Tasmaniosoma compitale, Mesibov, 2010

Mesibov, Robert, 2010, The millipede genus Tasmaniosoma Verhoeff, 1936 (Diplopoda, Polydesmida, Dalodesmidae) from Tasmania, Australia, with descriptions of 18 new species, ZooKeys 41 (4), pp. 31-80 : 53-56

Tasmaniosoma compitale sp. n.

urn:lsid:zoobank.org:act:B431F3B4-C271-4396-8ADB-8D56E804C2E7

Figs 1C, 1G, 4A, 13; map Fig. 23

Holotype. Male, Australia, Tasmania, Deep Gully Creek , 41°25'02"S 145°35'43"E ( CQ 825138 ) ± 100 m, 610 m, 13 October 1991, R. Mesibov, QVM 23 :45968.

Paratypes. 1 female, details as for holotype, QVM 23 :45969 ; 1 male, same details but 14 October 1991, QVM 23 :45970 ; 1 female, same details but 18 October 1991, QVM 23 :45971 ; 1 female, same details but 24 October 1991, QVM 23 :45974 ; 1 male, Fingerpost, Tas, 41°24'37"S 145°37'44"E ( CQ 853146 ) ± 100 m, 610 m, 17 September 1991, R. Mesibov, QVM 23 :45955 ; 2 females, same details, QVM 23 :45956 ;

Figure |3. Tasmaniosoma compitale sp. n. A Posterior view of gonopods in situ (paratype male ex QVM 23:45971) B medial view of right gonopod telopodite (ex QVM 23:45963, from close to type locality). Dashed line marks course of prostatic groove. Scale bar ca 0.2 mm.

1 male, same details but 18 September 1991, QVM 23 :45957 ; 1 female, same details, QVM 23 :45958 ; 1 female, 1 stadium VI male, same details but 23 September 1991, QVM 23 :45959 ; 1 female, same details but 26 September 1991, QVM 23 :45961 .

Other material examined. 53 males, 33 females, 3 stadium VI females and 1 stadium V female from 46 other sites (see Appendix).

Diagnosis. Metatergites with three transverse rows of large, low, contiguous tubercles; leg 7 sternal tab with dense brush of stout, rod-like setae; gonopod telopodite with central, flattened process notched into three parts and two comparably sized combs of long, stout, rod-like setae on posterior surface, the basal comb directed basally, the distal comb distally.

Description. Male/female approximate measurements: length 12/ 13 mm, ring 12 paranota width 1.4/ 1.6 mm. Freshly preserved specimens yellowish-brown to unaided eye, under microscope with complex pattern (Figs 1C, 1G): paired paramedian lightyellow patches on prozonite and anteriorly on metatergite, contrasting with adjoining dark brown patches; metatergite otherwise light mottled yellowish brown; rings laterally with mottled yellowish-brown and large yellowish patch (Fig. 1G, p) just under paranotal margin; head reddish; antennae dark brown; legs pale, reddish distally. Live specimens similarly coloured but yellow not so intense; in alcohol, long-preserved specimens completely decoloured.

Most non-gonopod details as for T. armatum , but relative widths tergite 6>5>4>head>(3,2)>collum, ring 12 paranota 1.3 × as wide as prozonite, leg 6 tarsus 1.5 × as long as femur and femur longer than prefemur. Anterior margin of metatergite smoothly curving into lateral edge of paranota (shoulder less distinct than in T. armatum ); metatergite almost completely covered with three transverse rows of 10–12 large, low tubercles, each with small seta near posterior edge. Ring 2 pit not apparent ( Fig. 4A ). Ring 6 sternite with no leg 6 tab; leg 7 tab long, thickened, with brush of stout setae; small rounded process medially on leg 7 coxa just posterior to sternal tab; anterior sternite margin with two long, fine, paramedian setae.

Gonopod telopodite (Fig. 13) straight, slender, slightly excavate basally on posterior surface, divided at ca 3/4 telopodite height into four processes: (a) short, slightly flattened, acute solenomere arising on medial surface and directed distally; (b) short, bladelike, acute process arising on anterolateral surface just basal to solenomere origin and directed distally and slightly anteriorly; (c) large central process, anteroposteriorly flattened, the wide distal margin divided into acute anterolateral branch and round-edged, tab-like posteromedial branch, the latter giving rise on distal edge to short, slender, tapered process directed posterodistally; (d) large, blade-like, acute process arising on lateral surface, abruptly bent and directed distally. Two dense clusters of stout, rod-like setae: 30–40 arising at ca 1/2 telopodite height on posterior surface, directed posteriorly or posterobasally; 20–30 in band running anterolaterally across posterior surface from ca 1/2 to ca 3/4 telopodite height, mainly directed distally. Sparse fine setae running from posterior surface near base anterodistally along lateral surface to ca 1/2 telopodite height. Prostatic groove running more or less directly on medial surface to base of solenomere.

Female with sternites as wide as long; legs 2 usually missing (Mesibov, in preparation).

Distribution. Sometimes locally abundant in wet eucalypt forest, cool temperate rainforest and riparian tea-tree forest over at least 3000 km 2 in northwest Tasmania, from Table Cape west to the Marrawah area, and from near sea level at Black River south to the Waratah area at 650 m elevation ( Fig. 23 ). The T. compitale range is bounded on three sides by the range of T. hickmanorum sp. n. and the two species are tightly parapatric at some localities (Mesibov, in preparation).

T. compitale has also been collected in plantations of Pinus radiata ( Bonham, Mesibov and Bashford 2002; specimens coded as Tasmaniosoma sp. 1).

Etymology. Latin compitalis, “of crossroads”, adjective. Th e types were collected near the Fingerpost, a well-known crossroads in northwest Tasmania.

Remarks. Gonopod structure is nearly constant across the T. compitale range, but overall body size varies, with the largest specimens (to ca 15 mm long) occurring in coastal and near-coastal areas.

The bright and complex pigmentation of T. compitale is lost with long storage in alcohol, and long-preserved females of T. compitale and T. hickmanorum n sp. cannot be separated. Live and freshly preserved females can be distinguished by colour: T. compitale yellowish-brown with a large, prominent yellowish patch just under the paranotal margin (Fig. 1G), T. hickmanorum reddish-brown with only a small yellowish patch under paranotal margin (Fig. 1I).

Figures

Figure 4. Male ring 2, ventral view of right side (anterior to right) showing variation in structure. A Tasmaniosoma compitale sp. n., paratype male QVM 23:45970, pit not apparent B T. armatum Verhoeff, 1936, topotypical male ex QVM 23:46567, pit fairly shallow, not well defined medially and posteriorly C T. cacofonix sp. n., voucher male ex QVM 23:46724, pit deep, small D T. decussatum sp. n., male paratype ex QVM 23:46699, pit deep, large. Scale bars = 0.2 mm.

Figure 23. A Localities as of 31 January 2010 for Tasmaniosoma hickmanorum sp. n. (squares), T. compitale sp. n. (stars) and T. armatum Verhoeff, 1936 (crosses). Scale bar = 100 km. B Preliminary mapping of eastern parapatric boundary between T. compitale sp. n. (stars) and T. hickmanorum sp. n. (squares). Bounding rectangle as in map (A); scale bar = 20 km.