Thyropygus brachyacanthus Pimvichai, Enghoff & Panha, 2009, n. sp.

Thyropygus brachyacanthus n. sp.

(Figs. 13 A–D, 18D)

Material: HOLOTYPE male THAILAND, Suratthani Province, Khiriratnikhom district, Sathitkhirirom Temple, 9° 0 1ˏ 49˝ N, 98° 59ˏ 12˝ E. 9 October 2008. H. Enghoff, S. Panha, P. Pimvichai and members of Animal Systematics Research Unit leg., (CUMZ). – Paratypes: 5 males, 5 females, same data as holotype (CUMZ), 2 males, 2 females (ZMUC), 1 male, 1 female, THAILAND, Suratthani Province, Ban Takhun district, Water supply Khaowong, 8° 56ˏ 5˝ N, 98° 55ˏ 30˝ E. 9 October 2008. H. Enghoff, S. Panha, P. Pimvichai and members of Animal Systematics Research Unit leg., (CUMZ).

Etymology: The species epithet is a Greek noun in apposition and refers to the short femoral spine of the gonopod telopodite.

Diagnosis: A species of the opinatus subgroup. Spatulate lobe (sl) at the apical part of telopodite rounded, spoon-like. Similar in this respect to T. inflexus, T. bearti, T. chelatus, T. cristagalli and T. loxia. Differs from all other species of the T. opinatus subgroup by having the lateral process of anterior coxal fold (alp) flattened, regularly curved, sickle-shaped, and by having the mesal process (amp) almost as long as alp, directed distad, slightly sigmoid, pointed

Description: Adult males with 63-67 podous rings, no apodous rings. Length ca. 10–11 cm, width ca. 4.5–5.1 mm. Adult females with 62–65 podous rings, no apodous rings. Length ca. 10–13 cm, width ca. 5.6–6.7 mm. Overall color of living animal (Fig. 18 D) grayish black. Metazona dark brown. Legs pink. Epiproct, paraprocts reddish orange.

Gonopods (Figs. 13 A–D): Anterior coxal fold (ac) (Fig. 13 A): lateral process (alp) flattened, long, slender, regularly curved; mesal process (amp) almost as long as alp, directed distad, slightly sigmoid, pointed. Posterior coxal fold (pc) (Fig. 13 B) basally with moderately high lateral paracoxites (px), distally truncate, forming shelf (sh) for accommodation of telopodite; mesal process (pmp) directed distolaterad.

Telopodite (Figs. 13 C–D) leaving coxite over shelf of posterior coxal fold; Femoral spine (fe) short, slightly curved, in situ resting behind alp; telopodite distally to fe with a round lobe (lo) projecting distolaterad; tibial spine (ti) very long, curving in horizontal plane, in situ resting close to tip of pmp; an additional protruding lamella at the origin of ti; spatulate lobe (sl) basally slender, distally broadly expanded; a small slender spine (ss) at base of apical part, opposite the origin of the tibial spine; palette (pa) simple, gutter-like, with a longitudinal rounded crest (cr) near tip, distally with about eight brownish blepharochaetae (bp).

Distribution (Fig. 20): Known only from the type locality and one further site in Suratthani Province, the two sites being separated by approximately 25 km.