Fig 1.
Procedures to generate a retopologised shell based on the aperture ontogeny from a shell by using Blender software.
(A) Procedure 3—Creating reference: Tracing aperture from shell model. (B) Procedure 3—Creating reference: Tracing ontogeny axis. (C) Procedure 3 –both traced aperture outline and ontogeny axis were converted to Bezier curves. (D) Procedure 4 –Retopologising aperture outlines from the reference by using NURBS circles in EDIT mode. (E) Retopologised aperture outlines. (F) Procedure 4 –Generating retopologised shell surface models from NURBS circles in EDIT mode. (G) Final retopologised NURBS surface shell model. (H) Retopologised 3D shell mesh converted from retopologised NURBS surface shell model.
Fig 2.
Retopologised shell 3D models obtained by repotologising real shells (A–D) and by transformation of retopologised shells (E–H).
(A) Shell of Plectostoma laidlawi Sykes 1902. (B) Shell of Plectostoma crassipupa van Benthem Jutting, 1952. (C) Shell of Plectostoma christae Maassen 2001. (D) Shell of Opisthostoma vermiculum Clements and Vermeulen, 2008. (E) Plectostoma laidlawi shell that was resized by one-half and with slight modification of the last aperture size. (F) Plectostoma christae shell that was reshaped into an elongated form by reducing the model size (linear dimension) by one-half along the x and y axes, and by doubling the size along the z axis. (G) Plectostoma christae shell that was reshaped into a depressed form by increasing by 1.5 the model size along the x and y axes, and by reducing the size by one-half along the z axis. (H) Opisthostoma vermiculum shell that consists of one Opisthostoma vermiculum original 3D model of which the aperture was connected to a second, enlarged, Opisthostoma vermiculum.
Fig 3.
Different data types that could be obtained directly from a 3D shell model that was retopologised on the basis of the aperture ontogeny and which can be used in theoretical modeling (A–D) and functional morphology studies (E–F).
(A) Aperture maps (sensu Rice, 1998) or growth vector maps (sensu Urdy et al., 2010). (B) same as (A), but the data can be obtained in a greater resolution. (C) Aperture outlines data for generating curve models. (D) Multiple ontogeny axes for helicospiral models. (E) Simple 3D surface shell model with no thickness. (F) 3D surface shell model with added thickness.
Fig 4.
Shell size (volume) and aperture ontogeny profiles in terms of aperture growth trajectory (curvature and torsion) and aperture form (size and shape) of eight shells.
(A) Shell of Plectostoma laidlawi Sykes 1902. (B) Shell of Plectostoma crassipupa van Benthem Jutting, 1952. (C) Shell of Plectostoma christae Maassen 2001. (D) Shell of Opisthostoma vermiculum Clements and Vermeulen, 2008. (E) Plectostoma laidlawi shell that was resized by one-half and with slight modification of the last aperture size. (F) Plectostoma christae shell that was reshaped into an elongated form by reducing the model size (linear dimension) by one-half along the x and y axes, and by doubling the size along the z axis. (G) Plectostoma christae shell that was reshaped into a depressed form by increasing by 1.5 of the model size along the x and y axes, and by reducing the size by one-half along the z axis. (H) Opisthostoma vermiculum shell that consists of one Opisthostoma vermiculum original 3D model of which the aperture was connected to a second enlarged Opisthostoma vermiculum.
Fig 5.
Dendrogram from permutation distribution clustering of the aperture ontogeny profiles of eight shells.
(A) Dendrogram from permutation distribution clustering of the four aperture ontogeny profiles, namely, curvature, torsion, aperture size, and aperture shape scores, of eight shells. (B) Four dendrograms from permutation distribution clustering of eight shells, which each for the four aperture ontogeny profiles, namely, curvature, torsion, aperture size, and aperture shape scores.
Table 1.
Dissimilarity matrix of aperture ontogeny profiles of eight shells obtained from Permutation Distribution Clustering.