Wikipedia
Tokudaia
Tokudaia is a genus of murine rodent native to Japan. Known as Ryūkyū spiny rats or spinous country-rats, population groups exist on several non-contiguous islands. Despite differences in name and appearance, they are the closest living relatives of the Eurasian field mouse ( Apodemus). Of the three species, both T. osimensis and T. tokunoshimensis have lost their Y chromosome and SRY gene; the sex chromosomes of T. muenninki, on the other hand, are abnormally large.
Named species are:
- Muennink's spiny rat, Tokudaia muenninki
- Ryukyu spiny rat, Tokudaia osimensis
- Tokunoshima spiny rat, Tokudaia tokunoshimensis
At least Tokudaia osimensis may be a cryptic species complex.