Colobognatha is a clade (formally considered a subterclass) of

helminthomorph Millipedes are a group of arthropods that are characterised by having two pairs of jointed legs on most body segments; they are known scientifically as the class Diplopoda, the name derived from this feature. Each double-legged segment is a resu ...

millipedes Millipedes are a group of arthropods that are characterised by having two pairs of jointed legs on most body segments; they are known scientifically as the class Diplopoda, the name derived from this feature. Each double-legged segment is a resu ...

containing four

orders Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...

: Platydesmida,

Polyzoniida __NOTOC__ Polyzoniida is an order of millipedes in the subterclass Colobognatha containing three families and at least 74 described species. Description Polyzoniidans have a somewhat domed dorsal surface with a flat ventral side. Their heads ar ...

Siphonocryptida Siphonocryptida is an order of millipedes, comprising the sole family Siphonocryptidae. With only seven described species, the Siphonocryptida is the second smallest millipede order, surpassed only by Siphoniulida, with two species. Classifica ...

, and

Siphonophorida Siphonophorida (Greek for "tube bearer") is an order of millipedes containing two families and over 100 species. Description Millipedes in the order Siphonophorida are long and worm-like, reaching up to in length and up to 190 body segments. ...

Description

The Colobognatha are united by several shared traits (

synapomorphies In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to hav ...

). Males have two pairs of simple, leg-like

gonopods Gonopods are specialized appendages of various arthropods used in reproduction or egg-laying. In males, they facilitate the transfer of sperm from male to female during mating, and thus are a type of intromittent organ. In crustaceans and millipe ...

, consisting of the rear leg pair of body segment 7 and the foreword-most leg pair of segment 8. They possess tubular defensive glands that open on the sides of the body, and lack a

palp Pedipalps (commonly shortened to palps or palpi) are the second pair of appendages of chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicerae ("jaws") and ...

-like structure on their gnathochilaria. Other traits found in colobognathans, but not exclusively, include a distinctly narrow head, lack of Tömösváry organs, and no more than two pairs of

ocelli A simple eye (sometimes called a pigment pit) refers to a form of eye or an optical arrangement composed of a single lens and without an elaborate retina such as occurs in most vertebrates. In this sense "simple eye" is distinct from a multi-le ...

References

{{Taxonbar, from=Q16980877 Millipede taxonomy Taxa named by Johann Friedrich von Brandt