Tactopoda

Tactopoda
	The tardigrade Hypsibius dujardini
	The blue crab Callinectes sapidus, an arthropod
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Clade:	ParaHoxozoa
Clade:	Bilateria
Clade:	Nephrozoa
(unranked):	Protostomia
Superphylum:	Ecdysozoa
(unranked):	Panarthropoda
(unranked):	Tactopoda; Budd, 2001

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

The competing hypothesis is Arthropoda (= Euarthropoda + Onychophora)^[3]

Classification

Phylum Tardigrada
- Class Eutardigrada
- Class Heterotardigrada
- Class Mesotardigrada
Phylum Arthropoda
- Clade Arachnomorpha
  - Class †Trilobita
  - Order †Aglaspida
  - Order †Strabopida
  - 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 polyphyletic class Maxillopoda
    - Clade Altocrustacea
      - Clade Multicrustacea
        The rest of polyphyletic 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

Velvet worms (Onychophora)

Tactopoda

Altocrustacea

Multicrustacea

Allotriocarida

	Insecta

^ ^a ^b 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. Archived from the original (PDF) on 2016-03-03. {{cite journal}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
^ 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.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^ J. Ortega-Hernández, “Making sense of ‘lower’ and ‘upper’ stem-group Euarthropoda, with comments on the strict use of the name Arthropoda von Siebold, 1848,” Biol. Rev., vol. 91, no. 1, pp. 255–273, 2016.

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