Integrative taxonomy reveals 10 new species, new records, new combinations, exotic and cryptogenic species of Tropical South-western Atlantic Chalinidae (Porifera: Demospongiae: Haplosclerida)

Abstract Chalinidae are a tough taxon for sponge taxonomists given their high diversity, with only a simple set of morphological characters available for identification and classification. In such groups, the use of integrative taxonomy markedly improves our ability to establish species boundaries with confidence. We have revised the taxonomy of Chalinidae from the tropical south-western Atlantic using an integrative taxonomic approach that combined morphological and molecular data (COI and 28S). This approach allowed us to recognize 30 species, 10 of them entirely new to science, four cryptogenic and one exotic species. Several species had their distribution expanded, while previous records of Chalinula zeae, Haliclona manglaris, Haliclona curacaoensis, and Cladocroce caelum were shown to be incorrect. We propose the synonymization of Chalinula with Haliclona, as this separation lacks support both from molecular phylogenies and morphological data. Additionally, we transferred Haliclona dura to Calyx. We revisited the usefulness of morphological characters used in the classification of Chalinidae, concluding that they are largely homoplastic and strongly influenced by the environment. This underscores the need to search for a new set of morphological characters that may enable a major rebuilding of Haplosclerida classification. We also discuss the global diversity and distribution of Haliclona and its subgenera.