Dichotomous Key/Cephalopoda

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Dichotomous Key: Cephalopoda
Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda

[edit] 1

• External shell
  • Present - Nautiloidea
  • Not present - 2

Mollusca keys

Classes

Aplacophora | Bivalvia | Caudofoveata | Cephalopoda | Gastropoda | Monoplacophora | Polyplacophora | Scaphopoda

[edit] 2: Coleoidea

• Modified (or lost) arm pair
  • Arm pair IV - 3
  • Arm pair II - 4

[edit] 3: Decapodiformes

• Cornea
  • Present - 6
  • Not present - 5

[edit] 4: Octopodiformes

• Photophores
  • Present - Vampyroteuthis infernalis
  • Not present - Octopoda

[edit] 5

• Shell shape
  • Horn-shaped - Spirula spirula
  • Other or not present - 7

[edit] 6: Sepioidea

• Cuttlebone
  • Present - Sepiidae
  • Not present - 8

[edit] 7

• Gladius
  • Present - Oegopsida
  • Not present - 10

[edit] 8: Sepiolida

• Depressions on funnel locking-apparatus
  • One - Sepiolidae
  • Two, or apparatus fused - Sepiadariidae

[edit] 9

• Adhesive organ on dorsal surface of mantle
  • Present - Idiosepiidae
  • Not present - Myopsida

[edit] 10

• Branchial canals in gills
  • Present - 11
  • Not present - 9

[edit] 11: Bathyteuthoida

• Buccal connectives attaching to border of arms IV
  • Dorsal border of arms IV - Bathyteuthidae
  • Ventral border of arms IV - Chtenopterygidae