Myrmarachne sabahna, 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 : 547-548

Myrmarachne sabahna sp. nov.

( Figs 37 A–G, 38A–F)

Type material. Holotype male (UMS), Guramboi, Sabah, BORNEO, 15 III 2008, T. Yamasaki leg. Paratypes: BORNEO: 1 female (UMS), Danum Valley, Sabah, 20 II 2005, T. Endo leg.; 1 male (UMS), same loc., 20 II 2005, Inoue leg.; 1 female (UMS), same loc., 16 XII 2006, R. Oie leg.; 1 male (UMS), Mahua, Sabah, 4 X 2009, T. Yamasaki leg.; 2 males and 1 female (UMS), Bukit tupai, Kinabalu Park, Sabah, 3 III 2008, T. Yamasaki leg; 2 males (BMNH), Gunung Alab substation, Crocker Range Park, Sabah, 17–19 III 2008, T. Yamasaki leg.; 1 male (MSNG), same loc., 4 X 2010, T. Yamasaki leg.

Diagnosis. Dark brown to black species. In males, chelicera in dorsal view tapering toward apex, with distinct incision on its outer margin basally ( Fig. 37 A); fang almost straight except for curved tip, and without tooth-like apophysis. In females, margins of copulatory atria indistinct ( Figs 38 D–F); sclerotised copulatory ducts twisted, narrow posteriorly; elongated median pocket located between sclerotised copulatory ducts.

Measurements (male/female). Carapace length 1.85–2.40 (2.35)/2.25–2.43, width 1.14–(1.52)/1.20–1.30. Abdomen length 1.88–(2.35)/2.50–2.77. Chelicera length 1.30–(2.35). Sternum length 1.05–1.38 (1.30)/1.13–1.27. Width of eye row I 1.05–(1.34)/1.18–1.27; II 0.92–(1.18)/1.08–1.15; III 1.16–(1.46)/1.30–1.42. ALE–PLE 0.83– (1.08)/0.98–1.00; ALE–PME 0.42–(0.54)/0.46–0.50. Eye size: AME 0.32–(0.40)/0.34–0.42, ALE 0.18–(0.22)/ 0.20–0.22, PME 0.04–(0.06)/0.06–0.07, PLE 0.19–(0.25)/0.20–0.24.

Male ( Figs 37 A–G). Cephalic part almost flat or weakly convex dorsally. Thoracic part in lateral view lower than upper margin of PLE; anterior dorsum of thoracic part almost flat, and posterior dorsum abruptly sloping downward. Chelicera in dorsal view tapering toward apex with distinct incision on outer margin basally, and with six or seven prolateral and seven retrolateral teeth. Fang almost straight except for curved tip, and without toothlike apophysis. Sternum broad, slightly overlapped by coxa II. Abdomen oval with broad dorsal scutum; scutum having incision anteriorly.

Palp ( Figs 37 E–G). Tegulum oval, with narrow seminal reservoir in anterior part and thick reservoir along posterior margin of tegulum. Embolus forming two oval coils; embolus coils occupying almost half of venter of cymbium. RTA weakly curved. Flange of RTA not well developed.

Leg spination. Femur I pd 0–1; patella I pv 1, rv 1; tibia I pv 5–7, rv 5–6; metatarsus I pv 2, rv 2; femur II pd 0– 1; tibia II pv 2–3, rv 3; metatarsus II pv 2, rv 2; femur III pd 1, rd 0–1; femur IV rd 0–1.

Coloration and pilosity. Carapace pale to dark brown; cephalic part sparsely covered with white hairs; thoracic part almost without hairs. Chelicera dark brown to brown. Maxilla, labium and sternum brown to light brown. Coxa I brownish cream, and partly tinged with blackish brown; coxae II, III and IV tinged blackish brown. Abdomen covered with fine hairs; dorsal scutum dark brown; integument except for scutum grey.

Female ( Figs 38 A–F). Cephalic part weakly convex dorsally. Dorsal concavity between cephalic and thoracic parts distinct. Thoracic part strongly convex dorsally. Chelicera with five or six prolateral and seven retrolateral teeth. Sternum almost same as in males. Abdomen oval, with two pairs of small concavities on middle part of dorsum, and without dorsal scutum.

Epigyne ( Figs 38 D–F). Margins of copulatory atria indistinct. Sclerotised copulatory ducts twisted, narrow posteriorly. Median pocket elongated, located between sclerotised copulatory ducts.

Leg spination. Patella I pv 1, rv 1; tibia I pv 5–7, rv 5–7; metatarsus I pv 2, rv 2; tibia II pv 3, rv 3; metatarsus II pv 2, rv 2.

Coloration and pilosity. Carapace dark brown; cephalic part black dorsally, covered with white fine hairs; thoracic part sparsely covered with short white hairs. Chelicera brown. Maxilla, labium and sternum light brown. Coxa I white; coxae II, III and IV cream tinged with pale brown. Abdomen blackish grey, covered with fine hairs; white narrow transverse band anteriorly.

Etymology. The specific name is derived from the type locality, Sabah.

Distribution. Borneo.

Remarks. The specimens from highlands (ca. 1500 m) are smaller than those from lowlands, and the chelicerae of the former are shorter than those of the latter.

Biology. The species occurs in low vegetation from lowlands to highlands (up to 1500 m alt.).

Figures

FIGURE 37. M. sabahna sp. nov., male. A, body, dorsal view; B, chelicera and carapace, lateral view; C, chelicera and fang, ventral view; D, maxillae, labium, sternum and coxae; E, palp, ventral view; F, palp, lateral view; G, palpal tibia, dorsal view. (Scales. A – D: 1 mm; E – G: 0.25 mm)

FIGURE 38. M. sabahna sp. nov., female. A, body, dorsal view; B, chelicera and carapace, lateral view; C, maxillae, labium, sternum and coxae; D and F, internal structure of epigyne, ventral view; E, internal structure of epigyne, dorsal view. (Scales. A – C: 1 mm; D – E: 0.25 mm; F: 0.10 mm)