microfauna
noun
mi·cro·fau·na
| \ ˌmī-krō-ˈfȯ-nə
, -ˈfä-\
, -ˈfä-\
Definition of microfauna
1
: minute animals
especially
: those invisible to the naked eye
the soil microfauna
2
: a small or strictly localized fauna (as of a microenvironment)