Abstract More than 2600 coprolites produced by vertebrates have been found in the
fluvial lacustrine beds of the Upper Cretaceous (Santonian) Csehbánya Formation, Iharkút,
western Hungary. In this study the mineral components, embedded dietary residues of
these coprolites were examined and their ecological significance are discussed. The
coprolite assemblage, containing mostly small-sized (length between 0.8 and 8.6 cm)
specimens, can be ordered into seven different morphotypes, among which the spiral
ones might have been produced by fish with spiral intestinal valves. The surface of
the coprolites is mostly smooth and desiccation cracks were observed in only one case,
suggesting that most of these coprolites were buried in-situ without long-term subaerial
exposure. The fine-grained matrix of coprolites contains small holes, partially digested
plant and animal residues but no sedimentary particles. CT-scanning was an effective
method for revealing embedded dietary residues despite that the coprolites contain
a large amount of pyrite. The coprolites contain cuticle remains, coalified seeds,
pollen grains and diatoms. Animal residues may be the evidence of predation: mollusk
shell and bone fragments, ganoid scales of Lepisosteiformes fish were frequent and
one Pycnodontiformes fish tooth was found as well. It is not possible to ascertain
the real producer of the coprolites, but, according to these remains, the Lepisosteiformes
and Pycnodontiformes fish were included in the producer's prey. Not only the bone-
but also the plant-bearing coprolites are highly phosphatic with mineral apatite in
their matrix. However, the embedding fluvial sediment has significantly different
chemical composition. The high phosphatic content of coprolites and the apatite might
be derived from the carnivorous diet. Plant remains in the phosphatic coprolites may
imply an omnivore producer or were the result of their incidental ingestion. Rapid
burial and the mineral content of the animal nutriment might have been the responsible
factors for the good preservation of the excrements.
