Moncharmontia De Castro 1967, benthic foraminifera from the middle-upper Cenomanian of the Sarvak Formation of SW Iran (Zagros Zone): a CTB survivor taxon

Abstract

Moncharmontia apenninca (De Castro 1966) is widely reported in the Upper Cretaceous (Turonian-Campanian) shallow-water successions of the Neotethyan realm (e.g., Italy, Croatia). With its "First Appearance Datum" (FAD) in the lowermost Turonian, it is considered a newcomer taxon in the aftermath of the Cenomanian/Turonian boundary (CTB) extinction event, and therefore a member of the Upper Cretaceous Global Community Maturation Cycle. Its common presence in the middle-pro parte upper Cenomanian Sarvak Formation and time-equivalent strata in Mexico (Valles-San Luis Potosi Platform) document that it represents a CTB extinction survivor taxon like Dicyclina, Nezzazata, Reticulinella and several others. The different local "FAD's" of Moncharmontia might possibly be linked to latitudinal differences, i.e., an earlier evolution of the species in the near-equatorial area (Mexico, Iran) compared to the low-middle latitudinal occurrences in the peri-Mediterranean realm (e.g., Italy, Turkey).