After Gon, 2001-2002, Budd, 2002, Regier, Shultz, Zwick, Hussey, Ball, Wetzer, Martin & Cunningham, 2010, Edgecombe, García-Bellido & Paterson, 2011, Briggs, Siveter, Siveter, Sutton, Garwood & Legg, 2012, Lamsdell, 2013, Ortega-Hernández, Legg & Braddy, 2013, and Vinther, Stein, Longrich & Harper, 2014

Note:

There is probably no more highly contested area in animal phylogeny than the origin and early evolution of arthropods. This subject has been under study of several generations of biologists and paleontologists. Recent views seem to devide arthropods to two monophyletic groups; chelicerates and their relatives (Cheliceramorpha) and crustaceans and their relatives (Mandibulata), which include also myriapods and insects. Lots of morphological phylogeny on arthropods revolves around the question of the identity and relationships of their limbs (appendages) and how they are related to the formation of the head. The key character separating chelicerates and mandibulates seem to be destiny of the first addendage, which in chelicerates turn to cheliceres and in crustaceans and their relatives turn to antenna. (Edgecombe et al., 2011, Lamsdell, 2013)

Trilobites and their relatives, Trilobitomorpha, have long been considered as close relatives of chelicerates. With chelecerates they have formed a larger group of arthropods (Artiopoda) (Hou & Bergström, 1997, Siveter, Briggs, Siveter, Sutton, Legg. & Joomun, 2014, but see Ortega-Hernández, Legg & Braddy, 2013) Now, based on separation in identity of the first appendage, causes several of these early arthropods, in which the first appendage has turned to antenna to end up with a new and novel relationship with these two great lineages. Namely, instead of being basal cheliceramorphs or closely related, most of trilobitomorphs end up as close relatives of mandibulates. This great group has been named as Antennata or Antennulata, depending of the source. (Lamsdell, 2013)

People more interested of the intrigues of arthropod head formation should visit “Wikipedia”.

Alternatives phylogenies of Arthropoda:

Alternative phylogeny of Crown Arthropoda after Conway Morris, 1993, Hou & Bergström, 1997, and Gon, 2001-2002

Alternative phylogeny of Crown Arthropoda after Hwang et al., 2001

Alternative phylogeny of Crown Arthropoda after Giribet et al., 2001, and Vaccarl, et al., 2004

Alternative phylogeny of basal Arthropoda after Budd, 2002

Alternative phylogeny of basal Arthropoda after Lamsdell, 2013

Alternative phylogeny of basal Arthropoda after Siveter, Briggs, Siveter, Sutton, Legg & Joomun, 2014

Alternative phylogeny of selected basal Artiopoda after Legg, 2014

<==o Arthropoda Siebold & Stannius, 1895 sensu Siveter, Briggs, Siveter, Sutton, Legg & Joomun, 2014 (arthropods; niveljalkaiset)
   `--o Dinocarida Collins, 1996 sensu Vinther, Stein, Longrich & Harper, 2014
      |-- †Opabinia regalis Walcott, 1912 [Opabinida]
      `--+-- †Caryosyntrips serratus Daley & Budd, 2010; M.Camb. WNAm.
         |--o †Radiodonta Collins, 1996 sensu Vinther, Stein, Longrich & Harper, 2014
         |  `-- †Anomalocarida Vinther, Stein, Longrich & Harper, 2014 (anomalocarids; anomalocaridit)
         `--o Euarthropoda sensu lato [Arthropoda sensu stricto] [Schizoramia sensu Hou & Bergström, 1997]
            |--o †Isoxys Walcott, 1890 [Isoxyida [Isoxyda]: Isoxyidae]
            |  |-- †I. chilhoweanus Walcott, 1890 [type]
            |  |-- †I. acutangulus (Walcott, 1908)
            |  |-- †I. auritus (Jiang, 1982) [Cymbia aurita]
            |  |-- †I. bispinatus Cui, 1991
            |  |-- †I. carbonelli Richter & Richter, 1927
            |  |-- †I. communis Glaessner, 1979
            |  |-- †I. curvirostratus Vannier & Chen, 2000
            |  |-- †I. glaessneri García-Bellido, Paterson, Edgecombe, Jago, Gehling & Lee, 2009
            |  |-- †I. longissimus Simonetta & Delle Cave, 1975
            |  |-- †I. minor
            |  |-- †I. paradoxus Hou, 1987
            |  |-- †I. volucris Williams, Siveter & Peel, 1996
            |  |-- †I. wudingensis Luo & Hu, 2006
            |  `-- †I. zhurensis Ivantsov, 1990
            `--+-- †Nereocaris exilis Legg, Sutton, Edgecombe & Caron, 2012; M.Camb. WNAm.
               `--+--+-- †Jugatacaris agilis Fu & Zhang, 2011
                  |  `--o †Pectocarididae Hou, 1999 sensu Hou, Bergström & Xu, 2004 [Pectocaridida Hou, 1999]
                  |     |?- †Vladicaris subtilis Chlupéc, 1995 [also treated as branchiopod]
                  |     `--o †Pectocaris Hou, 1999
                  |        |-- †P. spatiosa Hou, 1999
                  |        `-- †P. eurypetala (Hou & Sun, 1988) [Odaraia? eurypetala Hou & Sun, 1988]
                  `--+--+-- †Odaraia alata Walcott, 1912 [Odaraiida: Odaraiidae Simonetta & Delle Cave, 1975
                     |  `--o †Branchiocaris Briggs, 1976 [Protocaridida Simonetta & Delle Cave, 1975]
                     |     |-- †B. pretiosa Briggs, 1976
                     |     |-- †B. malongensis Luo et al., 2008
                     |     |-- †B. xundianensis Luo et al., 2008
                     |     |-- †B. yiliangensis Luo et al., 2008
                     |     `-- †B. yunnanensis Hou, 1987
                     `--+--o †Paracrustacea Hou & Bergström, 1997
                        |  `-- †Canadaspidida Novozhilov in Orlov, 1960 [incl. Hymenostraca Rolfe, 1969; Prophyllocarida Simonetta & Delle Cave, 1975]
                        `--+--o †Fuxianhuiida Bousfield, 1995 [Yunnata Hou & Bergström, 1997:]
                           |  |-- †Shankouia zhenghei Chen, Wang, Waloszek & Maas in Walossek, Chen, Maas & Wang 2005
                           |  `--+-- †Liangwangshania biloba Chen, 2005
                           |     `--+-- †Chengjiangocaris longiformis Hou & Bergström, 1991 [Chengjiangocarididae Hou & Bergström, 1997]; L.Camb. EAs.
                           |        `--+-- †Guangweicaris spinatus Luo, Fu & Hu, 2007 [Guangweicarididae Luo, Fu & Hu, 2007]
                           |           `-- †Fuxianhuia protensa Hou, 1987 [Fuxianhuiidae Hou & Bergström, 1997]; L.Camb.EAs.
                           `--o  Euarthropoda sensu stricto [last common ancester of chelicerates, myriapods, crustacenas and hexapods, and all it's decendants]
                              |--o Cheliceramorpha (chelicerates and relatives)
                              |  |--+-- †Sidneyia inexpectans Walcott, 1911 [Limulavida Walcott, 1911: Sidneyiidae Walcott, 1911]
                              |  |  `-- †Nettapezoura basilica Briggs et al., 2008
                              |  `--+?- †Sanctacaris uncata Briggs & Collins, 1988 [Sanctacaridea Bousfield, 1995: Sanctacarida Bousfield, 1995: Sanctacarididae]
                              |     `--+-- †Megacheira Hou & Bergström, 1997 sensu Edgecombe et al., 2011; Briggs et al., 2012, and Lamsdell, 2013
                              |        `--o Chelicerata Heymons, 1901 (chelicerates; kynsileukaiset)
                              |           |-- Pycnogonida Latreille, 1810 [Pantopoda; Arachnopoda Dana, 1853] (sea spiders; merilukit)
                              |           `-- Euchelicerata Weygoldt & Paulus, 1979
                              `--o Antennulata [“PanMandibulata”] (arthropods with antenna; antennalliset)
                                 |--o †Artiopoda Hou & Bergström, 1997 sensu Ortega-Hernández, Legg & Braddy, 2013
                                 |  |?- †Falcatamacaris bellua Ortega-Hernández, Lerosey-Aubril, Kier & Bonino, 2015; M.Camb. NAm.
                                 |  |--o †Vicissicaudata Ortega-Hernández, Legg & Braddy, 2013 [Aglaspidida Walcott, 1911 sensu lato?]
                                 |  |  |--+-- †Cheloniellida Broili, 1932 [Petalopleura Hou & Bergström, 1997 in partem]
                                 |  |  |  `--o †Xenopoda
                                 |  |  |     |-- †Sidneyia inexpectans Walcott, 1911 [Limulavida Walcott, 1911: Sidneyiidae Walcott, 1911]
                                 |  |  |     `-- †Emeraldella brocki Walcott, 1912 [Emeraldellida Störmer, 1944: Emeraldellidae Raymond, 1935]; M. Camb. WNA.
                                 |  |  `--+-- †Kwanyinaspis maotianshanensis Zhang & Shu, 2005
                                 |  |     `--+-- †Quasimodaspis brentsae Waggoner, 2003
                                 |  |        `--+--+-- †Kodymirus vagans Chlupac & Havlicek, 1965
                                 |  |           |  `--  †Beckwithia typa Resser, 1931 [Beckwithiidae Raasch, 1939]
                                 |  |           `-- †Aglaspidida Walcott, 1911 emend. Bergström, 1968 [sensu stricto?]
                                 |  `--o †Trilobitomorpha Moore 1959 pro Trilobita Walch, 1771
                                 |     `==o †Retifaciida Hou & Bergström, 1997 [Nectopleura Hou & Bergström, 1997 in partim]
                                 |        `--o †Retifaciidae Hou & Bergström, 1997
                                 |           |-- †Retifacies abnormalis Hou, Chen & Lu, 1989
                                 |           `--+--+-- †Squamacula clypeata Hou & Bergström, 1997
                                 |              |  `--+?- †Kiisortoqia soperi Stein, 2010
                                 |              |     `?- †Siriocaris trollae Lagebro, Stein & Peel, 2009
                                 |              `--+--o †Xandarellida Chen, Ramsköld, Edgecombe & Zhou in Chen et al., 1996 sensu Ortega-Hernández, Legg & Braddy, 2013 [Petalopleura Hou & Bergström, 1997 in partem]
                                 |                 |  |-- †Sinoburius lunaris Hou, Ramsköld & Bergström, 1991 [Sinoburiida Hou & Bergström, 1997: Sinoburiidae Hou & Bergström, 1997]
                                 |                 |  `--o †Xandarellidae Hou & Bergström, 1997 [incl. Almeniidae Hou & Bergström, 1997]
                                 |                 |     |-- †Xandarella spectaculum Hou, Ramsköld & Bergström, 1991
                                 |                 |     `-- †Cindarella eucalla Chen, Ramsköld, Edgecombe & Zhou in Chen et al., 1996 [Almenia spinosa Hou & Bergström, 1997]
                                 |                 `--+-- †Nectaspidida Raymond, 1920 emend. Hou & Bergström, 1997 [Nectaspida Raymond, 1920; Naraoidea Størmer, 1944; Naraoiformes Starobogatov, 1985] [Nectopleura Hou & Bergström, 1997 in partim]
                                 |                    `--+-- †Helmatiida Novozhilov, 1969 [Conciliterga Hou & Bergström, 1997:] (piilopyrstöiset)
                                 |                       `-- †Trilobita Walch, 1771 (trilobites; trilobiitit)
                                 `--+-- †Bradoriida Raymond, 1935 sensu Topper, Skovsted, Brock & Paterson, 2011
                                    |-- †Burgessia bella Walcott, 1912; M.Camb. WNAm.
                                    `--+-- †Marrellomorpha (Beurlen, 1934) Størmer, 1944
                                       `--o Mandibulata Snodgrass, 1938
                                          |-- Myriapoda Latreille, 1802 (myriapods; tuhatjalkaiset)
                                          |?- †Euthycarcinoidea Gall & Grauvogel, 1964 [Archicopepoda; Euthycarcinata]
                                          `--o Pancrustacea [Tetraconata; Crustaceomorpha (crustaceans; äyriäiset)]
                                             |--o Oligostraca Zrzavy, Hypsa & Vlaskova, 1997 [=? Maxillopoda sensu Maddison & Maddison, 1998]
                                             |  |-- Ostracoda Latreille, 1802 (ostracods, seed shrimps; raakkuäyriäiset)
                                             |  `--+-- Mystacocarida Pennack & Zinn, 1943
                                             |     `--o Ichthyostraca Zrzavy, Hypsa & Vlaskova, 1997
                                             |        |-- Pentastomida Diesing, 1836 (pentastomids, tongue worms; punkkimadot)
                                             |        `--+?- †Halicyna Gall & Grauvogel, 1967 [Cyclida] (cycloids)
                                             |           `-- Branchiura Thorell, 1864 (fish lice; kalatäit)
                                             `--o Altocrustacea Regier, Shultz, Zwick, Hussey, Ball, Wetzer, Martin & Cunningham, 2010
                                                |?- †Bredocaris admirabilis Müller, 1983; L.Camb. NEu.
                                                |?- †Rehbachiella kinnekullensis Müller, 1983; L.Camb. NEu.
                                                |?- †Yicaris dianensis Zhang, Siveter, Waloszek & Maas, 2007
                                                |--o Miracrustacea Regier, Shultz, Zwick, Hussey, Ball, Wetzer, Martin & Cunningham, 2010
                                                |  |-- Hexapoda Latreille, 1825 [incl. Insecta] (sixlegged arthropods; kuusjalkaiset niveljalkaiset)
                                                |  `--o Xenocarida Regier, Shultz, Zwick, Hussey, Ball, Wetzer, Martin & Cunningham, 2010
                                                |     |-- Remipedia Yager, 1981 (remipedes; remipedit)
                                                |     `-- Cephalocarida Sanders, 1955 (horseshoe shrimps)
                                                `--o Vericrustacea Regier, Shultz, Zwick, Hussey, Ball, Wetzer, Martin & Cunningham, 2010
                                                   |-- Branchiopoda Latreille, 1817 (branchiopods; kidusjalkaiset)
                                                   `--o Multicrustacea Regier, Shultz, Zwick, Hussey, Ball, Wetzer, Martin & Cunningham, 2010
                                                      |-- Copepoda Milne-Edwards, 1840 (copepods; hankajalkaiset)
                                                      `--o Communostraca Regier, Shultz, Zwick, Hussey, Ball, Wetzer, Martin & Cunningham, 2010
                                                         |-- Thecostraca Gruvel, 1905 [Branchiura in partim] [incl. Cirripedia Burmeister, 1834 (siimajalkaiset)]
                                                         `-- Malacostraca Latreille, 1802 (malacostracans; kuoriäyriäiset)

Arthropoda incertae sedis:

These animals were arthropods, but their position in the larger scheme of things is still uncertain.

Acanthomeridiida Hou & Bergström, 1997
        †Acanthomerididae Hou & Bergström, 1997
            †Acanthomeridion serratum Hou, Chen & Lu, 1989

    †Habeliidae Simonetta & Delle Cave, 1975
        †Habelia Walcott, 1912
            †H. optata Walcott, 1912
            †H.? brevicauda Simonetta, 1964

    †Thylacocephala Pinna et al., 1982
        †Concavicarida Briggs & Rolfe, 1983
            †Ainiktozoon Sil.
            †Harrycaris Dev.
            †Concavicaris Dev.-Carb.
            †Dollocaris Jur.
        †Conchyliocarida Secrétan, 1983
            †Convexicaris Carb.
            †Yangzicaris Trias.
            †Atropicaris Jur.
            †Austriocaris Jur.
            †Clausocaris Jur.
            †Kilianocaris Jur.
            †Ostenocaris Jur.
            †Paraostenia Jur.

    †Molariidae Simonetta & Delle Cave, 1975
        †Molaria spinifera Walcott, 1912

    †Tuzoiida Simonetta & Delle Cave, 1975

    †Vetulicolida Chen & Zhou, 1997 [Metazoa problematica, has also been treated as Deuterostomes]

After Legg, 2014 (fig. 5a)

<==o Artiopoda
   |-- †Retifaciida
   `--+--+-- †Squamacula
      |  `--+-- †Kiisortoqia
      |     `-- †Siriocaris
      `--+-- †Trilobitomorpha
         `--+--o Vicissicaudata
            |  |-- †Agalaspidida (s.l.)
            |  `--+-- †Cheloniellida
            |     `==o †Xenopoda
            |        |-- †Sidneyia
            |        `--+-- †Emeraldella
            |           `-- †Molaria
            `--o Chelicerata
               |-- Pycnogonida
               `--+-- †Sanctacaris
                  `--+--+-- †Offacolus
                     |  `-- †Sarotrocercus
                     `--o Euchelicerata
                        |--+-- †Dibasterium
                        |  `-- Xiphosura
                        `--+-- †Chasmaspidida
                           `--+-- †Eurypterida
                              `-- Arachnida

Reference(s):

  • Legg, D. A., 2014: Sanctacaris uncata: the oldest chelicerate (Arthropoda).
    –Naturwissenschaften: Vol. 101, #12, pp. 1065-1073 [doi: 10.1007/s00114-014-1245-4]

After Siveter, Briggs, Siveter, Sutton, Legg & Joomun, 2014

<==o Arthropoda
   |-- †Radiodonta
   `==o “Bivalved arthropods”
      |-- †Isoxys
      `--+-- †Nereocaris
         `--+--+-- †Jugatacaris
            |  `-- †Pectocaris
            `--+-- †Odaraia
               `--+-- †Protocaris
                  `--+--  †“Canadaspislaevigata
                     |--+-- †Branchiocaris
                     |  `-- †Loricicaris
                     `--+--o †Canadaspidida
                        |  |-- †Canadaspis perfecta
                        |  `-- †Perspicaris
                        `--o “Single-shielded arthropods”
                           |--o †Fuxianhuiida
                           |  |-- †Shankouia
                           |  `--+-- †Liangwangshania
                           |     `--+-- †Chengjiangocaris
                           |        `--+-- †Guangweicaris
                           |           `-- †Fuxianhuia
                           `==o †Megacheira
                              `==o “Antennate” megacheirans
                                 |--o †Kootenichelidae
                                 |  |-- †Worthenella
                                 |  `-- †Kootenichela
                                 `--+-- †Fortiforceps
                                    `--+-- †Jianfengia
                                       `--+-- †Tanglangia
                                          `--+--+-- †Yohoia
                                             |  `--+-- †Parapaytonia
                                             |     `--+-- †Haikoucaris
                                             |        `--o †Leancholiida
                                             |           |-- †Alalcomeneus
                                             |           |--o †Enaliktidae
                                             |           |  |-- †Bundenbachiellus
                                             |           |  `-- †Enalikter
                                             |           `--o †Leanchoiliidae
                                             |              |-- †Actaeus
                                             |              `--+-- †Oestokerkus
                                             |                 `-- †Leanchoilia
                                             `--o Euarthropoda
                                                |--o Artiopoda
                                                |  |-- †Retifaciida
                                                |  `--+--o †Trilobitomorpha (s.s.)
                                                |     |  |-- †Mollisoniida
                                                |     |  `--+--o †Petalopleura
                                                |     |     |  `-- †Xandarellida
                                                |     |     `--+-- †Conciliterga
                                                |     |        `--+==Nectaspida
                                                |     |           `-- †Trilobita
                                                |     `--o Vicissicaudata
                                                |        |--+-- †Agalaspidida
                                                |        |  `--+==Xenopoda
                                                |        |     `-- †Cheloniellida
                                                |        `--o Chelicerata
                                                |           |-- Pycnogonida
                                                |           `--o Euchelicerata
                                                |              |-- Xiphosura
                                                |              `--+--+-- †Chasmaspidida
                                                |                 |  `-- †Eurypterida
                                                |                 `-- Arachnida
                                                `--o ?PanMandibulata [Antennulata]
                                                   |-- †Bradoriida
                                                   `--+-- †Marrellomorpha
                                                      `--+-- †Agnostus
                                                         `--+--o †Oelandicarididae
                                                            |  |-- †Oelandicaris
                                                            |  `--+-- †Sandtorpia
                                                            |     `-- †Henningsmoenicaris
                                                            `--+-- †Musacaris
                                                               `--+--o †Cambropachycopidae
                                                                  |  |-- †Cambropachycope
                                                                  |  `-- †Goticaris
                                                                  `--+-- †Martinssonia
                                                                     `--+-- †Phosphatocopida
                                                                        `--o Mandibulata
                                                                           |-- Myriapoda
                                                                           `-- PanCrustacea

