Morphological diversification of defensive glands in Corydoradinae catfishes indicates a mixed Müllerian-Batesian mimicry system

Authors:
Open Access
Publisher website
Google Scholar
Abstract
Axillary and pectoral-fin spine glands play a central role in the defensive biology of Siluriformes by releasing toxic secretions; however, their distribution, structural diversity, and evolutionary significance within Corydoradinae remain poorly understood. Here, we present the first comparative histological analysis of these glands across seven genera of Corydoradinae. Axillary glands were present in all examined genera and exhibited a conserved lobular organization consistent with a holocrine secretion type as described previously in other Siluriformes. In contrast, venom-associated pectoral spine glands were restricted to a clade comprising Hoplisoma, Brochis, and Osteogaster. In these genera, gland position and cellular morphology closely match venom glands described in other siluriform lineages, supporting a lineage-specific derived condition. Conversely, Corydoras, Aspidoras, Scleromystax, and Gastrodermus lacked true venom-associated pectoral spine glands and instead displayed abundant epidermal granular cells and club cells, consistent with the retention of a non-venomous ancestral state. This pattern is congruent with phylogenetic relationships and implies that mimicry rings may involve Müllerian, quasi-Batesian, and Batesian components depending on their species composition and the degree of defense exhibited by the species present.
Funding Information
  • Convocatoria conjunta entre la Universidad del Rosario y la Universidad Nacional de Colombia sede Bogotá para proyectos de investigación, innovación y creación

This publication has 22 references indexed in Scilit: