Corasoides cowanae, 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 : 33-36

Corasoides cowanae sp. nov.

Figs 15 , 16

Holotype ♂, S.E. slope of Mt Akrik (Mt Ian), 15 km NW Tabubil WP, 5°10'S 141°09'E, 1625 m, PAPUA NEW GUINEA, Nov. 1996, M. S. Moulds & M. Humphrey, KS.71834 ( AM) . Paratypes as follows: 3♂♂, 1♀, SE slope Mt Akric (Mt Ian) 15 km NW Tabubil, 1625 m 5°10'S 141°09'E, 9 Oct. 1993, M. S. Moulds & S. Cowan, KS.71833 ( AM) ; 1♂, 5♀♀ S.E. slope of Mt Akrik (Mt Ian), 15 km NW Tabubil WP, 5°10'S 141°9'E, 1625 m, Nov. 1996, M. Humphrey & M. S. Moulds, KS.98072 ( AM) .

Diagnosis. CL less than 3.0 mm. Enlarged anterior retromarginal cheliceral teeth in male. ( Fig. 16b,c ). Conductor tip spout-like, pointing retrolaterally ( Fig. 15c ). Can be distinguished from closely related C. nebula sp. nov. by the presence of a simple, sclerotized retrodorsal tibial apophysis on the male palp and in the female by the genital openings of female epigyne which are positioned and directed posteriorly ( Fig. 16g ).

Description. Small spider. Carapace. Cream edged with dark tan. Other specimens cream to light tan. Abdomen. Basic pattern in holotype reduced to one pair of distinct dorsal spots ( Fig. 15d ). Otherwise variable, from basic pattern to dark with short dorsolateral stripe and indistinct central strip.

Male ( Figs 15 , 16a–c, i ). CL 2.8 (2.1), CW 2.0 (1.6), AL 3.3 (2.3), AW 2.3 (1.5), HW 1.3, EpGW 0.9, MOQL 0.45, MOQAW 0.38, MOQPW 0.80, SL 1.3, SW 1.2, ML 1.1, MW 0.5, LL 0.5, LL 0.5, ChelL 2.0 (1.1), ChelW 0.7 (0.4), clypeus height 0.3. Cephalothorax. Sternum roughly equal in length and width, blunt posterior point. Labium roughly equal in length and width, basally notched. Chelicerae. Long. Fangs without serrations ( Fig. 16a ). Cheliceral teeth ( Fig. 16b,c ) retromarginal 8 (7), distal tooth greatly enlarged and skewed retrolaterally, penultimate tooth less so, promarginal 3(4). No transverse ridges between rows of teeth. Legs. Banded, particularly ventrally. Leg lengths:

I II III IV Palp femur 4.6 3.9 3.6 4.7 3.4

patella 0.9 0.9 0.8 0.8 0.6

tibia 4.8 3.3 2.8 4.3 1.3 metatarsus 5.4 4.2 4.3 6.4 —

tarsus 3.3 2.1 1.8 2.7 4.4

total 19.0 14.3 13.3 18.9 9.6

Spination. Leg I: femur d2,2,3,3,2; tibia v2,22; metatarsus v1,1,1,2. Leg II: femur d1,1,1; tibia v2,2,2; metatarsus v1. Leg III: femur d1,1,1,1,1,1,1; patella d1; tibia d1,1,1,1,2 v2,2; metatarsus d2,2,2,4 v2,1,1,1,2. Leg IV: femur d1,1,1,1,1,1,3 v1; tibia d1,1,12 v1,1,2; metatarsus d2,2,2,2,2, v2,2,2,2,2. Palp: femur d1,2; d1; tibia d1 v1; tarsus several. Male palp. Digitiform portion of cymbium long, cymbium length at least four times the diameter of bulb. Retroventral apophysis absent. Retrodorsal apophysis present, simple and sclerotized. Retrolateral and ventral apophysis closely aligned with tuft of hairs passing between. Ventral apophysis erect, sclerotized, not enclosing any intersegmental membrane. Retrolateral apophysis with high base, spine-like portion organs, retrolateral; (d) carapace and abdomen, dorsal; (e) face. Arrows indicate ventral apophysis.

long, very fine, pointed away from bulb retrolaterally and then curving slightly apically. Embolus arises retrolaterally. Conductor stalked, unequally bifid with lightly sclerotized finger-like projection partially hidden behind larger, heavily sclerotized portion. Major sclerotized portion unridged, deeply curved almost forming circle. Trichobothria on cymbium in single row of 4 decreasing in length basally. Abdomen. No tail of spigots on anterior spinnerets.

Female ( Fig. 16d–i ), similar to male. CL 2.4 (2.2), CW 1.9, AL 3.4, AW 2.5, HW 1.1, EpGW 0.8, MOQL 0.45, MOQAW 0.3, MOQPW 0.42, SL 1.2, SW 1.2, ML 1.0, MW 0.5, LL 0.5, LW 0.4, ChelL 1.5 (1.2), ChelW 0.6, clypeus height

0.2. Cheliceral teeth. Retromarginal 7, no enlargement as in male; promarginal 4 ( Fig. 16d ). Leg lengths:

I II III IV Palp femur 4.1 2.8 2.7 3.8 1.4

patella 0.8 0.7 0.7 0.8 0.4

tibia 4.0 2.3 2.1 2.7 0.9 metatarsus 3.5 2.8 3.3 4.2 —

tarsus 2.4 1.5 1.3 1.7 1.3

total 14.8 10.1 7.5 13.1 3.0

Spination. Leg I: femur d1,2,2,2; metatarsus v1,2,2. Leg II: femur d1,2,1,1,3; tibia d1,1,1,1 v2,2; metatarsus d1,1,1,1,2 v1,1,1,2. Leg III: femur d1,2,1,2,1,2,1,2; tibia d1,2,1,2 v1,1; metatarsus d2,2,2,3 v1,1,1. Leg IV: femur d1,1,1,1,1,1; tibia d1,1,1,1; metatarsus d2,2,2,2,2,4 v1,1,1,1,1. Palp: femur d1,1,2 v2; tibia v2; tarsus several. Trichobothria on 1st tarsus: single row of four, decreasing in length proximally. Epigyne ( Fig. 16e ). Wider than long, wrinkled anterior. Beak projecting posteriorly over anterior of scape stalk. Scape stalk less than diameter of one genital atrium. Lateral extension of scape extending to lateral margin of genital atria. Genital openings and atria posterior. Insemination ducts proceed directly anteriorly, highly convoluted and coiled (at least three rotations with a change in direction and several bends) ( Fig. 16f,h ). No diverticula.

Habitat. Tropical rainforest, altitude 1,625 m. Webs common on embankments with retreats in earthen crevices or amongst leaf litter.

Distribution. Known only from the type locality, Mt Akric, Western Province, Papua New Guinea. ( Fig. 16i )

Etymology. Named after Sally Cowan who collected most of the type series.

Figures

Figure 15. Corasoides cowanae sp. nov. male: (a) palpal organs, prolateral; (b) palpal organs, ventral; (c) palpal

Figure 16. Corasoides cowanae sp. nov.: (a) male cephalothorax and abdomen, lateral; (b) male chelicerae and maxillae, ventral;(c) male chelicera;(d) female chelicera;(e) epigyne;(f) female internal genitalia, dorsal;(g) female genitalia, lateral, from centre; (h) female internal genitalia, dorsal exploded view; (i) distribution.