Type Species

Polycostella senaria Thierstein, 1971


Stellate nannoconid having 5-7 segments in plan view. The sutures between them meet at the periphery at its vertices. The side view is nannoconid with an extremely narrow axial canal. The wall has an alternating convex/concave periphery. The different profile of the same specimen was demonstrated in the mobile mount by Varol & Bowman (2019). The mobile mounting proved that at the side view, Polycostlla senaria could not be distinguished from Hexalithus spp., Nannoconus erbae and Nannoconus infans.


Thierstein, H.R., (1971): Tentative Lower Cretaceous Calcareous Nannoplankton Zonation. - Eclogae Geologicae Helvetiae, 64: 459-488.

Varol, O. & Bowman, A. R., (2019): Taxonomic revision of selected Late Jurassic (Tithonian) calcareous nannofossils and the application of mobile mounting. - Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 291: 65-87.