Otomis or African swamp rats are members of the mouse family and occupy the ecological niche of voles in Africa. This is expressed both in food preferences and in the appearance of the animals. The greatest species diversity of representatives of the genus Otomys is observed in the Eastern Afromontane Center of Biodiversity and Endemism, which includes the Ethiopian Highlands. The complex geomorphological structure of the highlands with many mountain ranges separated by the Rift Valley and deep river canyons limits the free movement of otomis, thereby creating the preconditions for active speciation processes. This is also facilitated by the pronounced diversity of habitats along the altitudinal gradient, where forest, heather and Afro-alpine belts are successively replaced.
An international team of scientists, including the head of the laboratory of mammalian microevolution of the Institute of Ecology and Evolution of the Russian Academy of Sciences, Doctor of Biological Sciences. Lavrenchenko L.A. and a junior researcher in the same laboratory, A.A. Martynov, conducted a phylogenetic analysis and taxonomic revision of Ethiopian Otomys. The study is based on the combined use of genomic (high-throughput sequencing using the ddRADseq method) and morphometric (skull shape analysis) methods.
The study results confirmed the presence of six endemic Otomys species in Ethiopia and significantly expanded the ranges of some of them. These six species are divided into two phylogenetic groups, each of which independently colonized the Ethiopian Highlands in the past. In addition, both molecular and morphological data identified a previously unknown lineage of Otomys, which is presumably a new species.
The work was carried out within the framework of the Russian Foundation for Basic Research project No. 19-54-26003.
The research results were published in the highly rated Zoological Journal of the Linnean Society.
Mizerovská, D., Martynov, A. A., Mikula, O., Bryjová, A., Meheretu, Y., Lavrenchenko, L. A., & Bryja, J. (2023). Genomic diversity, evolutionary history, and species limits of the endemic Ethiopian laminate-toothed rats (genus Otomys, Rodentia: Muridae). Zoological Journal of the Linnean Society, 199(4): 1059-1077.