Parasteatoda merapiensis Yoshida & Takasuka

Takasuka, Keizo, Yoshida, Hajime, Nugroho, Putra & Matsumoto, Rikio, 2011, A new record of Zatypota albicoxa (Hymenoptera: Ichneumonidae) from Indonesia, with description of a new species of its host spider (Araneae: Theridiidae), Zootaxa 2910, pp. 63-68 : 65-67

Parasteatoda merapiensis Yoshida & Takasuka , sp. nov.

Diagnosis. This species is similar to Parasteatoda wau ( Levi et al. 1982) , P. kaindi ( Levi et al. 1982) and P. vervoorti ( Chrysanthus 1975) , described from New Guinea, in general appearance and genital organs, but is distinguished from them by thick ducts and membranous seminal receptacles of female internal genitalia and coloration of the carapace and abdomen. It is also distinguished from P. wau by the absence of the anterior edge of the epyginal depression, from P. kaindi by the annulated color pattern of the legs, and from P. vervoorti by the short distance between the PMEs.

Female. Carapace oval with large round cervical groove ( Fig. 3 ). AMEs and PMEs separated by distance equal to their diameter. Diameters in ratio, AME: ALE: PME: PLE = 11: 7: 11: 13. MOA wider than long. Chelicera with basal large tooth and distal small one on anterior margin of fang furrow. Leg formula, 1, 4, 2, 3. First patella and tibia 1.3 times carapace length. Abdomen higher than long, longer than wide ( Figs 3–5 ). Genital organ as shown in Figs 6–8 : epigynum swelling with depression, anterior edge indistinct; two openings in both sides of depression; ducts thick and black, forming circle; seminal receptacles globular and membranous.

Coloration ( Figs 3–5 ). Carapace almost black. Chelicerae, maxillae, and labium blackish brown. Sternum brown with posterior black line between fourth coxae. Palpus: femora and patellae dusky brown with black flecks; tibiae and tarsi almost black. Legs dusky brown with black flecks: femora, patellae, tibiae and tarsi each with distal, and metatarsi with distal and median black rings; longitudinal ventral dusky line on first femora, but that of second and third femora indistinct. Abdomen dusky brown with many black flecks, linear median transverse and lateral downward white patches distinct; venter with pair of large white patches between epigynum and spinnerets, and with large black fleck anterior to spinnerets.

Male. Ground color brown with black flecks. Abdomen without distinct white marks. AMEs half their diameter apart. Diameters in ratio, AME: ALE: PME: PLE = 16: 8: 11: 11. Leg formula, 1, 2, 4, 3. First patella and tibia 1.8 times carapace length. Palpal organ as shown in Figs 9–10 : conductor long, ventrally projecting and tapering to apex; embolus thin and long, forming circle. Other characteristics as in female.

Measurements (in mm, Ƥ holotype / 3 allotype). Body length 4.74/ 2.63. Carapace length 1.63/ 1.21; width 1.26/ 1.11. Abdomen length 3.16/ 1.53; width 2.68/ 1.16; height 3.63/ 1.58. Length of legs [total (femur + patella and tibia + metatarsus + tarsus)]: I 7.37/ 6.85 (2.16/ 2.00 + 2.16/ 2.16 + 2.16/ 1.95 + 0.89/ 0.74); II 4.96/ 4.58 (1.37/ 1.32 + 1.37/ 1.47 + 1.21/ 1.21 + 0.68/ 0.58); III 3.69/ 3.26 (1.11/ 1.00 + 1.05/ 0.95 + 0.95/ 0.84 + 0.58/ 0.47); IV 5.58/ 4.15 (1.68/ 1.26 + 1.74/ 1.26 + 1.42/ 1.05 + 0.74/ 0.58). Diameters: AME 0.11/ 0.16; ALE 0.07/ 0.02; PME 0.11/ 0.11; PLE 0.13/ 0.11. Distances: AME-AME 0.11/ 0.08; AME-ALE 0.05/ 0.08; PME-PME 0.11/ 0.13; PME- PLE 0.09/ 0.11. MOA, anterior width 0.30/ 0.34; posterior width 0.30/ 0.26; length 0.26/ 0.29.

Variation. The ground color of females is variable; some specimens are almost blackish brown, and some are yellowish brown. In dark specimens, flecks on the abdomen and legs are indistinct and the sternum has a pair of lateral, large dark flecks. In pale specimens, the longitudinal dusky flecks on the legs are indistinct. The ground color of males is not so variable. Measurements (in mm, Ƥ/ 3): Body length 4.5-6.7/ 2.5–3.1; carapace length 1.9–2.3/ 1.2–1.5; abdomen length 2.5–4.8/ 1.4–1.7.

Type series. Holotype: Ƥ, and allotype: 3, Mt. Merapi, 1,100 m alt, Yogyakarta, Java, Indonesia, 15.Aug.2009, K. Takasuka leg. (NSMT-Ar 8714-8715). Paratypes: 6Ƥ and 63, 27-28.Feb.2010, same locality and collector as for holotype (NSMT-Ar 8716).

Other specimens examined. 15Ƥ and 193, same data as for paratypes. Three juveniles were collected with holotype and 55 juveniles with paratypes.

Biological notes. This species constructs irregular, three-dimensional webs exclusively on A. falcataria , under twigs or dead branches or between tree trunks ( Fig. 11–12 ). Adult spiders usually hang a dead leaf at the centre of the web as a refuge, in which they hide themselves ( Fig. 12 ). Preys captured in the web are mainly ants, caterpillars and rarely beetles.

Comments. The web construction of this species is similar to that of P. tepidariorum ( Achaearanea - type, sensu Benjamin & Zschokke (2003)). It consists of gumfooted lines (GF), a retreat (R) and supporting structures (SSt).

Distribution. Indonesia: Java (known only from type locality).

Etymology. The specific name is derived from Mt. Merapi, Java, the type locality.

Figures

FIGURES 3 – 10. Parasteatoda merapiensis sp. nov., female holotype (3 – 8) and male allotype (9 – 10) – 3, carapace and abdomen, dorsal view; 4 – 5, abdomen, ventral (4) and lateral (5) views; 6, epigynum, ventral view; 7 – 8, internal genitalia, dorsal (7) and ventral (8) views; 9 – 10, palpus, ventral (9) and retrolateral (10) views. Scales: 0.5 mm (3 – 5) and 0.1 mm (6 – 10).

FIGURES 11 – 12. Habitat of P. m e r a p i e n s i s sp. nov. Web (s) of P. merapiensis sp. nov. under twigs (arrow 1) and dead branches (arrow 2) (11), and between tree trunks with a shelter (12) of Albizia falcataria.