Pancrustacea is a
clade, comprising all
crustaceans and
hexapods. This grouping is contrary to the
Atelocerata hypothesis, in which
Myriapoda and
Hexapoda are
sister taxa, and
Crustacea are only more distantly related. As of 2010, the Pancrustacea taxon is considered well accepted. The clade has also been called
Tetraconata, referring to the square
ommatidia of many of its members. That name is preferred by some scientists as a means of avoiding confusion with the use of "pan-" to indicate a clade that includes a
crown group and all of its stem group representatives.