This paper introduces a method for analyzing shape variation and asymmetry in structures with internal symmetry, distinguishing between matching symmetry (where separate parts from the left and right sides are compared) and object symmetry (where the structure itself has an internal axis or plane of symmetry). The authors propose a method based on Procrustes superimposition to partition the total shape variation into components of symmetric variation among individuals and asymmetry. They apply this method to a dataset of 100 specimens of the lower pharyngeal jaw in the Neotropical cichlid fish *Amphilophus citrinellus*, which is a structure with object symmetry. The analysis reveals that the symmetric component of variation is dominated by the contrast between two alternative trophic morphs, and there is subtle but statistically significant directional asymmetry. The paper also provides recommendations for morphometric studies of symmetric shapes and discusses the implications of symmetry for statistical analysis.This paper introduces a method for analyzing shape variation and asymmetry in structures with internal symmetry, distinguishing between matching symmetry (where separate parts from the left and right sides are compared) and object symmetry (where the structure itself has an internal axis or plane of symmetry). The authors propose a method based on Procrustes superimposition to partition the total shape variation into components of symmetric variation among individuals and asymmetry. They apply this method to a dataset of 100 specimens of the lower pharyngeal jaw in the Neotropical cichlid fish *Amphilophus citrinellus*, which is a structure with object symmetry. The analysis reveals that the symmetric component of variation is dominated by the contrast between two alternative trophic morphs, and there is subtle but statistically significant directional asymmetry. The paper also provides recommendations for morphometric studies of symmetric shapes and discusses the implications of symmetry for statistical analysis.