A synthesis of the biogeographical distribution of Rotifera in Africa

Abstract

The rotifer fauna of Africa has been studied for >100 years, but there has been no recent synthesis. We compiled data from 265 publications that reported information on African rotifers. Our dataset yielded information on the distribution of 765 taxa from ~1850 separate sites; these included both natural and artificial habitats such as lakes, ponds, puddles, oases, artificial systems, rivers and wetlands. A heat map of predicted rotifer biodiversity indicated that the greatest diversity should be present in the sub-Saharan region including a large hotspot in Mali and several smaller ones scattered in that region. Lakes Kariba, Tanganyika and Malawi showed high-predicted diversity, but surprisingly, Lake Victoria had lower diversity than expected. Two regions showed unusually high-predicted diversity: northwestern Algeria extending into Morocco and Egypt. Equatorial Africa is rich in habitats well suited for rotifers, yet their predicted biodiversity seems low. Latitude and elevation were negatively correlated with richness, while permanent water source and littoral zone were positively correlated according to generalized linear modeling results. Partial RDA analyses showed significant correlations among several environmental features and species occurrences. It is clear that more survey work remains to be done to achieve a better understanding of African rotifers.

A georeferenced dataset for occurrence records of the phylum Rotifera in Africa

“…Our extensive screening of the published literature allowed us to report 957 taxa from the area and make the dataset freely available online through the Open Science Framework (OSF) and the Global Biodiversity Information Facility (GBIF). The number of known species from Africa increased from the 639 reported in the first review from 1986 (De Ridder, 1986) to the 765 in the most recent compilation in 2022 (Smolak et al, 2023). Segers (2008) reported 591 rotifer species (453 Monogononta, 138 Bdelloidea) from the Afrotropical biogeographic region, partially overlapping with the geographic scope of the current review.…”

“…The dataset includes 27,455 records of 957 valid taxa of rotifers: 39 at subspecies, 819 taxa at species, 1 at species group, 81 at genus, and 17 at family level. This detailed literature search increased the number of known rotifer taxa at species, subspecies, form and variety level reported in previous reviews, which were 639 in 1986 (De Ridder, 1986) and 765 in 2022 (Smolak et al, 2023). Of the taxa reported in the current dataset, 167 (18%) are Bdelloidea, 665 (69%) Ploima, 97 (10%) Flosculariaceae, 27 (3%) Collothecacea and one representative of Seisonacea, the marine epizoic rotifer Seison africanus Sørensen, Segers & Funch, 2005 described and recorded only from coastal waters of Kenya (Sørensen et al, 2005).…”

“…1). The records reported in four reviews, for the continent (De Ridder, 1986;Dumont, 1983;Smolak et al, 2023) and for a smaller area (Gondwe et al, 2021), were not included, given that they would represent only duplicate records, having gathered data from previous studies already included in our dataset. Unfortunately, we did not have access to 109 papers (Supplementary File SF1) and thus we could not code the data they contained: adding data from these papers may still change the picture of known diversity in Africa and sur-Tab.…”

“…But few of those studies report datasets of georeferenced records to be used for biogeographical inference: e.g. for Antarctica ( (Smolak et al, 2023), and Italy (Ferrari et al, 2023). The aim of our study is to produce a georeferenced dataset of rotifers on Africa and many of its surrounding islands.…”

Preface: Georeferenced Freshwater Biodiversity Data

“…2). In detail, Musazzi et al (2023) report 4,124 records of sedimentary diatoms in Lake Maggiore, a wide (2023) in comparison to 765 that were reported in the most recent review on African rotifers (Smolak et al, 2023); 584 species are reported for Italy by Ferrari et al (2023) in comparison to 483 reported in the most recent review on Italian rotifers (Fontaneto et al, 2022).…”