Systematic paleontology, biostratigraphy, paleobiogeography of Loftusia (foraminifera) and Rudist assemblages in a regressive sequence in the Hekimhan-Malatya area (Eastern Anatolia) Turkey

Abstract

The Maastrichtian regressive sequence of the Hekimhan-Malatya area in Eastern Turkey consists of dolomitic limestones, limestones and calcareous mudstones which are dominated by rudists and Loftusia (foraminifera) assemblages. Several Loftusia species indicating middle to late Maastrichtian age such as Loftusia anatolica Meriç, L. baykali Meriç, L. coxi Henson, L. harrisoni Cox, L. minor Cox and L. morgani Douvillé have been recorded. Other benthic foraminifers present include Orbitoides medius d' Archiac, Omphalocyclus macroporus (Lamarck), Laffitteina conica Drooger, Laffitteina mengaudi (Astre) and Laffitteina oeztuerki Inan. The rudists are abundant in the dolomitic limestones in the study area. The genus Miseia Patrulius is dominant and represented by Miseia bilacunosa Özer and Miseia hekimhanensis Karacabey-Öztemür. The Loftusia species and the Rudists assemblage indicates middle to late Maastrichtian age for the formation. The paleobiogeographic distribution of the assemblage has been discussed taking this find into account.

Taxonomy and paleobiogeography of rudist bivalves from Upper Cretaceous strata, Gulf Coastal Plain and Puerto Rico, USA

“…During the hothouse conditions of the middle to Late Cretaceous (Norris et al, 2002;Hay, 2017), rudist morphology diversified to include elevator, recumbent, and encruster forms in relation to the substrate (Skelton and Gili, 2002). Rudists exhibited a cosmopolitan distribution in warm, shallow epeiric seas, including the Mediterranean (Masse and Maresca, 1997;Masse and Fenerci-Masse, 2008) and Middle East in the Eastern Hemisphere (Fenerci, 1999;Çaglar and Önal, 2009), and Caribbean (Chubb, 1971;Kauffman and Sohl, 1974;Kauffman and Johnson, 1988;Johnson and Kauffman, 1990;Ross and Skelton, 1993;Mitchell, 2003Mitchell, , 2010Mitchell, , 2020Mitchell, , 2022, Central America (Scott, 1996;Pons et al, 2016), Mexico (Pons et al, 2013(Pons et al, , 2019(Pons et al, , 2021, and the Western Interior Seaway (WIS) (Caldwell and Evans, 1963;Hook and Cobban, 2013;Everhart, 2018) in the Western Hemisphere.…”