Nannotax Enabling nannofossil research

Description: Narrow, straight-sided species of Triquetrorhabdulus with c-axis perpendicular to length of nannolith.

Remarks: Similar to T. carinatus in shape but with c-axis perpendicular to length of nannolith. Often lie in an orientation in which they show birefringence, so gypsum plate is useful to show that they have c-axis perpendicular rather than parallel to nannolith length. N.B. rioi is a corrected form of the name rioensis as originally proposed by Olafsson (1989).