Apical region | anterior end of ceratolith, hence terms such as apical node. |
Arch | part of apical region connecting the two arms. |
Arm | rod-like extension back from apical region. |
Rod | rod-shaped structure attached to the nannolith, (e.g. Amaurolithus bizarrus). |
Spur | projection from apical region. |
Keel | lath-like structure running along an arm. Types: Dentate keel - keel formed of sub-parallel teeth. Smooth keel - keel without teeth. |
Tooth | rod-like sub-element of a keel. |
Wing | plate-like extension from main body of nannolith (e.g. Amaurolithus ninae). |
Longitudinal | parallel to length of nannolith. |
Transverse | perpendicular to length of nannolith. |
Blade | one of the three main sub-parts of the nannolith. |
Dentate blade | blade with transverse sub-structure of rod-shaped teeth. |
Lateral blade | one of two broader blades nearly in the same plane (e.g. T. rugosus) |
Median blade | narrowest of three blades. |
Ridge | subsidiary longitudinal structure on a blade. E.g. T. challengeri. |
Wing | blade greatly extended in transverse direction. E.g. T. finifer. |
Tooth | rod-like part of a dentate blade. |