Redescriptions of two little-known pimelodid catfishes from the São Francisco River basin, Brazil: Duopalatinus emarginatus and Bagropsis reinhardti (Teleostei: Siluriformes)

Abstract

The São Francisco River basin in eastern Brazil harbors a highly endemic ichthyofauna, including the poorly known pimelodid catfishes Duopalatinus emarginatus and Bagropsis reinhardti. Despite being described in the 19th century, these species have remained taxonomically obscure due to limited specimen availability and confusion with other taxa. In this study, we provide detailed redescriptions of both species based on recently collected and newly identified material, including misidentified museum specimens. Morphological comparisons and osteological data confirm that Duopalatinus emarginatus and Bagropsis reinhardti are distinct, differing in several skeletal and meristic characters, as well as habitat preferences. Our findings support a revised classification within Pimelodidae, with Bagropsis (now including Pimelodus atrobrunneus and P. paranaensis) and Duopalatinusemarginatus together forming the newly proposed tribe Bagropsini. We also present updated distributional data, highlighting the distinct ecological niches occupied by each species within the São Francisco basin. These redescriptions are crucial for accurate species identification and have direct implications for conservation assessments. Key identification to Pimelodidae species from São Francisco River basin is provided.

Keywords:
Endemic; Endangered species; Ichthyofauna; Identification key; Pimelodidae