Whenever you see a generic name (in this case Pseudomys) followed by the term "sp.", it means "species". Amongst some groups of animals
distinguishing between species can be difficult, and one has to be satisfied with reaching the Genus as the lowest level of classification.
This mouse was found north of Yetman in NSW on a fauna survey, and to this day I don't know what it is. There is a very good chance it is
actually an undescribed species. Collections of native rodents are very scant in that part of the world, and there are not enough rodent
taxonomists employed to sort out such mystery animals. One day i hope to find another specimen.