TWO NEW SPECIES OF RUDIST FROM AQRA FORMATION (MAASTRICHTIAN), KURDISTAN REGION, IRAQ

Abstract

Two new species of rudist (Dictyoptychus acutidentatus n.sp.; Dictyoptychus mukabaensis n.sp.) have been described from the Maastrichtian Aqra Formation in Iraq. Rudist species and other associated microfossils indicate a Maastichtian age. The depositional environment of Aqra Formation is determined by the occurrence of the rudist, foraminifera, and microfacies analysis. These gave a clue that the formation was deposited over an elongated discontinuous paleo-ridge that extended from North West towards South East of Iraq, and they indicate a shallow warm marine environment, with high energy at the beginning graded upward to low/ medium energy. The deposition of the formation was characterized by high rate of sedimentation and frequent relative sea level fluctuation.