Corasoides nimbus, 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 : 43-48

Corasoides nimbus sp. nov.

Figs 24 , 25

Holotype ♂, Mt. Giluwe 2500 m, [6°10'S 143°50'E], 7.vi.63, Sedlacek, NEW GUINEA SE [ Papua New Guinea] ( BPBM) . Paratypes as follows, all Papua New Guinea : 3♀♀, data as for holotype ( BPBM) ; 3♀♀, Mt Wilhelm , 3000 m, [5°47'S 145°0'E], VII4.1955, NEW GUINEA NE. ( BPBM) .

Other material examined all Papua New Guinea. 4 penultimate ♀♀, 2 juveniles, Mt Wilhelm , 3000 m, [5°47'S 145°0'E], VII4.1955, NEW GUINEA NE. ( BPBM) .

Diagnosis. The males of only C. nimbus sp. nov. and C. cowanae sp. nov. possess a simple, sclerotized retrodorsal tibial apophysis. The males of C. nimbus sp. nov. also differ from the males of C. angusi sp. nov. in having a bluntly pointed retrolateral apophysis bent towards the bulb rather than hooked. In addition, the tip of the conductor is ridged, and is not pointed. Females can be distinguished from C. stellaris sp. nov. and C. angusi sp. nov. by the number and configuration of the insemination ducts ( Fig. 25f–h ). Female C. nimbus sp. nov. cannot be distinguished externally from C. angusi sp. nov., Corasoides nimbus sp. nov. or C. angusi sp. nov. Corasoides can be distinguished from C. stellaris sp. nov. by the lateral extension of their scapes, which are no wider than half the width of the epigyne.

Description. Medium to large spider. Carapace. Basic pattern barely discernible in alcohol specimens. Abdomen. Basic pattern barely discernible in alcohol specimens.

Male ( Figs 24 , 25a–d,i ). CL 4.3, CW 3.7, AL 4.8, AW 3.3, HW 2.4, EpGW 1.5, MOQL 0.73, MOQAW 0.58, MOQAP 0.70, SL 2.1, SW 2.4, ML 2.0, MW 0.9, LL 0.9, LW 0.9, ChelL 3.5, ChelW 1.1, clypeus height 0.5. Cephalothorax.

Sternum; length roughly equal to width, moderate posterior point Labium longer than wide, with basal notch ( Fig 25c ). Cheliceral teeth. retromarginal 5(6), promarginal 4, unequal size, no fusions. No ridges between teeth margins. Leg lengths:

I II II IV Palp femur 8.9 7.4 5.9 8.4 3.6

patella 2.0 1.9 1.4 1.8 0.9

tibia 8.9 6.1 4.3 6.8 1.5 metatarsus 8.9 6.6 6.1 8.8 —

tarsus 4.4 3.0 2.6 3.6 3.3

total 33.0 25.0 20.3 29.3 18.8

Spination. Leg I: femur d1,3,1,4,2,3; tibia v2,1,1,1,1,1,2,2; metatarsus d1,1 v2,2,2,2. Leg II: femur d1,3,3,3; tibia v2,2,2,2; metatarsus v2,2,2,2. Leg III: femur d1,2,2,2 p1; tibia d1,1,1,1,1,1 v1,1,1,2 r1,1; metatarsus d2,2,2,2 v2,2,2,2. Leg IV: femur d1,2,2,2 p1; tibia v1,2,1; metatarsus d1,1,1,1,1,1,1,1 v1,1,1,1,2; palp: femur d1,1,3; tibia v1; tarsus several. Male palp. Digitiform portion of the cymbium long—three times the diameter of the bulb. Retroventral apophysis absent. Ventral apophysis low, lobe-like and not enclosing any area of intersegmental membrane. Retrolateral apophysis simple, moderately robust, tapering but bluntly pointed and curved towards the bulb ( Fig. 24d ). Embolus maxillae; (d) cephalothorax, lateral; (e) epigyne; (f) female internal genitalia; (g) female internal genitalia,

exploded view; (h) female genitalia, right lateral.; (i) distribution. Arrows indicate ventral apophysis.

long, curved, arises on the retrolateral margin, enters conductor prolaterally. Conductor stalked, with narrow base. Sclerotized tip of conductor ridged, twists full rotation to point away from bulb ( Fig. 24a–c ). Three trichobothria on cymbium. Abdomen. Anterior lateral spinnerets with tail of small spigots.

