Three new species of Tasmaniosoma Verhoeff, 1936 (Diplopoda, Polydesmida, Dalodesmidae) from northeast Tasmania, Australia

Abstract The small-range millipedes Tasmaniosoma anubis sp. n., Tasmaniosoma interfluminum sp. n. and Tasmaniosoma nicolaus sp. n. are described, and the colour of live Tasmaniosoma barbatulum Mesibov, 2010 is documented.


Introduction
When reviewing Tasmaniosoma Verhoeff, 1936 several years ago I wrote that "more small-range species may remain to be discovered" (Mesibov 2010: 32). Here I describe three new Tasmaniosoma from northeast Tasmania with known range envelopes of <12, <40 and ca 100 km 2 . Tasmaniosoma now contains 22 species, or about one quarter of the 86 species in the suborder Dalodesmidea so far described from Tasmania (Mesibov 2006(Mesibov -2015.

Methods
"Male" and "female" in the text refer to adult (stadium 7) individuals. All specimens are stored in 75-80% ethanol in their respective repositories. Gonopods were cleared in 80% lactic acid and temporarily mounted in a 1:1 glycerol:water mixture for examination by optical microscopy. Body measurements were estimated with a Nikon SMZ800 binocular dissecting microscope using an eyepiece scale. Colour photographs were taken with a Canon EOS 1000D digital SLR camera mounted on the same microscope fitted with a beam splitter. The colour images in Figs 1 and 9 are manually stacked composites processed with Zerene Stacker 1.04. Scanning electron microscope images were acquired digitally using a FEI Quanta 600 (Fig. 2) or a Hitachi 6,8); specimens were examined after air-drying and sputter-coating with platinum. Images and drawings were prepared for publication using GIMP 2.8.

Taxonomy
Gonopore on distomedial bulge of leg 2 coxa, protected by tall, thin cowl. Short brushes of setae on sternite between legpairs 4 and 5. Legs 6 and 7 bases ( Fig. 2A) well-and equally separated; no sternal tab by leg 6; tall, rounded sternal tab by leg 7 with medial brush of thick, rod-like, pointed setae; leg 7 coxa with short, rounded distomedial bulge.
Gonopod aperture ovoid, ca 1/2 as wide as ring 7 prozonite, posterolateral margin raised. Gonocoxa short, subcylindrical, slightly tapering distally. Telopodites (Fig. 3) almost straight, parallel; extending nearly to leg 6 bases when retracted. Telopodite straight, subcylindrical, divided at about 3/4 telopodite height into three major processes: (a) short, slightly helicoid, pointed solenomere posteromedially, directed distally; (b) large, wide, anteroposteriorly flattened central process with apex twisted and flattened mediolaterally with rounded apical margin and narrow bursa-like fold at apex base, and with medial margin of central process curving posteriorly as rounded tab; (c) long, rod-like, tapering, apically rounded lateral process directed distally and slightly laterally. Telopodite projecting posteriorly at base as thin shelf, concave distally. Anterior surface of telopodite at about 2/3 telopodite height with tapering, anteromedially directed tab, longer than wide. Sparse, fine, mainly short setae on lateral and posterolateral surfaces to about 1/2 telopodite height, and on basal shelf. Two closely packed clusters of stout, rod-like, pointed setae: one (ca 12 setae) on posterior telopodite surface, arising just over 1/2 telopodite height and directed basally, the other (ca 10 setae) arising posterolaterally at level of solenomere base and directed distally and slightly posteriorly. Prostatic groove running more or less straight to base of solenomere on medial surface.
Female with legs more slender and prefemora and femora not swollen. Epigynum ca 1/3 width of ring 2, posterior margin produced medially as small, rounded triangle with irregular margin. Cyphopods not examined. (See also Remarks, below.) Distribution. Eucalypt forest and woodland within a range envelope of <12 km in the city of Launceston, Tasmania, with a core habitat area of <6 km 2 (Figs 4A, 5A). Locally abundant in the core habitat area and readily found in bark litter at the bases of Eucalyptus viminalis trees (Fig. 4B). Co-occurs with Tasmaniosoma armatum and the introduced julid millipedes Ommatoiulus moreleti (Lucas, 1860) and Cylindroiulus spp.

