Catalog - Hedbergella (Asterohedbergella)

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Hedbergella (Asterohedbergella)

Citation: Hedbergella (Asterohedbergella)

Type species: Hedbergella (Asterohedbergella ) asterospinosa Hamaoui, 1965.

Test free, concavo-convex to unequally biconvex, trochospirally coiled throughout, spiral side evolute, umbilical side involute, with true umbilicus, with or without pseudoumbilicus, peripheral margin rounded to acute, without carina! band. At least each adult chamber drawn out at the periphery into a conical or flask-shaped, tapering extension which may produce a variably oriented true tubulospine, never inflated terminally. The earliest chambers may be subglobular. The surface of the test may be finely hispid. but without rugosities or costellae. Wall structure calcitic, radiate, finely perforate, lamellar. Aperture a low arch, interiomarginal, extraumbilical-umbilical, bordered by a narrow lip, but lacking tegilla.

Family Globotruncanidae; subfamily Rotaliporinae. Cenomanian. Monotypic.

Taxonomic position and relationships. - The present writer follows Loeblich and Tappan (1961, 1964) in regarding Hedbergella Bronnimann and Brown, 1958 and Praeglobotruncana Bermudez, 1962 as separate genera, but includes Clavihedbergella Banner and Blow, 1959 as a subgenus of Hedbergella. Following Banner and Blow (1959) Hedbergella is placed in the Rotaliporinae which is regarded here as a subfamily of the Globotruncanidae (see Reiss, 1963, p. 73) and not of the Hantkeninidae (Banner and Blow, 1959). The Globigerinacea are considered to include all bilamellid Foraminiferida, in agreement with Reiss (1963, p. 95).

Hedbergella (Asterohedbergella) Hamaoui differs from its probable ancestor Hedbergella (Hedbergella) Bronnimann and Brown, 1958 by its peripheral radially elongated, pointed to tubulospinate chambers. From Hedbergella (Clavihedbergella) Banner and Blow, 1959, this new subgenus differs by the shape of its radially elongated chambers which are pointed to tubulospinate. but neither simply protruding, nor terminally inflated and club-shaped (clavate). H. (Asterohedbergella) resembles Hastigerinoides Bronnimann, 1951, but is trochospiral throughout, not biumbilicate. and has an aperture which is never equatorial. H. (Asterohedbergella) resembles furthermore Schackoina Thalmann. I932, but is trochospiral throughout and its aperture does not become equatorial. H (Asterohedbergella) is distinguished from Rugoglobigerina (Plummerita) Bronnimann, 1951 by the absence of meridional rugosities (costellae) and of large umbilical flaps or tegilla with intralaminal accessory apertures.

Introduced as a sub-genus Hedbergella (Asterohedbergella).

References:

Banner, F. T. & Blow, W. H. (1959). The classification and stratigraphical distribution of the Globigerinaceae. Palaeontology. 2(1): 1-27. gs V O

Hamaoui, M. (1965). On a new subgenus of Hedbergella (Foraminiferida). Israel Journal of Earth Sciences. 13(3-4): 133-142. gs

Loeblich, A. R. & Tappan, H. (1961). Cretaceous planktonic foraminifera: Part I-Cenomanian. Micropaleontology. 7: 257-304. gs

Loeblich, A. R. & Tappan, H. (1964b). Sarcodina, Chiefly "Thecamoebians" and Foraminiferida. In, Moore, R. C. (ed.) Treatise on Invertebrate Paleontology, Protista 2, pt. C. University of Kansas Press, Lawrence 1-900. gs

Reiss, Z. (1963). Reclassification of perforate foraminifera. Bulletin of the Geological Survey of Israel. 35: 1-111. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Hedbergella (Asterohedbergella)

Hedbergella (Asterohedbergella)

References:

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