Bivalve borings in Maastrichtian fossilNypafruits: Dakhla Formation, Bir Abu Minqar, South Western Desert, Egypt

Disconnected aggregates of allochthonous fossilNypafruits occur in the Ammonite Hill Member of the Dakhla Formation (Maastrichtian), exposed at the Bir Abu Minqar section, south Western Desert of Egypt. In a pale brown, calcareous siltstone and/or fine-grained sandstone layer, the fossil fruits found are densely infested by the boringsTeredolites clavatusandApectoichnus longissimus. In the specimens described, wood borings assigned toA.longissimusare more abundant thanT. clavatus. Remains of the boring bivalves are not preserved. These aggregates of bored fruits likely accumulated in a warm, shallow, well-oxygenated marine environment. Prior to final accumulation,Nypafruits drifted in seawater only for a short time and exhibit evidence of biostratinomic alterations. The present study is the first to systematically describe the occurrence of both nominal ichnotaxa from the Maastrichtian rocks in Egypt.

Automated summary

The study describes the occurrence of disconnected aggregates of allochthonous fossil Nypa fruits infested by the borings Teredolites clavatus and Apectoichnus longissimus in the Maastrichtian rocks of Egypt. These bored fruits likely accumulated in a warm, shallow, and well-oxygenated marine environment prior to final deposition. This is the first systematic description of both nominal ichnotaxa in Egypt from the Maastrichtian rocks.