Nematodes

"If all matter in the universe except the nematodes were swept away, our world would still be dimly recognizable, and if, as disembodied spirits, we could then investigate it, we should find its mountains, hills, vales, rivers, lakes and oceans represented by a thin film of nematodes. The locations of towns would be decipherable since for every massing of human beings there would be a corresponding massing of certain nematodes. Trees would still stand in ghostly rows representing our streets and highways. The location of the various plants and animals would still be decipherable and, had we sufficient knowledge, in many cases even their species could be determined by an examination of their erstwhile nematode parasites." 

Nathaniel Cobb, ‘Nematodes & their Relationships’, Yearbook of the US Department of Agriculture, 1914.