Nannotax3 - ntax_mesozoic - Broinsonia parca

Distinguishing features:
Parent taxon (Broinsonia): Outer rim of V-units, with slight clockwise obliquity, visible on distal surface and form dark rim in LM; central-area spanned by an axial cross, grill or perforate plate. 3 tiers visible in side view.
This taxon: Large (>9 µm) central structure perforate plate; rim broad.

Citation: Broinsonia parca (Stradner, 1963) Bukry, 1969

Basionym: Arkhangelskiella parca Stradner, 1963

Taxonomic discussion: This is a stratigraphically useful lineage, it is discussed in detail in Hattner et (1980) and Wise (1983) and the sub-species definitions follow those works. Linnert et al. (2014) suggest separating B. parca from B. enormis based on size, with a 9 µm cut-off.

In well-preserved specimens of all three sub-species there are often 3 - 5 delicate radial bars at the base of each pore.

Geological Range:
Last occurrence (top): within Campanian Stage (72.05-83.64Ma, top in Campanian stage). Data source: Burnett 1998
First occurrence (base): within Coniacian Stage (86.26-89.77Ma, base in Coniacian stage). Data source: Burnett 1998

References:

Bukry, D. (1969). Upper Cretaceous coccoliths from Texas and Europe. University of Kansas Paleontological Contributions, Articles. 51 (Protista 2): 1-79. gs O

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

Crux, J. A. (1980). A biostratigraphical study of Upper Cretaceous nannofossils from South-east England and North France. PhD thesis, University College London. -. gs

Hattner, J. G., Wind, F. H. & Wise, S. W. (1980). The Santonian-Campanian boundary: comparison of nearshore-offshore calcareous nannofossil assemblages. Cahiers de Micropaléontologie. 3: 9-26. gs O

Romein, A. J. T., Willems, H. & Mai, H. (1996). Calcareous nannoplankton of the Geulhemmerberg K/T boundary section, Maastrichtian type area, the Netherlands. Geologie en Mijnbouw. 75: 231-238. gs

Stradner, H. (1963). New contributions to Mesozoic stratigraphy by means of nannofossils. Proceedings of the Sixth World Petroleum Congress. Section 1 Paper 4: 167-183. gs

Wise, S. W. (1983). Mesozoic and Cenozoic calcareous nannofossils recovered by DSDP Leg 71 in the Falkland Plateau region, Southwest Atlantic Ocean. Initial Reports of the Deep Sea Drilling Project. 71: 481-550. gs O

Sub-taxa & variants (time control age-window is: 0-800Ma)
				Broinsonia parca subsp. expansa Broad central plate; plate width >2 x margin width
				Broinsonia parca subsp. parca Intermediate width central plate; plate width 1-2 x margin width
				Broinsonia parca subsp. constricta Narrow central plate; plate width <1 x margin width

Broinsonia parca

References:

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