Discussion of Phylogenetic Relationships
The monophyly of both suborders is well established. Young and Vecchione (1996) found two apomorphic character states that defined the monophyly of the Incirrata:
- Presence of a cornea.
- Hectocotylization of one of the third arms.
Another character can probably be added to the list of apomorphies although it hasn't been included in a cladistic study:
- Chorion of egg drawn out into a stalk (Young, et al., 1999).
Young and Vecchione (1996) found three character states that defined the monophyly of the Cirrata:
- Spermatophores as sperm packets without ejaculatory apparatus.
- Presence of horizontal arm septa.
- Buccal position of posterior salivary glands.
No one has provided updates yet.