Taxidiotisoma portabile Mesibov & Car

Mesibov, Robert & Car, Catherine A., 2015, A new genus and species of native exotic millipede in Australia (Diplopoda, Polydesmida, Paradoxosomatidae), ZooKeys 498, pp. 7-16 : 10-14

Taxon classification Animalia Polydesmida Paradoxosomatidae

Taxidiotisoma portabile Mesibov & Car sp. n. Figs 1, 2, 3, 4

Holotype.

Male, Munmorah State Reserve, NSW, 0.5 km along beach track opposite National Parks and Wildlife Service Station turnoff, site MUNI01/09, -33.2094 151.5894 ± 25 m, pitfall 13-23 May 1998, L. Wilkie, AM KS.94041.

Paratypes.

2 males, 1 female, details as for holotype but 21 April - 1 May 1997, site MUNI01/10, AM KS.93366.

Other material.

100 males, 22 females and 5 juveniles (see Suppl. material 1 for details).

Description.

Male/female approximate measurements: length ca 20/20 mm, maximum midbody width 1.5/1.8 mm. Body shiny (Fig. 1), colour in alcohol medium brown, dark brown either side of waist and dorsal portion of sides, dorsally with large, light brown patch spanning rear of metazonite and front of prozonite; antennae medium brown, darker distally; legs tan to pale brown, darker distally.

Male with vertex and frons almost bare, clypeus sparsely setose; clypeus strongly depressed, head truncate in profile (Figs 1D, 1E); vertigial sulcus distinct, ending above level of antennal sockets; post-antennal groove moderately deep; antennal sockets separated by 1.3 × socket diameter. Antenna slightly clavate, reaching dorsally only to rear of collum; antennomeres with relative lengths (2=3)>(4=5=6); 6 thickest but 5 and 6 subequal in apical width. Collum with subparallel anterior and posterior margins in dorsal view, strongly convex, lateral corner rounded. Head very slightly narrower than collum; collum to ring 18 nearly uniform in width, rings 2 and 3 slightly narrower. Ring 2 paranotum a thin, longitudinal ridge set low on ring, a little below collum corner; no paranota on other rings. No trace of pleural keels. Prozonites and metazonites (Fig. 1B, C) smooth, bare; transverse furrow at ca 2/3 metazonite length from waist, indistinct, not extending laterally as far as ozopores; waist very short, shallow, indistinctly sculptured with longitudinal ridges; limbus a narrow, thin, continuous sheet. Pore formula normal; ozopore very small, round, opening just above 1/2 ring height and just posterior to 1/2 metazonite length; slight bulging of ring around ozopore. Spiracles on diplosegments above and just anterior to leg bases; anterior spiracle ovoid, long axis subvertical, rim produced anterodorsally as rounded tab; posterior spiracle subtriangular, rim low; spiracular filters slightly emergent. Midbody sternites very sparsely setose, longer than wide, cross impressions subequal in width and depth; no cones or projections on any sternites. Midbody legs with relative podomere lengths (prefemur=femur)>tarsus>(postfemur= tibia); femur ca 1.2 × as long as tarsus; anterior leg prefemora only very slightly swollen dorsally. Pre-anal ring sparsely setose; epiproct extending past anal valves, in dorsal view tapering and truncate, tip ca 1/4 width of pre-anal ring; hypoproct broadly paraboloid; spinnerets in rectangular array, wider than long. Leg 1 (Fig. 2A) with large, pointed process on medial femur surface, directed mediodistally and slightly anteriorly.

Gonopore small, round, opening on slight distomedial bulge of leg 2 coxa. Sternal lamella (Fig. 2B) wide,>90% of width between leg 4 bases on ring 5, strongly leaning anteriorly; lateral margins straight, vertical; corners rounded; ventral margin slightly raised medially. Dense brush setae on tibiae and tarsi of all legpairs except legpair 1 and last 2 legpairs; brush setae long, fine, curving distally.

Gonopod aperture just wide enough to accommodate gonocoxae, ca 1/2 ring 7 prozonite width. Gonopod telopodites (Figs 3, 4) straight, parallel, reaching leg 6 bases when retracted; sternite between legpairs 6 and 7 excavate. Gonocoxa (C) robust, much thicker than femorite but shorter, ca 1/2 femorite length; prefemur (PF) ovoid, ca 1/3 femorite length, leading directly into femorite with no noticeable process at femo rite base; femorite (F) ca 2/3 acropodite length, upright, cylindrical; non-seminiferous branch (NSB) slightly shorter than solenomere (S), curved, thickest mid-length with asymmetrical pointed tip and distinct “elbow” at base; S broad, proximal end as thick as femorite, curved, divided at mid-length into shorter, pointed process (s1) carrying prostatic groove, finger-like in anterior view, and longer, broader, cowl-shaped process (s2) carrying noticeable tooth (t) at about mid-length. Prostatic groove running straight along anteromedial surface of telopodite, looping slightly into base of NSB before touching base of S, then running on medial surface of S to tip of s1 (Fig. 4).

Female with depressed clypeus, without leg modifications; epigynum not raised, nearly straight, ca 1/4 ring 2 width; cyphopods not examined.

Distribution.

Taxidiotisoma portabile sp. n. has been collected over a north-south range of ca 1000 km in eastern Australia (Fig. 5). A set of localities in eastern New South Wales (filled circles in Fig. 5) are in natural habitats in national parks or partly disturbed rangeland. Eight localities outside that set (unfilled circles in Fig. 5) are in cities, towns or long-cleared agricultural areas. These eight localities are numbered in Fig. 5 as follows:

A small area of riparian vegetation on the Macquarie River, surrounded by farmland;

The town of Cowra (collecting site not more exactly known), surrounded by farmland;

The campus of Charles Sturt University in the city of Wagga Wagga;

A small area of remnant native vegetation in the city of Wagga Wagga;

Disturbed native vegetation on a roadside adjoining a large artificial lake;

A recreation reserve in the suburbs of the city of Melbourne;

A park in the centre of the city of Melbourne;

Riparian parkland under a highway bridge in the town of Perth, surrounded by farmland.

Sampling in the areas surrounding and between these eight locations, both by the authors and by other collectors, has not yet yielded any specimens of Taxidiotisoma portabile sp. n. We therefore suspect that the species was introduced to these locations from its native range in eastern New South Wales.

Name.

Latin portabilis, “portable”, adjective. This species is almost certainly being transported to new areas in Australia by cars or trucks.

Remarks.

We do not know whether the eight “outlying” New South Wales, Tasmanian and Victorian samples (Fig. 5) represent long-established populations or ephemeral colonies, but the broad scattering of records suggests that this species will be found elsewhere in Australia in coming years.