Taksinus Songsangchote, Sippawat, Khaikaew & Chomphuphuang, 2022

Songsangchote, Chaowalit, Sippawat, Zongtum, Khaikaew, Wuttikrai & Chomphuphuang, Narin, 2022, A new genus of bamboo culm tarantula from Thailand (Araneae, Mygalomorphae, Theraphosidae), ZooKeys 1080, pp. 1-19 : 1

Taksinus Songsangchote, Sippawat, Khaikaew & Chomphuphuang gen. nov.

Type species.

Taksinus bambus Songsangchote, Sippawat, Khaikaew & Chomphuphuang, 2021 from Tak, Thailand.

Diagnosis.

The characteristics of Taksinus gen. nov. that differ from Ornithoctonus and Cyriopagopus are: a low caput, a clypeus that is less than the width of the median ocular quadrangle (Fig. 6A ), and spermathecae with twin seminal receptacles (Fig. 7E, F ) ( Raven 1985; von Wirth and Striffler 2005; Smith and Jacobi 2015). The new genus differs from Citharognathus by the lack of incrassate tibia and metatarsus IV. Taksinus gen. nov. differs from Lampropelma by the absence of a dense brush of hair on the retrolateral side of the femora of the front limbs ( von Wirth and Striffler 2005) and males by lack of apical embolus swelling (Fig. 5A-E ; see Gabriel and Sherwood 2019: 143, figs 17, 18). Taksinus gen. nov. can be distinguished from Omothymus by male palpal bulb with a gently curved embolus with rounded embolic apex (Fig. 5A-E ) vs palpal bulb steep angle embolus and apex with a sharp point in Omothymus (Fig. 5F-J ; see Gabriel and Sherwood 2019: 139, figs 1-5). Taksinus gen. nov. differs from Phormingochilus by the lack of a single megaspine on the inside of the male tibial apophyses (Fig. 4A, B ; see Smith and Jacobi 2015: 41, fig. 38; Gabriel and Sherwood 2019: 142, figs 14-16), a short embolus compared to palpal bulb length (1:1) (Fig. 5A-E ), and the geographic distribution of Phormingochilus currently restricted to Borneo.

Etymology.

The generic name was named Phraya Tak (governor of Tak province), which is in honor of Taksin the Great, king of the Thonburi Kingdom, in commemoration of his early career.

Description.

Carapace longer than wide, low caput. Fovea deep, straight (males) or slightly procurved (females). Clypeus short, less than width of median ocular quadrangle in males and females. Eight eyes arranged on tubercle, anterior eye row slightly procurved and the posterior row straight. Outer cheliceral on lower surface from margin with five slightly curved pad of plumose setae on the retrolateral chelicerae. Maxillae longer than wide with>155 cuspules (male) or 149-183 (females), two horizontal rows of 10-11 stout thorn-like spines on the lower half of prolateral maxillae (below suture) and one horizontal row of six stout thorn-like spines on the upper half of prolateral maxillae (above suture). Spines of varying lengths, with the longest being at the top of the series; combined to form a stridulating organ. Labium wider than long, with 75 cuspules (male) or 125 (females). Sternum longer than wide, with two pairs of ovoid sigillae; Posterior sigilla is significantly remote from the edge, middle sigilla is close to the margin, and anterior sigilla is indistinguishable. Legs: formula 1423 (males); ± Total lengths of legs I and IV = 0.48, 4123 (females) ± Total lengths of legs I and IV = 2.41-3.33, RF = 101 (males) or 90.6-93 (females). Scopulae distinct, thickly set on tarsus; ventral surface not divided. Tibial spur capped with multitude of thin, short black spines, with no single megaspine on the inside of the tibial apophyses. Palpal bulb is ellipsoid and partly concave, embolus short compared to palpal bulb length (1:1), moderately curved, rounded apex, with single retrolateral keel. Spermathecae have twin seminal receptacles, rounded tombstone receptacles, fused in the basal region.

Distribution.

Tak province, Thailand

Figures

Figure 4. Taksinus bambus sp. nov. Holotype ♂ TAK 1. Tibial apophysis A ventral view B apical view C prolateral view D dorsal view. Scale bars: 1 mm.

Figures 5. Taksinus bambus sp. nov. holotype ♂ TAK 1 (A-E) and Omothymus sp. ♂ (F-J). Palpal bulb A prolateral view B retrolateral view C dorsal view D ventral view E apical view F prolateral view G retrolateral view H dorsal view I ventral view J apical view. Scale bars: 1 mm.

Figure 6. Taksinus bambus sp. nov. Paratype ♀ TAK 3 (A, B, D) Paratype ♀ TAK 2 (C). A carapace, dorsal view B sternum, labium, maxilla, and coxae, ventral view C maxilla, prolateral view D maxillae and labium with cuspules. Scale bars: 1 mm.

Figures 7. Taksinus bambus sp. nov. paratype ♀ TAK 2 (A-E) paratype ♀ TAK 3 (F). A chelicerae, prolateral view B chelicerae, retrolateral view C plumose hairs outer chelicerae, retrolateral view D chelicerae strikers, retrolateral view E spermathecae, dorsal view F spermathecae, dorsal view. Scale bars: 1 mm.