Multilocus phylogeny of East African gerbils (Rodentia, Gerbilliscus) illuminates the history of the Somali‐Masai savanna

Abstract

Aim The rodent genus Gerbilliscus is widespread in savannas throughout sub-Saharan Africa. The eastern clade comprises four species with distributions centred in the Somali-Masai biogeographical region of East Africa. We investigated the genetic diversity of the group with a view to illuminating the historical (Plio-Pleistocene) processes that formed contemporary biota of the understudied Somali-Masai region.Location Somali-Masai savanna, East Africa. MethodsWe performed multilocus genetic analyses of 240 samples from 112 localities, combining genotyping of recently collected samples (N = 145), 454pyrosequencing of museum material (N = 34) and published sequences (N = 61). We used Bayesian and maximum likelihood approaches for phylogenetic reconstructions, and coalescent-based methods to delimit species. We also estimated divergence times and modelled recent and past distributions to reconstruct the major evolutionary influences in the Somali-Masai region during the Plio-Pleistocene.Results Genetic analyses provided evidence for six lineages, possibly corresponding to distinct species. The two main species groups (with two and four putative species, respectively) have overlapping distributions, but species within each group are distributed parapatrically. The origin of the eastern clade dates back to the Pliocene, while individual species diverged in the Pleistocene. The distribution of genetic diversity and ecological niche modelling point to the importance of the Rift Valley and the presence of unsuitable xeric habitats in the allopatric diversification of Gerbilliscus in the Somali-Masai savanna within the last 5 Myr.Conclusions This is the first detailed phylo(bio-)geographical study of animals with predominant distribution in the Somali-Masai region. It revealed currently underestimated diversity of eastern clade of Gerbilliscus and proposed a scenario of its evolution during Plio-Pleistocene. Conspicuous genetic structure of these taxa can be now used to test detailed phylogeographical hypotheses related to Plio-Pleistocene history of gerbils and, to some extent, also biota of Somali-Masai bioregion in general.

Multiple radiations of spiny mice (Rodentia: Acomys) in dry open habitats of Afro-Arabia: evidence from a multi-locus phylogeny

“…Similarly, the mountains in north-eastern Tanzania (Kilimanjaro, Pare, Usambara) currently delimit distribution for some Acomys lineages ( Wil2 vs. Wil3 or cahirinus vs. spinosissimus groups), and, again, this pattern was found in other savanna rodents (e.g. Saccostomus [71], Gerbilliscus [72]). Further to the north, Kenyan highlands could have worked in similar way as they seem to limit distribution of several Acomys lineages ( Wil1 vs. Wil2 + Wil3, Ign3 vs. Ign4 ).…”

Phylogeography of a widespread sub-Saharan murid rodent Aethomys chrysophilus: the role of geographic barriers and paleoclimate in the Zambezian bioregion

“…Bryja et al 2010, while different vegetation types could be responsible for the current intraspecific genetic variability in southern Africa (Russo et al 2010). Recent studies from the eastern African savanna-woodland mosaic illustrated the processes involved in the forming of the fauna of open habitats and the effects of natural barriers (rivers and mountains) in combination with habitat specificity (Nicolas et al 2008, Colangelo et al 2013, McDonough et al 2015, Mikula et al 2016, Aghová et al 2017.…”

Genetic variation of the most abundant forest‐dwelling rodents in Central Africa (Praomys jacksoni complex): Evidence for Pleistocene refugia in both montane and lowland forests

“…Recently, African rodents have been used as biogeographical models for reconstruction of the evolutionary history of savannas (e.g. Aghová et al, 2017;Mazoch et al, 2018), as well as various types of forests (e.g. Bohoussou et al, 2015;Bryja, Mikula, Patzenhauerová, et al, 2014).…”