Manucodicola acantharx Gustafsson & Bush, new species

(Figs 451–456)

Type host. Manucodia ater (Lesson, 1830) — glossy-mantled manucode.

Type locality. Oriomo River, elev. 20 ft, Western District, Papua New Guinea.

Diagnosis. Manucodicola acantharx n. sp. is very similar to Mn. semiramisae n. sp., and females are best separated by vulval chaetotaxy (Figs 456, 462), especially the vss where there appears to be no overlap in the number of setae in the material examined (9–12 in Mn. semiramisae and 13–17 in Mn. acantharx). The female subgenital plate is wider distally in Mn. acantharx (Fig. 456) than in Mn. semiramisae (Fig. 462). Sternal plate IV present in both sexes of Mn. acantharx (Figs 451–452), but absent in both sexes of Mn. semiramisae (Figs 457– 458). Male genitalia hard to assess, as all examined males have partially everted genitalia. From what can be seen, males of the two species may be separated by the following characters: proximal mesosome short in Mn. acantharx (Fig. 455) but long in Mn. semiramisae (Fig. 461); mesosome square-shaped in Mn. acantharx (Fig. 455) but more oval in Mn. semiramisae (Fig. 461); gonopore open distally in Mn. semiramisae (Fig. 461) but closed distally in Mn. acantharx (Fig. 455); mesosomal lobes with fused, shallowly V-shaped thickening distal to gonopore in Mn. acantharx (Fig. 455) but without such thickening in Mn. semiramisae (Fig. 461).

Description. Both sexes. Head shape, structure, and chaetotaxy as in genus description and Fig. 453. Head pigmentation generally darker than in Manicodicola semiramisae . Thoracic and abdominal segments as in genus description and Figs 451–452. Sternal plate IV present in both sexes.

Male. Abdominal chaetotaxy as in Table 2 and Fig. 451. Male genitalia partially everted in all specimens examined, and illustrated and described only tentatively (Fig. 455). Basal apodeme broadly trapezoidal. Proximal mesosome short, broad; anterior margin flat. Gonopore heart-shaped, closed distally. Mesosomal lobes fused distally, broad, quadratic, with large postero-lateral extensions; 2 sensilla on each side visible near anterior margin of lobes. Parameres distorted in all material examined. Measurements ex Manucodia ater (n = 16 except n = 15 for TL and AW): TL = 1.41–1.62 (1.50); HL = 0.46–0.51 (0.48); HW = 0.43–0.47 (0.45); PRW = 0.29–0.32 (0.30); PTW = 0.38–0.42 (0.40); AW = 0.48–0.62 (0.55).

Female. Abdominal chaetotaxy as in Table 2 and Fig. 452. Subgenital plate rounded triangular (Fig. 456), narrowing markedly near vulval margin. Vulval margin bulging, with 4–5 long, slender vms on each side, and 13– 17 stout, thorn-like vss on each side (Fig. 456); most vss arranged in two rows; 7–8 long, slender vos on each side; distal 1–2 vos median to vss. Measurements ex Manucodia ater (n = 12): TL = 1.53–1.88 (1.70); HL = 0.49–0.54 (0.51); HW = 0.45–0.52 (0.48); PRW = 0.29–0.34 (0.32); PTW = 0.40–0.46 (0.43); AW = 0.48–0.67 (0.59).

Etymology. The species epithet is formed by Greek “ ake ” for “thorn”, “ anthus ” for “flower” and Latin “ arx ” for “citadel” or “fortress”, referring to the many thorny setae “guarding” the vulval margin (Fig. 456).

Type material. Ex Manucodia ater: Holotype ♂, Oriomo River, elev . 20 ft, Western District, Papua New Guinea, 22 Feb. 1964, H. Clissold, BBM-NG-29646 (BPBM) [marked by black dot on slide]. Paratypes: 5♂, 4♀, same data as holotype (BPBM); 2♀, Oriomo River, elev . 20 ft, Western District, Papua New Guinea, 25 Feb. 1964, H. Clissold, BBM-NG-50018 (BPBM) .