Nannotax3 - ntax_main - Lapideacassis

Citation: Lapideacassis Black 1971

Type species: Lapideacassis mariae Black 1971

Taxonomic discussion: This is strange group with rare and sporadic stratigraphic distribution. Many species are recorded in both the Cenozoic and the Cretaceous, but it is not clear how meaningful the species-level taxnomy is.

Distinguishing features:
Parent taxon (Lapideacassaceae): Hemispherical to cylindrical nannoliths, with walls constructed from one to several cycles of thin elements, enclosing a hollow central space; the nannolith tapers distally, and may have long apical spines or processes.
This taxon: Hemispherical to cylindrical nannoliths, with walls constructed from one to several cycles of thin elements, enclosing a hollow central space; the nannolith tapers distally, and may have long apical spines or processes.
Species arranged here by number of spines.

The numerous described species are based on numer of tiers in the body and especially on the number and arrangement of spines. It is likely the genus is oversplit but it is rare to find enough specimens to enable a useful study. In the table species are arranged by number of spines.

Geological Range:
Last occurrence (top): at top of Eocene Epoch (100% up, 33.9Ma, in Priabonian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within Early Aptian Substage (118.70-121.40Ma, base in Aptian stage). Data source: Total of ranges of species in this database

References:

Black, M. (1971b). Problematical Microfossils from the Gault Clay. Geological Magazine. 108(4): 325-327. gs

Black, M. (1971a). Coccoliths of the Speeton Clay and Sutterby Marl. Proceedings of the Yorkshire Geological Society. 38: 381-424. gs

Burnett, J. A. (1997c). New species and new combinations of Cretaceous nannofossils and a note on the origin of Petrarhabdus (Deflandre) Wise & Wind. Journal of Nannoplankton Research. 19(2): 133-146. gs

Crux, J. A. (1981). New calcareous nannofossil taxa from the Cretaceous of South East England. Neues Jahrbuch für Geologie und Paläontologie, Monatshefte. 1981: 633-640. gs

Forchheimer, S. & Stradner, H. (1973). Scampanella, eine neue Gattung kretazischer Nannofossilien. Verhandlungen der Geologischen Bundesanstalt (Wien). 1973(2): 286-289. 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

Perch-Nielsen, K. & Franz, H. E. (1977). Lapideacassis and Scampanella, calcareous nannofossils from the Paleocene at sites 354 and 356, DSDP Leg 39, Southern Atlantic. Initial Reports of the Deep Sea Drilling Project. 39: 849-862. gs

Daughter taxa (time control age-window is: 0-800Ma)
				Lapideacassis glans 0 spines; dome shaped; proximal collar
				Lapideacassis mariae 0 spines; elongate, tiered; proximal collar
				Lapideacassis asymmetrica 1 spine; asymmetric cone
				Lapideacassis blackii 1 spine; symmetric cone, tiered
				Lapideacassis magnifica 1 spine, with apical cross-shaped calyx;
				Lapideacassis bispinosa 2, asymmetric, spines; proximal collar
				Lapideacassis cornuta 2, apical spines at about 45 degrees.
				Lapideacassis wisei 3, asymmetric, spines; proximal collar
				Lapideacassis trispina 3 spines sub-horizontal, evenly spaced; tiered; proximal collar
				Lapideacassis tricornus 3, near-vertically orientated, tapering apical spines.
				Lapideacassis multispinata >3 spines; tiered; proximal collar
				Lapideacassis sp. Specimens which cannot be assigned to any established species

Lapideacassis

References:

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