Dasystigma bonhami, 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 : 202

Dasystigma bonhami sp. nov.

Figures 2, 3A, 5A, 6, 7, 14 (map)

Material examined. Holotype. Male , Australia, Tasmania. Sandspit R., EN700712 (42°42´30´´S 147°51´17´´E), 230 m, 31 Jul 1991, R. Mesibov, QVM 23 :41726.

Paratypes. 2 males, details as for holotype, QVM 23 :15219; 1 female, details as for holotype, QVM 23 :15261; 2 males, Sandspit R., EN688712 (42°42´30´´S 147°50´24´´E), 200 m, 26 Jun 1988, R. Mesibov, NMV K-8803, K-8804 (formerly QVM 23 :15220) ; 2 males, Nugent, EN559711 (42°42´37´´S 147°40´57´´E), 400 m, 9 Aug 1998, K. Bonham and R. Crookshanks, AM KS85095 (formerly QVM 23 :40807) .

Other material. 30 males, 25 females and 45 juveniles from 27 unique localities including Baldy Creek, Bellettes Creek, Bishop and Clerk (Maria I.), Black Hill, Blind Creek (Maria I.), Blue Gum Spur, Carlton R., Chauncy Vale, Douglas Creek, Flash Tier, Macgregor Peak, Maclaines Creek, Mother Browns Bonnet, Mt Walter, Ravens Hill, Sand R., Sandspit R., Sheepdip Creek and Three Thumbs.

Diagnosis. Differs from other Dasystigma in its slender, upright femoral process with a small mesal spike, from D. huonense and D. tyleri in having posterior spiracle on diplosegments located above anterior leg, and from D. tyleri in having large spiracles (unusually large for dalodesmids) with much greater spiracular “hairiness.”

Description. As for the genus except in the following details. Both spiracles on diplosegments ( Fig. 5A) positioned over anterior leg, hair-like structures emergent from spiracles and apparent at low magnification, spiracles unusually large for a dalodesmid. Paranotal margin very slightly convex; posterior corner projected caudad ( Fig. 3A). Gonopod telopodite ( Figs 6, 7) with prefemoral process narrowing slightly distad, apex curving caudad, with 2 teeth on lateral edge near apex and single tooth on mesal edge more proximad. Femoral process projecting parallel to prefemoral process and terminating just proximal to flexed apex of latter. Femoral process a narrow, somewhat flattened rod with a few, minute terminal teeth, a small, slender spike arising at about three-quarters of process length and projecting mesad.

Distribution and macrohabitat. Common in dry and wet eucalypt forest over c. 2000 km 2 in south-eastern Tasmania, from Campania east to Maria I. and from the Forestier Peninsula north to the Little Swanport River valley ( Fig. 14); c. 100–600 m elevation.

Etymology. In honour of the Tasmanian malacologist Kevin J. Bonham, a very talented collector whose “bycatch” of millipedes nearly always contains specimens of interest.

Remarks. D. bonhami varies little in size and form across its range. However, even syntopic adults differ considerably in the depth of dorsal body coloration, with some pale and others honey- or chestnut-coloured.