Capturing the moment: a snapshot of Mediterranean bryozoan diversity in the early 2023

This paper provides an update on Mediterranean bryozoan diversity since the annotated checklist of Rosso & Di Martino (2016), following the publication of numerous papers describing new taxa and new species, and the addition of new records of non-indigenous species. Some of the 32 new species described after the previous checklist (plus one only figured) replace re-cords of cosmopolitan or widespread species, while others are the result of the dismantling of species complexes. New records include mainly species and genera previously known from the near-Atlantic and subordinately from the Pacific. In addition to replacements, removal of species/genera is also linked to formalized synonymies. These changes also reflect modifications in the composition and representation of families. The updated bryozoan fauna consists of 588 species, 220 genera and 99 families. The proportions at order level remain largely unchanged with cheilostomatids (ca 77%) dominating over cyclostomatids (ca 13%) and ctenostomatids (ca 10%). Ten families account for about half of the total species diversity. The newly available information is the result of investigations of habitats and localities previously overlooked, the examination of historical collections in museums, as well as the more routine use of Scanning Electron Microscopy, with increasing support from molecular sequencing. Regularly up-dated species checklists represent a unique, simple tool to monitor biodiversity in agreement with the Kunming-Montreal Global Biodiversity Framework adopted by the United Nations.