Meristic and different morphometric
approaches were employed to assess the discrimination of 7 species of Mugilidae fishes (Mugil cephalus, M.
liza, M. curema, M. hospes, Liza aurata, L. ramada, and Chelon labrosus), but also to contribute to a better
understanding of body-shape differences among this valuable species group. Three types of variables and
their corresponding morphometric approaches
... [Show full abstract] were employed: 1) linear morphometrics measurements (LMMs);
2) interlandmark distances (IlDs); and 3) coordinate data (landmarks). Before the analyses, data exhibiting
allometric growth were normalized. Data analysis included a one-way ANOVA (meristic data), a principal
component analysis (PCA), and a cross-validated discriminant analysis (DA). The ANOVA showed significant
differences in both lateral and transverse series scales. The PCA based on LMMs allowed the characterization
of 6 groups, although some overlap between them was detected. The DA correctly classified 68.4% of the
fishes according to their LMMs. The centroids of the 8 groups were separated for both the 1st and 2nd
discriminant functions. The morphometric analysis based on IlDs yielded the best discrimination rates of the 3
approaches employed (96% for the DA). In the geometric morphometric analysis, the DA correctly classified
83.8% of the fishes according to their body shape. Although 8 groups were defined, some overlap among
samples was detected. Mugil hospes was the best defined and most isolated species as observed in both the
PCA and DA. Interestingly, the 3 morphometrics approaches employed separated M. curema specimens in 2
groups (Argentinean and Mexican samples). Moreover, European and Mexican samples of M. cephalus plotted
separately in the PCA of the LMM- and IlD-based approaches. These shape differences among M. curema of
Argentina/Mexico and M. cephalus of Europe/Mexico reinforce the current hypothesis of a species complex, or
even undescribed species as previously suggested by the authors.