Key to orders of Australian millipedes

There are 8 native and 1 introduced orders of millipedes in Australia. The introduced order is Julida, with at least 9 introduced species including the well-known 'Portugese millipede' Ommatoiulus moreleti.

There are also introduced species in 4 of the native Australian orders. If you key out a millipede to Julida, it is definitely not a native. If you key out a millipede to one of the native orders Polydesmida, Polyxenida, Spirobolida or Spirostreptida, the species may or may not be native.

1a.  Less than 5 mm long; 'hairy' with bristles in obvious rows or clumps..........Polyxenida

Polyxenida Polyxenida

1b.  Usually greater than 5 mm long; if 'hairy' then with no obvious clumps of bristles..........go to 2


2a.  Body about half as wide as long, strongly convex on top;
          animal can curl up into a ball..........Sphaerotheriida


2b.  Body much longer than wide, animal cannot curl up into a ball..........go to 3


3a.  Body convex above, flat beneath (A)..........go to 4

3b.  Body cylindrical (B).........go to 5

body sections


4a.  Eyes present, head triangular, body often with colorful stripes..........Polyzoniida


4b.  No eyes, head with long 'beak', body usually pale..........Siphonophorida



5a.  Adults with 19 or 20 body rings, no eyes..........Polydesmida


5b.  Adults with more than 20 body rings, usually with eyes..........go to 6


6a.  Adults with 30 or 32 body rings,
          usually with 6 long bristles on top of each ring..........Chordeumatida


6b.  Adults with more than 32 body rings, body smooth and shiny..........juliform millipedes (below)


The juliform millipede orders are Julida, Spirobolida and Spirostreptida and they can be difficult to separate without looking closely at the head and the first few legs, as shown below.

Spirobolida have a distinct median suture line (arrow) on the clypeus (lower part of the 'face'). This line is missing in Julida and Spirostreptida:

juliform faces

On the underside of the head, the lateral plates (gnathochilarial stipetes, singular stipes, gs) meet broadly along the midline towards the back of the head in Julida, but are well-separated in Spirobolida and Spirostreptida:

juliform gnathochilaria

The fifth body ring has 2 pairs of legs in Julida and 1 pair of legs in Spirobolida. Spirostreptida have 2 pairs of legs on ring 5 but no legs at all on ring 4:

Julida ventral Spirobolida ventral Spirostreptida ventral

Image credits: Peter Decker (Julida drawing), Cuong Huynh and Megan Short (Polyxenida), Maria Minor and Alastair Robertson, SoilBugs (whole-animal Siphonophorida).