Biogeographia – The Journal of Integrative Biogeography

scanning 21 papers we found that were published between 1993 and 2020, expanding the regional records and including four papers older than 1993 with overlooked records in the previous checklist. The Rotifera data are part of the updated Checklist of the Italian Fauna, which is viewable on the LifeWatch Italy platform at https://www.lifewatchitaly.eu/en/initiatives/checklist-fauna-italia-en/checklist and is freely available on the LifeWatch Italy Data Portal (https://dataportal.lifewatchitaly.eu/data). The checklist will be dynamically updated with new records; this paper describes the state of the art of the data set regarding Rotifera on May 2021.


INTRODUCTION
Italy was likely the first country in the world to have a complete list of all the species of animals known for its territory, thanks to the project 'Checklist delle Specie della Fauna d'Italia' (Minelli et al. 1993(Minelli et al. -1995. The aim of this data paper is to provide information on the updated checklist, within the project for a new checklist of the Italian fauna started in 2018 (Bologna et al. 2022), limited to the phylum Rotifera, with the description of the state of the art of the updated data as it currently stands in May 2021. The data described in this data paper will be progressively updated on the LifeWatch Italy Data Portal under the new 'Checklist of the Italian fauna', allowing for a dynamically updated knowledge on the occurrence of the fauna in the country (Bologna et al. 2022).
The phylum Rotifera is composed of about 2,000 species of microscopic animals ( Fig.  1) living in any type of water, including freshwater and marine environments, and limno-terrestrial habitats such as mosses, lichens, and soil . Rotifers are here considered in their traditional meaning, without the inclusion of Acanthocephala, a group of obligate parasites, which is known to be phylogenetically included within Rotifera, but with different morphology, body size, and ecology, as suggested by Fontaneto & Plewka (2021).
Rotifers are peculiar animals due to their desiccation capabilities, cyclical and obligate parthenogenesis, and potential for massive horizontal gene transfer in bdelloid rotifers . They have also been considered not relevant for biogeography given that most species have a very wide distribution (Dumont 1983). Here we report the currently biogeographical knowledge for the known species of rotifers in Italy.

Summary statistics
The checklist of Rotifera accounts to 483 taxa at the species and subspecies level, with 119 taxa of Bdelloidea, 362 of Monogononta, and 2 of Seisonacea. The previous checklist (Braioni & Ricci 1995) reported 245 taxa: 54 Bdelloidea, 189 Monogononta, 2 Seisonacea. The current update includes 241 more taxa, mostly added since 1995. Three taxa listed in Braioni & Ricci (1995) were removed because currently considered not valid.
Northern Italy, with 429 species, has a higher number of known speciesis much better known than Southern Italy, with only 219 species. The regions with the highest number of known species are Piemonte (198), Emilia Romagna (188) and Lombardia (185), whereas for five regions (Valle d'Aosta, Marche, Abruzzo, Molise, Basilicata) no species are known. No species are known either for San Marino Republic or Vatican City (Fig. 2).
The marine areas with most species are M2 (Northern Tyrrhenian Sea) with 58 species and M9 (Northern Adriatic Sea) with 45; all marine areas have some records for rotifers (Fig. 2).

Data set description
The data were structured according to the Data Scheme of the LifeWatch Italy Data Portal, which is based on Darwin Core standard (Wieczorek et al. 2012) and controlled vocabularies (http://ecoportal.lifewatch.eu).
The first eight columns refer to the taxonomic ranks from phylum to family, followed by genus and genus authorship, species and species authorship, or eventually, when existing, subspecies and subspecies authorship ( Table 1).
Two columns (Table 1) report whether the species is currently known to be endemic to Italy and whether it is a recent alien introduction, according to the definition of the Secretariat of the Convention on Biological Diversity (2002).
The following 33 columns (Table 1) are related to the occurrence of each taxon and report the known occurrence of rotifers in different geographical areas (Fig. 2): in terrestrial areas, according to the administrative Regions of the country (ISO 3166-2:IT), including San Marino and Vatican City; in marine Italian areas, according to the biogeographical divisions identified by the Società Italiana di Biologia Marina, SIBM (Relini 2008(Relini , 2010. The two final columns (Table 1) report the nomenclatorial changes that occurred since the publication of the previous checklist by Braioni & Ricci (1995) and the literature reference used to expand the species list and the distribution of the species since Braioni & Ricci (1995).
Further details on the column and column headers of the data set (data table attributes) for the Rotifera part of the Checklist, with the corresponding definitions, are reported in the new 'Checklist of the Italian fauna' metadata record published on the LifeWatch Italy Data Portal (https://dataportal.lifewatchitaly.eu/view/ urn%3Auuid%3Ac1f2ab37-61e4-48e9-b3a9-15bdbf002f9d).
A simplified version of the checklist is given in Supplementary File S1.   6

