Set number: 476

  • Orthorhabdus serratus 22722 1
  • Orthorhabdus serratus 22725 2
  • Orthorhabdus serratus 22726 3
  • Orthorhabdus serratus 22729 4
  • Orthorhabdus serratus 22723 5
  • Orthorhabdus serratus 22724 6
  • Orthorhabdus serratus 22727 7
  • Orthorhabdus serratus 22728 8

Symmetrical inclined extinction, possibly not belong to this species

Triamutilaferrum martinii, Middle Miocene, ODP Leg 154, Site 925C, Ceara Rise, Equatorial Atlantic Ocean

Set number: 477

  • Triamutilaferrum martinii 27657 1
  • Orthorhabdus serratus 27656 2
  • Orthorhabdus serratus 27653 3
  • Orthorhabdus serratus 27661 4
  • Orthorhabdus serratus 27658 5
  • Orthorhabdus serratus 27655 6
  • Orthorhabdus serratus 27654 7
  • Orthorhabdus serratus 27659 8

Oblique inclined extinction

Triamutilaferrum martinii, Middle Miocene, DSDP Leg 25, Site 242, Mozambique Channel (Davie Ridge), Indian Ocean
Final Epithet
Triamutilaferrum martinii (Gartner, 1967a) Varol, n. comb.

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.