Female ( Fig. 25e–i ), similar to male. CL 6.9 (6.6), CW 5.3 (4.8), AL 10.0, AW 7.9, HW 3.4, EpGW 1.8, MOQL 0.97, MOQAM 0.72, MOQPA 0.91, SL 3.4, SW 2.8, ML 2.5, MW 1.2, LL 1.4, LW 1.2, Chel L 4.4 (3.6), ChelL 1.5 (1.4), clypeus height 0.6. Chelicerae slightly bent, cheliceral teeth: retromarginal 6, promarginal 3. Leg lengths:

I II II IV Palp femur 9.4 7.6 6.6 8.4 4.0

patella 2.5 1.8 1.8 2.3 1.3

tibia 9.8 6.9 4.6 7.3 2.5 metatarsus 9.5 7.1 7.6 10.3 —

tarsus 4.1 3.4 2.8 2.8 3.4

total 35.3 26.8 23.4 30.8 11.2

Spination. Leg I: femur d1,1,1,1,1 p1,1,1,1,1,1,1 r1,1,1,1,1,1; tibia v1,2,2,1,1; metatarsus v2,2,2,2. Leg II: femur d1,1,1,1,1 p1,1,1,1,1,1,1 r1,1,1,1,1,1,1; tibia v 2,1,1,1,2,1,2; metatarsus v2,2,2,2. Leg III: femur d3,3,3,3,3; tibia d1 v2,1,2,2 p2; metatarsus v2,2,2,2 p2. Leg IV: femur d1,1,1,1,1,1,2 p1,1,1; tibia d1 v1,1,1,2 p1 r1; metatarsus v2,2,2,2 p2; palp: femur d1,1,1,3, patella d1 tibia d1,1; tarsus several. Trichobothria on 1st tarsus: 6, evenly spaced, decreasing in length proximally. Epigyne ( Fig. 25e ). Similar to C. angusi sp. nov. and C. stellaris sp. nov. Length 0.69, width 1.25, Smooth. Genital openings near transverse midline. Scape stalk short, slightly narrower than diameter of genital opening. Lateral extensions of scape wide, greater than diameter of genital openings and extending almost to lateral margin of genital openings. Anterior and lateral surfaces of epigyne covered in long, posteriorly directed hairs. Genital openings arising on transverse midline. Insemination ducts highly convoluted, with at least eight bends. Very small diverticula at site of entry into spermathecae ( Fig. 25f–h ).

Remarks. The material examined from Mt Wilhelm differs only superficially in the female internal genitalia from specimens of C. nimbus sp. nov. from Mt Giluwe and is otherwise indistinguishable from them. No male was available from Mt Wilhelm and it is possible that it may prove to be a separate species. However, the females of C. angusi sp. nov. and C. nimbus sp. nov. appear identical externally and C. stellaris sp. nov. almost so, yet the internal genitalia are all different. For this reason, I have included specimens from Mt Wilhelm in C. nimbus sp. nov.

Habitat. Unknown, but presumed from the collection site localities to be mist forest.

Distribution. Mt Giluwe (2500 m), Southern Highlands Province and Mt Wilhelm (3000 m), Chimbu Province, Papua New Guinea ( Fig. 25i ).

Etymology. From the Latin nimbus (masculine) meaning a rain cloud and referring to the misty, high altitude where the types were collected.

Figures

Figure 24.Corasoides nimbus sp. nov., male:(a) palpal organs, prolateral; (b) palpal organs, ventral; (c) palpal organs, retrolateral; (d) tibial apophyses; (e) face.

Figure 25.Corasoides nimbus sp. nov.:(a) carapace, dorsal;(b) cheliceral teeth;(c) sternum, labium and