Lapideacassaceae


Ancestry: Mesozoic -> Nannoliths -> Lapideacassaceae
Sister taxa: Braarudosphaeraceae, Goniolithaceae, Eoconusphaeraceae, Lapideacassaceae, Microrhabdulaceae, Nannoconaceae, Polycyclolithaceae, Nannoliths inc sed - radiate multielement, Nannoliths inc sed - other,

Short diagnosis: Hemispherical to tall cylindrical nannoliths, with narrow walls constructed from one to several cycles of thin elements, enclosing a hollow central space; the nannolith tapers distally, and may have apical spines or processes.


Daughter taxa (blue => in age window 0-300Ma) Granddaughter taxa
Large hemispherical to tall cylindrical nannoliths with narrow walls constructed from one to several cycles of thin elements, enclosing a hollow central space; the nannolith tapers distally, and may have apical spines or processes. Protruding ledges often mark the junction of different cycles in the wall.

Taxonomy:

Citation: Lapideacassaceae Black, 1971
Rank: Family
Type species: Lapideacassis Black, 1971.

Farinacci & Howe catalog pages:

Short diagnosis: Hemispherical to tall cylindrical nannoliths, with narrow walls constructed from one to several cycles of thin elements, enclosing a hollow central space; the nannolith tapers distally, and may have apical spines or processes.


Morphology remarks: Rare and sporadic stratigraphical distribution, but K/T boundary survivor.

Evolution & Phylogeny: Forchheimer & Stradner (1973) suggested L. cornuta might be a holococcolith based on TEM images of their paratype specimen which showed a rhombohedral ultrastructure. However, this has not been supported by any other observations and they show much better developed cycles of plates than s normal in holococcoliths. Re-examination of their micrographs shows that the rhombohedra are more variable in size than is normal in holococcoliths, so they may be a diagenetic fabric [my interpretation - JRY 2015]. So, they appear more likely to be heterococcoliths.
The group does not seem to have ben affected by the K/Pg extinctions, with most species also occurring the Paleogene.

Geological Range:
Notes: The groups is always rare.  
Last occurrence (top): within Bartonian Stage (37.75-41.15Ma, top in Bartonian stage). Data source: Total of range of species in this database
First occurrence (base): within Aptian Stage (112.95-126.30Ma, base in Aptian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

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

Forchheimer, S. & Stradner, H., (1973). Scampanella, a new genus of Cretaceous nannofossils. Verhandlungen der Geologischen Bundesanstalt (Wien), 2: 286-289.


Nannotax3 - Mesozoic - Lapideacassaceae by: Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 28-3-2017

Taxon
Search
Search term: in module
Advanced
Search




Comments (0)

No comments yet. Be the first!

Add Comment

* Required information
1000
Captcha Image
Powered by Commentics