The oldest fossils of the Sphagnopsida belong to the order Protosphagnales. This order was created because fossils differed from Sphagnum in having less-pronounced dimorphism of leaf cells, and both in having a costa (midrib) in the center of the leaves and hints of lateral nerves. These characters are what might be expected in a primitive moss morphology, but sphagnologists still disagree concerning this interpretation. Hundreds of well-preserved gametophytes have been found in Permian deposits from Russia by Nejburg and Fefilova, and have been assigned to the genera Junjagia (Early Permian), Protosphagnum (Late Perm.), and Vorcutannularia (Early & Late Perm.).
Fossil leaves of Sphagnophyllites triassicus are the oldest known evidence of Sphagnales. These leaves from the Triassic of India have full cell dimorphism and lack a costa. By the Jurassic, morphologically modern fossils of Sphagnum are known, and numerous spore records occur (see Oostendorp 1987).
In addition to leaving their own fossils behind, Sphagnum bogs have preserved information about the ancient lives of other organisms. The highly acidic bogs prevent decay of materials such as pollen grains and plant fibers. Thus, pollen which settles in bogs provides a layered record of plants which grew near the bog.
Bogs also preserve human remains, and some of our best information about the lives and culture of ancient peoples in northern Europe comes from mummified bodies found in peat bogs. These bodies provide information about clothing, tools, and even diet. Some of the oldest finds date back to the Stone Age, some 8600 years ago; others may be as recent as a few hundred years old.