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Abathomphalus intermedius


Classification: pf_mesozoic -> Globotruncanidae -> Abathomphalus -> Abathomphalus intermedius
Sister taxa: A. intermedius, A. mayaroensis, A. sp.,

Taxonomy

Citation: Abathomphalus intermedius (Bolli, 1951)
Rank: Species
Basionym: Globotruncana intermedius
Synonyms: Globotruncana intermedia difformis; Globotruncana hanzawai; Globotruncana pessagnoi

Type images:

Original description: Globotruncana intermedia Bolli 1951: The test is usually slightly convex on the dorsal side, flat or often slightly convex ventrally, and distinctly lobate, but this is less pronounced than in G. citae. The five, occasionally four, chambers of the last whorl usually possess a marked peripheral edge or keel, and sometimes a second keel is developed (transition to G. mayaroensis). The sutures on the dorsal side are distinctly curved, whereas ventrally they are radial. The chambers often appear slightly inflated and a few show striations, which are radial on the ventral side and more tangential dorsally. The state of preservation of the specimens so far examined has not allowed detailed study of the aperture or apertures, which probably open into the umbilicus.

Entries in the Catalog of original descriptions: Globotruncana hanzawai;
Globotruncana intermedia;
Globotruncana intermedia difformis;
Globotruncana pessagnoi;

Geological Range:
Last occurrence (top): within P. hariaensis zone (66.39-67.30Ma, top in Maastrichtian stage). Data source: [copied from Chronos database]
First occurrence (base): within A. mayaroensis zone (67.30-69.18Ma, base in Maastrichtian 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:Circularcoiling axis:Lowchamber arrangement:Trochospiralumbilicus:Wide
edge view:Spiroconvexumbilical or test sutures:Moderately depressedspiral sutures:Strongly depressedshell porosity:Macroperforate: >2.5
wall texture:Mod. Pustuloseaperture:Umb.-extraumbilicalaperture border:Coalescing porticiaccessory apertures:None
periphery:Double keelumb chamber shape:Petaloidsp chbr shape:Petaloidperiph margin shape:Moderately rounded
umb depth:Deepdiameter mm:0.3 to 0.6width mm:breadth mm:0.15 to 0.3
final-whorl chambers:4.5-5.5

References:

Bolli, H.M., (1951). The genus Globotruncana in Trinidad. Journal of Paleontology, 25(2): 187-199.


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Abathomphalus intermedius compiled by the pforams@mikrotax project team viewed: 23-7-2017

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