Distinguishing features: Small to medium (ca 3-8 µm), elliptical; central area narrow with discrete bright tube cycle and dark core.
Daughter taxa (time control age-window is: 0-800Ma)![]() | ||||
Biscutum constans spp. cavum | ||||
Biscutum constans subsp. cavum A large, elliptical Biscutum with a large central opening |
Taxonomy:
List of Cretaceous synonyms, from Verbeek (1977)
Farinacci & Howe catalog pages: D. constans * , B. testudinarium * , B. castrorum * , C. tectiforma * , C. polycingulatus * , B. blacki * , M. blackii * , M. pulchra * , B. multiforme * , B. concavum * , B. gartneri * , B. martellum * , B. sulcata *
Distinguishing features: Small to medium (ca 3-8 µm), elliptical; central area narrow with discrete bright tube cycle and dark core.
Morphology: Minute to medium biscutaceans without any discernible (LM) structure inside their birefringent central tube cycle. These forms show considerable variation in size and in the relative width of the central tube. The smallest forms (c.1.5µm) are barely discernible in the LM.
Tags | LITHS: placolith, elliptical, CA: ca_disjunct, closed, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent, |
Metrics | Lith size: 3->6µm; Data source notes: illustrated specimens |
Geological Range:
Last occurrence (top): within Late Maastrichtian Substage (66.04-69.91Ma, top in Maastrichtian stage). Data source: Bown et al. 1998
First occurrence (base): within Bathonian Stage (166.07-168.28Ma, base in Bathonian stage). Data source: Bown et al. 1998
Plot of occurrence data:
Applegate, J. L. & Bergen, J. A. (1988). Cretaceous calcareous nannofossil biostratigraphy of sediments recovered from the Galicia Margin, ODP Leg 103. Proceedings of the Ocean Drilling Program, Scientific Results. 103: 293-348. gs V O Black, M. & Barnes, B. (1959). The structure of Coccoliths from the English Chalk. Geological Magazine. 96(5): 321-328. gs Black, M. (1971a). Coccoliths of the Speeton Clay and Sutterby Marl. Proceedings of the Yorkshire Geological Society. 38: 381-424. gs Black, M. (1972a). British Lower Cretaceous Coccoliths. I-Gault Clay (Part 1). Palaeontographical Society Monograph. 126: 1-48. gs Bown, P. R. & Concheyro, A. (2004). Lower Cretaceous calcareous nannoplankton from the Neuquen Basin, Argentina. In, Villa, G., Lees, J. A. & Bown, P. R. (eds) Calcareous Nannofossil Palaeoecology and Palaeocenographic Reconstructions, Proceedings of the INA9 conference, Parma 2002. Marine Micropaleontology. 52(1-4): 51-84. gs Bown, P. R. (2005c). Early to Mid-Cretaceous Calcareous Nannoplankton from the Northwest Pacific Ocean, Leg 198, Shatsky Rise. Proceedings of the Ocean Drilling Program, Scientific Results. 198: 1-82. gs V O Bown, P. R., Rutledge, D. C., Crux, J. A. & Gallagher, L. T. (1998). Early Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 86-131. gs Bown, P. R., Gibbs, S. J., Sheward, R., O’Dea, S. & Higgins, D. (2014). Searching for cells: the potential of fossil coccospheres in coccolithophore research. Journal of Nannoplankton Research. 34(special): 5-21. gs V O Bukry, D. (1969). Upper Cretaceous coccoliths from Texas and Europe. University of Kansas Paleontological Contributions, Articles. 51 (Protista 2): 1-79. gs V O Burns, D. A. (1976). Nannofossils from the Lower and Upper Cretaceous deposits, Nettleton,Lincolnshire, England. Revista Española de Micropaleontología. 8(2): 279-300. gs Covington, J. M. & Wise, S. W. (1987). Calcareous nannofossil biostratigraphy of a Lower Cretaceous deep-sea fan complex: Deep Sea Drilling Project Leg 93 Site 603, lower continental rise off Cape Hatteras. Initial Reports of the Deep Sea Drilling Project. 93: 617-660. gs V O Covington, M. (1994). New taxa from the Niobrara Formation (Upper Cretaceous) of Kansas, USA. Journal of Nannoplankton Research. 