| Atelocerata | |
|---|---|
 | |
| Scolopendra, a myriapod | |
 | |
| Chrysoperla, a hexapod | |
| Scientific classification | |
| Kingdom: | |
| Phylum: | |
| (unranked): | Atelocerata Heymons, 1901 |
Atelocerata is a proposedclade ofarthropods that includesHexapoda (insects and a few related taxa) andMyriapoda (millipedes,centipedes, and similar taxa), but excludesCrustacea (such asshrimp andlobsters) andChelicerata (such asspiders andhorseshoe crabs). The name is currently used interchangeably withTracheata.[1] orUniramiasensu stricto. It is an extensive division ofarthropods comprising all those that breathe bytracheae, as distinguished fromCrustacea, which breathe by means ofgills.
The name Tracheata is an older term, originally proposed byErnst Haeckel in 1866 as a grouping of arachnids, myriapods and insects. Tracheata was redefined to exclude arachnids byPocock in 1893.(reviewed in Koenemann et al.[1]) The name Atelocerata was first proposed byRichard Heymons in 1901,[2] and the two names are considered equivalent.[1][3]
The status of Atelocerata as a true clade is now doubted bymolecular phylogenetic studies. Some recent authors have viewed the crustaceans as more closely related to hexapods than myriapods are.[1][4] If this is true, then characters shared by hexapods and myriapods, but not crustaceans, must be the result of eitherconvergence, or secondary loss in the Crustacea.[5]
