Iris003's picture

Flat-backed millipede

Observed: 28th October 2009 By: Iris003Iris003’s reputation in InvertebratesIris003’s reputation in InvertebratesIris003’s reputation in Invertebrates
Flat backed Millipede 01
Flat backed Millipede 02
Flat backed Millipede 03
Flat backed Millipede 04

About 20 segments, 2 pairs of legs on MOST segments, 10mm long, brown legs, found outdoors in soil.

Species interactions

No interactions present.


John Bratton's picture

There are several flat-backed

There are several flat-backed millipedes. The ones I find are always Polydesmus, can't remember which species. You really need to look at the genitalia on the underside of a male to identify them.

John Bratton

Martin Harvey's picture

flat-back millipedes

John is quite right to warn that these are tricky to identify, but if your size measurement of 30mm is correct then there are only two species to choose from I think: Polydesmus angustus or P. coriaceus. Of these, P. angustus is more likely, on the grounds that it is the commoner of the two and ranges further north, but I can't confirm it from the photo.

Brachydesmus superus is not supposed to grow over 10mm long. What size are the squares in the background of your photos? I count about ten squares for the length of this millipede, which means that if it is 30mm long each square is 3mm, is that correct? It's a great idea to photograph it over the squares so we can get a good estimate of the size!

Entomologist and biological recorder

Iris003's picture


Dear Martin, sorry! We got the measurement wrong, each square is one mm long, not three!


Martin Harvey's picture


Oh well, never mind! I'm afraid that means there are several species it could be, so we'll have to stick with identifying it just to family Polydesmidae.

Entomologist and biological recorder