Evolutionary Aspects of the Miogypsinidae from Azkand Formation (Oligocene-Miocene) in Kirkuk Area, Iraq

Abstract

The biometric analysis on Miogypsina from bioclastic limestone (Azkand Formation) in Kirkuk area, Iraq reveals that the evolutionary trend based on a distinct overall change in morphology of the nepiont, which change is in agreement with the principle of nepionic acceleration as defined by Tan Sin Hok,1936. The oldest species of Miogypsinoides represented by Miogypsinoides complanata and Miogypsinoides formosensis accompanied by the association Miogypsina gunteri which exhibit in the lower part of Azkand Formation of Late Oligocene age (Chattian). The early Miocene association of Miogypsina s.s. represented by Miogypsina gunteri-tani are often accompanied by Miogypsinoides. Most of these are close to Miogypsinoides bantamensis