Liphistius lansak Sivayyapram & Warrit sp. nov.

Figs 1, 5

Type material.

Holotype: Thailand • 1♀; Uthai Thani, Lan Sak District, Rabam; alt. 200 m; 29 October 2020; V. Sivayyapram leg.; ARA-2021-067. Paratype: Thailand • 1♀, same data as for the holotype; ARA-2021-068.

Diagnosis.

Liphistius lansak sp. nov. is a small Liphistius species recognized by the unique vulva: pore plate with receptacular cluster flanked by a pair of large vesicles.

Description.

Male. Unknown.

Female (Holotype: ARA-2021-067; Fig. 5A, B). Coloration (in alcohol): carapace pale brown with black marking on the cephalic region and the margin of the thoracic region; abdominal tergites pale brown, with black marking on the anterior and lateral margins of each plate; membranous part of the opisthosoma cream colored with thin mottled black marking; chelicerae dark brown, with black marking, except on the proximal part; palp and legs pale brown, with black annulations on the proximal and distal part of each joint (Fig. 5B).

Vulva (Fig. 5C, D): vulva plate hexagonal, wider than long, genital atrium without lateral hair; posterior stalk short but wide, posterior margin W-shaped; pore plate rectangular, wider than long, lateral margin not projected into a lip, anterior margin invaginated, thickened and projected into a lip; receptacular cluster racemose, as long as wide, flanked by a pair of large vesicles; central dorsal opening round and wide.

Measurements: Total length 14.17; carapace 5.98 long, 5.46 wide; opisthosoma 8.19 long, 6.89 wide; ocular tubercle 0.91 long, 1.04 wide; palpal coxa 2.21 long, 1.17 wide; labium 0.78 long, 1.82 wide; sternum 3.12 long, 1.95 wide (1.30 on ventral surface); palp 10.79 long (3.77 + 1.95 + 2.47 + - + 2.60); leg I 14.04 long (4.55 + 2.08 + 2.86 + 2.99 + 1.56); leg II 15.08 long (4.81 + 2.21 + 2.99 + 3.38 + 1.56); leg III 17.16 long (4.68 + 2.47 + 3.25 + 4.03 + 2.73); leg IV 20.94 long (5.33 + 2.47 + 4.03 + 5.98 + 3.13).

Etymology.

The specific epithet lansak refers to Lan Sak District, the type locality of the new species in Uthai Thani, Thailand.

Distribution.

Known only from the type locality.

Comment.

This new species name was mentioned as Liphistius sp. HKK in Sivayyapram et al. (2023).