Gamasomorpha fortdekock, Bai & Bian & Tong & Hörweg, 2025

Bai, Yang, Bian, Dongju, Tong, Yanfeng & Hörweg, Christoph, 2025, Three new species of the genus Gamasomorpha Karsch, 1881 (Araneae, Oonopidae) from the Philippines and Sumatra, Indonesia, ZooKeys 1258, pp. 313-331 : 313-331

Gamasomorpha fortdekock sp. nov.

Figs 4 , 5 , 12 D – F

Material examined.

Holotype Indonesia • ♂ ( NHMW -ZOO-AR-207 ); Sumatra, Fort de Kock ; leg. Edward Richard Jacobson . Paratype. Indonesia • 2 ♂ ( NHMW -ZOO-AR-30392 ); same data as holotype .

Etymology.

The specific name is a noun in apposition taken from the type locality.

Diagnosis.

The new species is similar to G. comosa Tong & Li, 2009 from China in the smooth carapace and the pointed conical extension of bulb, but can be distinguished by the abdomen strongly constricted at anterior part (vs not constrict; cf. Fig. 4 A and Tong and Li 2009: fig. 1 A), pedicel tube with colorless, almost transparent directed hairs (vs lacking; cf. Fig. 4 I and Tong and Li 2009: fig. 2 C), and the scuto-pedicel region with a curved scutal ridge and a small round knob (vs lacking, but with nearly rectangular lateral ridge; cf. Fig. 4 I and Tong and Li 2009: fig. 2 B, C).

Description.

Male ( holotype). Total length 2.34; carapace 0.95 long, 0.78 wide; abdomen 1.68 long, 1.00 wide. Habitus as in Fig. 4 A – C . Body yellow, chelicerae and legs lighter. Carapace (Fig. 4 C, D, F ): surface smooth; pars cephalica strongly elevated in lateral view; lateral margin with a row of finely hairs. Eyes (Fig. 4 D, F ): ALE largest, PLE smallest; posterior eye row recurved viewed from above, procurved from front; ALE separated by less than their radius; ALE separated from edge of carapace by about 0.5 times their diameter. Sternum (Fig. 4 E ): finely reticulate, with narrow, transverse palpal groove, covered with thin hairs standing in small pits, radial furrows present. Abdomen (Fig. 4 A, H, I ): dorsal scutum ovoid, punctate, densely covered with short setae, anterior part strongly constricted; booklung covers very small; pedicel tube short, without dorsolateral extension, with colorless, almost transparent directed hairs; scuto-pedicel region with curved scutal ridge and a small round knob. Palp (Figs 5 A – F , 12 D – F ): yellowish; bulb distally tapering, ending as pointed conical extension ( ce); cymbium not extending beyond distal tip of bulb; with long slender, lamellar embolus ( em), adjacent to an embolic accessory appendage ( ma) and a lamellar conductor ( co).

Female. Unknown.

Distribution.

Known only from the type locality (Fig. 13 ).

Figures

Figure 4. Gamasomorpha fortdekock sp. nov., male holotype. A – C. Habitus, dorsal, ventral and lateral views, arrows show the constriction; D – G. Prosoma, dorsal, ventral, anterior and lateral views; H, I. Abdomen, ventral and anteroventral views. Abbreviations: boc = booklung covers; kno = knob; scr = scutal ridge; trh = transparent hairs. Scale bars: 0.4 mm.

Figure 5. Gamasomorpha fortdekock sp. nov., male left palp, SEM. A, C, E. Prolateral, dorsal and anterior-retrolateral views; B, D, F. Distal part of bulb, prolateral, dorsal and anterior-retrolateral views. Abbreviations: ce = conical extension; co = conductor; em = embolus; ma = mesal embolic accessory appendage. Scale bars: 0.1 mm.

Figure 12. Gamasomorpha spp., male left palp. A – C. G. bakeri sp. nov.; D – F. G. fortdekock sp. nov.; G – I. G. jacobsoni sp. nov.; J – L. G. shoushanensis (Tong & Li, 2014). A, D, G, J. Prolateral view; B, E, H, K. Dorsal view; C, F, I, L. Retrolateral view. Scale bars: 0.1 mm.

Figure 13. Distribution records of the four Gamasomorpha species: 1. G. bakeri sp. nov.; 2. G. fortdekock sp. nov.; 3. G. jacobsoni sp. nov.; 4. G. shoushanensis (Tong & Li, 2014).