Name.
Greek "Anubis", a jackal-headed god of ancient Egypt; noun in apposition. The tip of the gonopod telopodite in posterolateral view resembles popular representations of the head of Anubis (Fig. 5B). The "snout" of the jackal corresponds to the medial tab of the central process, and the "ears" to the the lateral process and the apical portion of the central process. This name was suggested by collector Lisa Clarkson.
Remarks. The core habitat area for T. anubis sp. n. includes the 440 ha Trevallyn Nature Recreation Area (TNRA; Fig. 4A), which is managed as urban parkland. Large populations of T. anubis sp. n. can be found in grassy woodland adjacent to bitumenised roads in the TNRA.
T. anubis sp. n. has not been found more than ca 1.5 km from the South Esk River near its confluence with the Tamar River at Cataract Gorge in the city of Launceston (Fig. 4A). The land snail Pasmaditta jungermanniae (Petterd, 1879), the pseudoscorpion Neopseudogarypus scutellatus Morris, 1948 and the spider Migas plomleyi Raven & Churchill, 1989 are also believed to be restricted to the Cataract Gorge area, or to the Gorge area and small outlying localities (Fearn 2003). However, one possible male specimen of T. anubis sp. n., examined years ago and unfortunately now lost, and two possible female specimens (QVM 23:52256) have been collected in small, degraded remnants of native vegetation close to the South Esk River in the town of Evandale, ca 15 km southeast of Launceston. I suspect that T. anubis sp. n. was more widespread along the lower South Esk River in pre-European times, i.e. before the early 19th century. Millipede populations would have declined as sheep grazing degraded the local eucalypt woodlands, and would have disappeared over most of the Launceston area as woodlands were cleared for residential development.
Unlike the similar-sized, co-occurring dalodesmid Atrophotergum pastorale Mesibov, 2004 and unlike most Tasmaniosoma species, T. anubis sp. n. do not usually run away rapidly when disturbed, but remain "crouched" and stationary on the bark, leaf or wood pieces among which the animals are sheltering.
As with Tasmaniosoma compitale Mesibov, 2010and T. hickmanorum Mesibov, 2010(Mesibov 2010, most T. anubis sp. n. females are missing their second pair of legs and have plugs of sclerotised scar tissue where these legs have broken off. Diagnosis. Very similar to T. decussatum, but without a setose sternal tab adjoining leg 7, with the anterolateral telopodite process prominently notched, with the solenomere tabs curving posteriorly and less deeply separated, and with the medial process tongue-like and curving posterobasally, rather than forming a rounded, mediolaterally flattened, tab-like solenomere extension as in T. decussatum. Description. Male/female approximate measurements: length 12/11 mm, midbody paranota width 1.4/1.4 mm, maximum vertical diameter 1.1/1.1 mm. Live and freshly preserved adults with yellowish ground colour (Figs 1B, 1E), antennae and distal podomeres pale reddish brown, reddish brown transverse streaks or cellular margins anterior to transverse furrow and near posterior margin of metatergite, and laterally on prozonites and below paranota. Colouring fades in alcohol; long-preserved animals entirely decoloured or more or less uniformly pale yellowish white.
Gonopod aperture ovoid, ca 1/2 as wide as ring 7 prozonite, posterolateral margin raised. Telopodites (Figs 5C, 6) almost straight, parallel; extending to leg 6 bases when retracted. Telopodite with shallow concavity over most of posterior surface, the margin continuing as posterior margin of posterobasal shelf; anterior surface strongly and broadly ridged. Telopodite divided at ca 2/3-3/4 height into four processes: (a) long, rod-like, tapering, apically rounded lateral process directed distally and slightly posteriorly; (b) large anterolateral process curving posteriorly with distinctive, V-shaped notch on anterior edge, S-shaped distal to notch with acuminate apex directed distally and slightly laterally; (c) posteromedial solenomere developed as parallel, subquadrangular, transverse tabs separated by narrow slit, curving posteriorly; (d) tongue-like medial process curving basally and directed slightly medially. Sparse setae posterolaterally to ca 1/2 telopodite height, with small, separate patch of fine, short setae on posterior surface ca 1/3-1/2 telopodite height. Prostatic groove running up medial surface of telopodite, curving laterally across posterior surface in slit between solenomere tabs, then running along lateral margin of more basal tab to open near medial corner of tab (Figs 5C,6).
Female about as robust as male but shorter, with posterior rings not elongated; legs more slender and prefemora and femora not swollen. Epigynum ca 1/3 width of ring 2, posterior margin produced medially as low trapezoid with irregular margin. Cyphopods not examined.
Distribution. Eucalypt forest over ca 100 km 2 north and east of Fingal, Tasmania, with an outlying record near the town of Scamander on the east coast (Figs 5A, 7A). Co-occurs with T. barbatulum, T. nicolaus sp. n. and T. orientale in bark and leaf litter in the Nicholas Range.
Name. Latin inter (between) + fluminum (genitive plural of flumen = river); adjective. The largest populations of this species are found between the upper South Esk and Break O'Day Rivers.
Remarks. The gonopod telopodite structure of T. interfluminum sp. n. is remarkably similar to that of T. decussatum, the two differing only in the details noted above

