The 88 specimens projected onto the plane of the first principal component PC1 (52.7% of variance) and PC2 (20.9% of variance). Pleurodira and Cryptodira are not distinguished in the analysis. Group I (filled circles): Testudinidae (specimens 1–36). Group II (open squares): Emydidae (37–44), Bataguridae (45–52), Chelydridae (53), Platysternidae (54), Kinosternidae (55, 56), Chelidae (57–59), Pelomedusidae (60, 61), Podocnemididae (62–64). Group III (solid squares): Trionychidae (65–76), Carettochelyidae (77). Group IV (open triangles): Cheloniidae (78–87) and Dermochelyidae (88). For species names, see Table 1. Solid lines: shape changes along PC1 and PC2; dotted lines: consensus (mean shape).