Tactopoda

Tactopoda
The tardigrade Hypsibius dujardini
The blue crab Callinectes sapidus, an arthropod
Scientific classification
Kingdom:	Animalia
Subkingdom:	Eumetazoa
(unranked):	Bilateria
(unranked):	Protostomia
Superphylum:	Ecdysozoa
(unranked):	Panarthropoda
(unranked):	Tactopoda

Tactopoda is a proposed clade of protostome animals that includes the phyla Tardigrada and Euarthropoda, supported by various morphological observations.^[1][2]

Classification

• Phylum Tardigrada
  • Class Eutardigrada
  • Class Heterotardigrada
  • Class Mesotardigrada
• Phylum Arthropoda
  • Class Pycnogonida (?)
  • Clade Arachnomorpha
    • Class †Trilobita
    • Order †Aglaspida
    • Order †Strabopida
    • Class Pycnogonida (?)
    • Order †Cheloniellida
    • Subphylum Chelicerata
      • Class Xiphosura
      • Class †Eurypterida
      • Class †Chasmataspidida
      • Class Pycnogonida (?)
      • Class Arachnida
  • Clade Mandibulata
    • Order †Euthycarcinoidea
    • Subphylum Myriapoda
      • Class Chilopoda
      • Class Symphyla
      • Class Diplopoda
      • Class Pauropoda
    • Clade Pancrustacea
      • Clade Oligostraca
        • Class Ostracoda
        • Some of paraphyletic class Maxillopoda
      • Clade Altocrustacea
        • Clade Multicrustacea
          • The rest of paraphyletic class Maxillopoda
          • Class Malacostraca
        • Clade Allotriocarida
          • Class Branchiopoda
          • Clade Miracrustacea
            • Superclass Xenocarida
              • Class Cephalocarida
              • Class Remipedia
            • Subphylum Hexapoda
              • Paraphyletic class Entognatha
              • Clade Ectognatha
                • Class Insecta

Phylogeny

Tactopoda

Tardigrada Eutardigrada Heterotardigrada Mesotardigrada Arthropoda †Trilobitomorpha/Trilobita ?Pycnogonida Chelicerata Xiphosura Eurypterida Chasmataspidida Arachnida ?Pycnogonida Mandibulata Myriapoda Symphyla Chilopoda Diplopoda Pauropoda Pancrustacea Oligostraca Ostracoda Some of Maxillopoda Altocrustacea Multicrustacea The rest of Maxillopoda Malacostraca Allotriocarida Xenocarida Remipedia Cephalocarida Branchiopoda Hexapoda Ellipura Collembola Protura ?Diplura ?Diplura Ectognatha Insecta

References

1. Graham E. Budd (2001). "Tardigrades as 'stem-group arthropods': the evidence from the Cambrian fauna" (PDF). Zoologischer Anzeiger 240 (3–4): 265–279. doi:10.1078/0044-5231-00034.
2. Smith, M. R.; Ortega Hernández, J. (2014). "Hallucigenia’s onychophoran-like claws and the case for Tactopoda". Nature 514 (7522): 363–366. doi:10.1038/nature13576. PMID 25132546.