Catalog - Globotruncana dentata

CATALOG OF ORIGINAL DESCRIPTIONS: Globotruncana dentata Hooper 1977

This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.


Higher levels: pf_cat -> G -> Globotruncana -> Globotruncana dentata
Other pages this level: << < G. canaliculata ventricosa, G. carpathica, G. carteri, G. churchi, G. citae, G. coldreriensis, G. concavata cyrenaica, G. conica, G. conica plicata, G. contusa galeoidis, G. contusa patelliformis, G. contusa scutilla, G. contusa witwickae, G. convexa, G. culverensis, G. dentata, G. dorreeni, G. dupeublei, G. erevanica, G. falsocalcarata, G. falsostuarti, G. fareedi, G. flexuosa, G. fornicata, G. fornicata ackermanni, G. fornicata cesarensis, G. fornicata globulocamerata, G. fornicata manaurensis, G. fornicata motai, G. fornicata plummerae, G. fresnoensis> >>

Globotruncana dentata

Citation: Globotruncana dentata Hooper 1977
Rank: Species
Type locality: C-Y Creek. northwestern Western Australia; Toolonga Calcilutite; Sample G.S.W.A. No. 25702.
Type age (chronostrat): Santonian-Campanian transition.
Type repository: Perth; Palaeontology Collection (G.S.W.A.), Mineral House.

Current identification/main database link: Globotruncanita elevata (Brotzen, 1934)


Original Description
Test low trochospiral, slightly lobulate, widely and deeply umbilicate, planoconvex with two and one-half to three whorls, double-keeled in early whorls and commonly single-keeled in last whorl; the six to seven chambers of last whorl expanding very regularly in size, so that ratio of diameter of last whorl to that of penultimate whorl (Da - D'a/Db - D'b, of Pessagno, 1967) is estimated to range approximately 1.6 to 1.9. Spiral side slightly convex at inner whorls, becoming planiform or even concave at the outer; curved, raised, beaded sutures; chambers spirally crescent-shaped, but may become somewhat petaloid later; surfaces smooth, flat in earlier whorls, becoming concave later. Umbilical side highly convex, especially last few chambers; angle XDU of Pessagno (1967) increasing from about 45° at beginning of last whorl to about 85° at last formed chamber; chambers crudely subrectangular tending to become shaped like human canine tooth in last part of last whorl; sutures slightly depressed, but commonly partially filled with curved, beaded ridge extending in arc from umbilical shoulders to merge with keel; umbilical surface rugose. Primary aperture interiomarginal, umbilical; tegilla commonly broken off, leaving a flange, but infralaminal apertures sometimes indicated at margins of flanges. 

Size: Measured diameters of seven specimens range from 0.65 to 0.75 mm.

Extra details from original publication
Comparison with other species: Globotruncana dentata Hooper. n. sp. appears to be closely related to G. ventricosa White, a species that also possesses a G. linneiana early stage. The early double keel of G. dentata commonly is modified to form a single keel in the final whorl. whereas the keel of G. ventricosa is always double. Globotruncana dentata has a Da - D'a/Db- D'b ratio ranging from 1.6 to 1.9. a value that is very close to the 1. 7 to 2.1 range of G. ventricosa. This species is also similar to the form figured as G. paraventricosa (Hofker) by Edgell (1957) from the Campanian of Western Australia. However. G. paraventricosa has 8 chambers in the final whorl. a somewhat convex spiral side. and a double keel throughout and thus differs from G. dentata. Globotruncana dentata also bears a superficial resemblance to G. elevata (Brotzen) which has a similar Da- D'a/Db - D'b ratio. but the latter species is sing le-keeled throughout. G. dentata chiefly differs from G. concavata (Brotzen) = Marginotruncana concavata (Brotzen) of Pessagno by having a single rather than narrow double keel in the final whorl of mature specimens and in having less rapidly expanding chambers.

References:

Hooper, K. (1977). Globotruncana dentate, a new species of Planktonic foraminifer from the Toolonga Calcilutite of Western Australia. Micropaleontology. 23(3): 361-364. gs


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Globotruncana dentata compiled by the pforams@mikrotax project team viewed: 19-9-2021

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