29 Sept.1993,M. Humphrey, KS.71673 ; 1♂, Jewel Cave , 34°05'S 115°06'E, 02 Oct. 1993, M. Humphrey, KS.71681 ; 2♂♂, Kalbarri NP, 27°40'S 114°22'E, 09 Oct. 1993, M. Humphrey, KS.71679 ; 3♂♂, 2♀♀, Stokes River NP, 33°50'S 121°08'E, 13 Oct.1993, M. Humphrey, KS.71678 ; 1♂, 1♀, Stirling Ranges NP, 34°22'S 118°08'E, 30 Sept. 1993, M. Humphrey, KS.71676 ; 3♂♂ 2♀♀, Corrigin , 32°20'S 117°52'E, 10 Oct. 1993 M. Humphrey, KS.71677 ; 2♀♀, Gelorup , 33°23'S 115°39'E, 03 Oct. 1993, M. Humphrey, KS.71680 ; 3♂♂, Gelorup , 33°23'S 115°39'E, 03 Oct.1993, M. Humphrey, KS.71671 and KS.71684 ; 1♂, Glen Forrest , 31°55'S 116°04'E Oct. 1993, M. Humphrey, KS.71682 ; 1♂, Toodyay , 31°33'S 116°28'E, 04 Oct. 1993, M.Humphrey, KS.1683 ( AM) . 1♂, Cannington Bot Res. , 32°01'S 115°58'E, Dec. 1986, W.Humphreys et al., 92/31 ; 1♀, Gordon River at Albany H’way crossing, 34°17'S 117°30'E, 10 Nov. 1990, A. F. Longbottom 19/40 ; 1♂, Gelorup Rise (lot 101), 33°45'S 115°38'E, 14 Oct. 1991, K. Longbottom ; 1♂, Bold Park , 31°57'S 115°46'E, 20 Dec. 1988, Jiang Wang Gao 92/26 ; 1♂, 6.5 km NW of Meelup , 33°33'30"S 115°01'00"E, 25 Oct. 1985, G. A. Harold, 92/47 ; 1♀, Bold Park , 31°57'07"S 115°45'30"E, 15 Mar 1987, W. Humphreys et al., 92/24 ; 1♀, 15 km E of Mount Barker , 34°40'S 117°31'E, 22 Feb. 1990, M. S. Harvey & M. E. Blosfelds, 92/49 ; 1♂, Jandakot , 32°06'S 115°52'E, 31 Dec. 1981, S. R. Robinson, 92/16 ; 1♂, Naval Base , 32°12'S 115°47'E, 19 Dec. 1971, E. L. Joll, 92/18 ; 1♂, 9.6 km E of Green Head , 30°04'S 114°58'E, Dec 1971, (no collector), 19/13 ; 1♀, Kallaroo , 31°47'28"S 115°44'28"E, T. C. Connolly, 92/14 ; 1♀, Cape Naturaliste , 33°32'S 115°00'E, 12 Nov. 1979, G. B. Muir, 92/2 ; 1♂, Albany (37 Parker St ), 35°00'S 117°53'E, ... Apr. 1964, A. Twaddle, 92/1 ; 1♂, Stirling Range NP 6.8 km S of Bull Knoll , 34°29'S 118°15'E, 18 Oct. 1989, G. Friend, G. Hall & D. Mitchell, 92/23 ; 1♂, Glen Forrest , 31°55'S 116°06'E, 09 Dec. 1974, E. Postmus, 92/11 ; 1♂, 1♀, Chesapeake Rd & Gardener Rd junction, 34°46 S 116°10'E, 01 May 1990, M. S. Harvey & J. M. Waldock, 92/34-35; 1♂, Parmelia , 32°15'S 115°47'E, 27 Dec. 1989, A. E. de Jong, 92/19 ; 1♂, Gelorup Rise , 33°23'S 115°38'E, 11 Dec. 1990, K. Longbottom, 92/3 ; 1♀, Mt Cooke , 32°25'S 116°18'E, 17 Feb. 1991, M. S. Harvey, 92/53 ; 1♂, Perth Airport , 31°55'24"S 115°58'40"E, Dec. 1986, W. Humphreys et al., 92/58 ; 1♂, 6 km at 15° from Mullalloo Beach, 31°47'S 115°44'E, 10 Sept. 1978, A. Chapman & R. How, 85/13; male, Salter’s Point , 31 Oct. 1987, M. Koch, 88/49 ; 1♂, Augusta , 1.5 km NE of, 34°18'15"S 115°10'15"E, 30 Nov. 1985, G. A. Harold, 92/21 ( WAM) .

