flat-backed millipede

not listed

NNR - Unranked

not listed

Pleuroloma flavipes is a common, widespread, and well-known flat-backed millipede. It occurs in the United States east of the Great Plains and in Ontario, Canada. It is found on the ground and under logs in deciduous and mixed woodlands and in adjacent fields and other open areas. Occasionally large numbers appear in mass aggregations, sometimes migrating across a field or forest floor.

The adult is ⅜″ to 19⁄16″ (10 to 40 mm) long and appears flattened when viewed from the side. The head is large and round. It is blind, it has no eyes. There are 20 body rings. Each ring is covered above with a hard, rigid plate (tergite). Each tergite is blackish-brown with yellow or yellowish markings, a wrinkled or roughened surface, and a distinct horizontal ridge (keel). There is no dorsal groove. The color pattern is variable, common throughout a single population but differing between neighboring populations. The rear (posterior) margin is has a yellow band that widest in the middle. The lateral margin of each tergite is slightly extended horizontally, and this extension is usually yellow. There is sometimes a wedge-shaped yellow or orange mark at the forward (anterior) corners of each tergite.

The legs are yellow. Segments 5 through 18 each have two pairs of legs, segments 3 and 4 each have one pair of legs, and segments 2 and 19 have no legs. There is one pair of legs in front of segment 3, but this is not on segment 2, which is little more than an upper plate. On the male, the front pair of legs on the seventh ring are modified as reproductive structures (gonopods). The structure of the gonopod is unique to each species and is an important identifying feature. The hind pair of legs on the seventh ring of the male are normal walking legs. The ninth and tenth legs (L9 and L10) on both sexes are are normal walking legs, not reduced in size.

Total length: ⅜″ to 19⁄16″ (10 to 40 mm)

Mixed and deciduous forests, and adjacent fields and other open areas

Eggs and juveniles overwinter in chambers in the soil deep enough to not freeze.

Rotting vegetation and fungi

Sources

24, 29, 30.

Shelley, Rowland M. and Snyder, Bruce A., "Millipeds from the eastern Dakotas and western Minnesota, USA, with an account of Pseudopolydesmus serratus (Say, 1821) (Polydesmida: Polydesmidae); first published records from six states and the District of Columbia" (2012). Insecta Mundi. 752.

Not uncommon

This species has no common name. The common name of the order Polydesmida is flat-backed millipedes, and it is applied here for convenience.