An integrated taxonomic investigation into the identity of Corydoras julii, with comparisons with allied forms (Siluriformes: Callichthyidae)

• Grant number: 24/03613-8
• Support Opportunities: Scholarships in Brazil - Master
• Start date: August 01, 2024
• End date: August 31, 2025
• Field of knowledge: Biological Sciences - Zoology - Taxonomy of Recent Groups
• Principal Investigator: Mario Cesar Cardoso de Pinna
• Grantee: Lam Shu Him
• Host Institution: Museu de Zoologia (MZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

With more than 200 valid species recorded, Corydoras is the richest genus in the neotropical catfish family Callichthyidae. Despite prolific description of species, there has been limited revisionary work on the taxonomy of Corydoras, so that many hidden species, as well as synonyms, are expected to exist in the genus. The research herein proposed aims to conduct a comprehensive taxonomic revision of Corydoras julii, based on material deposited in museums worldwide, and to unravel the actual taxonomic boundaries, variation, diagnosis and geographical distribution of the species. Extensive recent collection efforts in the Parnaíba and Lower Tocantins basins have yielded various forms potentially allied to, yet not conspecific with, Corydoras julii, which have not been studied in detail and are simply identified provisionally as Corydoras julii. A taxonomic revision on Corydoras julii and its allied forms is necessary to untangle an apparently complex situation. As a taxonomic revision project that employs a multidimensional approach (i.e., morphological, osteological and molecular analyses) to delimit potential hidden species, this work aims to lay the groundwork for future taxonomic work on species groups that are highly similar morphologically, and where morphological diagnosis alone may not be sufficient to properly delineate species. Additionally, the research will contribute to understanding of the diversity of Corydoras in the Parnaíba basin, a region that remains relatively under-sampled in comparison with other major neotropical basins. With only three Corydoras species described from the basin, discovery of any new species will be highly significant for the ichthyological diversity of the region. Finally, species of Corydoras are highly targeted in the ornamental fish trade and therefore deserving of special conservation attention. Taxonomic research is fundamental in conservation management, providing fine-scale knowledge for realistic estimates of species diversity.