Base of the evolutionary tree for Nephrozoa

• Nephrozoa (1407281 species)
  • Protostomes (Protostomia) → (1324343 species)
    • unnamed group 911287 → (1324187 species)
      • Ecdysozoa → (1173386 species)
        • unnamed group 1062349 → (1173125 species)
        • Penis worms and more (Scalidophora) → (261 species)
      • Spiralia → (150801 species)
        • unnamed group 914955 → (147134 species)
        • Gnathifera → (3667 species)
    • Arrow worms (Chaetognatha) → (156 species)
      • Aphragmophora → (83 species)
        • Ctenodontina → (78 species)
        • Flabellodontina → (3 species)
        • Bathybelos typhlops
        • Pterokrohnia arabica
      • Phragmophora → (51 species)
        • Spadellidae → (34 species)
        • Eukrohniidae → (14 species)
        • Krohnittellidae → (3 species)
      • Heterokrohnia → (17 species)
        • Heterokrohnia mirabiloides
        • arrow worm (Heterokrohnia involucrum)
        • Heterokrohnia curvichaeta
        • Heterokrohnia bathybia
        • Heterokrohnia davidi
        • Heterokrohnia wishernae
        • Heterokrohnia heterodonta
        • Heterokrohnia longidentata
        • Heterokrohnia fragilis
        • Heterokrohnia discoveryi
        • Heterokrohnia furnestinae
        • Heterokrohnia mirabilis
        • Heterokrohnia wishnerae
        • Heterokrohnia murina
        • Heterokrohnia angeli
        • Heterokrohnia biscayensis
        • Heterokrohnia alvinae
      • Archeterokrohnia → (4 species)
        • Archeterokrohnia longicaudata
        • Archeterokrohnia docrickettsae
        • Archeterokrohnia palpifera
        • Archeterokrohnia rubra
      • Xenokrohnia sorbei
  • Deuterostomes (Deuterostomia) → (82938 species)
    • Chordates (Chordata) → (74058 species)
      • unnamed group 837105 → (74027 species)
        • Vertebrates (Vertebrata) → (70817 species)
        • Tunicates (Tunicata) → (3210 species)
      • Lancelets (Cephalochordata) → (31 species)
        • lancelets (Branchiostoma) → (24 species)
        • Asymmetron → (2 species)
        • Epigonichthys → (5 species)
    • Starfish and more (Ambulacraria) → (8880 species)
      • Starfishes, sea urchins, and more (Echinodermata) → (8741 species)
        • Eleutherozoa → (8046 species)
        • feather stars and sea lillies (Crinoidea) → (695 species)
      • Acorn worms (Hemichordata) → (139 species)
        • acorn worms (Enteropneusta) → (114 species)
        • Pterobranchia → (25 species)