Going out on a limb here and guessing a combination of fungus, bacteria and earthworms, and maybe some few fly larvae.
How come everyone forgot the cockroach ?-)
I can't post URLs just yet. They have a quota here on number of posts before one can post a URL. However, my searches have revealed:
'Cockroachoids' first appear in the fossil record in the Carboniferous. They had features that were 'intermediate' between mantises and cockroaches. The 'true' cockroach appears in the fossil record in the early Cretaceous.
'True' roaches have an internal ovipositor. There is even one roach that is oviviparous.
Most of the roaches are believed to eat dung (i.e., coprophagous). However, there is one family of extinct roach, now extinct, whose geographical range largely overlaps those of dinosaurs.
This roach is called the Blattudae. Well maybe I got the spelling a little wrong. Regardless of how one spells it, this guy was probably a major consumer of dinosaur poop. That's pronounced BBllaatttidae.
The dung beetles as a group don't appear in the fossil record until the midCreteceous. They don't seem to be a major consumer of dinosaur poop. However, the dung beetles expanded all over the tropics after the KT extinction. The dung seem to have specialized in the dung of large mammals rather than birds and reptiles. So the major coprophage insects in the Mesozoic may have different species of dung beetle.
Termites seem to have been an early consumer of poop from herbivore dinosaurs. True, termites mostly eat woody material. However, they don't seem picky about where that wood has been.
The flies don't seem to have dominated waste disposal until after the KT period. Some dung eating flies seem to have arose in late Creteceous. Again, they don't seem to have come into their own until large mammals arrived.
Note that I am not talking about extant species of insects. Most of these species are now extinct. However, I am listing insects on a higher taxonomic level. The German roach may not have been around in the Cretaceous, but it has cousins that were alive in the Carboniferous. Similarly, there are hundreds of termite species that are alive today and hundreds more that are extinct. I am sure that there were hundreds of species of roaches, termites and beetles that ate dinosaur scat.
It is interesting that the flies were late comers in the scat disposal industry. Basically, dioptera took over in the Cenozoic. A lot have insects have specialized into eating large mammal poop.
Hey, this has turned out to be a very interesting question. It is funny, but it isn't silly.
What is just as important is who eats the insect crud. Fungi, bacteria, other insects, etc.
