Millipede species: Polyxenida 

The tiny polyxenidans, or 'bristle millipedes', have tufts of bristles on their sides, and rows or clumps of bristles on the back of each segment. Some species have two long brushes of bristles at the rear end. Adults reach 3-4 mm in length. Polyxenidans seem to be most abundant in dry forest and heathland at low elevations in eastern and northern Tasmania, but specimens have also been found in rainforest near Weldborough, at ca 650 m. They are typically found in small groups in relatively dry shelters, such as cavities under loose bark on standing trees.

The following key to species was very kindly contributed by polyxenidan specialist Megan Short, who also supplied the images. 

1a.  Scales present on dorsal surface, rear of body conical, bristles at rear not in bundle, 17 pairs of legs in adult
..........Phryssonotus novaehollandiae (Silvestri, 1923)

Phryssonotus novaehollandiae

P. novaehollandiae may be Australia's most widely distributed millipede. It has so far been found in Queensland, New South Wales, Victoria, South Australia, Tasmania and Western Australia.

Short and Huynh (2006, 2009)

Tasmania map

1b.  Hair-like bristles on dorsal surface arranged in rows or rosettes, rear not conical in shape, 13 pairs of legs in adult
..........go to 2 

2a.  Bristles at rear arranged in a single bundle
..........Unixenus corticolus Short and Huynh, 2011

Short and Huynh (2011)

Tasmania map
Unixenus tail

2b.  Bristles at rear arranged in two bundles with extra bristles arranged above in a fan shape
..........go to 3

Other tail

3a.  Two distinct rows of short bristles on each segment, a pair of bristles in midline of the vertex of the head
..........Polyxenus lagurus (Linnaeus, 1758)

Polyxenus lagurus

Not yet recorded in Tasmania, but possibly introduced into cities or towns. Probably European in origin, now widespread; found in Melbourne.

Blower (1985)

3b.  More than two rows of bristles on each dorsal segment, bristles may be arranged in rosettes with rows less obvious
..........go to 4 

4a.  Adult (13 pairs of legs) more than 3 mm long, 6 ocelli in adult, dorsal bristles long and arranged in pairs of rosettes
..........Propolyxenus forsteri Condé, 1951

Propolyxenus forsteri

First described from New Zealand. An uncommon species in northwest Tasmania, found in wet eucalypt forest and Nothofagus forest.

Condé (1951), Mesibov (2000, 2001c) 

Tasmania map

4b.  Adult (13 pairs of legs) less than 2 mm long, 5 ocelli in adult, dorsal bristles short and arranged in 3 distinct rows across each segment
..........Propolyxenus australis Short and Huynh, 2010

Propolyxenus australis

Also found in South Australia and Victoria.

Short and Huynh (2010)

Tasmania map