Triamutilaferrum martinii

Triquetrorhabdulus martinii Gartner, 1967a

Triquetrorhabdulus sp. Martini, 1965, p. 408, Pl. 36, Fig. 6

Elongated nannofossil have two blades and a ridge pointed at one end but truncated at the other. This species can naturally settle in plan and side view. In plan view, it is extinct (the c-axis is parallel to the microscope axis. In the side view, this species is a hockey-stick shape displaying high birefringence having a tangential c-axis [perpendicular to the length of the specimen]. The oblique inclined extinction angle varies depending on which way the toe of the hokey stick' faces.

Triamutilaferrum martinii is distinguished from Orthorhabdus serratus by having an oblique inclined extinction and lacking toot-like projection. The latter species has parallel extinction and tooth-like projection. Both above species differ from the biconical species of Triquetrorhabdulus by having a tangential c-axis, whereas species of Triquetrorhabdulus have an axial c-axis.

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., 1967a. Calcareous nannofossils from Neogene of Trinidad, Jamaica, and Gulf of Mexico. University of Kansas Paleontological Contributions, Papers 29, 1-7.

Martini, E., 1965. Mid-Tertiary calcareous nannoplankton from Pacific deep-sea cores. Colston Papers 17, 393-411.