Nannotax3 - ntax_mesozoic - Eprolithus moratus

Distinguishing features:
Parent taxon (Eprolithus): Moderately tall, circular to stellate, multiradiate nannoliths with 5-9 petaloid wall-cycle elements surrounding a wide central area spanned by a median diaphragm. Typically H-shaped in side view.
This taxon: Eprolithus with seven wall-elements

Citation: Eprolithus moratus (Stover, 1966) Burnett 1998

Basionym: Lithastrinus moratus Stover, 1966

Synonyms:

Eprolithus eptapetalus Varol 1992

Taxonomic discussion: Varol (1992) used L. moratus for polcycloliths with seven long rays and E. eptapetalus with polycycloliths with 7 short rays. Burnett (1998, p.192) recombined moratus into Eprolithus since Stover's type illustrations of L. moratus clearly show it having short rays. She used L. septentarius Forcheimer 1972 for the species with 7 long rays. Corbett & Watkins (2014) also used the same

Seven wall elements are arranged vertically in a ring of two stacked cycles around a central depression. These cycles are connected in the middle of this central depression bya thin plate, or diaphragm, of 7 overlapping lath-shaped ele- ments. The central depression is wide and greater than half the width of the central area measured across the wall elements be- tween the rays. The central depression appears dull in polarized light, giving the impression of a thin, wide diaphragm; however, in SEM the diaphragm is much smaller than the central depression itself (Pl. 4). Rounded to pointed rays project radially from the wall elements in a rosette or petaloid pattern and form a continuous ridge between the two cycles. A slight twisting of these rays may be evident at the proximal or distal end of each element, but generally they remain at less than 15° angle. [Corbett & Watkins 2014]

Geological Range:
Last occurrence (top): within Santonian Stage (83.65-85.70Ma, top in Santonian stage). Data source: Burnett 1998 (subzonal marker)
First occurrence (base): at base of UC6b subzone (0% up, 93.9Ma, in Cenomanian stage). Data source: Burnett 1998 (subzonal marker), fig.6.3

References:

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 O

Bralower, T. J. & Bergen, J. A. (1998). Cenomanian-Santonian calcareous nannofossil biostratigraphy of a transect of cores drilled across the Western Interior Seaway. In, Dean, W. E. & Arthur, M. A. (eds) Stratigraphy and paleoenvironments of the Cretaceous Western Interior Seaway. SEPM Concepts in Sedimentology and Paleontology . (6): -. gs

Bralower, T. J. & Siesser, W. G. (1992). Cretaceous calcareous nannofossil biostratigraphy of Sites 761, 762, and 763, Exmouth and Wombat Plateaus, northwest Australia. Proceedings of the Ocean Drilling Program, Scientific Results. 122: 529-556. gs

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

Corbett, M. J. & Watkins, D. K. (2014b). Transitional forms in the Eprolithus-Lithastrinus lineage: a taxonomic revision of Turonian through Santonian species. Micropaleontology. 60(2): 175-193. gs

Hardas, P. & Mutterlose, J. (2006). Calcareous nannofossil biostratigraphy of the Cenomanian/Turonian boundary interval of ODP Leg 207 at the Demerara Rise. Revue de Micropaléontologie. 49(3): 165-179. 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

Linnert, C., Mutterlose, J. & Erbacher, J. (2010). Calcareous nannofossils of the Cenomanian/Turonian boundary interval from the Boreal Realm (Wunstorf, northwest Germany). Marine Micropaleontology. 74: 38-58. gs

Püttmann, T. & Mutterlose, J. (2019). Calcareous nannofossils from a Late Cretaceous nearshore setting. Journal of Nannoplankton Research. S4: 81-88. gs

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

Stover, L. E. (1966). Cretaceous coccoliths and associated nannofossils from France and the Netherlands. Micropaleontology. 12(2): 133-167. gs

Varol, O. (1992). Taxonomic revision of the Polycyclolithaceae and its contribution to Cretaceous biostratigraphy. Newsletters on Stratigraphy. 27(93-127): -. gs

Eprolithus moratus

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