Other material examined all Western Australia. 2 juv., Cape le Grande , 34°00'S 122°00'E, 01 Sept. 1993, M. Humphrey ; 1♂, palps of another male, 2♀♀, Glen Forrest , 31°55'S 116°06'E, 04 Oct. 1993, M. Humphrey, KS.71685 ; 2 juv, Toodyay , 31°33'S 116°28'E, 04 Oct. 1993, M. Humphrey ; 3♀♀, Yallingup , 33°42'S 115°02'E, 02 Oct. 1993, M. Humphrey ; 3♂♂ and pair male palps, Gelorup , 33°23'S 115°39'E, 03 Oct. 1993, M. Humphrey ; 4 juv., Kalbarri NP, 27°40'S 114°22'E, 09 Oct. 1993, M. Humphrey ; 1♀ abdomen, 3 juv., Corrigin , 32°20'S 117°52'E, 10 Oct. 1993, M. Humphrey ; 3 juv, pair male palps, Jewel Cave , 34°05'S 115°06'E, 02 Oct. 1993, M. Humphrey ; 3 juv, Stirling Ranges NP, 34°22'S 118°08'E, 30 Sept. 1993, M. Humphrey ; 1 juv, Stokes River NP, 32°35'S 134°08'E, 13 Oct. 1993, M. Humphrey ; 1 juv., Fitzgerald River NP, 34°05'S 120°35'E, 29 Sept. 1993, M. Humphrey ( AM) . 1♀, E King River , 34°45'6"S 117°55'9"E, D. Hirst, ARA5322 DH2536 ( SAM) . 1♂, Gelorup Rise , 33°23'12"S 115°38'43"E, 25 Nov. 1990, A. F. Longbottom, 19/10 ; 1♀, Cervantes , 30°30'S 115°04'E, 14 Jan.1977, K. Zwanenburg, 19/33 ; 1♂, Cannington Bot Res , 32°01'29"S 115°58'57"E, 27 Jan. 1987, W. Humphreys et al., 92/32 ; 1♀, Chinocup Reserve 6.4 km E of Pingrup, 33°32'S 118°24'E, 14 Feb. 1972, W. H. Butler, 92/36 ; 1♂, Gelorup , 33°23'12"S 115°38'43"E, 25 Nov. 1990, A.F. Longbottom, 19/10 ( WAM) .

Diagnosis. The male can be distinguished from other Australian species by the very long cymbium, which is up to six times as long as the diameter of the bulb and also by the presence on the conductor tip of a flange which sweeps around it about 180° ( Figs 26a–c,e,f , 28a–d ). The female can be distinguished by the lateral profile of the epigyne in which the scape protrudes at almost 90° ( Fig. 27g ).

Description. Medium to large spider. Carapace. Light tan. Dark tan on chelicerae and head region, extending posteriorly to fovea and then diverging to either side of petiole area. Dark brown edging to carapace except in petiole region. Abdominal pattern. Similar to basic pattern but with central stripe wide and almost merging with row of spots.

Male ( Figs 19a , 26 , 27a–d,f , 28 , 29 ). CL 6.7 (3.1–6.8), CW 5.3 (2.5–5.3), AL 6.0, AW 4.0, HW 2.9, EpGW 1.8, MOQL 0.73, MOQAW 0.61, MOQPW 0.70, SL 3.5, SW 2.7, ML 2.9, MW 2.4, LL 1.5, LW 1.2, ChelL 5.6 (3.0–5.8), ChelW 1.9 (1.1–1.9), clypeus height 0.85 (1.3), clypeus concave.

