Reconstruction of Mollisonia plenovenatrix by J. Liang, from Aria & Caron (2019).

Belongs within: Arthropoda.
Contains: Pycnogonida, Euchelicerata, Artiopoda, Marrellomorpha, Myriapoda, Hymenocarina, Euthycarcinoidea, Oligostraca, Allotriocarida, Tantulocarida, Thecostraca, Copepoda, Malacostraca.

The name Euarthropoda refers to the most exclusive clade formed by crown-group arthropods. Recent analyses agree on a division of living arthropods between three major clades, the Chelicerata, Myriapoda and Pancrustacea, with the latter two usually being united to form a clade of arthropods possessing mandibles. Fossil euarthropod taxa not belonging to these clades are best known from the Cambrian period with the exception of the Artiopoda (the clade including the trilobites). The Chelicerata have a single pair of pre-oral appendages, the chelicerae, that are usually adapted for manipulating food.

The Cambrian Mollisoniidae are a group of likely stem-chelicerates characterised by a broad, helmet-like head shield bearing wide eye notches, seven free segments in the anterior portion of the trunk extending into short pleurae, and posterior trunk segments fused into a pygidium (Aria & Caron 2019). The Middle Cambrian genus Sanctacaris has a biramous pre-oral limb, raptorial post-oral head limbs, and a flabellate telson (Bousfield 1995). Another Cambrian group, the Retifaciida, are characterised by a short, broad head shield, a large, oval pygidium and an elongate, multisegmented telson).

The clade Pancrustacea includes the modern crustaceans and insects with the latter a derived subgroup of the former (Regier et al. 2010). This last grouping is primarily supported by molecular data; potential synapomorphies of the Pancrustacea have all become modified in various subclades. Relationships within the pancrustaceans remain subject to analysis. A relationship between the Tantulocarida and Thecostraca has been suggested on the basis of gonopore position in the two groups; tantulocarids and basal thecostracans are also both sessile parasites.

<==Euarthropoda (see below for synonymy)
    |  i. s.: Dala peilertae Müller 1983ZS07
    |         Walossekia quinquespinosa Müller 1983ZS07
    |         Hexona Risso 1826R26
    |           `--*H. parasitica Risso 1826R26
    |         Zuphea Risso 1826R26
    |           `--*Z. sparicola Risso 1826R26
    |    |--+--Sanctacaris Briggs & Collins 1988AC19, CB04 [Sanctacarida, Sanctacaridea]
    |    |  |    |--‘Utahcaris’ orion Conway Morris & Robison 1988B95
    |    |  |    `--Sanctacaris uncata Briggs & Collins 1988WD02
    |    |  `--HabeliidaB95
    |    |       |--EcnomocarisLSE13
    |    |       `--Habelia Walcott 1912AC19, CB04
    |    |            `--H. optataAC19
    |    `--ChelicerataAC19
    |         |  i. s.: Wisangocaris barbarahardyae Jago, García-Bellido & Gehling 2016BS20
    |         |--PycnogonidaRS10
    |         |--EuchelicerataRS10
    |         `--Mollisoniidae [Mollisoniida]AC19
    |              |--Thelxiope Simonetta & Delle Cave 1975AC19
    |              |--Urokodia Hou, Chen & Lu 1989AC19
    |              |--Corcorania Jell 1980AC19
    |              |    `--C. trispinosaAC19
    |              `--Mollisonia Walcott 1912AC19, CB04 [incl. Houghtonites Raymond 1931AC19]
    |                   |--*M. symmetrica Walcott 1912 [incl. M. rara Walcott 1912]AC19
    |                   |--M. gracilis Walcott 1912 [=Houghtonites gracilis]AC19
    |                   |--M. plenovenatrix Aria & Caron 2019AC19
    |                   `--M. sinica Zhang et al. 2002AC19
       |    |--Retifacies Hou, Chen & Lu 1989LSE13, CB04
       |    |    `--R. abnormalis Hou et al. 1989CB04
       |    `--+--PygmaclypeatusLSE13
       |       `--+--+--KiisortoqiaAC19
       |          |  `--SiriocarsLSE13
       |          `--SquamaculaLSE13
       |               |--S. buckorumLSE13
       |               `--S. clypeatusLSE13
             `--+--Aquilonifer Briggs, Siveter et al. 2016AC19, BS16
                |    `--*A. spinosus Briggs, Siveter et al. 2016BS16
                `--Mandibulata [Antennata, Atelocerata, Biantennata, Labiophora, Labrophora, Opisthogoneata, Tracheata]AC17
                     |  i. s.: Ercaia [Promandibulata]C12
                     |           `--E. minusculeC12
                     |         MusacarisLSE13
                     |         CambropachycopidaeLSE13
                     |           |--Cambropachycope clarksoni Walossek & Müller 1990BWW93
                     |           `--Goticaris longispinosa Walossek & Müller 1990BWW93
                     |         Devonopilio Tihelka, Tian & Cai 2020P-GS21, TTC20
                     |           `--*D. hutchinsoni Tihelka, Tian & Cai 2020TTC20
                        |  `--+--EuthycarcinoideaAC19
                        |     `--Fuxianhuiida [Fuxianhuiata, Proarthropoda]LSE13
                        |          |  i. s.: LiangwangshaniaLSE13
                        |          |--+--Shankouia zhengheiAC19, C12
                        |          |  `--ChengjiangocarisAC19
                        |          |       |--C. kunmingensis Yang, Ortega-Hernández et al. 2013YO-H13
                        |          |       `--C. longiformis Hou & Bergström 1991B95
                        |          `--+--GuangweicarisLSE13
                        |             `--FuxianhuiaAC19
                        |                  |--F. protensa Hou 1987B95
                        |                  `--F. xiaoshibaensis Yang, Ortega-Hernández et al. 2013YO-H13
                        `--Pancrustacea (see below for synonymy)AC17
                             |  i. s.: Nippotantulus heteroxenus Huys, Ohtsuka & Boxshall 1994MA01
                             |         NeomysisM02
                             |           |--N. americanaM02
                             |           `--N. vulgarisCS77
                             |         Perosquilla armataK-MC02
                             |           |--P. a. armataK-MC02
                             |           `--P. a. capensisK-MC02
                             |         Mesosoma Otto 1821C92
                             |         Mixodiaptomus laciniatusD51
                             |         Pleuroncodes planipesCH97
                             |         Phalangites priscus Münster 1836D07
                             |         Cryptophthalmus Rafinesque 1814BR05
                             |         Cymodocea Rafinesque 1814BR05
                             |         ‘Cymodocea’ Leach 1818 nec Rafinesque 1814 nec Lamouroux 1816BR05
                             |         ‘Dactylopus’ Claus 1862 non Gill 1859BR05
                             |         Donovania Leach 1814BR05
                             |         Orientalina Kolosnitsyna 1973BR05
                             |         Pagodina van Beneden 1853BR05
                             |         ‘Trichia’ de Haan 1839 non Haller 1768BR05
                             |         Fenneropenaeus chinensisDH08
                             |         Limnadella kitei Girard 1854DS89
                             |         Anatanais robustoBBB-S95
                             |         Anthonema Walther 1904H75
                             |           `--*A. problematica Walther 1904H75
                             |         ‘Acherusia’ Lucas 1846 non Laporte & Gory 1837E12
                             |           `--A. dumerilii Lucas 1846E12
                             |         Naesea edwardsii Lucas 1846E12
                             |         Ovalia Latreille in Griffith & Pidgeon 1833KA-Z11
                             |         CycloideaFGS04
                             |           |--Cyclus de Koninck 1841 [incl. Paraprosopon Gemmellaro 1890]FGS04
                             |           `--Oonocarcinus Gemmellaro 1890FGS04
                             |         HeymonsicambriaEL11
                             |         Hymenodora glacialisCS77
                             |         Ozolus Latreille 1802L02a
                             |           `--*O. gasterostei Latreille 1802L02b (see below for synonymy)
                             |         AmymoneL02b
                             |           |--A. baccha [=Monoculus bacchus]L02b
                             |           |--A. faunus [=A. fauna, Monoculus faunus]L02b
                             |           |--A. moenasL02b
                             |           |--A. satyrus [=A. satyra, Monoculus satyrus]L02b
                             |           |--A. silene [=A. silenus, Monoculus silenus]L02b
                             |           `--A. thyasL02b
                             |         NaupliusL02b
                             |           |--N. bracteatus [=Monoculus bracteatus]L02b
                             |           `--N. saltatorius [=Monoculus saltatorius]L02b
                             |         Microdentopus gryllotalpaPP64
                             |         Aristeomorpha foliaceaPP64
                             |         Ligur ensiferusPP64
                             |         Paromola cuvieriPP64
                             |         Anamathia rissoanaPP64
                             |         Ergasticus cloueiPP64
                             |         Dorynchus thompsoniPP64
                             |         Cymopolia caroniPP64
                             |         Halopsyche de Saussure 1857BR17
                             |         Palpipes Roth 1851K18
                             |         Berndtia purpureaCG97
                             |         Trypetasa lampasCG97
                             |         Amblyops crozetiiO01
                             |         Harpactocarcinus tumidusH79
                             |         TuzoiidaeO68
                             |           |--TuzoiaO68
                             |           `--*Dioxycaris argenta (Walcott 1888) [=Leperditia argenta, Isoxys argenta]O68
                             |         Corynuropsis Scott 1894E00
                             |         Cytherea spinosaR26
                             `--Altocrustacea [Ostraca, Phyllopodomorpha, Thoracopoda]RS10
                                  `--Multicrustacea [Communostraca, Vericrustacea]SC17
                                       |  i. s.: Arenosicaris inflataSC17
                                       |  `--ThecostracaSC17

Euarthropoda [Arachnata, Arachnomorpha, Aspidonia, Aspidota, Cormogonida, Eotrilobitacea, Myriochelata, Paradoxopoda, Polymeria, Skaracarida]

*Ozolus gasterostei Latreille 1802L02b [incl. Argulus delphiniL02b, Monoculus delphinusL02a, M. gyriniL02b]

Pancrustacea [Archoptera, Copepodoida, Copepodomorpha, Crustacea, Crustaceanomorpha, Entomostraca, Eucrustacea, Gymnota, Maxillopoda, Pneumonura, Poecilopoda, Progonomorpha, Pseudopoda, Tetraconata, Thecostracomorpha]AC17

*Type species of generic name indicated


[AC17] Aria, C., & J.-B. Caron. 2017. Burgess Shale fossils illustrate the origin of the mandibulate body plan. Nature 545: 89–92.

[AC19] Aria, C., & J.-B. Caron. 2019. A middle Cambrian arthropod with chelicerae and proto-book gills. Nature 573: 586–589.

[BS20] Baker, C. M., K. Sheridan, S. Derkarabetian, A. Pérez-González, S. Vélez & G. Giribet. 2020. Molecular phylogeny and biogeography of the temperate Gondwanan family Triaenonychidae (Opiliones: Laniatores) reveals pre-Gondwanan regionalisation, common vicariance, and rare dispersal. Invertebrate Systematics 34: 637–660.

[BBB-S95] Boubezari, K., G. Bitar & D. Bellan-Santini. 1995. Structure et organisation de trois moulières (Mytilus galloprovincialis et Perna perna) de la région d’Alger. Mésogée 54: 63–72.

[BR05] Bouchet, P., & J.-P. Rocroi. 2005. Classification and nomenclator of gastropod families. Malacologia 47 (1–2): 1–397.

[BR17] Bouchet, P., J.-P. Rocroi, B. Hausdorf, A. Kaim, Y. Kano, A. Nützel, P. Parkhaev, M. Schrödl & E. E. Strong. 2017. Revised classification, nomenclator and typification of gastropod and monoplacophoran families. Malacologia 61 (1–2): 1–526.

[B95] Bousfield, E. L. 1995. A contribution to the natural classification of Lower and Middle Cambrian arthropods: food-gathering and feeding mechanisms. Amphipacifica 2: 3–34.

[BS16] Briggs, D. E. G., D. J. Siveter, D. J. Siveter, M. D. Sutton & D. Legg. 2016. Tiny individuals attached to a new Silurian arthropod suggest a unique mode of brood care. Proceedings of the National Academy of Sciences of the USA 13 (16): 4410–4415.

[BWW93] Briggs, D. E. G., M. J. Weedon & M. A. Whyte. 1993. Arthropoda (Crustacea excluding Ostracoda). In: Benton, M. J. (ed.) The Fossil Record 2 pp. 321–342. Chapman & Hall: London.

[CH97] Castro, P., & M. E. Huber. 1997. Marine Biology 2nd ed. WCB McGraw-Hill: Boston.

[C12] Chen, J.-Y. 2012. Evolutionary scenario of the early history of the animal kingdom: evidence from Precambrian (Ediacaran) Weng’an and Early Cambrian Maotianshan biotas, China. In: Talent, J. A. (ed.) Earth and Life: Global biodiversity, extinction intervals and biogeographic perturbations through time pp. 239–379. Springer.

[CG97] Cohen, B. L., & A. B. Gawthrop. 1997. The brachiopod genome. In: Kaesler, R. L. (ed.) Treatise on Invertebrate Paleontology pt H. Brachiopoda, Revised vol. 1. Introduction pp. 189–211. The Geological Society of America: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).

[CB04] Cotton, T. J., & S. J. Braddy. 2004. The phylogeny of arachnomorph arthropods and the origin of the Chelicerata. Transactions of the Royal Society of Edinburgh: Earth Sciences 94: 169–193.

[CS77] Cramp, S., & K. E. L. Simmons (eds) 1977. Handbook of the Birds of Europe, the Middle East and North Africa: The Birds of the Western Palaearctic vol. 1. Ostrich to Ducks. Oxford University Press: Oxford.

[C92] Crawford, R. L. 1992. Catalogue of the genera and type species of the harvestman superfamily Phalangioidea (Arachnida). Burke Museum Contributions in Anthropology and Natural History 8: 1–60.

[D51] Dobzhansky, T. 1951. Genetics and the Origin of Species 3rd ed. Columbia University Press: New York.

[DS89] Dundee, H. A. & H. M. Smith. 1989. Nomenclatural eponym endings revisited. Systematic Zoology 38 (3): 279–283.

[D07] Dunlop, J. A. 2007. Paleontology. In: Pinto-da-Rocha, R., G. Machado & G. Giribet (eds) Harvestmen: The Biology of Opiliones pp. 247–265. Harvard University Press: Cambridge (Massachusetts).

[DH08] Dunn, C. W., A. Hejnol, D. Q. Matus, K. Pang, W. E. Browne, S. A. Smith, E. Seaver, G. W. Rouse, M. Obst, G. D. Edgecombe, M. V. Sørensen, S. H. D. Haddock, A. Schmidt-Rhaesa, A. Okusu, R. M. Kristensen, W. C. Wheeler, M. Q. Martindale & G. Giribet. 2008. Broad phylogenomic sampling improves resolution of the animal tree of life. Nature 452: 745–749.

[E00] Engel, M. S. 2000. Classification of the bee tribe Augochlorini (Hymenoptera: Halictidae). Bulletin of the American Museum of Natural History 250: 1–89.

[EL11] Erwin, D. H., M. Laflamme, S. M. Tweedt, E. A. Sperling, D. Pisani & K. J. Peterson. 2011. The Cambrian conundrum: early divergence and later ecological success in the early history of animals. Science 334: 1091–1097.

[E12] Evenhuis, N. L. 2012. Publication and dating of the Exploration Scientifique de l’Algérie: Histoire Naturelle des Animaux Articulés (1846–1849) by Pierre Hippolyte Lucas. Zootaxa 3448: 1–61.

[FGS04] Feldmann, R. M., A. A. Garassino & C. E. Schweitzer. 2004. The presumed decapod, Palaeopemphix Gemmellaro, 1890, is a unique member of the Phyllocarida (Palaeopemphicida: Palaeopemphidae). Journal of Palaeontology 78: 340–348.

[H79] Haast, J. von. 1879. Geology of the Provinces of Canterbury and Westland, New Zealand. A report comprising the results of official explorations. “Times” Office: Christchurch.

[H75] Häntzschel, W. 1975. Treatise on Invertebrate Paleontology pt W. Miscellanea. Supplement 1. Trace Fossils and Problematica 2nd ed. The Geological Society of America: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).

[K-MC02] Klein-MacPhee, G., & B. B. Collette. 2002. Scorpionfishes. Family Scorpaenidae. In: Collette, B. B., & G. Klein-MacPhee (eds) Bigelow and Schroeder’s Fishes of the Gulf of Maine 3rd ed. pp. 331–338. Smithsonian Institute Press: Washington.

[K18] Kury, A. B. 2018. Familial nomina in harvestmen (Arachnida, Opiliones). Bionomina 13: 1–27.

[KA-Z11] Kury, A. B., & M. A. Alonso-Zarazaga. 2011. Addenda and corrigenda to the “Annotated catalogue of the Laniatores of the New World (Arachnida, Opiliones)”. Zootaxa 3034: 47–68.

[LS02] Lange, S., & F. R. Schram. 2002. Possible lattice organs in Cretaceous Thylacocephala. Contributions to Zoology 71 (4): 159-169.

[L02a] Latreille, P. A. 1802a. Histoire Naturelle, générale et particulière des crustacés et des insectes vol. 3. Familles naturelles des genres. F. Dufart: Paris.

[L02b] Latreille, P. A. 1802b. Histoire Naturelle, générale et particulière des crustacés et des insectes vol. 4. Familles naturelles des genres. F. Dufart: Paris.

[LSE13] Legg, D. A., M. D. Sutton & G. D. Edgecombe. 2013. Arthropod fossil data increase congruence of morphological and molecular phylogenies. Nature Communications 4: 2485.

[MA01] Martínez Arbizu, P. 2001. Psammocyclopinidae fam. n., a new monophyletic group of marine Cyclopoida (Copepoda, Crustacea), with the description of Psammocyclopina georgei sp. n. from the Magellan region. Revista Bras. Zool. 18 (4): 1325–1339.

[M02] Munroe, T. A. 2002. Herrings. Family Clupeidae. In: Collette, B. B., & G. Klein-MacPhee (eds) Bigelow and Schroeder’s Fishes of the Gulf of Maine 3rd ed. pp. 111–160. Smithsonian Institute Press: Washington.

[O01] Ohlin, A. 1901. On a new “bipolar” schizopod. Annals and Magazine of Natural History, series 7, 7: 371–374.

[O68] Öpik, A. A. 1968. Ordian (Cambrian) Crustacea Bradoriida of Australia. Commonwealth of Australia, Bureau of National Development, Bureau of Mineral Resources, Geology and Geophysics, Bulletin 103: 1–45.

[PP64] Peres, J. M., & J. Picard. 1964. Nouveau manuel de bionomie benthique de la mer Mediterranee. Recueil des Travaux de la Station Marine d’Endoume, Bulletin 31 (27): 5–137.

[P-GS21] Pérez-González, A., & J. W. Shultz. 2021. On the problematic placement of the fossil arthropod Devonopilio hutchinsoni in Opiliones (Arachnida). Zootaxa 4915 (2): 294–298.

[RS10] Regier, J. C., J. W. Shultz, A. Zwick, A. Hussey, B. Ball, R. Wetzer, J. W. Martin & C. W. Cunningham. 2010. Arthropod relationships revealed by phylogenomic analysis of nuclear protein-coding sequences. Nature 463: 1079–1083.

[R26] Risso, A. 1826. Histoire naturelle des principales productions de l’Europe méridionale et particulièrement de celles des environs de Nice et des Alpes maritimes vol. 5. F.-G. Levrault: Paris.

[SC17] Schwentner, M., D. J. Combosch, J. P. Nelson & G. Giribet. 2017. A phylogenomic solution to the origin of insects by resolving crustacean-hexapod relationships. Current Biology 27: 1818–1824.

[TTC20] Tihelka, E., L. Tian & C. Cai. 2020. A new Devonian harvestman from the Rhynie chert (Arachnida: Opiliones). Bulletin of Geosciences 95 (3): 313–318.

[WD02] Waloszek, D., & J. A. Dunlop. 2002. A larval sea spider (Arthropoda: Pycnogonida) from the Upper Cambrian ‘Orsten’ of Sweden, and the phylogenetic position of pycnogonids. Palaeontology 45 (3): 421–446.

[YO-H13] Yang, J., J. Ortega-Hernández, N. J. Butterfield & X.-G. Zhang. 2013. Specialized appendages in fuxianhuiids and the head organization of early euarthropods. Nature 494: 468–471.

[ZS07] Zhang, X.-G., D. J. Siveter, D. Waloszek & A. Maas. 2007. An epipodite-bearing crown-group crustacean from the Lower Cambrian. Nature 449: 595–598.

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