Tasmaniosoma orientale, 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 : 71-72

Tasmaniosoma orientale sp. n.

urn:lsid:zoobank.org:act:783D6984-EE76-4BC7-86A8-8C9B883E5C30

Fig. 21; map Fig. 26

Holotype. Male, Australia, Tasmania, Elephant Pass , 41°38'26"S 148°14'32"E ( FP 034892) ± 25 m, 340 m, 20 August 2009, R. Mesibov, QVM 23 :51551.

Paratypes. 1 male, Tinmine Creek , Tas, 41°41'55"S 148°11'41"E ( EP 993828) ± 250 m, 530 m, 11 June 1988, R. Mesibov, QVM 23 :45991 ; 1 male, same details but 41°42'08"S 148°12'38"E ( FP 006824) ± 250 m, 450 m, 22 June 1988, QVM 23 :46000 ; 1 female, same details, QVM 23 :46001 ; 1 female, same details but 41°41'33"S 148°10'36"E ( EP 978835) ± 250 m, 550 m, 29 June 1988, QVM 23 :46008 ; 1 male, same details but 41°41'59"S 148°11'15"E ( EP 987827) ± 250 m, 500 m, 30 June 1988, QVM 23 :51550 .

Other material examined. 37 males and 38 females from 43 other sites (see Appendix).

Diagnosis. Metatergites without tubercles; ring 6 sternite with discrete setal brushes on anterior margin; gonopod telopodite with stout, rod-like setae in longitudinal tract on posteromedial surface and solenomere divided into apically bifid distal branch and distally curved, acuminate basal branch.

Description. Male/female approximate measurements: length 16/ 16 mm, ring 12 paranota width 1.8/ 1.8 mm. Male as for T. armatum in live colour and most non-gonopod details, but long-preserved specimens completely decoloured, overall widths tergite 6>5>4>3>(2,head)>collum, ring 12 paranota 1.4 × as wide as prozonite. Ring 6 sternite as for T. armatum , but with very short, thin sternal tab by leg 6, not bearing setae.

Gonopod telopodite (Fig. 21) similar to that of T. armatum (see Fig. 7A ), but process 1 simply acute (but see Remarks) rather than Y-shaped; process 2 undivided, curving medially, apically expanded and flattened with dentate margin; distal margin of laminate process not extended posteriorly, instead curving smoothly to posterior extension, the latter shorter and straighter than in T. armatum ; solenomere divided into distal branch with bifid tip carrying prostatic groove, and basal branch directed posteriorly but curving distally, with pointed tip; process 3 an anteroposteriorly flattened, quadrate tab, the margin free distally apart from central attachment; process 4 as in T. armatum ; laterally with group of 5–6 setae, rather than three.

Female with posterior margin of epigynum raised in centre as irregularly edged triangle.

Figure 2 |. Tasmaniosoma orientale sp. n. A Posterolateral view of gonopods in situ, voucher male ex QVM 23:46018 B medial and C posterolateral views of left gonopod telopodite of paratype male ex QVM 23:51550. Setation not shown in A and C; dashed line marks course of prostatic groove. Processes labelled as in Fig. 7A . Scale bars = 0.2 mm.

Distribution. Common and sometimes locally abundant in dry and wet eucalypt forest over ca 1500 km 2 in the northern part of the east coast and Eastern Tiers of Tasmania, from near sea level to at least 1000 m elevation ( Fig. 26 ). Not yet found north of Beaumaris or south of Bicheno on the coast, or west of St Pauls Dome in the Fingal Valley. Sympatric with T. barbatulum sp. n. and T. fragile sp. n.; co-occurs with the latter. T. orientale may be parapatric with T. armatum in the west and south of its range, and with T. cacofonix sp. n. in the north; further sampling is needed to better define the range boundaries of these three species.

Etymology. Latin orientalis, “eastern”, for the eastern Tasmanian distribution of this species.

Remarks. The lateral process on the gonopod telopodite (process 1) is simply acute in the holotype and the specimen illustrated in Figs 21B and 21C. In some East Coast males the process is apically forked, as in the right telopodite in Fig. 21A. In the west of the T. orientale range, the lateral process is wider and Y-shaped, as in T. armatum .

Female T. orientale are readily distinguished from those of sympatric, similarly sized T. fragile sp. n. by the presence of large tubercles on T. fragile tergites.

Figures

Figure 2. Tasmaniosoma armatum Verhoeff, 1936 male (ex QVM 23:46567). A Leg 2 bases, posterior view, showing position of gonopore (go) and cowl (c) B enlargement of cowl on left leg 2 coxa C sphaerotrichomes on leg 6 postfemur D brush setae on leg 6 prefemur E spiracles on midbody ring, left lateral view, anterior to left F spinnerets, ventral view. Scale bars A, E = 0.1 mm F = 0.05 mm B = 0.025 mm D = 0.02 mm C = 0.01 mm.

Figure 7. A Tasmaniosoma armatum Verhoeff, 1936, topotypical male ex QVM 23:46567 B Tasmaniosoma alces sp. n., paratype male ex QVM 23:46762. Left posteroventral views of gonopods in situ, showing solenomere S, laminate process L and processes numbered in text. Medial bend in laminate process on T. alces telopodite is a preparation artifact. Scale bars = 0.2 mm.

Figure 26. A Localities as of 31 January 2010 for Tasmaniosoma cacofonix sp. n. (crosses), T. fasciculum sp. n. (squares), T. gerdiorivum sp. n. (triangles) and T. orientale sp. n. (open circles). See also Fig. 23. Scale bar = 50 km. B Map of Tasmania showing location of main map (rectangle).