Pennalithus farnsworthii

Ceratolithus? farnsworthii Gartner, 1967

Triquetrorhabdulus farnsworthii (Gartner,1967) Perch-Nielsen, 1984

Broad species of Pennalithus have three unequal size blades. The c-axis is vertical (vertical to the natural settling of the form). The blades are pointed at both ends but more pointed at one end than the other end. Perpendicular ridges ornament the broadest lateral blade. The median blade is distinctly curved.

Pennalithus farnsworthii differs from Pennalithus rugosus (Bramlette & Wilcoxon, 1967) by having a distinctly curved narrowest median blade, whilst the latter has a straight narrowest median blade. It is distinguished from Pennalithus striatus (Müller, 1974) by lacking additional longitudinal ridges.

Bramlette, M. N. & Wilcoxon, J. A., (1967): Middle Tertiary calcareous nannoplankton of the Cipero section, Trinidad, W.I. - Tulane Studies in Geology and Paleontology. 5: 93-131.

Gartner, S., (1967): Calcareous nannofossils from Neogene of Trinidad, Jamaica, and Gulf of Mexico. - University of Kansas Paleontological Contributions, Papers. 29: 1-7.

Müller, C., (1974): Calcareous nannoplankton, Leg 25 (Western Indian Ocean). - Initial Reports of the Deep Sea Drilling Project. 25: 579-633.

Perch-Nielsen, K., (1984): Validation of new combinations. - INA Newsletter. 6(1): 42-46.