Zoology 250 Phylogenetic Trees (2017)


(onychopheran)
The PANARTHROPODA
(ALTERNATIVE MOLECULAR PHYLOGENY)

(after Regier et al. 2010; based on 41 KB of aligned DNA sequence from 62 single-copy nuclear protein-coding genes from 75 arthropod species; additional support from Zwick et al. 2012 PLoS ONE 7(11): e47450 & Campbell et al. 2011 PNAS 108:15920-24)


(tardigrade)


(pycnogonid sea spider)

(horseshoe crab)

(true spider)
Phylum ARTHROPODA
(diplopod myriapod)

(chilopod myriapod)

(extinct trilobite)

KEY SIMILARITIES AND DIFFERENCES BETWEEN TRADITIONAL AND MOLECULAR PHYLOGENY
SIMILARITIES:
  • Chelicerates are monophyletic and the sister group to all remaining Arthropoda
  • Pycnogonida are the sister group to all remaining Chelicerata
  • Myriapoda are monophyletic
  • Relations among major myriapod groups remain the same
  • Relations among major malacostracan groups remain the same
  • Hexapoda are monophyletic
  • Relations among basal hexapod groups remain the same
DIFFERENCES:
  • Relations between Onychophora, Tardigrada and Arthropoda remain abiguous
  • Myriapoda are NOT part of Uniramia, but instead are sister group to the Pancrustacea (all remaining Arthoropoda)
  • Hexapoda (insects and relatives) are NOT part of Uniramia, but instead are nested within the Pancrustacea
  • Sister group to the Hexapoda are the two most 'primitive' crustacean phyla (Remipedia, Cephalocarida); so the Hexapoda are derived from well-defined crustacean ancestors
  • The most basal Pancrustacea include the Ostracoda and some odd parasitic groups, rather than the Remipedia or Cephalocarida
  • The Maxillopoda (copepods, ostracods, barnacles, etc.) are NOT a monophyletic group
  • The Malacostraca are more closely related to copepods and barnacles than to Branchiopoda
  • The Myriapoda and Hexapoda represent two independent invasions of land instead of one (the Uniramia)

 


PANARTHROPODA

                    =============== ONYCHOPHORA (velvet worms; fossil Hallucigenia)
<<==================|
                    |  ============ TARDIGRADA (water bears)
                    ===|
                       ============================== TO ARTHROPODA =======>


ARTHROPODA

                                          ======== Pycnogonida (sea spiders)
                                          |
    ====================CHELICERATA=======|    === Merostomata (horseshoe crabs)
    |                                     =====|
    |                                          === Arachnida (spiders, mites, scorpions, etc.)
    |
<<==| =(added by ARP) TRILOBITOMORPHA============= (extinct trilobites)
    | |
    ==|                             ============== Chilopoda (centipedes)
      |                             |
      |  ===============MYRIAPODA===|    ========= Symphyla (symphylans)
      |  |                          =====|
      Ma=|                               ========= Diplopoda (millipedes)
         |
         |                               ========= Ostracoda (seed shrimp)
         |  ============OLIGOSTRACA======|
         |  |                            ========= odd parasites (Branchiura, Pentastomida)
         Pa=|
            |      ======BRANCHIOPODA============= Branchiopoda (fairy shrimp, water fleas, etc.)
            |      |
            |  =Ve=|  ===COPEPODA================= Copepoda (copepods)
            |  |   |  |
            |  |   Mu=|   ==THECOSTRACA=========== Cirripedia (barnacles)
            |  |      =Co=|
            |  |          |               ======== Phyllocarida (Or. Leptostraca)
            |  |          ==MALACOSTRACA==|
            |  |                          |   ==== Hoplocarida (mantis shrimps)
            Al=|                          =Eu=|
               |                              | == Peracarida (mysids, amphipods, isopods, etc.)
               |                              ==|
               |                                == Eucarida (krill, shrimps, lobsters, crabs, etc.)
               |
               |                     ============= Remipedia
               |     ====XENOCARIDA==|
               |     |               ============= Cephalocarida
               ==Mi==|
                     |             ==Entognatha=== Collembola (springtails)
                     ====HEXAPODA==|
                                   |            == Thysanura (silverfish and firebrats)
                                   ==Ectognatha=|
                                                == Pterygota (winged insects)
                                                   (Insecta)

(groups in green are all from the traditional subphylum Chelicerata,
groups in red are all from the traditional subphylum Crustacea,
groups in blue are all from the traditional subphylum Uniramia)

Ma- MANDIBULATA
Pa- PANCRUSTACEA
Al- ALTOCRUSTACEA
Ve- VERICRUSTACEA
Mi- MIRACRUSTACEA
Mu- MULTICRUSTACEA
Co- COMMUNOSTRACA
Eu- EUMALACOSTRACA

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Copyright (c) 2017 by A. Richard Palmer. All rights reserved.
(revised Dec. 19, 2016)