Hexapods — six-legged arthropods that include all the insects and a few "allied" groups — have long been assumed to be a monophyletic group, whose evolutionary tree, if traced to its single ancestral root, would include every member of this vast and varied taxon. In the March 21
Nardi et al. performed whole-mitochondrial sequencing on Gomphiocephalus hodgsoni (a collembolan) and an insect with ancient roots, a member of the Zygentoma order. They combined these data with published sequences for 33 other arthropods to create a phylogenetic tree showing the most likely lineages and branching points. ...