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

Pimvichai, Piyatida, Enghoff, Henrik & Panha, Somsak, 2011, A revision of the Thyropygus allevatus group. Part 4: the T. cuisinieri subgroup (Diplopoda: Spirostreptida: Harpagophoridae), Zootaxa 2980, pp. 37-48 : 44

Thyropygus jarukchusri n. sp.

( Figs. 4 A–D, 5C)

Material examined. HOLOTYPE male THAILAND, Roi-Et Province, Chaturaphakphiman district, Ban Nong Phue, 15° 49ˏ 34˝ N, 103° 31ˏ 11˝ E. 12 April 2009. J. Pimvichai, C. Pimvichai and P. Pimvichai leg., ( CUMZ). – Paratypes: 21 males, 6 females, same data as holotype ( CUMZ, ZMUC).

Etymology. The specific epithet is a combination of the names of PP’s parents, in recognition of their support. The name is to be treated as a noun in apposition.

Diagnosis. A species of the cuisinieri subgroup. Differing from all other species in the subgroup by smaller body size and by having the tibial spine (ti) distinctly constricted at base.

Description. Adult males with 57–59 podous rings, no apodous rings. Length ca. 6 cm, width ca. 3.9–4.4 mm. Adult females with 56–60 podous rings, no apodous rings. Length ca. 7–9 cm, width ca. 5.0– 5.2 mm. Overall color of living animal ( Fig. 5 C) brownish orange, with anterior metazona dark brown.

Gonopods ( Figs. 4 A–D): Anterior coxal fold (ac) ( Fig. 4 A) basally almost parallel-sided, becoming broader towards tip, with a prominent projecting lobe (apl) on the lateral surface; distally with two processes: a lateral slen- der, sharp spine, curving mesad, and a mesal, broadly expanded, terminally pointed process pointing distad. Posterior coxal fold (pc) ( Fig. 4 B) basally with relatively high lateral paracoxites (px); mesal process (pmp) a short, rounded, slightly twisted lamella; lateral process (plp) a small, thumblike, directed distolaterad. Telopodite ( Figs. 4 C–D) leaving coxite over shelf of posterior coxal fold between pmp and plp; femoral spine (fe) long, curving mesad, without crenulated along inner curvature, in situ resting against posterior surface of ac, telopodite distally to fe with a round lobe (lo) projecting distolaterad, further distally with an additional small round lobe (asl); tibial spine (ti) very long, slender, distinctly constricted at base, with longitudinal crest (lc) along outer surface, recurved, its tip in situ resting close to lo; apical part with a slender, sharply pointed, transparent lamellar lobe (sll); palette (pa) simple, flattened; distally with about four to seven brownish blepharochaetae (bp).

Distribution ( Fig. 6 ). Known only from the type locality, where it co-exists with T. foliaceus . Although these taxa are quite similar, there are clear difference in gonopod structure, body size ( Fig. 7 ) and color. Furthermore, T. foliaceus and T. jarukchusri showed a divergence in COI sequences by 11.2% (74 out of 658 positions) (cf. discussion in Pimvichai et al., 2011). We regard T. jarukchusri and T. foliaceus as a sympatric species (their strict sympatry excludes the possibility of treating them as subspecies).

Figures

FIGURE 4. Thyropygus jarukchusri, 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 6. Known distribution of species of the Thyropygus cuisinieri subgroup.

FIGURE 7. Relationship between number of podous rings and body diameter in adult males of Thyropygus foliaceus and Thyropygus jarukchusri from strictly sympatric Roi-Et populations.

FIGURE 5. A, B: Thyropygus foliaceus, living males, A: from Phataem National Park. B: from Roi-Et. C: Thyropygus jarukchusri, living male (holotype).