The Atelocerata (Heymons, 1901[1]) is an obsolete monophyletic group formed by the Hexapoda + Myriapoda, and sister group of the Eucrustacea, if the Mandibulata concept is favored. The subphylum Hexapoda (from the Greek for six legs) constitutes the largest (in terms of number of species grouping of Arthropods and includes the Myriapoda is a Subphylum of Arthropods containing Millipedes Centipedes and others Structure of crustaceans As Arthropods crustaceans have a stiff Exoskeleton, which must be shed to allow the animal to grow ( Ecdysis or molting In arthropods the mandible is either of a pair of Arthropod Mouthparts used for biting cutting and holding food
Some authors use the name interchangeably with Uniramia and Tracheata. S M Manton's (1973 polyphyletic Arthropod hypothesis with Uniramia as one of three Phyla The Atelocerata (Heymons 1901 is an obsolete Monophyletic group formed by the Hexapoda + Myriapoda, and sister group of the Eucrustacea, if