Class Diplopoda - Millipedes

thousand-leggers, millipeds

'double-legged'

worldwide, >12,000 described spp.(1), many more undescribed (estimated 80,000 spp., based on known degrees of endemism), arranged in 2 subclasses, 16 orders, and 145 families; >900 described spp. in 217 genera of 52 families (of which 17 are endemic to NA, and 7 are non-native) in our area, but hundreds await description, particularly in the Glomeridae, Parajulidae, Atopetholidae, Cleidogonidae, Trichopetalidae, Striariidae, Polydesmidae, and Nearctodesmidae(2)(3); 66 documented & ~100 estimated spp. in Canada(4)

Families represented in our area

Classification adapted from(2). Taxa not yet in the guide are marked (*), non-native taxa in brackets.

CLASS DIPLOPODA

Subclass PENICILLATA

Order Polyxenida

Superfamily Polyxenoidea Polyxenidae

Subclass CHILOGNATHA

Infraclass Pentazonia

Superorder Oniscomorpha

Order Glomerida Glomeridae

Infraclass Helminthomorpha

Subterclass Colobognatha

Order Platydesmida Andrognathidae

Order Polyzoniida Hirudisomatidae, Polyzoniidae, Siphonotidae

Order Siphonophorida Siphonophoridae, Siphonorhinidae

Subterclass Eugnatha

Superorder Juliformia

Order Julida

Superfamily Blaniuloidea Blaniulidae, *Zosteractinidae

Superfamily Juloidea [Julidae]

Superfamily *Nemasomatoidea *Chelojulidae, *Nemasomatidae, *Telsonemasomatidae

Superfamily Paeromopodoidea *Aprosphylosomatidae, Paeromopodidae

Superfamily Parajuloidea Parajulidae

Order Spirobolida

Suborder Spirobolidea *Allopocockiidae, Atopetholidae, *Floridobolidae, [Rhinocricidae], Spirobolidae

Suborder Trigoniulidea [Trigoniulidae]

Order Spirostreptida

Suborder Cambalidea Cambalidae

Suborder Epinannolenidea Choctellidae

Suborder Spirostreptidea

Superfamily Spirostreptoidea Spirostreptidae

Superorder Nematophora

Order Callipodida

Suborder Schizopetalidea Abacionidae, Schizopetalidae

Order Chordeumatida

Suborder Craspedosomatidea

Superfamily Anthroleucosomatoidea Anthroleucosomatidae

Superfamily *Brannerioidea *Branneriidae, *Microlympiidae, *Tingupidae

Superfamily Cleidogonoidea Cleidogonidae, Trichopetalidae

Superfamily Craspedosomatoidea [Craspedosomatidae]

Suborder Heterochordeumatidea

Superfamily Conotyloidea *Adritylidae, Conotylidae

Suborder Striariidea

Superfamily Caseyoidea Caseyidae, *Urochordeumatidae

Superfamily Striarioidea *Apterouridae, Rhiscosomididae, Striariidae

Superorder Merocheta

Order Polydesmida

Suborder Leptodesmidea

Superfamily Sphaeriodesmoidea Sphaeriodesmidae

Superfamily Xystodesmoidea Eurymerodesmidae, Euryuridae, Xystodesmidae

Suborder Strongylosomatidea [Paradoxosomatidae]

Suborder Polydesmidea

Infraorder Oniscodesmoides

Superfamily Pyrgodesmoidea Pyrgodesmidae

Infraorder Polydesmoides

Superfamily *Haplodesmoidea *[Haplodesmidae]

Superfamily Polydesmoidea [Polydesmidae]

Superfamily Trichopolydesmoidea Macrosternodesmidae, Nearctodesmidae

3-270+ mm worldwide; the longest millipede of our fauna (Paeromopus paniculus) up to 160 mm

key to some orders and families in (5), Loomis (1968)

Two pairs of legs on all but the first three body segments (47-375 leg pairs and 25-189 body segments, not counting head and tail segment). Body flattened or cylindrical. In some groups, notably Polydesmida, body segments are laterally explanate. Pill Millipedes (Glomerida) are short-bodied, can roll into a ball, and look similar to pillbugs.

Sexing: Mature males usually have modified legs (gonopods). Most have 1-2 pairs of gonopods on segment 7, but in the Glomerida they are on posterior segments, while Polyxenida lack gonopods altogether.

worldwide and throughout NA

Moist habitats under rocks, rotting logs, organic debris, etc.

usually decaying plant material; a few spp. occasionally carnivorous. Some may feed on living plant tissue.

Millipedes hatch with 3 pairs of legs, and add segments/legs as they molt; some live up to 7 years.

To protect themselves, millipedes coil or roll into a ball; many emit poisonous (e.g., cyanide-containing) or foul substances (e.g., benzoquinones). It is sometimes assumed some species can produce hydrochloric acid, but this has never been tested and Shear (2015) makes no mention of this substance.

"Millipedes lack the structures to bite, pinch, or sting, and are harmless to humans, although the defensive secretions burn if they get into the eyes. Millipedes are non-toxic to humans and can be picked up by hand. Some secretions discolor the skin, with no lasting effects. Some large, cylindrical, tropical species squirt defensive secretions up to a half meter and can blind chickens and dogs." --Rowland Shelley

Centipedes have only one pair of legs per body segment, and the last pair of legs extends backwards behind the body; they can run fast and can bite. Millipedes are slow-moving and unable to bite.(6)

(7)