Fig. 7From: Homology problems in cephalopod morphology: deceptive (dis)similarities between different types of ‘caecum’Phylogenetic tree of the Coleoidea with focus on protoconch-relevant characters and their evolutionary transformations (tree topology based on Fuchs et al. 2013; Klug et al. 2016; Sutton et al. 2015). The spirulid caecum accordingly evolved de novo (instead of directly from their bactritoid ancestors)Back to article page