Phylum Rotifera in Peru: a review of studies on biodiversity and annotated checklist of taxa.

Peru is a megadiverse country, home to some of the world's most important biodiversity hotspots. This paper systematically reviews published studies on the phylum Rotifera in Peru, aiming to identify key features, knowledge gaps, and research challenges, thereby contributing to the conservation of rotifers. A brief history of rotifer studies is presented, and the first annotated checklist is provided of all rotifer taxa recorded according to their most recent taxonomic status, valid nomenclature, and department distribution. The number of studies on Peruvian rotifer fauna is limited, with only 35 publications. These papers are primarily in the Spanish language and are published in national journals. Ecological studies, often conducted on a short-term basis, frequently dominate classical taxonomic works. Additionally, many departments and types of freshwater environments in the country remain understudied. To date, 203 valid rotifer species have been recorded. This number is unrepresentative, as more than half of the departments lack documented records. Most recorded rotifer species in Peru are from freshwater habitats in the eastern of the country, particularly near the Amazon Basin. Several important gaps are highlighted, including the need for precise revision of existing records, promoting taxonomic harmonization, and enhancing sampling efforts.