Pancrustacean phylogeny: Hexapods are terrestrial crustaceans and maxillopods are not monophyletic

  • Regier J
  • Shultz J
  • Kambic R
  • 324


    Mendeley users who have this article in their library.
  • 222


    Citations of this article.


Recent molecular analyses indicate that crustaceans and hexapods form a clade (Pancrustacea or Tetra-conata), but relationships among its constituent lineages, including monophyly of crustaceans, are contro-versial. Our phylogenetic analysis of three protein-coding nuclear genes from 62 arthropods and lobopods (Onychophora and Tardigrada) demonstrates that Hexapoda is most closely related to the crustaceans Branchiopoda (fairy shrimp, water fleas, etc.) and Cephalocarida þ Remipedia, thereby making hexapods terrestrial crustaceans and the traditionally defined Crustacea paraphyletic. Additional findings are that Malacostraca (crabs, isopods, etc.) unites with Cirripedia (barnacles, etc.) and they, in turn, with Cope-poda, making the traditional crustacean class Maxillopoda paraphyletic. Ostracoda (seed shrimp)—either all or a subgroup—is associated with Branchiura (fish lice) and likely to be basal to all other pancrustaceans. A Bayesian statistical (non-clock) estimate of divergence times suggests a Precambrian origin for Pancrustacea (600 Myr ago or more), which precedes the first unambiguous arthropod fossils by over 60 Myr.

Author-supplied keywords

  • Arthropod phylogeny
  • Cambrian explosion
  • Crustacea
  • Hexapoda
  • Molecular systematics
  • Pancrustacea

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document


  • Jerome C. Regier

  • Jeffrey W. Shultz

  • Robert E. Kambic

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free