Insights of Otoliths Morphology to Reveal Patterns of Teleostean Fishes in the Southern Atlantic

Abstract

The sagitta otoliths of teleostean fishes are usually used in diverse studies. Their shapes are species-specific, and the qualitative description of their morphological features seems to be a simple task, despite its subjectivity. On the other hand, morphometric techniques have been developed with a focus on objectivity, reproducibility, and accuracy. Considering this, the otoliths morphology was reviewed and evaluated in terms of robustness as a taxonomic tool and to highlight ecomorphological patterns. The otoliths morphology of 179 teleostean fishes from the Southern Atlantic were analyzed. For each species, the fish total length range, eighteen otolith morphological features (OMFs), and relative proportions were annotated. Species habitat and habit were also recorded. Data analyses were based on exploratory analysis, correlation, nonmetric multidimensional scaling, and a two-way permutational analysis of variance. The most descriptive OMFs were: colliculum, sulcus acusticus (morphology, position, orientation, and opening), and otolith profile. The otolith morphology was significantly related to species habitat and habit, with a new pattern described for deep-ocean pelagic species. In conclusion, otoliths morphology is robust whenever it is based on the comparative method application (otoliths among otoliths), considering the constant updates of fishes’ taxonomy and the use of proper sample sizes linked to morphometric techniques.