Platnickina adamsoni ( Berland, 1934 )

Dhiya’ulhaq, Naufal Urfi, Buchori, Damayanti, Hidayat, Purnama, Scheu, Stefan & Drescher, Jochen, 2025, Two new species and three new records of the cobweb spider Platnickina (Araneae, Theridiidae) from Sumatra, Evolutionary Systematics 9 (2), pp. 203-220 : 203-220

Platnickina adamsoni ( Berland, 1934)

Figs 1 , 2 , 3

Theridion adamsoni : Berland 1934: 102, figs 6–9 ( ♀); Levi 1959: 111 (synonym of Theridion hobbsi ); Marples 1964: 409, fig. 11 ( ♂); Levi 1967: 181, figs 20–23 ( ♂ ♀); Kumada 1986: 2, figs 1–8 ( ♂ ♀); Chikuni 1989: 43, fig. 61 ( ♂ ♀); Saito 1992: 946, fig. 6 ( ♀); Zhu 1998: 162, fig. 101 A – E ( ♂ ♀); Song, Zhu and Chen 1999: 137, fig. 71 G – H, M – N ( ♂ ♀); Namkung 2002: 99 ( ♂ ♀).

Coleosoma adamsoni : Saaristo 1978: 117, figs 183–191 ( ♂ ♀).

Platnickina adamsoni : Ono 2011: 452, figs 56–61 ( ♂ ♀); Sherwood and Sharp 2023: 356, fig. 1 a – d ( ♂ ♀).

Theridion hobbsi : Gertsch & Archer, 1942: 5, fig. 6 ( ♀); Archer 1946: 46 (synonym of Theridion blatcheyii ); Levi 1957: 62, figs 198–199, 209, 213–214 ( ♂ ♀, synonym of Chindellum magnificum and Theridion insulicola ).

Theridion blatchleyii : Bryant 1945: 205, fig. 5 ( ♂).

Theridion insulicola : Bryant 1947: 88, fig. 1 ( ♀).

Chindellum magnificum : Archer, 1950: 13, pl. I, fig. 2 ( ♂ ♀).

Keijia mneon [misidentifications]: Yoshida 2001: 172, figs 8, 53–55 ( ♂ ♀); Namkung 2003: 101 ( ♂ ♀); Yoshida 2003: 84, figs 213–215 ( ♂ ♀); Saaristo 2006: 62, figs 34–42 ( ♂ ♀); Yoshida 2009: 374, figs 171, 172 ( ♂ ♀); Yin et al. 2012: 352, fig. 144 a – c ( ♀).

Platnickina mneon [misidentifications]: Saaristo 2010: 257, fig. 37, 75–80 ( ♂ ♀); Jin 2018: 29, fig. 4-19. A – C, pl. 7 ( ♀); Suzuki and Nakama 2021: 32, figs 1, 5 ( ♂); Dippenaar-Schoeman et al. 2021: 65 ( ♂ ♀); Baert et al. 2023: 32, fig. 121 A – C ( ♂ ♀).

Material examined.

INDONESIA – Jambi Province • 1 ♂; Batang Hari, Bajubang, Singkawang ; 01°47'13.8"S, 103°16'14.7"E; elev. 46 m; 18 Jul. 2013; J. Drescher leg.; canopy fogging in oil palm plantation; GOET 2013_HO 4.3_AraTrid 020 N_001 (to be transferred to MZB) . • 1 ♂; Batang Hari, Bajubang, Bungku ; 01°55'41.6"S, 103°15'34.2"E; elev. 48 m; 5 Jul. 2013; J. Drescher leg.; canopy fogging in jungle rubber plantation; GOET 2013_HJ 1.2_AraTrid 020 N_001 (to be transferred to ZMH) . • 1 ♀; Sarolangun, Bukit Duabelas National Park ; 01°56'30.8"S, 102°34'50.6"E; elev. 91 m; 4 Oct. 2013; J. Drescher leg.; canopy fogging in rainforest; GOET 2013_BF 4.1_AraTrid 020 N_001 (to be transferred to MZB) .

Diagnosis.

Among the sterninotata - group, males of P. adamsoni are most similar to P. yoshidai by the conductor extending into a pointed, sclerotised distal part (Figs 1 C, D , 3 A, B ) but can be distinguished by shorter embolus, not coiled at the tip (vs longer, tip with horizontal coiling in P. yoshidai ) ( Huang et al. 2025: fig. 10 A – C). Females are most similar to P. harapan sp. nov. by the inflated, sclerotised distal part of copulatory ducts but can be distinguished by the rectangular initial part of copulatory ducts (Figs 2 C, D , 3 C, D ) (vs copulatory ducts arc-shaped in P. harapan Dhiya’ulhaq , sp. nov.) (Figs 11 C, D , 12 C, D ).

Description.

Male ( 2013_HO 4.3_AraTrid 020 N_001 ; Figs 1 , 3 A, B ). Total length 1.83. Prosoma length 0.79; width 0.74. Opisthosoma length 1.04; width 0.89. Diameter of eyes: AME 0.11; ALE 0.08; PLE 0.08; PME 0.09. Interdistances between eyes: AME – AME 0.09; AME – ALE 0.02; ALE – ALE 0.30; PME – PME 0.06; PME – PLE 0.06; ALE – PLE 0.01; AME – PME 0.09; PLE – PLE 0.36. Leg measurements: leg I 5.18 (1.62, 0.31, 1.51, 1.32, 0.42); leg II (1.30, 0.30, 1.08, 1.05, –); leg III 2.77 (0.89, 0.26, 0.52, 0.74, 0.36); leg IV 2.76 (0.91, 0.24, 0.56, 0.72, 0.33).

