Trilacuna triseta Tong & Li, 2020

Tong, Yanfeng, Li, Shuqiang & Bian, Dongju, 2020, Taxonomic studies on the genus Trilacuna (Araneae, Oonopidae) from Myanmar, ZooKeys 960, pp. 39-62 : 39

Trilacuna triseta Tong & Li sp. nov. Figs 11 , 12 , 14J-L , 16G , 16H

Type material.

Holotype ♂: Myanmar, Kachin State, Putao, Hponkanrazi Wildlife Sanctuary; 27°32.032'N, 97°00.036'E; elevation ca 2010 m; 15.V.2017; Wu J. and Chen Z. leg. (IZCAS AR-25155).

Diagnosis.

The new species is similar to T. bilingua Eichenberger, 2011 but can be distinguished by the three black, thick setae on the endites of the male (Figs 11G , 16G , 16H ) and the slender anterior branch (ab) of the embolus system (Fig. 12E , 12F , 12H ). Trilacuna bilingua lacks black, thick setae on the endites, and the embolus system has two very short lobes basally (Eichenberger et al. 2011: fig. 5-6).

Description.

Male. Body: reddish brown, chelicerae and sternum lighter, legs yellow; habitus as in Figure 11A-C ; body length 1.97. Carapace: 0.95 long, 0.74 wide; sides smooth; lateral margin rebordered (Fig. 11B ); posterior surface with several large setal bases (Fig. 11H ). Eyes: ALE largest; PLE and PME nearly equal in size; ALE-PLE separated by less than ALE radius; PME touching each other; posterior eye row recurved as viewed from above, procurved as viewed from front (Fig. 11D, I ). Clypeus: height about 0.85 times of ALE diameter, with a triangular, pointed, median projection (cmp). Mouthparts (Figs 11F, I , 16G, H ): endites with three thick, black setae. Sternum (Fig. 11F ). Abdomen: 1.05 long, 0.80 wide; booklung covers ovoid, surface smooth (Fig. 11B ); dorsal scutum not fused to epigastric scutum; apodemes present; posterior spiracles connected by groove (Fig. 11C ). Palp (Figs 12 , 14J-L ): orange; 0.72 long (0.17, 0.11, 0.11, 0.33); femur elongated (width/length = 0.53) (Fig. 12A, B ); bulb oval, tapering apically; embolus system (Fig. 12E , 12F , 12H ) with an anterior branch (ab), a dorsal branch (db), a ventral branch (vb), and a median lobe (ml) in prolateral view.

Female. Unknown.

Etymology.

The species epithet is a noun in apposition composed of the Latin words tri (three) and seta and refers to the three black, thick setae on the male’s endites.

Distribution.

Known only from the type locality.

Remarks.

There are two species reported from a single female specimen in this study, and one described from a single male: T. loebli Grismado & Piacentini, 2014, T. zhigangi Tong & Li, sp. nov., and T. triseta Tong & Li, sp. nov., respectively. The following characters indicate that neither of the two females are conspecific with T. triseta Tong & Li, sp. nov. T. loebli is dark brown (Fig. 10A ) with a reticulated carapace (Fig. 10D ), and T. zhigangi has small eyes (Fig. 13A ) and lacks the triangular, pointed, median projection of the clypeus (Fig. 13H ). The male, T. triseta Tong & Li, sp. nov. has a reddish-brown body, a smooth carapace, normal-sized eyes, and a triangular, pointed, median projection (Fig. 11A, D, I ).

Figures

Figure 10. Trilacuna loebli, female (IZCAS AR- 25156) A-C habitus in dorsal, ventral, and lateral views D-F, H prosoma in dorsal, ventral, lateral, and anterior views G abdomen in ventral view. Abbreviations: boc = booklung covers; cmp = clypeus median projection; esb = elevated seta base; ldi = labium deep incision; sep = semicircular plate. Scale bars: 0.4 mm.

Figure 11. Trilacuna triseta sp. nov., male holotype A-C habitus in dorsal, lateral, and ventral views D-F, H, I prosoma in dorsal, lateral, ventral, posterior, and anterior views G labium and endites in ventral view (arrow shows the three black, strong setae). Abbreviations: boc = booklung covers; cmp = clypeus median projection; esb = elevated seta base; ldi = labium deep incision. Scale bars: 0.4 mm (A-F, H, I); 0.2 mm (G).

Figure 12. Trilacuna triseta sp. nov., male holotype, left palp, SEM A, B, G prolateral, retrolateral, and dorsal views C, D palpal bulb in prolateral and retrolateral views E, F, H distal part of palpal bulb in prolateral, retrolateral, and dorsal views. Abbreviations: ab = anterior branch; db = dorsal branch; emb = embolus; ml = median lobe; vb = ventral branch.

Figure 13. Trilacuna zhigangi sp. nov., female holotype A-C habitus in dorsal, ventral, and lateral views D-F, H prosoma in dorsal, ventral, lateral, and anterior views G abdomen in ventral view. Abbreviation: esb = elevated seta base; ldi = labium deep incision. Scale bars: 0.4 mm.

Figure 14. Trilacuna spp., left male palp A-C T. besucheti D-F T. changzi sp. nov. G-I T. hponkanrazi sp. nov. J-L T. triseta sp. nov. A, D, G, J prolateral views B, E, H, K dorsal views C, F, I, L retrolateral views. Scales: 0.2 mm.

Figure 16. Trilacuna spp., male labium and endites, ventral view A, B T. changzi sp. nov., white arrow shows the long, strongly curved spines C, D T. hponkanrazi sp. nov. E, F T. besucheti G, H T. triseta sp. nov., black arrow shows the three black, strong setae. Abbreviations: bts = bent thick setae; cos = comb-like setae.