The first record of exceptionally-preserved spiral coprolites from the Tsagan-Tsab formation (lower cretaceous), Tatal, western Mongolia

Abstract

Abstract In this paper, seven coprolites from the Lower Cretaceous of Tsagan-Tsab formation have been described. Thus, producing a significant contribution to what we perceived as the first detailed study of coprolites from the Mesozoic deposits in Mongolia. The collected coprolites encompass a total of six spiral amphipolar and one scroll coprolites. We prominently identified four new coprolite ichnotaxa, such as: Hyronocoprus tsagantsabensis and Hyronocoprus hunti, to which both are ichnosp. nov.; followed by Megakalocoprus barremianensis and Scrollocoprus tatalensis, where both are ichnogen. et ichnosp. nov. Notably, CT scans revealed that all specimens showed various amounts of bony inclusions and scales, hence, deducing that the producers could have had a low acidic digestive track and were unable to dissolve bone matters. Moreover, SEM–EDS analysis concluded its carnivorous nature, thus, pointing towards piscivorous diet. The small sized Scrollocoprus is considered to be the second findings of Mesozoic era’s scroll coprolites, which contain possible plant pollens, a complete infraorbital bone, clusters of bone fragments and rhomboidal-shaped ganoid scales of the prey; and bioerosional scars have been observed on the surface. We suggest those amphipolar spiral ichnotaxa were produced by Asipenceriformes, with Pholidophoriformes as the prey, while Scrollocoprus represents fecal excrement of underived fish, possibly of sarcopterygian origins.