Nannotax3 - ntax_mesozoic - Laguncula dorotheae

Distinguishing features:
Parent taxon (Laguncula): Murolith coccoliths with large bulbous/spherical, hollow spines or processes.
This taxon: Small murolith coccoliths with large globular, hollow spines constructed from interlocking rhombiform elements.

Citation: Laguncula dorotheae Black, 1971

Variants: Laguncula pitcherensis Rai (2006) - smaller form

Rare and rather sporadically recorded. Wind & Cepek (1979) reported similar forms from the Valanginian-Hauterivian of DSDP Site 397A (northwest African margin), but their illustrations show larger basal coccolith rims and slightly more elongate distal processes. They are also considerably older than other records of this taxon.

Geological Range:
Last occurrence (top): within Early Cenomanian Substage (96.24-100.50Ma, top in Cenomanian stage). Data source: Bown et al. 1998
First occurrence (base): within Late Aptian Substage (113.20-118.70Ma, base in Aptian stage). Data source: Bown et al. 1998

References:

Black, M. (1971b). Problematical Microfossils from the Gault Clay. Geological Magazine. 108(4): 325-327. gs

Bown, P. R., Rutledge, D. C., Crux, J. A. & Gallagher, L. T. (1998). Lower Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 86-131. gs O

Gale, A. S. et al. (2011). The uppermost Middle and Upper Albian succession at the Col de Palluel, Hautes-Alpes, France: An integrated study (ammonites, inoceramid bivalves, planktonic foraminifera, nannofossils, geochemistry, stable oxygen and carbon isotopes, cyclostratigraphy). Cretaceous Research. 32: 59-130. gs

Kanungo, S., Bown, P. R. & Gale, A. S. (2020). Cretaceous (Albian-Turonian) calcareous nannofossil biostratigraphy of the onshore Cauvery Basin, southeastern India. Cretaceous Research. 118 [2021]: 1-22. gs

Kennedy, W. J. et al. (2000). Integrated stratigraphy across the Aptian-Albian boundary in the Marnes Bleues, at the Col de Pre _-Guittard, Arnayon (Drome), and at Tartonne (Alpes-de-Haute-Provence), France: a candidate Global Boundary Stratotype Section and Boundary Point for the base of the Albian Stage. Cretaceous Research. 21: 591-720. gs

Wind, F. H. & Cepek, P. (1979). Lower Cretaceous calcareous nannoplankton from DSDP Hole 397A (northwest African Margin). Initial Reports of the Deep Sea Drilling Project. 47A: 221-235. gs

Wise, S. W. & Wind, F. H. (1977). Mesozoic and Cenozoic calcareous nannofossils recovered by DSDP Leg 36 drilling on the Falkland Plateau, south-west Atlantic sector of the Southern Ocean. Initial Reports of the Deep Sea Drilling Project. 36(269-491): -. gs O