Keys — Introduction
Which multipede is which?
Millipedes (fig. 1) have 2 pairs of legs on most body segments.
Centipedes (fig. 2), Pauropoda and Symphyla never have more than 1 pair of legs on a body segment.
Velvet worms (fig. 3) do not have obvious body segments, and their legs (unlike those of the other multipedes) are not divided into joints.
Pauropoda (fig. 4) have branched antennae and 9 or 10 pairs of legs.
Symphyla (fig. 5) have unbranched antennae, 12 pairs of legs and 2 tail-like appendages, called cerci, at the rear end.
Centipedes have at least 15 pairs of legs as adults. Some juvenile centipedes have fewer than 15 pairs of legs (fig. 6), but these juveniles can be distinguished from Pauropoda because the antennae are unbranched, and from Symphyla because the rear end lacks cerci. (Figs 4-6 not to same scale.)
Pauropod drawing from (Harrison 1914). Symphyla drawing by Graham Milledge, used with permission.
(1) The identification keys on this website are designed for the Tasmanian fauna and should not be used for non-Tasmanian multipedes.
There are two good reasons for this warning. First, nearly all of Tasmania's native multipedes are endemic to Tasmania. This means that even if you find a multipede somewhere else in the world which looks almost exactly like one of the native Tasmanians on this website, it is highly unlikely that they are the same animal. Second, there are whole groups of multipedes found elsewhere in Australia and on other continents (such as Spirobolida millipedes) which do not occur in Tasmania and are missing from these keys.
(2) The keys used here are not all dichotomous. In other words, you may have more than two choices at each step. Pay close attention to all the clues at each step, whether multiple-choice or not, and you won't need to backtrack.
(3) For most identifications you will need a low-power microscope or a strong hand-lens. Once you get to know the Tasmanian multipede fauna a bit better, you may be able to identify many species with your unaided eyes, but even experts need magnification for 100%-certain identifications of most species.
(4) You definitely need to count legs (or pairs of legs) to identify many multipedes. Sorry, but 'about 30' isn't good enough. Multipedes are very careful about the number of legs they grow, and multipede identifiers have to be equally careful, or mistakes will happen.