CORALS OF THE K/T-BOUNDARY: SCLERACTINIAN CORALS OF THE SUBORDERS ASTROCOENIINA, FAVIINA, RHIPIDOGYRINA AND AMPHIASTRAEINA

Abstract

This taxonomic review of the scleractinian corals of the Maastrichtian and Paleocene period focuses on the scleractinian suborders Astrocoeniina, Faviina, Rhipidogyrina and Amphiastraeina. This, the first extensive compilation of coral species of the K/T (Cretaceous/Tertiary) boundary, deals with more than 2500 records of 550 nominal taxa. In addition to the re-examination and re-evaluation of described forms, this study also includes the first description of the largest Maastrichtian coral assemblage known (consisting of about 4000 specimens from Jamaica), as well as new material from the Campanian-Maastrichtian of Argentina, Lower Maastrichtian of Mexico (Cerralvo), and the Paleocene of Austria (Kambuhel-Kalke). A diagnosis is provided for each species, as well as for each higher-level taxonomic category and issues concerning taxonomic assignment are discussed in detail. The descriptions are accompanied by illustrations of representatives of each species and, in many cases, include illustrations of type or original material. Also included is the first comprehensive overview of the stratigraphical and geographical ranges of each taxon. In the four suborders evaluated in this paper, 123 valid species can be reliably documented as occurring in the Maastrichtian and/or the Paleocene. The largest number of species is in the suborders Faviina and Astrocoeniina. In the Faviina 62 valid species are known from the Maastrichtian, of which 35 (56.5%) crossed the K/T-boundary, while in the Paleocene 14 new species appeared. In the Astrocoeniina 18 valid species occurred in the Maastrichtian, eight of which (44.4%) crossed the K/T-boundary and 16 new species appeared in the Paleocene. Only eight species of Rhipidogyrina and five species of Amphiastraeina occurred in the Maastrichtian and although two amphiastraeinid made it into the Paleocene, only one of the rhipidogyrinids crossed the K/T-boundary. No new species of Amphiastraeina appeared in the Paleocene. According to this revision on the genus level 44 out of the 65 genera crossed the K/T-boundary, which is 67.7% (12 genera went extinct, 9 genera have their first occurrence in the Paleocene). In comparison to previous estimates this result (generic extinction of around 32%) represents the best estimation for scleractinian corals at present and corresponds to recently reported results of other macroinvertebrate groups after taxonomic revision (e.g. echinoids).