Acanthochaetetes Fischeri N. Sp. (Coralline Demosponge) From the Upper Paleocene (Thanetian) of Iraq (Kurdistan Region) and Iran (Sistan Suture Zone)

Abstract

The new coralline demosponge Acanthochaetetes fischeri n. sp. is described from the upper Paleocene (Thanetian) of Iraq (Kurdistan Region, Khurmala Formation) and Iran (Sistan Suture Zone). The genus Acanthochaetetes Fischer is a long-ranging genus known from the Upper Jurassic (A. foroiuliensis), through Upper Cretaceous (e.g., Coniacian A.? krumbachensis) and Eocene (A. eocenica) to Recent. A. fischeri n. sp. is the first record from the Paleocene following the K-Pg mass-extinction, thereby closing the gap within the Santonian-Eocene interval. It occurs in platform-margin/upper slope depositional settings associated with coralline algae, corals, and echinoids.