Cis castaneus
Cis castaneus is a species of tree-fungus beetles in the family Ciidae.
The nematode species Caenorhabditis monodelphis is a free-living species that can be found in galleries inside of the fungus Ganoderma applanatum which grows on the stump of trees a few centimeters above ground. It is phoretic on C. castaneus.