Nannotax3 - ntax_cenozoic - Mesozoic Survivors

Citation: Mesozoic Survivors sensu Young & Bown, 1997

taxonomic rank: informal group of families

Taxonomic discussion: Mesozoic survivors are nannoplankton that survived the K-Pg mass extinction event 65.5 Ma. Many of these taxa are discussed in more depth in the Mesozoic section. Other survivor taxa include Calciosolenia and Braarudosphaera.

Distinguishing features:
Parent taxon (ntax_cenozoic): Extant coccolithophores and Cenozoic calcareous nannofossils - Mesozoic nannofossils are in a separate module
This taxon: Mesozoic taxa which occur in low abundances in the early Palaeogene.

Useful discussion of the K/Pg extinctions effect on nannoplankton include: Bramlette & Martini (1964); MacLeod et al. (1997); Mai et al. (1997); Burnett (1998); Pospichal (1996); Bown (2005);Medlin et al. (2008);Jiang et al. (2010); Schulte et al. (2010);

Geological Range:
Notes: Most of these taxa only occur in the Palaeocene, however, the Watznaueriacean cocolith Tergestiella adriatica is now known to still be extant (Hagino et al. 2015).
Last occurrence (top): Extant. Data source: Total of ranges of the species in this database
First occurrence (base): within Jurassic Period (143.10-201.36Ma, base in Hettangian stage). Data source: Total of ranges of species in this database

References:

Bown, P. R. (2005e). Selective calcareous nannoplankton survivorship at the Cretaceous-Tertiary boundary. Geology. 33(8): 653-656. gs

Bramlette, M. N. & Martini, E. (1964). The great change in calcareous nannoplankton fossils between the Maestrichtian and Danian. Micropaleontology. 10(2): 291-322. gs

Burnett, J. A. (1998). Upper Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 132-199. gs O

Hagino, K. et al. (2015). Re-discovery of a “living fossil” coccolithophore from the coastal waters of Japan and Croatia. Marine Micropaleontology. 116(1): 28-37. gs

Jiang, S., Bralower, T. J., Patzkowsky, M. E., Kump, L. R. & Schueth, J. D. (2010). Geographic controls on nannoplankton extinction across the Cretaceous/Palaeogene boundary. Nature Geoscience. 3(4): -. gs

MacLeod, N. et al. (1997). The Cretaceous-Tertiary biotic transition. Journal of the Geological Society of London. 1254(265-293): -. gs

Mai, H., von Salis, K., Willems, H. & Romein, A. J. T. (1997). Fossil coccospheres from the K/T boundary section from Geulhemmerberg, The Netherlands. Micropaleontology. 43: 281-303. gs

Medlin, L. K., Sáez, A. G. & Young, J. R. (2008). A molecular clock for coccolithophores and implications for selectivity of phytoplankton extinctions across the K/T boundary. Marine Micropaleontology. 67(1-2): 69-86. gs

Pospichal, J. J. (1996). Calcareous nannoplankton mass extinction at the Cretaceous/Tertiary boundary: An update, in Ryder, G., et al., eds., The Cretaceous-Tertiary event and other catastrophes in Earth history. Geological Society of America, Special Papers. 307: 335-360. gs

Schulte, P. et al. (2010). The Chicxulub asteroid impact and mass extinction at the Cretaceous-Paleogene boundary. Science. 327: 1214-1218. gs

Young, J. R. & Bown, P. R. (1997). Cenozoic calcareous nannoplankton classification. Journal of Nannoplankton Research. 19(1): 36-47. gs

Daughter taxa (time control age-window is: 0-800Ma)		Granddaughter taxa
	Biscutaceae Placoliths with two broad shields; central area narrow; distal shield formed from V-units; proximal shield and tube formed from R-units.	Biscutum Discorhabdus
	Chiastozygaceae Loxolith coccoliths with variably-developed proximal/inner-cycles and a central-area spanned by axial, non-axial or diagonal crossbars or a single transverse bar. LM image includes both unicyclic and bicyclic types. Outer rim clockwise-imbricate.	Jakubowskia Neocrepidolithus Staurolithites Zeugrhabdotus
	Markalius Circular placoliths with moderately birefringent shields, bright inner tube cycle and narrow or closed central areas.	Markalius apertus Markalius inversus Markalius latus Markalius neuquenensis Markalius walvisensis Markalius sp.
	Watznaueriaceae Placoliths or modified placoliths with R-unit well developed, forming proximal and distal shield elements with opposite senses of imbrication; the V-unit typically forms a narrow distal cycle near the inner edge of the shield. Central-area structures are typically disjunct. Birefringent LM image, in which the V-unit cycle appears only as a thin, dark line.	Cyclagelosphaera Tergestiella Watznaueria

Mesozoic Survivors

References:

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