Helenea conus
Set number: 3098
-
1
-
2
-
3
-
4
10µm
Staurolithites? conus Worsley, 1971
Calculated holococcolith diameter: 9.50 µm
Large (>6.0 µm), circular to subcircular (ellipticity <1.15) species of Helenea are characterised by a large central area spanned by a cross with bifurcated arm terminations, supporting a short distal process with a distinct square-shaped termination.
Helenea conus was originally defined as a circular species, but is emended here to include subcircular specimens.
Optical properties consistent with those of Helenea, but its elongation direction cannot be determined.
Bown, P. R., Rutledge, D. C., Crux, J. A. & Gallagher, L. T. (1998). Lower Cretaceous. In: Bown, P. R. (Ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 86-131
Worsley, T. R., 1971. Calcareous nannofossil zonation of Upper Jurassic and Lower Cretaceous sediments from the Western Atlantic. In: Farinacci, A. (ed.), Proceedings of the Second Planktonic Conference Roma 1970. Edizioni Tecnoscienza, Rome vol. 2, pp. 1301-1321.
Holotype
Helenea conus
Worsley, 1971
Berriasian - Valanginian
JOIDES, DSDP Leg 1, Site 5A, Caribbean Sea.