Biscutum monocavum

Bukry, 1969 Jan 13, 2026

Set number: 2750

  • Biscutum monocavus 12697 1
  • Biscutum monocavus 12698 2
  • Biscutum monocavus 12700 3
  • Biscutum monocavus 12701 4
  • Biscutum monocavus 12705 5
  • Biscutum monocavus 12703 6
  • Biscutum monocavus 12704 7
  • Biscutum monocavus 12702 8
    10µm
Biscutum monocavum, Early Berriasian, DSDP Leg 76, Site 534, Blake-Bahama Basin, Atlantic Ocean

The assignment of this species to Biscutum monocavum is questionable, given its large size and significantly older stratigraphic occurrence.
Final Epithet
Biscutum monocavum Bukry, 1969
Basionym

Bidiscus monocavus Bukry, 1969

Holotype

Calculated size: 3.10 µm; number of segments in the proximal shield: 17–21; number of segments in the tube cycle: 18–22.

Optical Properties

In plan view under XPL, the distal shield is in constant extinction because the optic axis (c-axis) is perpendicular to the microscope stage, whereas the proximal shield and tube cycle display a white interference colour and exhibit length-fast (–) elongation.

Remarks

The circular placolith has a distal shield larger than the proximal shield and a tube cycle surrounding a featureless central opening.

References

Bukry, D. 1969. Upper Cretaceous coccoliths from Texas and Europe. University of Kansas Paleontological Contributions, Articles 51 (Protista 2): 1-79.

Taxonomy
Biscutum
Biostratigraphy
  • Phanerozoic
    • Mesozoic
      • Cretaceous
        • Late Cretaceous
          • Senonian
            • Santonian
              • Late Santonian
        • Early Cretaceous
          • Neocomian
            • Berriasian
              • Early Berriasian
Stratigraphic Range
Early Berriasian - Late Santonian
Age (Ma)
143.10? - 83.65?
Holotype
Biscutum monocavus 12697

Bidiscus monocavus Bukry, 1969

Santonian

Knox County, Nebraska, USA