Thyropygus siamensis Verhoeff, 1938

Pimvichai, Piyatida, Enghoff, Henrik & Panha, Somsak, 2011, A revision of the Thyropygus allevatus group. Part 3: the T. induratus subgroup (Diplopoda: Spirostreptida: Harpagophoridae), Zootaxa 2941, pp. 47-68 : 55-56

Thyropygus siamensis Verhoeff, 1938

( Figs. 4 A–D, 9A)

Thyropygus siamensis Verhoeff, 1938: 318

Thyropisthus siamensis: Attems, 1942: 87

Thyropisthus (Duplopisthus) siamensis: Demange, 1961: 107 Thyropisthus ligulus Demange, 1961: 133 , syn. n. Thyropygus ligulus: Hoffman, 1975: 127

Material examined. 2 males SYNTYPES, THAILAND, Ninlap, leg. Fruhstorfer ( ZSM), 1 male, 1 female THAI- LAND, Nakhon Nayok Province, Khao Yai National Park. 14° 27ˏ 32˝ N, 101° 22ˏ 24˝ E. 29 September–6 October 1984. Karsholt, Lomholdt and Nielsen leg., ( ZMUC). 5 males THAILAND, Saraburi Province, Kaeng Khoi District, close to reservoir, Chulalongkorn University area, 14° 35ˏ 12˝ N, 100° 59ˏ 54˝ E. 8 September 2007. P. Tongkerd and P. Prasankok leg., ( CUMZ), 1 male, Saraburi Province, Kaeng Khoi District, Ched-Kod waterfall, 14° 35ˏ 11˝ N, 100° 59ˏ 54˝ E. 8 June 2009, S. Panha leg., ( CUMZ), 10 males, 3 females, Saraburi Province, Muang District, Sam Lan waterfall National Park, 14° 26ˏ 19˝ N, 100° 57ˏ 47˝ E. 1 November 2009. P. Pimvichai and R. Chanabun leg., ( CUMZ), 5 males, 5 females, Saraburi Province, Muaklek District, Ched Sao Noi waterfall, 14° 43ˏ 51˝ N, 101° 11ˏ 36˝ E. 7 March 2009. S. Panha and members of Animal Systematics Research Unit leg., ( CUMZ). 10 males, 10 females, THAILAND, Nakhonrachasima Province, Pak-Chong District, Khao Look-Chang, 14° 31ˏ 33˝ N, 101° 21ˏ 36˝ E. 26 April 2009. S. Panha, P. Pimvichai and members of Animal Systematics Research Unit leg., ( CUMZ).

Diagnosis. A species of the induratus subgroup. Differing from all other species in the subgroup by having femoral spine (fe) curving rearwards and closely appressed to telopodite shaft.

Description. Adult males with 66–68 podous rings, no apodous rings. Length 20–22 cm, width 11.1–12.1 mm. Adult females with 63–68 podous rings, no apodous rings. Length 14–23 cm, width 11.0–13.0 mm. Overall color of living animal ( Fig. 9A ) dark brown. Legs and antennae whitish brown. Epiproct and paraprocts yellowish brown.

Gonopods ( Figs. 4 A–D): Anterior coxal fold (ac) ( Fig. 4 A) basally parallel-sided, distally expanded, with a lateral, rounded lobe and another obliquely disto-mesad, rounded lobe, in posterior view apical margin folded caudad, with a rounded process between the two rounded lobes. Posterior coxal fold (pc) ( Fig. 4 B) basally with moderately high (but lower than in T. macrosiamensis ) lateral paracoxites (px); mesal process (pmp) forming shelf (sh) for accommodation of telopodite, distally directed anteriad. Telopodite ( Figs. 4 C–D) leaving coxite over shelf of posterior coxal fold; femoral spine (fe) relatively long, originating from mesal part of the telopodite ‘knee’, curving rearwards and closely appressed to telopodite shaft, in situ resting against base of apical part of ac; tibial spine (ti) very long, slender, curving in an oblique-sagittal plane, in situ resting between the two ac; apical part: lamellar lobe (ll) flattened, broadly expanded, rounded, transparent; palette (pa) simple, basally with an uncate subterminal lobe (usl) ventrally; distally with about seven to eight brownish blepharochaetae (bp).

Discussion. Based on our study of T. siamensis SYNTYPES, the very accurate description of T. ligulus by Demange (1961), and several additional specimens we have studied we regard T. ligulus ( Demange, 1961) as a synonym of T. siamensis because all gonopodal characters are identical and there are no further differences between the two nominal species. See also discussion under T. macrosiamensis below.

Figures

FIGURE 4. Thyropygus siamensis (specimen from Chulalongkorn University area), gonopods. A: anterior view, left telopodite removed. B: posterior view, left telopodite removed. C: left telopodite, posterior-mesal view. D: left telopodite, anterior-lateral view.

FIGURE 9. A: Thyropygus siamensis (specimen from Sam Lan waterfall National Park), living male. B: Thyropygus macrosiamensis, living male (paratype). C: Thyropygus induratus (specimen from Yotdome), living male. D: Thyropygus laterolobatus, living male (paratype).