Myrmarachne melanocephala (Mac Leay, 1839)

Figs 7–10

Myrmarachne melanocephala MacLeay, 1839: 11 (original description); Benjamin, 2025: 2625, figs 17A–D, 18A–D, 19A–D; Caleb, 2016b: 410, figs 20–30.

Myrmarachne calcuttaensis Biswas, 1984: 126, figs 17–19 (original description); synonymized by Caleb & Joseph (2025).

MATERIAL EXAMINED. Vietnam: Ben Tre Province, Ben Tre City, low shrubs in front of government buildings, 10.229174N, 106.413805E, h= 2 m, 3. III 2025, 1♂, coll. Tam Van Truong (CTU-SP.002.01); Long An Province, Can Giuoc District, low shrubs inside the Can Giuoc High School Campus, 10.59817N, 106.65966E, h= 2 m, 20.III 2025, 1♀, coll. Dang Bao Tran (CTU-SP.001.02).

DESCRIPTION OF VIETNAMESE SPECIMENS (measurements in mm). Male: Total body length 6.41, carapace length 3.14, width 1.74; abdomen length 2.66, width 1.36. Leg measurements: I 5.7 (1.77, 0.78, 1.65, 0.96, 0.54), II 4.31 (1.38, 0.65, 1.09, 0.75, 0.44), III 4.55 (1.47, 0.53, 1.01, 1.09, 0.45), IV 6.34 (2.10, 0.69, 1.48, 1.56, 0.51). Cephalic region dark brown, slightly elevated above the thoracic region; surface finely rugulose and covered with fine grey setae. Thoracic region reddish, distinctly separated from the cephalic part by a prominent transverse furrow, gradually sloping posteriorly. Chelicerae shorter than the carapace, light brown, rugulose, and dorsally flattened; cheliceral dentition consisting of 10 promarginal and 10 retromarginal teeth. Fangs gradually tapering, slender, bearing a distinct apophysis. Abdomen elongate, with a dorsal scutum and a marked constriction; anterior portion reddish brown, posterior portion dark brown, uniformly covered with fine setae (Fig. 7). The palps with rounded tegulum bearing a C-shaped seminal reservoir positioned at approximately 2 to 3 o’clock; embolus forming two coils. Retrolateral tibial apophysis twisted, strongly curved, S-shaped, with a well-developed flange (Figs 9–10).

Female: Body length 5.35, carapace length 2.67, width 1.21; abdomen length 2.08, width 1.19. Leg measurements: I 3.14 (1.02, 0.4, 0.8, 0.52, 0.4), II 3.2 (1.06, 0.52, 0.81, 0.42, 0.39), III 4.45 (0.92, 1.12, 1.27, 0.75, 0.39), IV 5.59 (1.82, 0.61, 1.41, 1.32, 0.43). The chelicerae bear 7 teeth on the prolateral margin and 8 teeth on the retrolateral margin. Legs I and II are light yellowish, except for coxa I, which is brownish. Legs III and IV are brownish, with a white trochanter IV and patella IV. Thin, dark brown stripes are present along the lateral margins of the first two pairs of legs. The abdomen is elongated, lacking a scutum, with fine white hairs along the lateral sides near the weak constriction. Faint white transverse markings are visible on the dorsum (Fig. 8). The epigyne possess large, oval copulatory openings. The copulatory ducts coil in an ∞-shaped pattern before connecting to the spermathecae. Additionally, two small lateral pockets are observed just above the epigastric furrow.

HABITAT. The specimens were collected from dense low shrubs.

REMARKS. Overall, the female individual is lighter in color than the male.

DISTRIBUTION. From Pakistan to Indonesia (WSC, 2025), Vietnam (new record).