Origin and Evolution of Mice: An Appraisal of Fossil Evidence and Morphological Traits

Systematics of mice has progressed during the last 16 years owing to biochemical genetics (Selander et al. 1969, other references to be found mainly in Marshall and Sage 1981, Thaler et al. 1981a, 1981b, Bonhomme, this symposium). Such studies have brought about the collapse of most older ideas which were based on morphology. However the very progress due to genetics has promoted a revival of morphology. The genus Mus as well as its taxonomic components (species, subspecies, chromosomal races), have recently been redefined. The interactions between these taxa (sympatry, parapatry; syntopy and allopatry; various degrees and modes of introgression; direct and indirect competition) are now better understood. These have revealed complex phylogenetic relationships: diverging and reticulate evolution. It now becomes necessary to place the evolution of mice in real time in history, prehistory and geology. Thus, the fossil and subfossil remains of mice have to be studied, morphologically and biometrically.