In order to clarify the taxonomic status and variability of early maeneceratids, a large population (nearly 300
 specimens) from a single bed low in UD II-G at Hassi Nebech (southern Tafilalt, Anti-Atlas) has been used for
 morphometric investigation.  Apart from usual shell parameters (whorl height and width, apertural height), the
 number and extent of mould constrictions per whorl and the relative proportions between the two adventitious
 lobes have been measured.  There is moderate variation in whorl expansion rates but larger variation can be
 seen in whorl width.  A nurnber of specimens reach values as in the lectotype of M. rotundum (Wedekind) but
 there is only a slight separation of thicker and more compressed specimens.