Thyropygus induratus Attems, 1936

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 : 50-52

Thyropygus induratus Attems, 1936

( Figs. 1 A–E, 9c)

Thyropygus induratus Attems, 1936: 262

Thyropygus punctatus Attems, 1938: 281 , syn. n. Thyropisthus induratus: Attems 1942: 87

Thyropygus allevatus induratus: Hoffman 1975: 136 Thyropygus allevatus punctatus: Hoffman 1975: 136 Thyropisthus resimus: Demange 1961: 142

Material examined. SYNTYPES (only gonopods) THAILAND (East Siam). 5 May 1917. C. Boden Kloss leg., don. Calcutta Mus. ( NMW 2606). 1 male HOLOTYPE of T. punctatus VIETNAM, Cochinchina, Poulo-Condore December 1933. C. Dawydoff leg. ( NMW). 4 males, 3 females SIAM, Angkor Vat, Coll. Brolemann, 1902 ( MNHN). 3 males, 2 females THAILAND, Khonkean Province, Phu-Wiang District, Phu-Wiang National Park, 16° 41ˏ 59˝ N, 102° 13ˏ 41˝ E. 11 October 2008. S. Satan and P. Pimvichai leg., ( CUMZ). 5 males, 7 females THAILAND, Mahasarakham Province, Muang District, Ban Tha-Toom, 16° 10ˏ 43˝ N, 103° 27ˏ 4˝ E. 30 July 2010. R. Chanabun leg., ( CUMZ). 10 males, 10 females THAILAND, Srisaket Province, Kantraraluk District, 14° 38ˏ 27˝ N, 104° 38ˏ 58˝ E. 26 October 2010. P. Prasankok leg., ( CUMZ). 2 males, 5 females THAILAND, Ubon Ratchathani Province, Nam-Yeun District, Kang Lam-duan, 14° 26ˏ 8˝ N, 105° 6ˏ 18˝ E. 10 October 2010. P. Pimvichai, P. Prasankok, P. Tongkerd and members of Animal Systematics Research Unit leg., ( CUMZ). 1 male, 1 female THAILAND, Ubon Ratchathani Province, Nam-Yeun District, Yotdome wildlife sanctuary, 14° 26ˏ 4˝ N, 105° 6ˏ 13˝ E. 9 October 2010. P. Pimvichai and members of Animal Systematics Research Unit leg., ( CUMZ). 5 males, 6 females THAILAND, Udornthani Province, Non-Sa-Ard District, Nangrin waterfall, 17° 3ˏ 56˝ N, 102° 44ˏ 4˝ E. 8 September 2009. R. Chanabun and members of Animal Systematics Research Unit leg., ( CUMZ). 10 males, 5 females THAILAND, Surin Province, Muang District, Phanom Sawai Forest Park, 14° 15ˏ 45˝ N, 103° 22ˏ 7˝ E. 26 April 2009. S. Panha, P. Pimvichai, P. Prasankok and members of Animal Systematics Research Unit leg., ( CUMZ). 3 males, 3 females THAILAND, Chaiyaphum Province, Muang District, Tard-Tone waterfall, 15° 58ˏ 52˝ N, 102° 2ˏ 8˝ E. 8 June 2009. R. Chanabun and members of Animal Systematics Research Unit leg., ( CUMZ). 1 male THAILAND, bought in pet shop ( ZMUC).

Diagnosis. A species of the induratus subgroup. Differing from all other species (except T. quietus ) in the subgroup by having two processes of anterior coxal fold (ac), the outer forming a slender, sharp spine, the inner broadly rounded and flexible, and by a very thick ac laterally. Differs from T. quietus by being much larger and by having extremely high paracoxites (px).

Description. Adult males with 61–66 podous rings, no apodous rings. Length 17–21 cm, width 10.2–14.3 mm. Adult females with 59–67 podous rings, no apodous rings. Length 19–22 cm, width 10.5–15.1 mm. Overall color of living animal ( Fig. 9 C) dark brown. Head, anterior body rings, epiproct and paraprocts reddish brown. Prozonite yellowish brown.

