Chalcovietnamicus vietnamensis (Żabka, 1985) (ḋDzffiḋff)

Figs 118–140, 145–146

Chalcoscirtus vietnamensis Żabka, 1985: 209, figs 71–75.

Chalcoscirtus (Chalcovietnamicus) vietnamensis Marusik, 1991: 26 .

Chalcovietnamicus vietnamensis Logunov, 2020: 524 .

Type material. Holotype: ♁ (MNHN 22980), VIETNAM: Ha Noi (examined by Dmitri Logunov, who shared his illustrations).

Other material examined. VIETNAM: 1♁ (TNU), Bac Giang Province, Son Dong District, Mt. Tay Yen Tu, 21.1810°N, 106.7228°E, 352 m elev., 7 July 2022, leg. Quang D. Hoang ; 3♁ 4♀ (TNU), Dak Lak Province, Krong Bong District, Chu Yang Sin National Park, 12.4336°N, 108.2579°E, 450 m elev., 22 Feb. 2022, leg. Quang D. Hoang. SINGAPORE: 1♁ 2♀ (UBCZ; KYU-SAL525), Sugei Buloh Wetland Reserve, near Visitor Centre, 1.440°N, 103.734°E, 19 June 2019, leg. W.P. Maddison, K. Marathe & N. Morehouse , WPM#19-064.

Diagnosis. Males can be distinguished from C. lii by the presence of a distal retro-ventral keel (dK) on the embolus (Fig. 133; vs. absent in C. lii) and the dorsal extension on the distal part of retrolateral tibial apophysis (RTA), which is visible in retrolateral view (Figs 137–140); females can be distinguished by the extremely short copulatory ducts and the small accessory glands hidden at the back of the base of the fertilization ducts, invisible in the ventral view of the rounded spermathecae (Fig. 136); the golden setal bands are absent on the lateral sides of male carapace (Fig. 124).

Description. Male. Habitus as shown in Figs 124, 126. Measurements of the one from Dak Lak, Vietnam: carapace length 1.42; abdomen length 1.54; measurements of eyes: AME 0.35, ALE 0.24, PME 0.03, PLE 0.18; measurements of legs: I 2.28 (0.80, 0.43, 0.48, 0.36, 0.21), II 2.12 (0.72, 0.40, 0.43, 0.37, 0.20), III 2.19 (0.77, 0.35, 0.39, 0.46, 0.22), IV 2.58 (0.85, 0.41, 0.53, 0.54, 0.25); leg formula 4132. Endite with anterior lateral subtriangular extension (Fig. 129). Color (Figs 118–120): body black except for metatarsus and tarsus dark reddish and patellae to tarsi II–IV gray-pink; tibiae II–IV with dark annuli distally; golden setal bands present on axis and posterior lateral edge of abdomen, golden setal band of abdominal axis hollow.

Palp as in Figs 130–132: Cymbium slightly longer than palpal bulb in length, cymbial process (CyP) laminalike, covered by tegulum and invisible ventral view; tegular lobe stout, subconical; embolus rather short, sticking out of large and oval embolic disc which hidden behind bulb; with large flag-like embolic apophysis on back side; with retro-ventral keel on distal half of embolus; retrolateral tibial apophysis (RTA) slightly curved in its ventral edge.

Female. Habitus as shown in Figs 125, 127. Measurements of one from Dak Lak, Vietnam: carapace length 1.54; abdomen length 1.64; measurements of eyes: AME 0.37, ALE 0.23, PME 0.03, PLE 0.17; measurements of legs: I 2.34 (0.81, 0.43, 0.50, 0.37, 0.23), II 2.20 (0.74, 0.43, 0.42, 0.38, 0.23), III 2.29 (0.80, 0.36, 0.40, 0.49, 0.24), IV 2.64 (0.86, 0.41, 0.55, 0.56, 0.26); leg formula 4132. Body form and color like male, but without anterior lateral subtriangular extension and with central setal tuft on sternum, setae on the tuft slightly clavate (Fig. 128); golden setal bands present on dorsal axis and lateral sides of both carapace and abdomen (Fig. 125).

Vulva as in Figs 129, 138, 145: Copulatory ducts rather short; spermathecae subspherical, accessory glands covered by base of fertilization ducts, invisible in ventral view.

Variation. In the retrolateral view, the dorsal edge of RTA is bent in the male from Bac Giang, Vietnam (Fig. 138), whereas straight in other males (Figs 137, 139–140).

Natural history. All specimens from Vietnam were found on tree trunks, hiding in small silk cocoons built in crevices of the bark. All specimens from Singapore were found in large grass tussocks in an open habitat near mangroves.

Distribution. Singapore, Vietnam (Bac Giang, Dak Lak, Ha Noi).

Remarks. By comparing with the illustrations of the male palp of the holotype shared with us by Dr. Dmitri V. Logunov, we confirmed that the male specimen from Singapore used in this study is indeed C. vietnamensis .