Reference(s):

  • Siveter, D. J., Briggs, D. E. G., Siveter, D. J., Sutton, M. D., Legg, D. & Joomun, S., 2014: A Silurian short-great-appendage arthropod.
    –Proceedings of the Royal Society B: Biological Sciences: Vol. 281, #1778, pp. [doi: 10.1098/rspb.2013.2986]

After Legg, Sutton, Edgecombe & Caron, 2012, and Legg, 2013

<==+-- †Opabinia
   `--+-- †Radiodonta
      `--o Arthropoda
         |-- †Nereocaris
         `--+--+-- †Jugatacaris
            |  `-- †Pectocaris
            `--+--+--+-- †Perspicaris
                  |  `-- †Branchiocaris
                  `--+-- †Canadaspidida
                     `--+--o †Fuxianhuiida
                        |  |-- †Shankouia
                        |  `--+-- †Liangwangshania
                        |     `--+-- †Chengjiangocaris
                        |        `--+-- †Guangweicaris
                        |           `-- †Fuxianhuia
                        `==o †Megacheira
                           |--o †Kootenichelidae
                           |  |?- †Pseudoiulia
                           |  |-- †Worthenella
                           |  `-- †Kootenichela
                           `--+-- †Fortiforceps
                              `--+-- †Jianfengia
                                 `--+-- †Tanglangia
                                    `--+--+-- †Yohoia
                                       |  `--+-- †Parapaytonia
                                       |     `--+-- †Haikoucaris
                                       |        `--o †Leancholiida
                                       |           |-- †Alalcomeneus
                                       |           `--+-- †Oestokerkus
                                       |              `-- †Leanchoilia
                                       `--o Euarthropoda
                                          |-- Pycnogonida
                                          `--o Cormogonida
                                             |-- Euchelicerata
                                             `--o Antennulata
                                                |--+-- †Burgessia
                                                |  `-- †Artiopoda
                                                `--+-- †Marrellomorpha
                                                   `-- Mandibulata

Reference(s):

  • Legg, D., 2013: Multi-Segmented Arthropods from the Middle Cambrian of British Columbia (Canada).
    –Journal of Paleontology: Vol. 87, #3, pp. 493-501 [doi: 10.1666/12-112.1]
  • Legg, D. A., Sutton, M. D., Edgecombe, G. D. & Caron, J.-B., 2012: Cambrian bivalved arthropod reveals origin of arthrodization.
    –Proceedings of the Royal Society B: Biological Sciences: Vol. 279, #1748, pp. 4699-4704 [doi: 10.1098/rspb.2012.1958]

After Lamsdell, 2013

<==o Arthropoda
   |?- Tardigrada
   |-- Loboboda
   `--+-- †Radiodonta
      `--o Euarthropoda
         |--o Cheliceriformes
         |  |-- †Megacheira
         |  `-- Chelicerata
         `--o Antennulata
            |-- †Trilobitomorpha
            `--o Mandibulata
               |?- “Myriapoda”
               `--o Pancrustacea
                  |-- Hexapoda
                  `== “Crustacea”

Reference(s):

  • Lamsdell, J. C., 2013: Revised systematics of Palaeozoic ‘horseshoe crabs’ and the myth of monophyletic Xiphosura.
    –Zoological Journal of the Linnean Society: Vol. 167, #1, pp. 1-27 [doi: 10.1111/j.1096-3642.2012.00874.x]

