Redescription and neotype designation of Aglauropsis kawari Moreira & Yamashita, (Cnidaria: Hydrozoa, Limnomedusae) based on an integrative taxonomy approach

Abstract Aglauropsis kawari Moreira & Yamashita, 1972 (Cnidaria: Hydrozoa: Limnomedusae: Olindiidae) was originally described solely on the basis of formalin-preserved material, leading to morphological inconsistencies and not providing crucial details on juvenile individuals and the cnidome. Subsequent records similarly lacked comprehensive data. The present study addresses these gaps by providing a detailed redescription of A. kawari based on newly collected, live specimens from the São Sebastião Channel, São Paulo State, Brazil, and preserved material from the type locality (Rio Grande do Sul State). We provide high-quality photographs of living individuals, morphometric analyses across different maturity stages (young, subadult, mature), and a comprehensive cnidome description. Given the loss of the original type material and inaccuracies in the original description, a neotype is designated herein for A. kawari . A molecular characterization, based on 16S and 28S ribosomal DNA markers, provides insights into its phylogenetic placement within the family Olindiidae Haeckel, 1879. The 16S tree groups A. kawari with Vallentinia gabriellae Vannucci Mendes, 1948, whereas the 28S tree shows a stronger relationship with Aglauropsis aeora Mills, Rees & Hand, 1976. The reconstruction based on the concatenated dataset (16S+28S) provided a more robust phylogenetic tree, resolving these incongruences. The integrated approach clarifies the species identity, establishes reliable diagnostic characters, and enhances its taxonomic understanding, contributing to a broader knowledge of the Limnomedusae diversity in the southwestern Atlantic.