Myrmarachne brevichelicera, 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 : 515-518

Myrmarachne brevichelicera sp. nov.

( Figs 11 A–G, 12A–F)

Type material. Holotype male (UMS), Poring Hot Spring, Kinabalu Park, Sabah, BORNEO, 11 XI 2009, T. Yamasaki leg. Paratypes: BORNEO. 2 males and 3 females (1 male and 2 females: UMS; 1 male and 1 female: BMNH), same loc. as the holotype, 13–14 XI 2010, T. Yamasaki leg.

Diagnosis. Small, orange to light brown species. In males, chelicera very short ( Figs 11 A–B); leg I robust and femur I basally broad. In females, spermathecae elongate-oval; anterior part of sclerotised copulatory ducts twisted once; posterior part of sclerotised copulatory ducts very narrow ( Figs 12 D–F); median pocket present in front of epigastric furrow.

Measurements (male/female). Carapace length 1.90–(2.13)/1.75–1.95, width 1.14–(1.24)/0.93–1.04. Abdomen length 2.00–(2.55)/2.10–2.20. Chelicera length 0.85–(0.93). Sternum length 1.00–(1.20)/0.88–1.15. Width of eye row I 1.16–(1.24)/0.98–1.14; II 0.98–(1.10)/0.86–0.96; III 1.12–(1.22)/0.96–1.08. ALE–PLE 0.85– (0.90)/0.69–0.79; ALE–PME 0.43–(0.44)/0.34–0.40. Eye size: AME 0.39–(0.44)/0.34–0.40, ALE 0.19–(0.21)/ 0.18–0.19, PME 0.05–0.06 (0.05)/0.05–0.06, PLE 0.19–(0.21)/0.16–0.19.

Male ( Figs 11 A–G). Cephalic part almost flat dorsally. Thoracic part strongly convex dorsally. Chelicera much shorter than carapace, with four prolateral and one to three very small retrolateral teeth; in lateral view ventral margin of chelicera strongly convex. Fang short and weakly sinuous, without tooth-like apophysis. Sternum relatively broad, scarcely overlapped by coxae. Leg I robust; femur I basally broad: coxa I large compared with other coxae. Abdomen elongate-oval with dorsal scutum that is weakly incised on each lateral outline anteriorly.

Palp ( Figs 11 E–G). Cymbium without apical spine. Tegulum large oval with thin seminal reservoir in prolateral part and thick reservoir along posterior edge of tegulum. Embolus forming two large oval coils; embolus coils occupying more than half of venter of cymbium. RTA curved, well developed. Flange of RTA poorly developed.

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

Coloration and pilosity. Carapace pale orange to orange; cephalic part covered with sparse black hairs; surroundings of eyes black, covered with white hairs; thoracic part almost without hairs. Chelicera brown; its dorsum tinged with black. Maxilla and labium light brown. Sternum pale orange. Coxae cream. Abdomen dorsally covered with fine hairs; scutum translucent pale brown; seen through translucent scutum, anterior part cream and posterior part tinged with black.

Female ( Figs 12 A–F). Cephalic part almost flat dorsally. Thoracic part strongly convex dorsally. Chelicera with four prolateral and five or six retrolateral teeth. Sternum and abdomen almost same as in males.

Epigyne ( Figs 12 D–E). Copulatory atria indistinct. Spermathecae elongate-oval; anterior part of sclerotised copulatory ducts twisted once; posterior part of sclerotised copulatory ducts very narrow. Median pocket present between proximal ends of sclerotised copulatory ducts.

Leg spination. Patella I rv 1; tibia I pv 6, rv 6; metatarsus I pv 2, rv 2; tibia II pv 3, rv 3; metatarsus II pv 2, rv 2.

Coloration and pilosity. Carapace light brown; cephalic part covered with sparse white hairs; white hairs forming lateral markings between cephalic and thoracic parts; thoracic part almost without hairs. Chelicera pale brown. Maxilla, labium, sternum and coxae almost as in males. Abdomen covered with fine hairs dorsally; narrow cream transverse band in anterior part of abdomen; dorsal scutum translucent pale brown; integument except for scutum pale grey.

Etymology. The specific name is derived from the short male chelicera (Latin prefix “brevi-” (short) and noun “chelicera”).

Distribution. Borneo.

Remarks. The species is in external appearance very similar to Myrmarachne mariaelenae , but M. brevichelicera is distinguishable from M. mariaelenae by the dentition of the male chelicera: M. brevichelicera has retrolateral teeth on cheliceral venter, but M. mariaelenae without any retrolateral teeth (cf. Prószyński 2001). Biology. The species occurs in the lower vegetation of forest interior.

Figures

FIGURE 11. M. brevichelicera 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, palp, dorsal view. (Scales. A – D: 1 mm; E – G: 0. 25 mm)

FIGURE 12. M. brevichelicera 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)