After Budd, 2002

<==o Arthropoda
   |-- Lobopoda
   `--+-- Tardigrada
      `--+-- †Kerygmachela
         |?- †Pambdelurion
         `--+-- †Radiodonta
            `--+?- †Habeliidae
               |?- †Molariidae
               |?- †Bradoriida
               |?-o †Acanthomeridiida
               |  `-- †Acanthomerididae
               |?-o †Tuzoiida
               |  `-- †Tuzoiidae
               |--o †Leanchoiliida
               |  |-- †Leanchoiliidae
               |  |-- †Actaeidae
               |  `-- †Alalcomenaeidae
               `--+--o †Proschizoramia
                  |  `--o †Yohoniida
                  |     `-- †Yohoiidae
                  `--+--o †Sanctacaridea
                     |  `--o †Sanctacarida
                     |     `-- †Sanctacarididae
                     `--+--+--o †Fortiforcipida
                        |  |  `-- †Fortiforcipidae
                        |  `--+-- †Occacaris
                        |     `--+-- †Clypecaris
                        |        `--+--o †Yunnata
                        |           |  `--o †Fuxianhuiida
                        |           |     |-- †Fuxianhuiidae
                        |           |     `-- †Chengjiangocarididae
                        |           `--o †Paracrustacea
                        |              `--o †Canadaspidida
                        |                 |-- †Canadasipididae
                        |                 |?- †Hymenocarididae
                        |                 `-- †Perspicarididae
                        `--o Euarthropoda [Schizoramia]
                           |--+?- Pycnogonida
                           |  `-- Euchelicerata
                           `--+--o †Xenopoda
                              |  |--o †Emeraldellida
                              |  |  `-- †Emeraldellidae
                              |  `--o †Limulavida
                              |     `-- †Sidneyiidae
                              `--o Mandibulata
                                 |-- Myriapoda
                                 `--o Pancrustacea
                                    |-- Hexapoda
                                    `-- Crustacea

Reference(s):

  • Budd, G. E., 2002: A palaeontological solution to the arthropod head problem.
    –Nature: Vol. 417, pp. 271-275

After Giribet et al., 2001, and Vaccarl, et al., 2004

<==o Arthropoda
   |-- Loboboda
   `--+-- Tardigrada
      `--o Euarthropoda
         |-- Pycnogonida
         `--o Cormogonida
            |-- Euchelicerata
            `--o Mandibulata
               |-- †Euthycarcinoidea
               `--+-- Myriapoda
                  `--o Pancrustacea
                     |-- Hexapoda
                     `-- Crustacea

Reference(s):

  • Giribet, G., Edgecombe, G. D. & Wheeler, W. C., 2001: Arthropod phylogeny based on eight molecular loci and morphology.
    –Nature: Vol. 413, pp. 157-161
  • Vaccarl, N. E., Edgecombe, G. D. & Escudero, C., 2004: Cambrian origins and affinities of an enigmatic fossil group of arthropods.
    –Nature: Vol. 430, pp. 554-557

After Hwang et al., 2001

<==o Arthropoda (niveljalkaiset)
   |--o Paradoxopoda [Myriochelata]
   |  |-- Myriapoda
   |  `-- Chelicerata
   `--o Pancrustacea
      |-- Hexapoda
      `-- Crustacea

Reference(s):

  • Hwang, U. W., Friedrich, M., Tautz, D., Park, C. J. & Kim, W., 2001: Mitochondrial protein phylogeny joins myriapods with chelicerates.
    –Nature: Vol. 413, pp. 154-157

After Conway Morris, 1993, Hou & Bergström, 1997, and Gon, 2001-2002

<==o Arthropoda
   |?-+?- Tardigrada
   |  `--+-- Loboboda
   |     `-- Uniramia
   `--+-- †Radiodonta
      `--o Schizoramia
         |-- †Yunnata
         `--+?- †Bradoriida
            |?- †Tuzoiida
            |?- †Vetulicolida
            |--o †Proschizoramia
            |  |-- †Paracrustacea
            |  `-- †Megacheira
            |-- †Sanctacaridea
            `--+--o Lamellipedia
               |  |-- †Marrellomorpha
               |  `--o Artiopoda
               |     |-- †Nectopleura
               |     |-- †Conciliterga
               |     |-- †Trilobita
               |     `--+-- †Xenopoda
               |        |-- †Aglaspidida
               |        `--o Chelicerata
               |           |-- Pycnogonida
               |           `-- Euchelicerata
               `--o Crustaceomorpha
                  |-- †Euthycarcinoidea
                  |-- †Agnostida
                  `--+-- †Waptiida
                     `--o Labrophora
                        |-- †Phosphatocopida
                        `-- Crustacea

Reference(s):