Myrmarachne gedongensis Badcock, 1918

Yamasaki, Takeshi & Ahmad, Abdul Hamid, 2013, Taxonomic study of the genus Myrmarachne of Borneo (Araneae: Salticidae), Zootaxa 3710 (6), pp. 501-556 : 524-526

Myrmarachne gedongensis Badcock, 1918

( Figs 18 A–G, 19A–E)

Myrmarachne gedongensis Badcock, 1918: 315 , Fig. 11 ; Edmunds & Prószyński, 2003: 308, Figs 48–52.

Type material examined. 1 syntype male (BMNH), labelled as “ Myrmarachne gelongi ”. (We lost the other information on the label, but see under Remarks)

Non-type material examined. BORNEO: 1 female, Danum Valley, Sabah, 9 IX 2005, Y. Hashimoto leg.; 1 male, Monggis substation, Kinabalu Park, Sabah, 6 X 2009, T. Yamasaki leg.; 3 males, Sukau, Sabah, 21–22 X 2009, T. Yamasaki leg.; 2 males, Poring Hot Spring, Kinabalu Park, Sabah, 10–11 XI 2009, T. Yamasaki leg.; 1 female, Tabin Wildlife Reserve, Sabah, 14 X 2010, T. Yamasaki leg.

Diagnosis. Slender, dark brown to black species. In males, chelicera distinctly shorter than carapace ( Fig. 18 A); fang short, its basal half strongly arched ( Fig. 18 B); cymbium flattened dorsoventrally ( Fig. 18 E). In females, spermathecae and sclerotised copulatory dusts very narrow and straight ( Figs 19 D–E); median pocket present in front of epigastric furrow.

Measurements (male/female). Carapace length 2.25–2.80/2.65, width 1.30–1.56/1.40. Abdomen length 2.70– 3.30/3.10. Chelicera length 1.20–1.50. Sternum length 1.30–1.55/1.45. Width of eye row I 1.28–1.56/1.48; II 1.12– 1.32/1.22; III 1.38–1.66/1.54. ALE–PLE 1.04–1.28/1.22; ALE–PME 0.48–0.58/0.56. Eye size: AME 0.43–0.50/ 0.48, ALE 0.23–0.29/0.28, PME 0.08/0.08, PLE 0.28–0.34/0.31.

Male ( Figs 18 A–G). Cephalic part almost flat dorsally. Dorsum of thoracic part weakly convex, and gradually sloping downward posteriorly. Chelicera very short, with five to eight prolateral and six to eight retrolateral teeth. Fang short, its basal half strongly arched, without tooth-like apophysis. Sternum slender, overlapped by coxa II. Abdomen elongate-oval, and weakly constricted anteriorly, with two dorsal scuta.

Palp ( Figs 18 E–G). Cymbium flattened dorsoventrally. Tegulum very large round with thick seminal reservoir along edge of tegulum. Embolus forming very large round coils; embolus coils wider than cymbium, and occupying more than half of venter of cymbium. RTA well developed and curved. Flange of RTA well-developed.

Leg spination. Femur I md 1–2, pd 1; patella I pv 1, rv 1–2; tibia I pv 5–6, rv 5–6; metatarsus I pv 2–4, rv 2–3; femur II md 0–1, pd 1, rd 0–1; tibia II pv 3–4, rv 3–4; metatarsus II pv 2, rv 2; femur III pd 1–2, rd 1; femur IV pd 1, rd 1.

Coloration and pilosity. Carapace brown to dark brown, covered with spares black or grey hairs; dorsum between cephalic and thoracic parts light coloured; in lateral view carapace fringed with white hairs above coxa I, and above coxa II. Chelicera brown to dark brown. Maxilla, labium and sternum brown. Coxa I cream; coxae II, III and IV tinged with black. Abdomen covered with brown hairs dorsally and grey hairs ventrally; two dorsal scuta dark brown; area except for scuta black to grey.

Female ( Figs 19 A–E). Carapace almost as in males. Chelicera with seven prolateral and seven retrolateral teeth. Sternum almost as in males. Abdomen oval, constricted on anterior part, with two dorsal scuta.

Epigyne ( Figs 19 D–E). Copulatory atria appear as large round openings. Spermathecae very narrow, not twisted, extending straight anteriorly, and curved posteriorly in front of epigastric furrow. Small median pocket present in front of epigastric furrow.

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

Coloration and pilosity almost as in males.

Distribution. Malay Peninsula (Badcock 1918; Edmunds & Prószyński 2003), Borneo.

Remarks. Myrmarachne gedongensis was described based on two males (Bukit Besar and Gedong, Malay states, 1901–1902, Nelson Annandale & H. C. Robinson leg.) by Badcock (1918). According to Prószyński (2012), the type material is deposited at BMNH, and labelled as “ Myrmarachne gelongi ”. I examined a type specimen labelled as “ Myrmarachne gelongi ” at BMNH, and the specimen matched the original description of M. gedongensis but slightly different from “ M. gedongensis ” redescribed by Edmunds & Prószyński (2003). The specimen labelled as “ M. gelongi ” and “ M. gedongensis ” by Edmunds & Prószyński (2003) share the same conditions of the cheliceral dentition and the structures of the male palp, but the length of the chelicera is clearly different from each other. Specimens collected in the present study are identical with “ M. gedongensis ”. Although the latter might be an undescribed species, I here consider the similarities in the dentition of the chelicera and the structures of the palp to be important regardless of the difference in the length of the chelicera. Specimens collected in the present study are therefore tentatively identified as M. gedongensis . It is unknown why the probable type material is labelled as “ M. gelongi ”, for which no description is available.

Biology. The species is mainly found on the forest floor. The appearance in the field resembles black Leptogenys ants like L. diminuta F. Smith or L. kitteli Mayr , which march on the ground.

Figures

FIGURE 18. M. gedongensis, male. A, body, dorsal view; B, chelicera and fang, ventral view; C, maxillae, labium, sternum and coxae; D, body, lateral 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 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 19. M. gedongensis, 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. (Scales. A – C: 1 mm; D: 0.25 mm; E: 0.10 mm)