Spotting mistakes: Reappraisal of Spotted Drum Stellifer punctatissimus (Meek & Hildebrand, 1925) (Teleostei: Sciaenidae) reveals species misidentification trends and suggests latitudinal sexual dimorphism

Abstract

A major part of the described species is understudied, falling into the Linnean shortfall. This is a major concern for cryptic species, which require integrative approaches to better evaluate their diversity. We conducted morphological analyses using specimens of Stellifer punctatissimus, S. gomezi, and S. menezesi to reassess their taxonomical identity. We evaluated the allometric and sexual components of the morphology of the Stellifer punctatissimus species complex, and tested and discussed species hypotheses. The combined evidence of our work and previous studies agrees with the current morphological hypothesis of three species, as opposed to the two-lineage molecular hypothesis. However, as cryptic species, they overlap in most their traits, especially females and juveniles. Previously unaccounted variation of allometric and sexually dimorphic characters in this species complex revealed a confounding effect that might explain past and current taxonomic errors. Taxonomical practice of using body depth as a diagnostic character had led to juveniles and females being, respectively, described as a different species or wrongfully identified. Hence, taxonomical studies demand better assessment of allometric and sexual dimorphism components. Herein, we present new characters in a key to the Atlantic species of Stellifer, which disclose size and sexual variation unnoticed in previous studies. The contrasting growth patterns among these species could imply distinct habitat use. As a result, it could be suggested that such species are under different threats, which highlights the need of differential management and conservation strategies.