Nannotax3 - ntax_mesozoic

Distinguishing features:
Parent taxon (images):
This taxon: Mesozoic nannofossils - Cenozoic and extant taxa are in a separate module

Taxonomic discussion: The Cretaceous/Paleogene extinctions had a massive effect on calcareous nannofossils with virtually all common species becoming extinct, hence it is convenient to treat Mesozoic and Cenozoic nannoplankton separately. They are not, however, phylogenetically separate groups since there are significant common features between them (e.g. V and R mode calcification in heterococcoliths, Young et al. 1992), and since it is commonly accepted that the Cenozoic orders each originated, separately, from Mesozoic precursors (e.g. Perch-Nielsen 1979, Medlin et al. 2008, Bown et al. 2017).
The most important overviews of Mesozoic nannofossils are given by Perch-Nielsen (1985) and in the various chapters in Bown (1998). In addition Bown & Young (1997) introduce the taxonomy used in Bown (1998), and we largely follow that taxonomy here.

Distinguishing features:
Parent taxon (images):
This taxon: Mesozoic nannofossils - Cenozoic and extant taxa are in a separate module

Geological Range:
Last occurrence (top): at top of (100% up, 0Ma, in "Holocene" stage). Data source: Total of ranges of the species in this database
First occurrence (base): within (-Ma, base in "Holocene" stage). Data source: Total of ranges of species in this database

References:

Bown, P. R. & Cooper, M. K. E. (1998). Jurassic. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 34-85. gs O

Bown, P. R. & Young, J. R. (1997). Mesozoic calcareous nannoplankton classification. Journal of Nannoplankton Research. 19(1): 21-36. gs

Bown, P. R. (1998b). Triassic. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 29-33. 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

Bown, P. R., Lees, J. A. & Young, J. R. (2017). On the Cretaceous origin of the Order Syracosphaerales and the genus Syracosphaera. Journal of Micropalaeontology. 36(2): 153-165. gs

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

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

Perch-Nielsen, K. (1979). Calcareous nannofossils from the Cretaceous between the North Sea and the Mediterranean. In, Weidmann, J. (ed.) Aspekte der Kreide Europas. International Union of Geological Sciences Series A . 6: 223-272. gs O

Perch-Nielsen, K. (1985). Mesozoic calcareous nannofossils. In, Bolli, H. M., Saunders, J. B. & Perch-Nielsen, K. (eds) Plankton Stratigraphy. Cambridge University Press, Cambridge (1): 329-426. gs

Young, J. R., Didymus, J. M., Bown, P. R., Prins, B. & Mann, S. (1992). Crystal assembly and phylogenetic evolution in heterococcoliths. Nature. 356: 516-518. gs

Daughter taxa (time control age-window is: 0-800Ma)		Granddaughter taxa
	Heterococcoliths
	Arkhangelskiales Tiered placoliths with 3-5 closely-appressed shields.	Arkhangelskiellaceae Kamptneriaceae
	Eiffellithales Murolith coccoliths with an upper/outer cycle of clockwise-imbricate V-units and a lower/inner cycle of R-units.	Chiastozygaceae Eiffellithaceae Rhagodiscaceae
	Stephanolithiales Murolith coccoliths with a distal/outer cycle of non-imbricating elements, i.e., in side view, the sutures are vertical or near-vertical.	Parhabdolithaceae Stephanolithiaceae
	Podorhabdales Placolith (or modified placolith) coccoliths showing little or no imbrication. Typically, V-units form distal shield, R-units form proximal shield.	Axopodorhabdaceae Biscutaceae Calyculaceae Cretarhabdaceae Mazaganellaceae Prediscosphaeraceae Tubodiscaceae
	Watznaueriales Placolith (or modified placolith) coccoliths with a distal cycle of clockwise-imbricating elements. R-units well developed, forming proximal and distal shield elements with opposite senses of imbrication; V-units typically form a narrow distal cycle near the inner edge of the shield.	Watznaueriaceae
	Syracosphaerales Heterocococcoliths with central area including a cycle of radial laths alternating with rim elements but with tangential c-axis orientations	Calciosoleniaceae Syracosphaeraceae
	Heterococcoliths inc sedis Heterococcolith genera which do not show characteristic features of any of the well-established families.	Papposphaeraceae Unidentified Mesozoic heterococcoliths globular inc sedis muroliths inc sedis placoliths inc sedis planoliths inc sedis
	Holococcoliths & Nannoliths
	Holococcoliths Coccoliths formed of minute (ca 0.1µm) rhombohedral micro-crystals. Often a life-cycle stage with heterococcolith counterpart(s).	Common genera Rarer genera
	Braarudosphaerales Nannoliths formed of multiple layers of thin elements, arranged with rotational symmetry, and showing tangential c-axis orientations.	Braarudosphaeraceae Transitional genera Nannoconaceae Polycyclolithaceae Other nannoliths with tangential c-axes
	Nannoliths inc sedis Nannofossils not obviously homologous with heterococcoliths, holococcoliths, or braarudosphaeralids	Goniolithaceae Eoconusphaeraceae Lapideacassaceae Microrhabdulaceae Nannoliths inc sed - radiate multielement Nannoliths inc sed - other
	Mesozoic non–coccoliths Calcispheres and other non-coccoliths found in nannofossil preps. Some taxa previously placed here have been moved to the calcareous dinoflagellates pages [Feb 2017].	Carnicalyxia Cassianospica Prinsiosphaera Schizosphaerellaceae

Mesozoic Nannoplankton

References: