engleski

Coprolite status of Coptocampylodon lineolatus Elliott 1963 (incertae sedis) from Middle Eocene deep-sea sediments of Istria (Croatia)

In the course of a study of planktonic and benthic foraminiferal associations from the Middle Eocene clastic sediments from Istria, Croatia, numerous specimens of Coptocampylodon lineolatus Elliot have been found. This problematical fossil has been so far observed only in the Lower Cretaceous shallow water, mostly carbonate sediments. Thus this is the first time that it has been found in deep-sea deposits of Paleogene age. A cylindrical shape, with longitudinal ribs radiating from rounded poles and the homogenous composition of C. lineolatus are features commonly observed in coprolites. The detailed study of C. lineolatus gave insight into its makeup, chemical composition and texture. Similar chemical composition of C. lineolatus and the surrounding sediment, and a considerably reduced amount of organic carbon and nitrate in C. lineolatus fragments compared to the marl from the same sample, imply that they have been used in a process of ingestion of a deposit feeding organism. It is therefore concluded that C. lineolatus represents a coprolite of a sediment dwelling invertebrate organism. Larger quantities of C. lineolatus fragments, when fossilized, are found in mesotrophic regimes.

Eocene; Istria; coprolite

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