Cranial morphometry of the Ethiopian multimammate mice of the genus Mastomys : taxonomic and ecological aspects

Cryptic diversity – the presence of genetically distinct but morphologically similar taxa – is a key feature of the genus Mastomys , widespread across sub-Saharan Africa. In Ethiopia, three such species are found in sympatry. In this study, geometric morphometrics was applied to 130 genetically identified specimens (skulls). Significant interspecific shape differences were detected, while centroid size largely overlapped. A high level of intraspecific variation was also observed, likely reflecting ecological flexibility and seasonal generation trends. These results suggest that morphological divergence can remain limited in genetically isolated lineages, highlighting the role of cryptic speciation as an important evolutionary process in generalist rodent taxa.