Nannotax Enabling nannofossil research

Description: Sphenoliths without prominent apical spines.

Species included:

Typical specimens	Outline description	Range
	S. abies - cuspate outline, with apical elements elongated into compound spine	caNN7 - NN15
	S. conicus - with small apical spine	Oligocene - NN3
	S.disbelemnos -similar to S. belemnos but with very small apical spine	NN2-3
	S. dissimilis - similar to S. moriformis but with apical cycle of elements extended to form circlet of spines	Oligocene - NN3
	S. moriformis - beehive shaped	Eocene - NN10

Species in this group are poorly defined and of very limited biostratigraphic value. A number of additional species have been described from the Early Miocene, as reviewed by Maiorano & Monechi (1998):

• Sphenolithus cometa de Kaenel & Villa 1996
  
  
• Sphenolithus milanetti Maiorano and Monechi, 1998
• Sphenolithus multispinatus Maiorano and Monechi, 1997
• Sphenolithus procerus Maiorano and Monechi, 1997
• Sphenolithus tintinnabulum Maiorano and Monechi, 1997