This month’s blog comes to us courtesy of Dawid Martyniuk, a Zoology student at the University of Reading.
One may come into contact with millipedes when moving logs and stones or uncovering leaf litter. Whatever the encounter, chances are that it was by accident (unless you study soil invertebrates) so you may not have had a good look at them, which can be forgiven considering their small size, usually dull colouration, and tendency to run away from light. I hope that this simple guide to five of the most common and easily identifiable millipedes on Campus will encourage readers to pay more attention to these creatures, as only with willingness to look closer can one appreciate their complexity and diversity.
Pill millipede (Glomeris marginata) adults ~1.5cm
One of the most distinct, most common, but also one of the most overlooked millipedes on campus. Pill millipedes may look like the well-known ‘Pill bug’ (Armadillidium spp.), but these are crustacean, while Pill millipedes are of course, millipedes.
The most reliable way to distinguish them is to look at them from the side and see how many legs they have. Woodlice such as Pill-bugs all have 7 pairs of legs, while Pill millipedes have many more (17-18 pairs). Another way to tell the difference is to look at the colours and patterns. Pill bugs tend to be grey, many with faint patterns, whereas adult Pill millipedes are usually black or dark brown with distinct pale outlines on each segment.
Flat-back millipede (Polydesmus angustus) adults ~2cm
In my opinion, the most common millipede on campus, the flat-back millipede is known for its flat, clearly segmented appearance. They are brown with a bumpy texture and have close to 30 pairs of legs that can be seen from above.
There are many species of flat-back millipedes (Order Polydesmida) which are difficult to distinguish without microscope examination, but Polydesmus angustus is the most common woodland species on Campus so we can assume an individual is Polydesmus angustus unless proven otherwise. All flat-back millipedes do not have eyes, so a hand lens/good camera may be useful in identification.
Blunt-tailed snake millipede (Cylindroiulus punctatus) adults ~2cm
This millipede has a shape typical of most millipedes: long and cylindrical, with many small legs. It is pinkish brown, with a pale underside and has spots along its side. The most important feature is the rounded/blunt ‘tail tip’ (tail telson) which is unique to this species (and two others, but they are significantly larger). You may need a hand lens or good camera to check this, but this can be vital in identification as there are other species such as Cylindroiulus britannicus that look identical but lack such a ‘tail tip’.
White-legged snake millipede (Tachypodoiulus niger) adults ~3cm
A distinct and relatively large species, this millipede is shiny black with white legs and a pointy ‘tail tip’ (tail telson). As with most other millipedes, you can sometimes find them resting in a curled position. Juveniles might not be as dark in colour and therefore be confused with species of similar shape and size, such as Ophyiulus pilosus but this species is hairier and browner. White-legged snake millipedes also have the very end of the tail tip bent slightly upwards, but this can only be seen with a good hand lens or microscope.
False flat-back millipede (Nanogona polydesmoides) adults ~2cm
These millipedes resemble the flat-back millipedes, but in truth they are from a completely different order (Chordeumatida). Unlike flat-back millipedes, these millipedes have conspicuous eyes and are generally more shiny or iridescent in the light. Other differences include thinner antennae and 30 body segments when adult (true flat-back millipedes only have 20).
Again, it may be useful to have a hand lens/ decent camera to see such details.
I hope that now, with this new knowledge, finding a millipede will be a much more interesting experience. You can submit your findings to irecord.org.uk to contribute to the National Recording Scheme.
For information on more species and how to identify them, see the BMIG millipede species list: https://www.bmig.org.uk/checklist/millipede-checklist
Many thanks to Dawid! If you’re interested in contributing to the Whiteknights blog, please get in tough with Vicky Boult: v.l.boult(at)reading.ac.uk.