Thyropygus macrosiamensis, Pimvichai, Piyatida, Enghoff, Henrik & Panha, Somsak, 2011

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 : 61-62

Thyropygus macrosiamensis n. sp.

( Figs. 8 A–D, 9B)

Material examined. HOLOTYPE male THAILAND, Ubon Ratchathani Province, Khong Chiam district, Phataem National Park, 15° 23ˏ 55˝ N, 105° 30ˏ 27˝ E. 25 April 2009 and 11 October 2010. S. Panha, P. Pimvichai and members of Animal Systematics Research Unit leg., ( CUMZ). – Paratypes: 10 males and 10 females, same data as holotype ( CUMZ), 3 males, 3 females, same data as holotype ( ZMUC).

Etymology. The specific epithet is a Greek/Latin adjective meaning “big siamensis ” and refers to the great similarity between this species and the smaller T. siamensis .

Diagnosis. A species of the induratus subgroup. Apical margin of anterior coxal fold (ac) in posterior view folded caudad, with a rounded process. Similar in this respect to T. siamensis . Differs from all other species of the T. induratus subgroup by having anterior coxal fold (ac) distolaterally broadly rounded and with an obliquely distomesad, relatively narrow lobe.

Description. Adult males with 65–69 podous rings, no apodous rings. Length 21–23 cm, width 12.9–14.8 mm. Adult females with 65 podous rings, no apodous rings. Length 20–21 cm, width 14.2–14.3 mm. Overall color of living animal ( Fig. 9 B) warm orange with strongly contrasting transverse bands constituted by the blackish metazona. Legs, antennae and metazona dark brown.

Gonopods ( Figs. 8 A–D): Anterior coxal fold (ac) ( Fig. 8 A) basally narrow, gradually widening towards tip, with a distolateral, broadly rounded lobe and an obliquely disto-mesad lobe (longer and narrower than in siamensis ), in posterior view apical margins folded caudad, with rounded process between the two ac lobes. Posterior coxal fold (pc) ( Fig. 8 B) basally with moderately high lateral paracoxites (px); mesal process (pmp) forming shelf (sh) for accommodation of telopodite, distally curved distolaterad. Telopodite ( Figs. 8 C–D) leaving coxite over shelf of posterior coxal fold; femoral spine (fe) short, slender, curving almost in horizontal plane, in situ curving behind 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 four to seven brownish blepharochaetae

Distribution ( Fig. 11 ). Known only from the type locality.

Notes. T. macrosiamensis is very similar to T. siamensis but differs clearly in body diameter ( Fig. 13 ). Also, the gonopodal femoral spine is completely different in the two species, being recurving and appressed to the telopodite shaft in T. siamensis , as opposed to curving in an almost horizontal plane in T. macrosiamensis .

Figures

FIGURE 8. Thyropygus macrosiamensis, holotype, 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 11. Known distribution of the Thyropygus induratus subgroup.

FIGURE 13. Relationship between number of podous rings and body diameter in adult males of Thyropygus siamensis and Thyropygus macrosiamensis.

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).