Cephalothorax. Sternum longer than wide, moderate point posteriorly. Labium longer than wide, basally notched. Chelicerae. Prominent pair of cheliceral bristles reduced, not crossing in front. Cheliceral teeth: retromarginal 5, promarginal 3 plus one undersized; evenly spaced and of near equal size. Transverse ridges present between teeth margins. Fangs slightly shorter than other Corasoides and with serrations. Leg lengths:

I II III IV Palp femur 9.4 7.9 6.4 9.1 5.7

patella 2.3 2.3 1.9 2.0 1.4

tibia 9.5 7.4 5.1 7.5 1.0 metatarsus 10.0 7.9 7.5 10.8 —

tarsus 3.6 2.8 2.1 2.9 6.4

total 34.8 28.1 23.0 32.5 14.5

Spination. Leg I: femur d2,2,2,1,1,1,1,2,3; tibia v1,1; metatarsus v2,2,2. Leg II: femur d3,3,1,3,3,3; tibia v1,1 p1; metatarsus v1,1,2 p1,1 r1. Leg III: femur d3,3,3,3,3; tibia d1,1,1,2 p1; metatarsus; d1,1,1,1,1,2 v2,2,2 p1,1. Leg IV: femur; 1,1,1,3,2,1,3; tibia; d1 p1 r1,1; metatarsus; d1,1,1,2,2,2, v1,1,1,1,1,1,2 p1,1 r1. Palp: femur; d1,2,3; patella: d1; tibia; p1; tarsus several. Male palp. Digitiform portion very long, cymbium length up to six times diameter of papal bulb but as little as four times in some small males. Bristled retroventral tibial apophysis present. Ventral apophysis partially membranous. Retrolateral apophysis long, tapering, curving and twisting slightly away from palp retrolaterally, reversing slightly and with final spinelike portion inclining towards base of cymbium for up to one third its own length, the medial section becoming more bent in specimens from north to south ( Figs 29a–d ). Conductor stalked with wide base. Conductor tip sclerotized, smooth, with sclerotized, semicircular flange around ventral/

(d) Albany, WA.

prolateral side for about 180° ( Fig. 26a–c,e,f ). Embolus long, spine-like, arising basally. Single row of 6 trichobothria on cymbium of specimens from type locality but 4–7 according to locality and size of specimen. Abdomen. Tail of spigots present on anterior lateral spinnerets.

Female ( Fig. 27e–h ), similar to male. CL 6.0 (6.8), CW 4.3 (5.1), AL 6.1, AW 3.4, HW 3.3, EpGW 1.5, MOQL

0.82, MOQAW 0.61, MOQPW 0.73, SL 3.0, SW 2.4, ML 2.3, MW 1.1, LL 1.3, LW 1.1, ChelL 2.9 (4.5), ChelW 1.7 (2.3), clypeus height 0.8. Chelicerae. Prominent pair of cheliceral bristles may or may not be reduced. Other bristles on chelicerae may be as long and almost equally robust. Cheliceral teeth: retromarginal 5, promarginal 3(4). Transverse ridges present between teeth margins. Leg lengths:

I II III IV Palp femur 7.0 6.0 4.9 6.9 3.6 patella 2.3 2.3 1.6 2.0 1.1 tibia 6.3 5.0 4.0 5.9 2.1 metatarsus 7.1 5.6 5.6 7.8 — tarsus 2.9 1.8 1.8 2.4 2.9 total 25.5 20.6 17.9 24.8 9.8

