Dichotomous Key/Oegopsida

Oegopsida Animalia Mollusca Cephalopoda Coleoidea Oegopsida 1 Buccal connective to arms IV Dorsal - 2 Ventral - 3 2 Funnel locking-cartilage Straight - 4 Inverted T - ../Ommastrephidae/ 3 Carpal locking-apparatus Present - 12 Not present - 13 4 Gladius conus Present - 5 Not present - 6 5 Anterior fin attachment Mantle - 8 Gladius - 7 6: Histioteuthids Comparative eye size Equal - wikipedia:en:Psychroteuthis glacialis Unequal, left eye larger - ../Histioteuthidae/ 7: Enoploteuthids Hooks on tentacular clubs Present - 9 Not present - 10 8 Free posterior fin lobes Present - ../Neoteuthidae/ Not present - ../Architeuthidae/ 9 Photophores on eyeballs Present - 11 Not present - wikipedia:en:Ancistrocheirus lesueurii 10 Hooks on arm pairs I - III Present - ../Pyroteuthidae/ Not present - ../Lycoteuthidae/ 11 Photophores on mantle Present - ../Enoploteuthidae/ Not present - ../Pyroteuthidae/ 12 Brachioteuthidae Cranchiidae Gonatidae Cycloteuthidae Onychoteuthidae Thysanoteuthidae 13 Secondary tentacular club Present - 14 Not present - 15 14: Chiroteuthids Number of series of suckers Six (on at least one arm) - 20 Other than six (on any arm) - 18 15 Proximal region of manus of club greatly expanded Present - ../Brachioteuthidae/ Not present - 16 16: Lepidoteuthids Tentacles Absent or reduced in adults - 17 Present - ../Pholidoteuthidae/ 17 Number of hooks Two or fewer - wikipedia:en:Lepidoteuthis grimaldii Many, in two series - ../Octopoteuthidae/ 18 Doratopsis paralarva Present - ../Chiroteuthidae/ Not present - 19 19 Shape of distal ends of tentacles Vermiform - wikipedia:en:Magnapinna pacifica Other - 21 20 Comparative arm length All arms comparable - wikipedia:en:Batoteuthis skolops Arm pairs I - III much longer than others - wikipedia:en:Joubiniteuthis portieri 21 Ink sac Present - ../Mastigoteuthidae/ Not present - ../Promachoteuthidae/ __NOTOC__