Victoriombrus acanthus, Mesibov, 2004

Mesibov, Robert, 2004, A new genus of millipedes (Diplopoda: Polydesmida: Dalodesmidae) from wet forests in southern Victoria, with brief remarks on the Victorian Polydesmida, Memoirs of Museum Victoria 61 (1), pp. 41-45 : 43-45

Victoriombrus acanthus sp. nov.

Figures 1 , 2 , 3 , 6 (map)

Material examined. Holotype. Male, Australia, Victoria. Young Creek Road, 0.2 km NE of Ciancio Creek crossing, 38°40'S, 143°29'E, pitfall 15.xi.1994 – 31.i.1995, G. Milledge, Nothofagus forest, sample NOH-1079, NMV K-8842.

Paratypes. 1 stadium 7 juvenile male, same details as holotype, NMV K-8843 ; 2 females, Aire Crossing Track , 0.5 km N of Aire River crossing, 38°40'S, 143°29'E, pitfall 15.xi.1994 – 31.i.1995, G. Milledge, Nothofagus forest, sample NOH-1084, NMV K-8844, K-8857 ; 1 male, same details but pitfall 31.i.–11.iv.1995, NMV K-8845 ; 2 males, 1 female, Maits Rest , 10 km W of Apollo Bay, 22.x.1991, K. Walker, Nothofagus litter and moss, NMV K-8846, K-8874, K-8875 ; 1 male, Beauchamp Falls , 38°39'S, 143°36'E, pitfall 6.ix.–15.xi.1994, G. Milledge, Nothofagus forest, sample NOH-1089, NMV K-8847 ; 2 females, same details but pitfall 15.xi.1994 – 31.i.1995, sample NOH-1090, NMV K-8848, K-8858 ; 5 males, Turtons Pass , 38°38'39''S, 143°41'20''E, 12.xii.2003, R. Mesibov and T. Moule, wet eucalypt forest litter, NMV K-8849, K-8859–K8862 ; 2 females, 9 stadium 7 juvenile males, 1 stadium 7 juvenile female, same details, NMV K-8851, K-8863–K8873; 1 stadium 7 juvenile male, same details but 38°38'43''S, 143°40'36''E, NMV K-8850 .

Diagnosis. Differs from V. seminudus sp. nov. in the form of the gonopod, notably the posterior curvature of the solenomere and the presence of small, branched, spiny processes on the lateral division of the telopodite.

Description. Males c. 15 mm long, c. 1.2 mm in maximum vertical diameter. In alcohol, freshly collected specimens with pale yellow head and antennae; ground colour of body pale yellow, patterned with brown patches: prozonite with a patch laterally and a pair of paramedian patches dorsally, metazonite with a triangular mid-dorsal patch anteriorly, a quadrangular mid-dorsal patch posteriorly, a small patch anteroventrally on paranotum; posterior margin of metazonite and distal podomeres brown.

Gonopod telopodites ( Figs 2 , 3 ) short, wide, closely appressed basally but not joined. Basal portion of telopodite excavated posteromesally, with variably long setae on posterolateral surface and surrounding the excavate area. Telopodite with a transverse constriction at between one-third to one-half its length, separating setose basal portion from bare distal portion, the latter divided basally into mesal, posteromesal and lateral branches. Mesal branch divides basally into a long, tapering, acutely pointed solenomere and a long, flattened process arising posterior to solenomere. Solenomere curves first anteriorly and basally, then turns sharply distally, curving slightly posteriorly but remaining parallel to long axis of telopodite, terminating at about two-thirds telopodite length. Prostatic groove running along mesal surface of telopodite, following curvature of the solenomere and terminating at its tip. Laterally flattened process accompanying the solenomere curves first mesally, then anteriorly, terminating just distal to solenomere; tip of process and a somewhat expanded portion at about mid-length with numerous marginal teeth and a roughened surface. Just distal and posterior to solenomere origin, posteromesal process arising as a narrow, rod-like, tapering process, laterally flattened from about half its length, curving slightly mesally, then laterally. Lateral branch of telopodite by far the largest, complicated in structure ( Figs 2 , 4 ), basically a laterally flattened process, curving slightly laterally and somewhat concave mesally, with marginal teeth of varying sizes; posterior edge giving rise to a mesally curving process ending in a rounded, somewhat expanded tip resembling a spanner or wrench midway between solenomere origin and tip; lateral and anterior surfaces of main process armed at about one-third the process length with small, short, branched, spiny structures resembling the tips of a thorny shrub.

Distribution and microhabitat. In wet eucalypt and Nothofagus forest litter in the Otway Ranges ( Fig. 6 ).

Etymology. Latin acanthus (“prickly shrub”), noun in apposition, from the appearance of the gonopod telopodite.

Figures

Figure 1. Victoriombrus spp. details. A, V. acanthus sp. nov., male paratype from NMV K-8849; B, V. seminudus sp. nov., male paratype from NMV K-8856. 1, Antenna; 2, posterior leg on somite 6; 3, posterior leg on somite 12; 4, dorsal outline view of somite 12; 5, posterior outline view of somite 12. Scale bar = 1.0 mm; setation and antennal cones not shown.

Figure 2. Victoriombrus acanthus sp. nov., male, paratype. Posterior view of gonopods in situ (specimen from NMV K-8849). Scale bar = 0.5 mm.

Figure 3. Victoriombrus acanthus sp. nov., male, paratype. Anterior (left) and mesal (right) views of right gonopod (specimen from NMV K-8849). Dashed line indicates course of prostatic groove; for clarity, the continuation of the groove to the solenomere tip is not indicated.

Figure 4. Victoriombrus seminudus sp. nov., male, paratype. Posterior view of gonopods in situ (specimen from NMV K-8853). Scale bar = 0.5 mm.

Figure 6. Localities in Victoria of Victoriombrus acanthus sp. nov. (crosses) and V. seminudus sp. nov. (squares).