16(3): 121-131. gs V 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 Górka, H. (1957). Les Coccolithophoridés du Maestrichtien supérieur de Pologne. Acta Palaeontologica Polonica. 2: 239-284. gs V O Grün, W. & Allemann, F. (1975). The Lower Cretaceous of Caravaca (Spain): Berriasian Calcareous Nannoplankton of the Miravetes Section (Subbetic Zone, Prov. of Murcia). Eclogae Geologicae Helvetiae. 68: 147-211. gs V O Grün, W. & Zweili, F. (1980). Das kalkige Nannoplankton der Dogger-Malm-Grenze im Berner Jura bei Liesberg (Schweiz). Jahrbuch der Geologischen Bundesanstalt. 123: 231-341. gs V O Hattner, J. G. & Wise, S. W. (1980). Upper Cretaceous calcareous nannofossil biostratigraphy of South Carolina. South Carolina Geology. 24: 41-117. gs Huh, J. M. & Smith, C. I. (1972). Coccoliths and related calcareous nannofossils from the Upper Cretaceous Fencepost Limstone of Northwestern Kansas. Contributions from the Museum of Paleontology, University of Michigan. 24(3): 17-22. 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 Mai, H. (2001). New coccolithophorid taxa fom the Guelhemmerberg airshaft. Lower Paleocene, The Netherlands. Micropaleontology. 47: 144-154. gs Mai, H., von Salis, K., Willems, H. & Romein, A. J. T. (1997a). Fossil coccospheres from the K/T boundary section from Geulhemmerberg, The Netherlands. Micropaleontology. 43(281-302): -. gs Perch-Nielsen, K. (1968c). Der Feinbau und die Klassifikation der Coccolithen aus dem Maastrichtien von Danemark. Biologiske Skrifter, Kongelige Danske Videnskabernes Selskab. 16: 1-96. gs Perch-Nielsen, K. (1973c). Neue Coccolithen aus dem Maastrichtien von Danemark, Madagaskar und Agypten. Bulletin of the Geological Society of Denmark. 22: 306-333. gs V O Pienaar, R. N. (1968). Upper Cretacous coccolithophorids from Zululand, South Africa. Palaeontology. 11(3): 361-367. gs Pospichal, J. J. & Wise, S. W. (1990b). Maestrichtian calcareous nannofossil biostratigraphy of Maud Rise ODP leg 113 sites 689 and 690, Weddell Sea. Proceedings of the Ocean Drilling Program, Scientific Results. 113: 465-487. gs V O Püttmann, T. & Mutterlose, J. (2019). Calcareous nannofossils from a Late Cretaceous nearshore setting. Journal of Nannoplankton Research. S4: 81-88. gs V O Püttmann, T., Linnert, C., Dölling, B. & Mutterlose, J. (2018). Deciphering Late Cretaceous (Cenomanian to Campanian) coastline dynamics in the southwestern Münsterland (northwest Germany) by using calcareous nannofossils: Eustasy vs local tectonics,. Cretaceous Research. 87: 174-184. gs Püttmann, T., Mutterlose, J., Kaplan, U. & Scheer, U. (2019). Reworking of Cenomanian ammonites decoded by calcareous nannofossils (southern Münsterland Basin, northwest Germany). Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 291(1): 1-17. gs Reinhardt, P. (1965). Neue Familien für fossile Kalkflagellaten (Coccolithophoriden, Coccolithineen). Monatsberichte der Deutschen Akademie der Wissenschaften zu Berlin. 7: 30-40. gs V O Roth, P. H. & Thierstein, H. R. (1972). Calcareous nannoplankton: Leg 14 of the Deep Sea Drilling Project. Initial Reports of the Deep Sea Drilling Project. 12: 546-559. gs V O Thibault, N. (2010). Calcareous nannofossils from the boreal Upper Campanian- Maastrichtian chalk of Denmark. Journal of Nannoplankton Research. 31(1): 39-56. gs V O Varol, O. & Girgis, M. (1994). New taxa and taxonomy of some Jurassic to Cretaceous calcareous nannofossils. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 192: 221-253. gs Wind, F. H. & Wise, S. W. (1983). Correlation of upper Campanian-lower Maestrichtian calcareous nannofossil assemblages in drill and piston cores from the Falkland Plateau, southwest Atlantic Ocean. Initial Reports of the Deep Sea Drilling Project. 71: 551-563. gs V OReferences:
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Biscutum constans compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 19-4-2021
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