Table 1 Scenarios on the (non)homology of cephalopod hooks, cirri, and suckers and their supporters (the role of ammonoid hooks not included)
From: Evolutionary development of the cephalopod arm armature: a review
Scenario 1 | Scenario 2 | |
|---|---|---|
Belemnoid hooks vs. suckers | Belemnoid hooks derived from primitive suckers | Belemnoid hooks evolved de novo |
→ Belemnoid hooks and suckers are homologous | → Belemnoid hooks and suckers are convergent | |
Naef (1922, p. 165, 188), Jeletzky (1966, p. 138), Haas (1989, p. 182), Boletzky (1999, p. 8, 2006: p. 35), herein | Berthold and Engeser (1987, p. 198), Engeser and Clarke (1988, p. 142), Young et al. (1998), Fuchs et. al. (2010, 2013b) |
Scenario 1A | Scenario 1B | ||
|---|---|---|---|
Belemnoid hooks vs. primitive sucker rings | Belemnoid hooks derived from primitive sucker rings | Belemnoid hooks evolved from suckers without sucker rings | |
→ Belemnoid hooks and sucker rings are homologous | → Belemnoid hooks and sucker rings are convergent | ||
Naef (1922), Jeletzky, 1966), Berthold and Engeser (1987, p. 198), Young et al., (1998, p. 395), Fuchs et. al. (2010, 2013b) | |||
Belemnoid hooks vs. decabrachian sucker rings | Decabrachian sucker rings adopted from belemnoid sucker rings | Decabrachian sucker rings evolved de novo | |
→ Belemnoid and decabrachian sucker rings are homologous | → Belemnoid and decabrachian sucker rings are convergent | ||
Herein | Berthold and Engeser (1987, p. 198), Engeser and Clarke (1988, p. 142), Young et al. (1998), Fuchs et. al. (2010, 2013b) | ||
Belemnoid hooks vs oegopsid hooks | Oegopsid hooks derived from toothed sucker rings | ||
→ Belemnoid and oegopsid hooks are parallel developments | → Belemnoid and oegopsid hooks are convergent | ||
Naef (1922), herein | Berthold and Engeser (1987, p. 198), Engeser and Clarke (1988, p. 142), Young et al. (1998), Fuchs et. al. (2010, 2013b) | ||
Belemnoid hooks vs. octobrachian cirri | Octobrachian cirri derived de novo | Octobrachian cirri derived from belemnoid hooks | |
→ Belemnoid hooks and octobrachian cirri are convergent | → Belemnoid hooks and octobrachian cirri are homologous | ||
Boletzky (2006), herein | Berthold and Engeser (1987, p. 198), Young et al., (1998, p. 395), Fuchs et. al. (2010, 2013b) | ||