Caycedoa conicus

(Perch-Nielsen, 1971b) Bowman & Varol, 2021 Dec 29, 2022

Set number: 597

  • Caycedoae conicus 66777 1
  • Caycedoae conicus 66774 2
  • Caycedoae conicus 66738 3
  • Caycedoae conicus 66743 4
  • Caycedoae conicus 66776 5
  • Caycedoae conicus 66775 6
  • Caycedoae conicus 66739 7
  • Caycedoae conicus 66742 8
  • Caycedoae conicus 66763 9
  • Caycedoae conicus 66766 10
  • Caycedoae conicus 66771 11
  • Caycedoae conicus 66752 12
  • Caycedoae conicus 66762 13
  • Caycedoae conicus 66765 14
  • Caycedoae conicus 66770 15
  • Caycedoae conicus 66745 16
  • Caycedoae conicus 66761 17
  • Caycedoae conicus 66759 18
  • Caycedoae conicus 66760 19
  • Caycedoae conicus 66741 20
  • Caycedoae conicus 66750 21
  • Caycedoae conicus 66748 22
  • Caycedoae conicus 66747 23
  • Caycedoae conicus 66751 24
    10µm
Caycedoa conicus, Late Paleocene, DSDP Leg 25, Site 245, Mozambique Channel (Davie Ridge), Indian Ocean

in mobile mount
Final Epithet
Caycedoa conicus (Perch-Nielsen, 1971b) Bowman & Varol, 2021
Basionym

Heliolithus? conicus Perch-Nielsen, 1971b

Description

Emended by Bowman & Varol, 2021: Large (7.0–12.0μm) and circular species of Caycedoa consisting of one disc and a column. The disc is wide (diameter of disc >diameter of column), displays a depression on the proximal side and appears concave. A narrow central canal occupies the distally tapering high column and the disc. A similar number of segments (about 20–32) comprise the disc and column.

Optical Properties

In the distal/column side, the extinction lines are dextrogyre, but the extinction lines are laevogyre in the proximal/disc side. When viewed using a gypsum plate, the horizontal axis appears within the blue sector on the distal side, but the vertical axis lies within the blue sector on the proximal side. In the plan view, the column appears yellowish and bluish-red (under polarised light). The disc is non-birefringent in plan-view. The disc and column are birefringent in the side-view.

Remarks

Caycedoae conicus differs from Caycedoae kaminadesneraidon by having a high and slightly tapering column, whereas the column of Caycedoae kaminadesneraidon is moderately low and notched distally. Caycedoae conicus is distinguished from Caycedoae micheliorum by having a taller than a wider tapering column, whereas, in the latter, the column is wider than taller.

References

Bowman, A. R. & Varol, O. 2021. A Taxonomic Revision of Heliolithaceae - Applications in Resolving the Problematic Calcareous Nannofossil Biostratigraphy of the Paleocene. In: M. Montenary, M. (Ed.). Calcareous nannofossil biostratigraphy of the Stratigraphy and timescales. 6: 43-223.

Perch-Nielsen, K. 1971d. Neue Coccolithen aus dem Paläozän von Dänemark, der Bucht von Biskaya und dem Eozän der Labrador See. Bulletin of the Geological Society of Denmark 21: 51-66.

Taxonomy
Caycedoa
Biostratigraphy
  • Phanerozoic
    • Cenozoic
      • Paleogene
        • Paleocene
          • Late Paleocene
            • Thanetian
Stratigraphic Range
Thanetian
Zone(s)
NP6 - NP9
Age (Ma)
59.15 - 57.07
Holotype
Caycedoae conicus 66763

Heliolithus conicus Perch-Nielsen, 1971d

Late Paleocene

DSDP Leg 12, Site 119, Cantabria Seamount, Bay of Biscay., North Atlantic Ocean