Figure 24 in Recognising variability in the shells of argonauts (Cephalopoda: Argonautidae): the key to resolving the taxonomy of the family

Figure 24. Argonauta hians shell from the North West Shelf, Western Australia: a–d, four perspectives of an A. hians shell from the North West Shelf, Western Australia (53.0 mm shell length, WAM S31510) displaying a clear shift from Type 1 shell formation (T1) to Type 2 formation (T2) indicated by a reduction in the size and spacing of the keel tubercles and a reduction in the ratio of ribs to keel tubercles (from approximately 1.5:1 to 1:1); a, right lateral view; b, oblique right lateral view; c, anterior aperture view; d, posterior keel view. Scale bar = 1 cm.