Coral fauna across the Cretaceous–Paleogene boundary at Zagros and Sistan Suture zones and Yazd Block of Iran

Abstract

From the upper Maastrichtian (Tarbur Fm.) and Paleocene of Iran, 20 species of scleractinian corals belonging to 17 genera and 14 families, and one species of the octocoral Heliopora are newly recorded. Furthermore, coral species previously described from the upper Maastrichtian Tarbur Fm. and the Paleocene are revised and included in the evaluation, resulting in a total of 37 species from 28 genera belonging to 20 families (including 3 subfamilies) for the Iranian K/Pg-boundary time period. The majority of the taxa (21 out of 37 = 57%) crossed the K/Pg-boundary. The genera Acropora and Stylocoeniella are recorded from strata older than the Paleogene (upper Maastrichtian) for the first time; for Lobopsammia it is the first report from strata older than the Eocene (Selandian‒Thanetian). The vast majority of the coral taxa occurring in both the upper Maastrichtian (Tarbur Fm.) and the Paleocene of Iran have been reported from a variety of both reefal and non-reefal paleoenvironments. On the species level, a slight majority of the corals from the upper Maastrichtian (Tarbur Fm.) are endemic (14 out of 27 species = 52%). In contrast, the vast majority of the Paleocene Iranian corals are cosmopolitan to subcosmopolitan; only 4 taxa are endemic during the Paleocene. While the upper Maastrichtian coral fauna of Iran shows greatest affinities to contemporaneous assemblages of Europe and the Caribbean, the Paleocene coral fauna is most closely related to contemporaneous coral associations of central Asia, Europe, and North America.