Nannotax Enabling nannofossil research

Description: Symmetric 5-rayed discoaster; rays with clockwise deflected (in distal view) proximal extensions. The central area is small with a featureless distal surface and small proximal knob.

Remarks: This species seems to have an identical structure to that of the 6-rayed species D. calcaris (q.v.). Typically only large specimens (>c.10 microns) have well developed offset proximal extensions, associated smaller specimens lack these and are better placed in D.bellus for biostratigraphic rigour. Both the D. calcaris and D. bellus morphotypes have longer stratigraphic ranges than true D. hamatus.

Range: Confined to Zone NN9, which it defines.