logo

Back to: growth
Forward to: colour



Size

Adult Polydesmida range in length from about 3 mm to more than 130 mm, depending on species. The largest species are in the tropics. In the temperate zone, most species are about 5 to 50 mm long.


AgathodesmusAgathodesmus Unknown

Agathodesmus steeli
Haplodesmidae; New South Wales, Australia
5 mm long
Hover cursor over image for close-up

Unidentified polydesmidan, Peruvian Amazon
100 mm long
Tentatively identified from this image
by R.M. Shelley as a species
of Barydesmus (Platyrhachidae)
Image © 2005 by Dan Rosenberg
Used with permission

 

 

Size can also vary within a species. The image at right shows two adult females of Lissodesmus hamatus (Dalodesmidae), a common species in eastern Tasmania. The larger female is from high-rainfall forest, and the smaller female is from low-rainfall woodland. Scale bar = 10 mm.

Lissodesmus

 

 

A good way to record polydesmidan sizes is with the two measurements shown at right. d is the maximum diameter of a diplosegment (posterior view), and mw is the maximum width of a ring, including the paranota.
 
Which body ring should you measure? Many published descriptions give figures for a 'midbody' ring, which is a ring roughly halfway along the length of the body. You can also specify which ring you measure, for example
 
...maximum diameter of ring 10, 1.9 mm;
maximum width across ring 10 paranota, 2.6 mm...

measure

Back to: growth
Forward to: colour