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Favusella washitensis


Classification: pf_mesozoic -> Favusellidae -> Favusella -> Favusella washitensis
Sister taxa: F. hoterivica, F. washitensis,

Taxonomy

Citation: Favusella washitensis (Carsey, 1926)
Rank: Species
Basionym: Globigerina washitensis
Synonyms: Favusella confusa; Favusella hedbergellaeformis; Hedbergella hiltermanni; Favusella nitida; Favusella orbiculata; Favusella papagayosensis; Favusella pessagnoi; Favusella planata; Favusella quadrata; Favusella scitula; Ascoliella scotiensis; Favusella stiftia; Favusella voloshinae; Favusella wenoensis
Taxonomic discussion: Favusella washitensis is regarded as a species comprising several morphotypes of common origin. The different morphotypes represent different polymorphic stages in the life cycle and ecophenotypes of a single taxon.
Specimens attributed to Favusella are distinguised from Hedbergella by having a distinctly trochoid chamber shape, thicker and distinctly ornamented wall, characteristic pore distribution pattern, and umbilical position of the aperture. [copied from Chronos database]

Type images:

Original description: Globigerina washitensis Carsey 1926: Test elongate, attenuate, moderately narrow, somewhat flattened, often curved, bent or slightly twisted; chambers quite numerous, biserially arranged, very gradually enlarging, full but not noticeably inflated; giving a rather straight appearance to the sides of the shell; sutures slightly depressed, usually not clear-cut but almost always discernible; apical end often truncate; apertural end rather broadly truncate; shell agglutinated, slightly rough. Length up to 1 mm.

Entries in the Catalog of original descriptions: Ascoliella scotiensis;
Favusella confusa;
Favusella hedbergellaeformis;
Favusella nitida;
Favusella orbiculata;
Favusella papagayosensis;
Favusella pessagnoi;
Favusella planata; Favusella quadrata;
Favusella scitula;
Favusella stiftia;
Favusella voloshinae; Favusella wenoensis;
Globigerina washitensis;
Hedbergella hiltermanni;


Emended description: Emended (E.A.M. Koutsoukos, 2005): Test a low to relatively high trochospiral coil, equatorial periphery lobate, peripheral edge rounded. Chambers spherical to subspherical; 1.5 to 3.5 whorls each with 3 to 6 chambers, usually 4 to 5 in last whorl. Last chamber in mature individuals is usually smaller (embryonic), bare or with smooth ornamentation, extending over the umbilicus and partially covering it. Primary aperture usually arcuate, low to moderate, interiomarginal, umbilical to umbilical-extraumbilical in position, bordered by wide or narrow lip. Umbilicus shallow, of variable width. Sutures radial to slightly curved, depressed. Test surface covered by variable sculptural ornamentation, progressively developing from fine rounded tubercles and well-defined rounded or elongated tubercles (some forming elongated quadrangles = ridges), to reticulate system of fine to coarse ridges forming irregular polygonal cells (honeycomb pattern) in ephebic (adult) stage. Numerous minute pores located nearly exclusively within polygonal cells and between tubercles; pores scattered on edges of cell-ridges and tubercles. Size (maximum diameter) <0.1-0.25mm in the neanic stage (1 to 2 whorls), 0.25-0.35mm in ephebic forms (2.5 to 3 whorls) and 0.35->0.5mm in gerontic specimens (3 to 3.5 whorls). [copied from Chronos database]

Geological Range:
Last occurrence (top): within T. globotruncanoides zone (96.08-100.50Ma, top in Cenomanian stage). Data source: [copied from Chronos database]
First occurrence (base): within T. bejaouaensis zone (113.26-118.02Ma, base in Aptian stage). Data source: [copied from Chronos database]

Plot of occurrence data:

NB Plotting of Neptune data has been disabled on the Mesozoic pages because the dataset is both small and badly affected by a few sites with erroneous age models (our obs Huber, Petrizzo, Young, Nov 2016). The data can still be viewed via the range plottertool - tools menu.

Character matrix

test outline:Lobatecoiling axis:Moderate-highchamber arrangement:Trochospiralumbilicus:Narrow
edge view:Spiroconvexumbilical or test sutures:Moderately depressedspiral sutures:Moderately depressedshell porosity:Microperforate: <1
wall texture:Reg. favolateaperture:Umbilicalaperture border:Thin lipaccessory apertures:None
periphery:N/Aumb chamber shape:Inflatedsp chbr shape:Inflatedperiph margin shape:Broadly rounded
umb depth:Shallowdiameter mm:width mm:breadth mm:
final-whorl chambers:4.0-6.0

References:

Carsey, D.O., (1926). Foraminifera of the Cretaceous of central Texas. University of Texas Bulletin, 2612: 1-56.


Favusella washitensis compiled by the pforams@mikrotax project team viewed: 26-6-2017

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