Siliquobolellus constrictus gen. et sp. nov.

Figs 2, 4, 6, 7

Material studied.

Holotype. 1 male (CUMZ-D00150-1), Thailand, Prachuap Khiri Khan Province, Kui Buri District, Ban Yang Chum; 12°04'19.64"N, 99°42'57.63"E; 149 m a.s.l.; 7 August 2014; C. Sutcharit leg.

Paratypes. 1 male (CUMZ-D00150-2), 2 females (CUMZ-D00150-3); same data as holotype .

Etymology.

The species epithet is a Latin adjective derived from the verb constringere = "to tighten" and refers to the constricted anterior gonopod coxa.

Diagnosis.

Differing from other species in the genus by having the anterior gonopod coxae constricted at middle of lateral margin, while the other two species have no constriction at middle of lateral margin of anterior gonopod coxae; externally differing by having a middorsal row of triangular dark brown spots, with dark brown bands on both lateral sides running parallel to the dorsal one.

Description.

Adult males with 41 or 42 podous rings, 1 apodous ring. Length ~3 cm, diameter 3.6-3.7 mm. Adult females with 42 or 43 podous rings, 1 apodous ring. Length ~3 cm, diameter 4.1-4.5 mm.

Colour. After 8 years in alcohol overall beige with 3 stripes from head to telson: a mid-dorsal row of triangular dark brown spots, with dark brown bands on both lateral side running parallel to the dorsal one (Fig. 2J).

Anterior gonopods (Fig. 4A, B, D, E) with a small triangular process between coxae (st), with high coxae, broad at base, gradually narrowing towards tip, distinctly constricted at middle of lateral margin, apical part flattened, curving mesad, mesal margin basally straight, curving towards tip, posterior surface folding cover more than half of telopodite. Telopodite small, directed distad, thumb-like process, with longitudinal ridge from base to tip (Fig. 4B, arrow).

Posterior gonopods (Fig. 4C, F-J) simple, rounded, with short, smooth coxal part (pcx); telopodital part (pt) twice the length of the pcx, lateral margin expanded, folding mesad, forming a concavity (not so deep as in the other two species).

Female vulvae (Fig. 4K): simple, valves prominent, the left valve slightly larger than the right valve.

DNA barcode.

The GenBank accession number of the COI barcode of the paratype is OP174622 (voucher code CUMZ-D00150).

Habitat.

Found under leaf litter.

Distribution.

Known only from the type locality in Prachuap Khiri Khan Province, Thailand (Fig. 7).