Prosoma pear-shaped, brownish yellow; dorsally with an elongated black mark; margins black (Fig. 1 A ). Eyes ringed in red; AME larger than the other eyes; AER strongly recurved; PER straight (Fig. 1 A ). Chelicerae brown. Maxillae brown (Fig. 1 B ). Labium fused with sternum, brown (Fig. 1 B ). Sternum triangular, brown (Fig. 1 B ). Opisthosoma egg-shaped, conspicuously tuberculate, pinkish-yellow with mottled black and white spots; distal end with larger black patches (Fig. 1 A ). Legs yellow, with numerous distinct black patches (Fig. 1 A ). Spinnerets brown (Fig. 1 B ).

Palp (Figs 1 C – E , 3 A, B ): Cymbium oval, yellow. Conductor membranous, twisted; middle part widened; tip claw-shaped, acute. TTA rhomboid; base curved. Embolus curved, wide, covering most of the bulb’s ventral surface; membranous, except for the distinctly dark outer margin; tip ventrally protruding, resting on the widened part of conductor.

Female ( 2013_BF 4.1_AraTrid 020 N_001 ; Figs 2 , 3 C, D ). Total length 1.96. Prosoma length 0.82; width 0.77. Opisthosoma length 1.14; width 1.05. Diameter of eyes: AME 0.10; ALE 0.07; PLE 0.08; PME 0.09. Interdistances between eyes: AME – AME 0.08; AME – ALE 0.02; ALE – ALE 0.27; PME – PME 0.05; PME – PLE 0.04; ALE – PLE 0.01; AME – PME 0.07; PLE – PLE 0.33. Leg measurements: leg I –; leg II 3.76 (1.22, 0.31, 0.92, 0.91, 0.40); leg III 2.91 (0.93, 0.24, 0.59, 0.74, 0.41); leg IV 2.93 (0.93, 0.28, 0.58, 0.75, 0.39). Habitus as in males, except sternum brownish yellow with black edges (Fig. 2 B ).

Epigynum (Figs 2 C, D , 3 C, D ): Atrium large, oval. Copulatory openings semicircular. Copulatory ducts boxy S-shaped; initial part with angled corners, forming a rectangular U-turn; latter part inflated and darkened. Spermathecae oval. Fertilization ducts curved.

Distribution.

Cosmopolitan. Newly recorded for Indonesia (Fig. 15 ).

Remarks.

This species appears to have been introduced to several countries, but its actual region of origin has not been investigated, and its true native distribution (particularly whether it includes Indonesia) remains uncertain. Levi (1967) remarked that it is likely introduced to the Americas given the apparent lack of closely related species in the region. The fact that the other species of the sterninotata - group are found in Asia (including P. harapan Dhiya’ulhaq , sp. nov.) might be an indication for this region to be the native distribution of P. adamsoni .

Figures

Figure 1. Platnickina adamsoni (Berland, 1934), male (2013 _ HO 4.3 _ AraTrid 020 N _ 001). A, B. Habitus. A. Dorsal view; B. Ventral view; C – E. Left palp; C. Prolateral view; D. Ventral view; E. Retrolateral view. Scale bars: 0.5 mm (A, B); 0.1 mm (C – E).

Figure 2. Platnickina adamsoni (Berland, 1934), female (2013 _ BF 4.1 _ AraTrid 020 N _ 001). A, B. Habitus; A. Dorsal view; B. Ventral view; C, D. Epigynum, cleared; C. Ventral view; D. Dorsal view. Scale bars: 0.5 mm (A, B); 0.1 mm (C, D).

Figure 3. Platnickina adamsoni (Berland, 1934). A, B. Male (2013 _ HO 4.3 _ AraTrid 020 N _ 001), left palp; A. Prolateral view; B. Ventral view; C, D. Female (2013 _ BF 4.1 _ AraTrid 020 N _ 001), epigynum; C. Ventral view; D. Dorsal view. Abbreviations: c = conductor; cd = copulatory duct; co = copulatory opening; e = embolus; fd = fertilization duct; tta = theridiid tegular apophysis; s = spermatheca. Scale bars: 0.1 mm.

Figure 11. Platnickina harapan Dhiya’ulhaq, sp. nov., female holotype (2013 _ HF 3.1 _ AraTrid 188 N _ 001). A, B. Habitus; A. Dorsal view; B. Ventral view; C, D. Epigynum, cleared; C. Ventral view; D. Dorsal view. Scale bars: 0.5 mm (A, B); 0.1 mm (C, D).

Figure 12. Platnickina harapan Dhiya’ulhaq, sp. nov. A – C. Male paratype (2013 _ HJ 2.1 _ AraTrid 188 N _ 001), right palpal bulb, mirrored; A. Prolateral view; B. Ventral view; C. Theridiid tegular apophysis; D, E. Female holotype (2013 _ HF 3.1 _ AraTrid 188 N _ 001), epigynum; D. Ventral view; E. Dorsal view. Abbreviations: c = conductor; cd = copulatory duct; co = copulatory opening; e = embolus; fd = fertilization duct; s = spermatheca. Scale bars: 0.1 mm.

Figure 15. Distribution of five species of Platnickina Koçak & Kemal, 2008 in Jambi Province, Sumatra, Indonesia. Spiders presented in this study were collected by canopy fogging in 32 permanent research plots of the EFForTS project (Drescher et al. 2016). Green areas on the globe belong to Indonesia, and Jambi Province in Sumatra, respectively.