Myrmarachne crassembolus, Yamasaki, Takeshi & Ahmad, Abdul Hamid, 2013

Yamasaki, Takeshi & Ahmad, Abdul Hamid, 2013, Taxonomic study of the genus Myrmarachne of Borneo (Araneae: Salticidae), Zootaxa 3710 (6), pp. 501-556 : 520-521

Myrmarachne crassembolus sp. nov.

( Figs 15 A–G)

Type material. Holotype male (UMS), Guramboi, Sabah, BORNEO, 15 III 2008, H. Takizawa leg. Paratype: BORNEO: 1 male (BMNH), Muaya, Sabah, 28 X 2009, T. Yamasaki leg.

Diagnosis. Orange or pale brown species. In males, chelicera shorter than carapace; with posterior margin of coxa I in ventral view angulate ( Fig. 15 B); embolus of palp broadened apically, with a short process at apex ( Fig. 15 E); palpal tibia bearing small protuberance on retrolateral side below retrolateral tibial apophysis ( Fig. 15 G).

Measurements (male). Carapace length (2.05)–2.15, width (1.22)–1.26. Abdomen length (2.20). Chelicera length (1.25)–1.38. Sternum length (1.15)–1.18. Width of eye row I (1.16)–1.22; II (1.01)–1.09; III 1.18–(1.28). ALE–PLE (0.85)–0.94; ALE–PME (0.42)–0.48. Eye size: AME 0.38–(0.40), ALE (0.18)–0.20, PME (0.05)–0.06, PLE (0.20)–0.23.

Male ( Figs 15 A–G). Cephalic part almost flat or weakly convex dorsally. Thoracic part weakly convex dorsally, and abruptly sloping downward posteriorly. Chelicera shorter than carapace, with five or six prolateral teeth and without any retrolateral teeth; in lateral view lower margin of chelicera strongly convex. Fang weakly curved, without tooth-like apophysis. Sternum relatively broad, and overlapped by coxae I and II; with posterior margin of coxa I in ventral view angulate. Abdomen oval with broad dorsal scutum that is incised on each lateral outline anteriorly.

Palp ( Figs 15 E–G). Tegulum oval, with strongly curved thin seminal reservoir in prolateral part and blurred thick seminal reservoir in retrolateral part of tegulum. Embolus broadened apically, with short process at apex, and forming two large oval coils occupying more than half of venter of cymbium. RTA well developed; retrolateral surface of tibia bearing small protuberance below RTA. Flange of RTA not developed.

Leg spination. Femur I pd 1; patella I rv 1; tibia I pv 5–6, rv 5; metatarsus I pv 2, rv 2; tibia II pv 0–1, rv 2–3; metatarsus II pv 2, rv 2; femur III pd 1, rd 1; femur IV pd 0–1, rv 1.

Coloration and pilosity. Carapace light brown or brown; cephalic part covered with black and white hairs sparsely; thoracic part shiny almost without hairs. Chelicera pale brown or brown. Maxilla, labium and sternum pale orange or pale brown; sternum paler than maxilla and labium. Coxae I, II and IV cream; coxa III tinged with greyish brown. Abdomen pale grey or grey, covered with fine hairs sparsely; dorsal scutum light brown or brown with shiny surface.

Etymology. The specific name refers to the apically broad embolus (Latin prefix “crass-” (thick) and noun “embolus”).

Distribution. Borneo.

Remarks. The females are unknown. M. crassembolus has a very characteristic embolus, which forms coils without tapering apically.

Biology. The species occurs in forest edges.

Figures

FIGURE 15. M. crassembolus sp. nov., male. A, body, dorsal view; B, maxillae, labium, sternum and coxae; C, body, lateral view; D, chelicera and fang, ventral view; E, palp, ventral view; F, palp, lateral view; G, palpal tibia, dorsal view. (Scales. A – D: 1 mm; E – G: 0.25 mm)