Trichobothria on first tarsus, 6, increasing in length distally. Spination. Leg I: femur d1,3,3,3,3; tibia v1,2 p1; metatarsus d2 v2,2,2 p1,1. Leg II: femur d1,3,3,3,3; tibia v1,1,2 p1; metatarsus d1,1,2 v2,2,2 p1,1. Leg III: femur d2,3,3,1,3,3; tibia d1,1 v1,2,2 p1 r1,1; metatarsus d1,2,2,2, v2,2,2. Leg IV: femur d1,1,1,1,1,1,3; tibia v2,2,2p1 r1,1; metatarsus d1,1,1,1,2 v1,1,1,1,1,2. Palp: femur d1,1,1,1,3 p1; patella d1; tibia d1 p1. Epigyne ( Fig. 27f ). Width almost twice length. Long hairs directed posteriorly from anterior and sides. Scape protruding ventrally at almost 90° ( Fig. 27g ). Lateral extension of scape extending to lateral margins of genital atria. Genital openings situated in posterior half of epigyne. Spermathecae large. Insemination ducts weakly convoluted (one full bend) with posteriorly directed diverticula where insemination ducts join spermathecae ( Fig. 27e,g ).

Habitat. Heathland, woodland, dry and wet sclerophyll forest.

Distribution. Coastal western and south western Western Australia, from Kalbarri National Park to Cape Le Grande and inland as far as Corrigin ( Fig. 27h ), following Thornthwaite’s (1948) humid and sub-humid zones.

Remarks. Corasoides occidentalis varies in size and morphology over its distribution. Small males become more common north of Cervantes, east of Fitzgerald River National Park and in general with increasing aridity and distance from the coast. The length of the cymbium and the number of trichobothria on it appears to vary directly according to the size of the specimen. Figure 26g shows the number of cymbial trichobothria decreasing from six or seven on the mid west coast of their distribution surrounded by a band of four or five and reducing to two or three trichobothria on the southern coast where males tend to reach their smallest size.

The width of the epigyne also varies. The width is greatest in the Glen Forrest and west coast areas and decreases eastward and inland in a geographical variation similar to that of the cymbial trichobothria.

The only observed discrete difference in morphology was the presence of a bifurcate tip to the retrolateral apophysis in some specimens from Glen Forrest ( Fig. 19a ). All other differences in morphology, particularly with respect to the conductor tip ( Fig. 28a–d ) and the height and twisting of the retrolateral apophysis ( Fig. 29a–d ) were due to individual variation or were continuous geographically. A distinct pit with an inner structure is present beneath the tip of the retrolateral apophysis in specimens from Stirling Ranges ( Fig. 29b ) but is absent in specimens from Perth, Gelorup and Albany ( Fig. 29a,c ). A less clearly defined pit structure is present in specimens from Glen Forrest. Similarly, a protrusion or crest on the outer final bend of the retrolateral apophysis ( Fig. 29d ) is present on specimens from Albany and to a lesser extent from Gelorup ( Fig. 29c ) but appears to be absent from specimens from other regions.

This species is sympatric with C. australis in some areas, e.g., Toodyay, Corrigin and some areas between Greenough and Cervantes.

Etymology. From the Latin, occidentalis , meaning “of the falling sun” or “of the west” and referring to the western distribution in Australia of this species.

Figures

Figure 19. (a) retrolateral apophysis tip of Corasoides occidentalis sp. nov., Glen Forrest, WA; (b) male cymbium of C. motumae sp. nov., Clyde Mountain, NSW; (c) retrolateral apophysis of C. motumae sp. nov., Clyde Mountain, NSW; (d) conductor tip of C. motumae sp. nov., Clyde Mountain, NSW.

Figure 26.Corasoidesoccidentalissp.nov.,male:(a) palpal organs,prolateral;(b) palpalorgans,ventral;(c) palpalorgans,retrolateral;(d) face; (e) conductor tip,retrolateral/dorsal view;(f) conductor tip, retrolateralview;(g) distribution ofnumber oftrichobothria present on cymbium.

Figure 27.Corasoides occidentalis sp.nov.: (a) dorsal carapace;(b) lateral carapace and chelicerae;(c)

Figure 28. Corasoides occidentalis sp. nov., conductor tips: (a) Perth, WA; (b) Stirling Ranges, WA; (c) Gelorup, WA;

Figure 29. Corasoides occidentalis sp. nov., retrolateral apophyses: (a) Perth, WA; (b) Stirling Ranges, WA; (c) Gelorup, WA; (d) Albany, WA.