Are Myxomycetes Living Fossils?

Myxomycetes are widespread and often common organisms, especially in the forests of the world. This may have been the case for a very long period of time, since the oldest known indisputable fossil of a myxomycete sporocarp dates back to the Cretaceous Period, about 100 million years ago. One could speculate that myxomycetes might well have been present in the coal swamp forests of the Carboniferous Period, but this may never be known. Since the oldest known fossils of myxomycetes do not appear to differ appreciably from a still extant species, there seems to be justification for considering these organisms as living fossils.