Phylogenetics and determination of evolutionary relationships of bats in Africa

Africa has a diverse mammalian fauna, of which the large mammals are world famous. Africa also has a very diverse small mammal assemblage, which is second only to the Neotropics. However, in terms of the predicted number of undescribed mammalian species, Africa is the top continent (Fisher et al. 2018). Species richness of African mammals has been severely under-represented, indeed, more mammals remain to be described on the African continent than on any other landmass, with an estimated 12% of species not yet discovered (Fisher et al., 2018). In addition, the bat fauna of Africa remains poorly known when compared to Europe or North America (Dietz and Kiefer, 2016). The reasons for this are diverse and include challenges in conducting fieldwork and the lack of financial resources. In addition, cryptic bat species may exist that are overlooked as they are difficult to distinguish from one another due to strong morphological overlap. Such species can only be revealed as genetically isolated entities using appropriate molecular markers (Chenuil et al., 2019). Thus, species richness can be severely underestimated due the existence of cryptic species being ignored (Funk et al., 2011). These species may be threatened and could be excluded from conservation actions as they are undescribed (Delić et al., 2017). Lastly, the systematic relationships of bats have been a matter of debate for decades. Thus, advanced taxonomic knowledge is a requirement for effective conservation of biodiversity (Isaac et al., 2004). Small mammals remain a key component of African ecosystems, with bats playing important roles in pollination, seed dispersal, and pest insect suppression – the last in agroecological landscapes. They are also fundamental to good conservation practice of identifying key biodiversity areas including areas of high endemism and high species richness e.g. Mount Nimba has been recognized as a biodiversity hotspot for bats (Monadjem et al. 2016) and for many other taxa too such as amphibians and plants.

Several new bat species have recently been described, for example, Monadjem et al. (2021a) in a review of the pipistrelle-like bats (family Vespertilionidae) in Africa, described two new genera and three new species from equatorial regions of the continent. Since 2013, five new species of bats (four from the family Vespertilionidae) and one new species of rodent have been described from Mount Nimba (also situated in tropical Africa) in West Africa that covers no more than 400 km2 (Monadjem et al. 2016, Monadjem et al., 2021b). New species have not only been uncovered in tropical forests, though. Mozambique is situated in subtropical southern Africa and is mostly covered by savanna habitats. Since 2012, three new species of Rhinolophus (family Rhinolophidae) and two new species of Miniopterus (family Miniopteridae) have been described from this country (Monadjem et al. 2013, 2020). A number of factors have contributed to the recent upsurge in the description of new taxa of African small mammals. One important reason is the development and availability of molecular techniques which have assisted in distinguishing morphologically similar (yet genetically divergence) taxa. These include sequencing of mitochondrial genes, with the most frequently used genes for small mammals being cytochrome b (cytb) and cytochrome oxidase I (COI). Mitochondrial DNA are useful markers for taxonomic studies as they are fast evolving and accumulation of differences between closely related species occurs more rapidly than nuclear DNA (Mindell et al., 1997). Thus, changes in mtDNA can reflect differences in species that have only recently been separated. This project requests funding to sequence cytb and COI genes of bats collected during a number of expeditions in 2018 and 2019 in the months leading up to the covid pandemic. These specimens have been deposited in the Eswatini National Museum of Natural History (Eswatini), and all the specimens have been morphologically examined. A small number of these specimens could be sequenced before the covid pandemic, of which two belonged to undescribed species (Monadjem et al. 2021a, Giarla et al. 2021). Morphological examinations of other specimens suggest additional cryptic species present in this collection, but without genetic confirmation, species descriptions are hampered and in fact impossible. The discovery of cryptic species or unique lineages could uncover as-yet-unknown pockets of endemism and diversity that might warrant reconsideration for particular habitats or sites for conservation.