Reduction of vertebrate coprolite diversity associated with the end-Permian extinction event in Vyazniki region, European Russia

• The Permo-Triassic section at Vyazniki contains a rich accumulation of coprolites.
• Coprolites were produced by a number of different vertebrate taxa.
• Coprolites are grouped into nine morphotypes and linked to producers.
• There is a reduction of coprolite morphotypes after of the end-Permian extinction.
• The reduction of coprolite diversity reflects the disappearance of vertebrate taxa.

This study investigates the paleoecological significance of vertebrate coprolites collected from seven sections and three lithofacies of the uppermost Permian and lowermost Triassic succession from the Vyazniki site in the European part of Russia. The analyzed specimens (coprolites and possibly some cololites) were grouped into nine morphotypes (A–I). The coprolite morphotypes were characterized geochemically and compared to the record of other Permian and Triassic coprolites worldwide. Based on the stratigraphic position, shape, structure and composition, all morphotypes were linked to supposed producers. The phosphatic composition of most of the morphotypes and inclusions of arthropod remains, fish scales and bone fragments, suggest that they were produced by carnivores, but non-phosphatic, carbonate-rich, large and oval-shaped coprolites with impressions after plant remains have also been found. The extinction of terrestrial vertebrates around the Permian–Triassic boundary in Russia is interpreted to have occurred within a few thousands of years. Here, we show a pattern of coprolite morphotypes disappearing across this boundary that is consistent with a relatively sudden change in the vertebrate faunal composition across this interval.