Dichotomous Key/Octopoda

Dichotomous Key

Octopoda
Kingdom	Animalia
Phylum	Mollusca
Class	Cephalopoda
Subclass	Coleoidea
Superorder	Octopodiformes
Order	Octopoda

1

• Cornea
  • Present - 2
  • Not present - 3

2: Incirrata

• Detachable hectocotylus
  • Present - 5
  • Not present - 6

3: Cirrata

• Secondary web
  • Present - 4
  • Not present - Opisthoteuthidae

4

• Shell shape
  • Saddle-shaped - Cirroteuthidae
  • U-shaped - Stauroteuthidae

5: Argonautoida

• Tissue consistency
  • Gelatinous - 10
  • Muscular - 9

6

• Eye shape
  • Tubular - Amphitretidae
  • Other - 7

7

• Eye shape
  • Laterally compressed - Bolitaenidae
  • Other - 8

8

• Eye shape
  • Rectangular - Vitreledonella richardi
  • Other - Octopodidae

9

• Web
  • Absent or greatly reduced except in four dorsal arms - Tremoctopodidae
  • Consistent - 11

10

• Web
  • Absent or greatly reduced except in four dorsal arms - Tremoctopus gelatus
  • Consistent - Haliphron atlanticus

11

• Funnel locking-apparatus
  • Contains circular pit - Argonautidae
  • Does not contain circular pit - Ocythoe tuberculata