Gonopods ( Figs. 1 A–E): Anterior coxal fold (ac) ( Figs. 1 A–B) basally slender, becoming broader towards tip, distally with two processes: the outer forming a slender, sharp spine, curving mesad; the inner broadly rounded, flattened, somewhat transparent, flexible; ac in posterior view very thickened laterally. Posterior coxal fold (pc) ( Fig. 1 C) basally with extremely high lateral paracoxites (px); mesal process (pmp) slightly shorter than ac, forming shelf (sh) for accommodation of telopodite, distally directed anteriad; pc fused with ac at base of the latter’s outer process. Telopodite ( Figs. 1 D–E) leaving coxite over shelf of posterior coxal fold; femoral spine (fe) relatively long, apically curved, in situ resting behind (sometime in front of) inner process of ac; tibial spine (ti) very long, slender, curving in an oblique-sagittal plane, its tip in situ resting close to distal-lateral part of pmp or resting between tips of ac; apical part: lamellar lobe (ll) relatively broad, rounded, bent down, transparent; palette (pa) simple, basally with an uncate subterminal lobe (usl) ventrally; distally with about six to eight brownish blepharochaetae (bp).

Notes. Anterior coxal fold (ac) with some variation ( Figs. 1 A–B): in some individuals the inner process originates lower than the base of the outer process (does not fuse directly with curve at the basal part of outer process) and the outer process fuses directly with the distal part of pmp. In some individuals the outer and inner processes of ac are shorter and smaller than in others. The femoral spine (fe) of specimens from Phu-Wiang, Nangrin waterfall and Tard Tone waterfall is relatively longer than in other specimens. All variable characters mainly separate northern (Phu-Wiang, Nangrin waterfall, Tard Tone waterfall and Ban Tha Toom) and southern populations (Kantraraluk District, Kang Lam-duan and Phanom Sawai Forest Park).

Discussion. We found the gonopods of a T. induratus SYNTYPES and those of the T. punctatus HOLOTYPE to be identical. These nominal species are also similar in diameter (11.5 mm and 11.0 mm respectively); the number of podous body rings in induratus is ca. 61–66 whereas in punctatus it is 56 (information on induratus also from Attems, 1936). Demange (1961: 146) noticed the strong similarity between quietus and punctatus and noted only a very small difference between these two species. Hoffman (1975) mentioned the similarities between punctatus , resimus and quietus , noticing that Attems’ gonopod drawings are so similar that they might have been made from the same gonopods in different positions. Attems (1936) distinguished these three species by three variable characters: size, segmental sculpture and form of the epiproct. Moreover, Hoffman (1975) discussed the gonopod structure of resimus as described by Demange (1961: figs. 184, 185) which he found not typical of resimus ; Hoffman preferred to regard this as an intermediate between induratus and some more southern population.

On the basis of our material we propose to treat punctatus as a synonym of induratus despite the smaller number of podous rings in the punctatus holotype. For quietus , we fully agree that the gonopods are identical with those of induratus , but the body size is significantly different ( Fig. 12 ). Furthermore, genetic distances between induratus and quietus ( Table 1 ) are consistently higher than conspecific distances between induratus and quietus individuals, see also discussion at end of paper. Altogether, we prefer to treat induratus and quietus as a separate species. On the other hand, we found the gonopod configuration of resimus ( Fig. 3 ) to be distinctly different from induratus .

Figures

FIGURE 1. Thyropygus induratus (specimen from Phu-wiang, except B), gonopods. A: anterior view, left telopodite removed. B: anterior view, anterior coxal fold (specimen from Yotdome). C: posterior view, left telopodite removed. D: left telopodite, posterior-mesal view. E: left telopodite, anterior-lateral view.

FIGURE 3. Thyropygus resimus (specimen from Phu-Kum-Khao), gonopods. A: anterior view, left telopodite removed. B: posterior view, left telopodite removed. C, D: left telopodite, posterior-mesal view. E: left telopodite, anterior-lateral view.

FIGURE 12. Relationship between number of podous rings and body diameter in adult males of Thyropygus induratus and Thyropygus quietus.

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).