Key to juliform millipedes
Most people instantly recognise 'juliforms' as millipedes. They are long, smooth-bodied and cylindrical, and mostly gray or black in colour. They can be found in every garden; some species invade houses. Almost all of these domestic juliforms are introduced species in the order Julida. Tasmania also has a large number of species of native, bush-living juliforms in the order Spirostreptida. Identification would be easier if the two orders stayed apart, but unfortunately they don't. Introduced julidans are now well established in the bush in many parts of the State (including wild, remote areas) and native spirostreptidans are at home in the backyard woodpile. Also unfortunately, there is no simple way for non-experts to separate Julida from Spirostreptida, especially the smaller species.
The key below will help you sort the juliforms you are most likely to find in Tasmania. (Let me know by email if you have a juliform that does not seem to fit the key, as it could be a new introduction.) First, some anatomy:
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Body segments with two pairs of legs are called diplosegments (see illustration at right). Each diplosegment is divided into an anterior prozonite (p) and a slightly larger, posterior metazonite (m). Prozonite and metazonite are joined along a just-visible suture (s). Posterior diplosegments in juliforms have on each side a small hole called an ozopore (o). The ozopore is the outlet for defensive secretions, which in juliforms include pungent-smelling benzoquinones (Huth 2000). Other millipedes (and other arthropods) should always be preserved separately from juliforms, as benzoquinones can harden alcohol-preserved specimens and stain them a dark red. |
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1a. Long, pointed projection on pre-anal ring ('tail') (left image)
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2a. Projection on pre-anal ring curved slightly upwards; no obvious bristles (setae) on posterior fringe of metazonites
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2b. Projection on pre-anal ring not curved upwards; long, obvious setae on posterior fringe of metazonites
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3a. Eyes absent (see image at right); body pale with red spots on sides (specimens in alcohol may be uniformly reddish)
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4a. Eyes present in line behind antenna (left image); body light brown
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5a. Older individuals usually less than 12 mm long, with two light-coloured stripes on either side of darker mid-dorsal line (image is dorsal view of midbody segments)
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5b. Older individuals more than 15 mm long, without light-coloured dorsal stripes
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6a. Ozopore (arrow) on suture line between prozonite and metazonite; colour gray or brown, fading in alcohol; generally slender, less than 2 mm in diameter
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6b. Ozopore (arrow) on metazonite, away from suture; colour usually black; many species large, greater than 2 mm in diameter
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