Diagnosis.
Member of the "anubis group" within Tasmaniosoma (see Discussion); distinguished from T. anubis sp. n., T. barbatulum and T. fragile by the absence of a basally directed cluster of stout, rod-like setae on the posterior surface of the gonopod telopodite; from T. clarksonorum, T. compitale and T. hickmanorum by the absence of a lateral process on the telopodite apex; and from T. fasciculum by the telopodite apex extending as a mediolaterally flattened process in the shape of a bird's head pointed posteriorly.
Description. Male/female approximate measurements: length 11/10 mm, midbody paranota width 1.3/1.2 mm, maximum vertical diameter 1.0/1.0 mm. Live and freshly preserved adults (Figs 1C, F, 9A) with dark reddish brown head and antennae; body with yellowish ground colour, dark reddish brown on paranotal margins, dorsolaterally on prozonites, as cellular borders in patches laterally, and as diffuse streaks and cellular borders dorsomedially and as margin lines posteriorly on pro-and metazonites; legs darkening slightly distally. Long-preserved animals almost entirely decoloured.
Telopodites (Fig. 8) almost straight, parallel; extending nearly to leg 6 bases when retracted; without prominent posterobasal shelves. Telopodite straight, subcylindrical, at about 3/4 telopodite height swelling distolaterally, centrally and medially projecting as large anteroposteriorly flattened process with apex twisted to be mediolaterally flattened, shaped like bird's head and pointed posteriorly; smaller sickle-shaped process arising at base of apex and directed posterodistally; and medial margin of large process curving posteriorly as thin tab with rounded margin. Solenomere short, slightly helicoid, pointed, arising posterior to base of large process and directed distally. Sparse, fine, fairly long setae on lateral and posterolateral surfaces to about 1/2 telopodite height. Two closely packed clusters of stout, rod-like, pointed setae: one (ca 12 setae) on anterolateral surface near base of large telopodite process and directed distally and slightly anteriorly, the other (ca 15 setae) arising posteromedially just posterior to solenomere base and directed distally and slightly posteriorly. Prostatic groove running more or less straight to base of solenomere on medial surface.
Female with legs more slender and prefemora and femora not swollen. Epigynum ca 1/3 width of ring 2, posterior margin produced medially as small, rounded triangle with irregular margin. Cyphopods not examined. (See also Remarks, below.) Distribution. Eucalypt forest over <40 km 2 on the Nicholas Range and the Mt Elephant area at the eastern end of the Fingal Valley in northeast Tasmania, on both north-and south-facing slopes at ca 300-500 m a.s.l. (Figs 5A, 7B). Co-occurs with T. barbatulum, T. interfluminum sp. n. and T. orientale in bark and leaf litter.
Name. Latinised "Nicholas" for the Nicholas Range, type locality of this species; noun in apposition.
Remarks. All of the known T. nicolaus sp. n. collection sites are in forest patches with evidence of past logging and burning, and part of the known range of T. nicolaus sp. n. is within the ca 800 ha Nicholas Range Regional Reserve. Like T. anubis sp. n., T. nicolaus sp. n. can be locally abundant: I found most of the 19 type specimens in bark litter under two Eucalyptus trees.
My identification of three females as T. nicolaus sp. n. (QVM 23:53635) is tentative. Two of the three females are missing legs 2.

Note on T. barbatulum
Alcohol-preserved specimens of T. barbatulum are almost entirely decoloured, i.e. more or less uniformly pale white (Mesibov 2010). Live and freshly preserved specimens are coloured very similarly to T. nicolaus sp. n. (Fig. 9). Where the two species co-occur they can be hard to distinguish in the field, but T. nicolaus sp. n. is a little longer and distinctly more robust than T. barbatulum.

Discussion
The new species Tasmaniosoma anubis sp. n. and T. nicolaus sp. n. join T. barbatulum, T. clarksonorum, T. compitale, T. fasciculum, T. hickmanorum and probably T. fragile in a well-defined group within Tasmaniosoma, first recognised in Mesibov (2010) and here called "the anubis group". Species in this group have complex but fugitive colouration; three rows of low, rounded, metatergal tubercles; a sternal tab with thick setae at the base of leg 7; and a gonopod telopodite with two or three tight clusters of stout, rod-like setae at or near the telopodite apex. The group occurs over most of Tasmania but has not yet been found in the far south or the southeast of the main island, or on islands in Bass Strait.
The relationships of T. interfluminum sp. n. are uncertain, but it is clearly very close to T. decussatum and the two species may be parapatric in northeast Tasmania.