Dasystigma huonense, Mesibov, 2003

Mesibov, Robert, 2003, A new genus of Tasmanian millipedes (Diplopoda: Polydesmida: Dalodesmidae) with unusual spiracles and a mosaic distribution, Memoirs of Museum Victoria 60 (2), pp. 197-206 : 203

Dasystigma huonense sp. nov.

Figures 3B, 5B, 8, 9, 14 (map)

Material examined. Holotype. Male , Australia, Tasmania. Edwards Rd, DN 797310 (43°04´23´´S 146°45´02´´E), 110–130 m, 15 Mar – 6 Apr 1988, R. Mesibov, QVM 23 :41728.

Paratypes. 3 males, details as for holotype, QVM 23 :15195; 1 male, Huon R. (Arve Rd), DN788280 (43°06´00´´S 146°44´22´´E), 150 m, 22 May 1997, R. Mesibov, plot 3M5, QVM 23 :40805; 1 female, Huon R. (Manuka Rd), DN769286 (43°05´41´´S 146°42´58´´E), 100 m, 29 Apr 1997, R. Mesibov, plot 1R4, QVM 23 :40800; 2 males, Coopers Creek , DN507635 (42°46´45´´S 146°23´50´´E), 460 m, 23 Feb 1994, R. Mesibov, AM KS85096 (formerly QVM 23 :15199) ; 1 male, Picton Valley , DN737146 (43°13´14´´S 146°40´34´´E), 300 m, 15 Jul 1994, K. Michaels, pitfall collection, NMV K-8806 (formerly QVM 23 :21294) .

Other material. 13 males, 18 females and 18 juveniles from 22 unique localities including Collins Cap, Coopers Creek, the Huon/Picton Rivers junction, the Huon R. crossing on the Port Davey track, Lake Sydney, Mt Mangana and Mt Tobin (Bruny I.), Mystery Creek Cave environs, Palmers Lookout, Picton R., South Cape Bay, Waterfall Bay and Arve, Edwards and Manuka Rds in the vicinity of Tahune Bridge on the Huon R.

Diagnosis. Differs from other Dasystigma in the sinuous curve of lateral edge of prefemoral process and corresponding curvature of apposed femoral process; from D. bonhami and D. margaretae in having posterior spiracle on diplosegments located between anterior and posterior legs; from D. tyleri in lacking a toothed anterior margin on femoral process and in closer spacing of spiracles on diplosegments, spiracles being larger than those in D. tyleri (or in other dalodesmids).

Description. As for the genus except in the following details. Posterior spiracle on diplosegments ( Fig. 5B) between anterior and posterior leg, hair-like structures emergent from spiracles; spiracle ‘hairiness’ and separation of spiracles both apparent at low magnification, spiracles unusually large for a dalodesmid. Paranotal margin slightly convex; posterior corner projected caudad and slightly laterad ( Fig. 3B). Gonopod telopodite ( Figs 8, 9) with prefemoral process narrowing slightly distad and strongly flattened anterioposteriorly, the apex broadly rounded with a small terminal notch, mesal edge of prefemoral process straight, lateral edge sinusoidal, convex near apex with a small tooth projecting caudad. Femoral process curving mesad in parallel with concavity on lateral edge of prefemoral process, and terminating about halfway between thickened uncus and apex of prefemoral process. Femoral process flattened with a few, minute terminal teeth, a short thick spike arising at about three-quarters of process length and projecting mesad and distad.

Distribution and macrohabitat. In wet eucalypt forest and rainforest over c. 6000 km 2 in southern Tasmania including South Bruny I., from Tasman Peninsula south to South Cape and west to the vicinity of Lake Pedder ( Fig. 14); from near sea level to c. 700 m elevation.

Etymology. After the Huon River in southern Tasmania.

Remarks. Dasystigma huonense varies very little in size and form across its range. Adult colour varies considerably, from very pale yellow-brown to deep chestnut brown.