DATA ON THE UNKNOWN: THE EMBRYO OF IRAQIA SIMPLEX HENSON, 1948 (LARGER BENTHIC FORAMINIFERA; EARLY APTIAN, CENTRAL IRAN)

Iraqia simplex Henson, the type-species of this orbitolinid genus, is classified among the Dictyoconinae Schubert that is principally defined by a simple megalospheric embryo. However, neither the original nor any later description of the taxon contained any specifications (or illustration) of this taxonomically important feature except that it should be situated eccentrically at the beginning of an early spiral stage. Abundant material from the early Aptian Taft Formation of Central Iran, that is in perfect conformity with Henson’s Iraqi type-material, shows the presence of a simple embryo positioned centrically at the apex of the generally high-conical tests. Apart from other differences in the internal test structure, this feature therefore appears to represent a further distinguishing criterion to the allied genus Orbitolinopsis Henson. The available material also provides a relatively good overview of the so far unknown embryo’s biometric variability. Among the Dictyoconinae, a centric embryo can be considered as the exception rather than the rule.