Myrmarachne lambirensis, 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 : 529-531

Myrmarachne lambirensis sp. nov.

( Figs 22 A–G, 23A–F)

Type material. Holotype male (FRCS), Lambir Hills National Park, Sarawak, BORNEO, 4 XI 2009, T. Yamasaki leg. Paratypes: BORNEO: 1 female (FRCS), same loc., 29 VI 2005, H. O. Tanaka leg.; 1 male and 1 female (UMS), same loc., 1–7 XI 2009, T. Yamasaki leg.; 1 male (UMS), Poring Hot Spring, Kinabalu Park, Sabah, 10 XI 2009, T. Yamasaki leg.; 1 male (MSNG), Tawau Hills Park, Sabah, 17 XI 2009, T. Yamasaki leg.; 2 males (BMNH), Maliau Basin, Sabah, 7–10 XI 2011, T. Yamasaki leg.

Non-type material examined. J AVA: 1 male, Kebun Raya, Bogor, 27 XI 2009, T. Yamasaki leg.

Diagnosis. In males, chelicera apically swollen and basally narrow; first apical prolateral tooth bifid ( Fig. 22 D); embolus coils occupying more than half of venter of cymbium ( Fig. 22 E); palpal tibia having long protuberance below RTA ( Fig. 22 G). In females, with body in ventral view posterior margin of coxa II and anterior margin of coxa III densely fringed with black hairs ( Fig. 23 C); median pocket and lateral pockets absent in front of epigastric furrow.

Measurements (male/female). Carapace length (2.30)–2.80/2.65–2.83, width (1.36)–1.46/1.14–1.18. Abdomen length (2.05)–2.45/2.15–2.57. Chelicera length 2.20–2.65 (2.25). Sternum length (1.28)–1.53/1.23–1.37. Width of eye row I (1.26)–1.38/1.20–1.23; II (1.12)–1.22/1.04–1.07; III 1.26–1.36 (1.30)/1.18–1.25. ALE–PLE 0.90–0.98 (0.92)/0.85–0.88; ALE–PME 0.42–(0.46)/0.40–0.43. Eye size: AME (0.40)–0.46/0.42–0.43, ALE (0.21)–0.24/0.19–0.22, PME 0.05–0.08 (0.06)/0.05–0.06, PLE (0.21)–0.23/0.21.

Male ( Figs 22 A–G). Cephalic part almost flat dorsally. Constriction between cephalic and thoracic parts deep and narrow. Thoracic part convex dorsally. Chelicera apically swollen and basally narrow, with five to eight prolateral and eight to ten retrolateral teeth; first apical prolateral tooth bifid. Fang almost straight with curved tip, without tooth-like apophysis. Sternum slender, and slightly overlapped by coxae I and II. Abdomen oval with broad dorsal scutum that is incised on each lateral outline anteriorly.

Palp ( Figs 22 E–G). Tegulum very large oval with strongly curved seminal reservoir. Embolus forming two large oval coils; embolus coils wider than cymbium, and occupying more than half of venter of cymbium. RTA weakly curved. Flange of RTA not well-developed. Palpal tibia bearing long narrow apophysis on retrolateral surface below RTA.

Leg spination. Patella I pv 0–2, rv 1–2; tibia I pv 6–8, rv 7; metatarsus I pv 2, rv 2; patella II pv 0–1, rv 0–1; tibia II pv 4, rv 4–5; metatarsus II pv 2, rv 2.

Coloration and pilosity. Carapace light brown to black, and densely covered with white hairs; reversed Vshaped band on dorsum of thoracic part running from base of coxa III to summit, thoracic part almost without hairs; cephalic part darker than thoracic part. Chelicera pale brown to dark brown; anterior part of chelicera lighter than posterior part. Maxilla, labium and sternum light brown to pale yellow. Coxae brownish cream, and slightly tinged with grey. Abdomen densely covered with fine hairs; dorsal scutum pale brown; integument except for scutum brownish cream, and tinged with grey.

Female ( Figs 23 A–F). Cephalic part convex dorsally. In lateral view, dorsal concavity between cephalic and thoracic parts deep and distinct. Thoracic part convex dorsally. Chelicera with seven prolateral and seven retrolateral teeth. Sternum slender. Abdomen oval without distinct constriction or dorsal scutum.

Epigyne ( Figs 23 D–F). Copulatory atria containing openings elongate-oval, but margins indistinct. Spermathecae elongate-oval. Sclerotised copulatory ducts simply and loosely twisted, extending almost straight, and proximally curved below lower margins of copulatory atria. Median pocket or lateral pockets absent or indistinct in front of epigastric furrow.

Leg spination. Patella I pv 1, rv 1; tibia I pv 6–7, rv 6–7; metatarsus I pv 2, rv 2; tibia II pv 4, rv 4; metatarsus II pv 2, rv 2.

Coloration and pilosity. Carapace dark brown; cephalic part covered with fine hairs; lateral part of carapace above coxa I white; thoracic part covered with short white hairs; reversed V-shaped band fringed with thick white hairs on dorsum of thoracic part running from base of coxa III to summit ( Figs 23 A, B). Chelicera pale brown. Maxilla and labium brownish cream tinged with grey. Sternum brownish cream except for cream anterior part; posterior part covered with long black hairs. Coxa I cream; coxa II greyish brown, and its posterior margin densely fringed with black hairs; coxae III greyish brown, and its anterior margin densely fringed with black hairs; coxa IV greyish brown. Abdomen grey, and covered with fine hairs.

Etymology. The specific name is derived from the type locality, Lambir Hills National park in Sarawak.

Distribution. Java, Borneo.

Remarks. Myrmarachne lambirensis is closely related to M. wanlessi Edmunds & Prószyński, 2003 . In males of M. wanlessi the semicircular plate-like extension present below the RTA (cf. Figs 85, 86, 91and 98 in Edmunds & Prószyński 2003), but in M. lambirensis the extension almost absent or not developed well. The female of M. lambirensis closely resembles that of M. hispidacoxa Edmunds & Prószyński, 2003 , but is distinguished from the latter by the more loosely twisted sclerotised copulatory ducts (cf. Fig. 68 in Edmunds and Prószyński 2003 for the epigyne of M. hispidacoxa ).

According to a detailed comparison of M. lambirensis and M. wanlessi based on our material, the former is confined to Borneo and Java, and the latter to continental Asia and Sumatra.

Biology. The species is arboreal, and occurs in gardens and forest canopies.

Figures

FIGURE 22. M. lambirensis sp. nov., male. A, body, dorsal view; B, chelicera and carapace, lateral view; C, maxillae, labium, sternum and coxae; 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: 0.33 mm)

FIGURE 23. M. lambirensis sp. nov., female. A, body, dorsal view; B, chelicera and carapace, lateral view; C, maxillae, labium, sternum and coxae; D – E, internal structure of epigyne, ventral view (D, E from the same specimen); F, internal structure of epigyne (different specimen from D, E), ventral view. (Scales. A – C: 1 mm; D, F: 0.25 mm; E: 0.10 mm)