Data set information
In this section we provide information on the data set with metadata record already published on the LifeWatch Italy Data Portal (https://dataportal.lifewatchitaly.eu/view/urn%3Auuid%3 Ac1f2ab37-61e4-48e9-b3a9-15bdbf002f9d), with additional specific information related to the Rotifera part.

Geographic information
General description: The data set includes records from the national territories of Italy, including the two major islands Sardinia and Sicily, together with archipelagos and minor islands politically under the Italian legislation. Sampling design: We did not perform any additional sampling to collect records of rotifers, but we used only published data.
Habitat type: Any type of habitat where rotifers can be found was considered . These include all terrestrial and aquatic habitats. The aquatic habitats refer to any freshwater, brackish and marine environment. The terrestrial habitats refer mostly to limno-terrestrial environments such as lichens, mosses, soil, and sediments.
Biogeographic region: Within the Palearctic realm, according to the definitions of the European Environmental Agency (2017), the data set covers three European biogeographical regions: Alpine, Continental, and Mediterranean.
Quality control for geographic data: We checked that the georeferenced records and the published localities in the papers indeed matched the geographical units used for the checklist at the level of administrative regions for terrestrial records and at the level of marine regions for marine records.

Literature records
General description: Only published records are included in the data set. A search through the literature was performed on 15 th June 2020.

Literature search methods:
We searched through Web of Science, Scopus, and Google Scholar for keywords ('rotifer' or 'Rotifera') and ('Italy' or 'Italian').
Quality control for literature data: Additional references were searched through the grey literature with online searches outside the three academic databases and no new records were found. In addition, we scanned the cited references of each paper and we did not find additional overlooked records. We do not claim that the checklist is absolutely complete, but that it is the best we could do. The dynamic nature of the online data set at LifeWatch Italy will allow including potentially overlooked records.

Taxonomic information
General description: Only records reporting species or subspecies were included, disregarding records at higher levels like genus, family, etc.
Taxonomic coverage: phylum Rotifera, intended in its traditional inclusion of Bdelloidea, Monogononta, and Seisonacea, and the exclusion of Acanthocephala .
Taxonomic rank: Only species and subspecies are reported; the data set reports higher taxonomic ranks for each species, including Phylum, Class, Order, Family, Genus.
Nomenclature: The adopted nomenclature followed the species names in the List of Available Names (LAN) for Rotifera (Segers et al. 2012, Jersabek et al. 2018) for all species described before year 2000, and the name of the original descriptions, potentially amended by subsequent revisions, for all species described after year 2000. The Rotifer LAN is also the basis for nomenclature in the World Register of 8 Marine Species, WoRMS (Horton et al. 2021). Species authorships follow the rules of art. 51.3 of the 4 th edition of the International Code of Zoological Nomenclature (International Commission on Zoological Nomenclature 1999) for the use of parentheses.
Taxonomic remarks: Any taxonomic change that occurred since the publication of the previous checklist (Braioni & Ricci 1995) is mentioned, according to the nomenclature of the Rotifer LAN. Species that were included in the previous checklist and are now considered not valid by the Rotifer LAN are excluded from the data set.
Quality control for taxonomic data: Taxonomic data were checked and updated to include revision of names, synonyms, delimitation of genera and higher taxa, all conducted through a comparison with the List of Available Names for Rotifera (Segers et al. 2012, Jersabek et al. 2018) for all species described before year 2000, and with the original descriptions for all species described after year 2000.