Catalog - Globorotalia gemma

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Globorotalia gemma

Citation: Globorotalia gemma Jenkins 1966

Type specimens: Fig. 11, Nos. 97-103. TF 1505: holotype and 4 paratypes.

Type age (chronostrat): Lower part of Whaingaroan Stage (Lower Oligocene)

Type locality: F 9398, S136/694, Grid ref. 482554, Kakanui River, south bank near mouth, 2ft 6 in. above bored surface, calcareous glauconitic finegrained sandstone, MacDonald Limestone. Collected by M. Gage.

Type repository: Lower Hutt, New Zealand; New Zealand Geological Survey

Test free, small, dextrally coiled, very low trochospiral, equatorial periphery distinctly lobulate; axial periphery rounded. Wall calcareous, finely perforate, surface smooth. Chambers globular, slightly compressed, 10 arranged in about 1 1/2 whorls with 5 in the first whorl and 5 1/2 in the last increasing slowly in size; proloculus diameter about 0·02 mm. Sutures on the spiral and umbilical sides slightly recurved, depressed. Umbilicus small, open. Aperture, very low, lipped arch, interiomarginal, umbilical-extraumbilical.

The specific name is derived from the latin gemma meaning "gem""."

1953 Globigerina postcretacea; Subbotina, Trudy, VNIGRI n.s. 76: 60, pI. 2, figs. 16a-20c.
1962 Globorotalia (Turborotalia) postcretacea; Blow and Banner (in Eames et al., 1962): 120, pI. 12, figs. G-J.
1964 Globorotalia postcretacea; Saito and Be, Science 145 (3633): 704, fig. 2.

Remarks: Since the original description of Globigerina postcretacea Myatliuk (1950) from the Northern Carpathian Mountains it has been recorded from the Caucasus region by Subbotina (1953), by Blow and Banner (in Eames et al. 1962) from the Lindi area of Tanganyika and by Saito and Be (1964) from Alabama, U.S.A. In the writer's opinion the last three records of G. postcretacea do not agree with Myatliuk's original figure and description (Myatliuk, 1950; Ellis and Messina, 1940 et seq.) but belong to the new species described here under the name of Globorotalia gemma.

Globrotalia gemma n. sp. differs from Globigerina postcretacea Myatliuk in its more compressed test, which tends to be planispirally coiled in many specimens, in having 5-6 chambers in the final whorl contrasted with 4-4-1, and in having an extraumbilical to umbilical aperture as compared to the umbilical aperture of G. postcretacea.
In all the New Zealand populations of G. gemma examined, there is a wide range in variation. Most of the tests are nearly planispirally coiled as in the holotype; at the other extreme the final chamber tends to be nearer the umbilicus and out of the plane of coiling (No. 103), giving the test a different appearance from that of the holotype. The more usual form of G. gemma as exemplified by the holotype becomes more numerous and dominates the populations in the upper part of its stratigraphic range in the lower part of the Whaingaroan
Stage.

The article was published in the December 1965 issue of the journal but appeared in early 1966, so for taxonomy the correct date is 1966

References:

Blow, W. H. & Banner, F. T. (1962). The mid-Tertiary (Upper Eocene to Aquitanian) Globigerinaceae. In, Eames, F. E., Banner, F. T., Blow, W. H. & Clarke, W. J. (eds) Fundamentals of mid-Tertiary Stratigraphical Correlation. Cambridge University Press, Cambridge 61-151. gs

Huber, B. T., Olsson, R. K. & Pearson, P. N. (2006). Taxonomy, biostratigraphy, and phylogeny of Eocene microperforate planktonic foraminifera (Jenkinsina, Cassigerinelloita, Chiloguembelina, Streptochilus, Zeauvigerina, Tenuitella, and Cassigerinella) and Problematica (Dipsidripella). In, Pearson, P. N., Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (eds) Atlas of Eocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication . 41(Chap 16): 461-508. gs O

Jenkins, D. G. (1966b). Planktonic foraminiferal zones and new taxa from the Danian to lower Miocene of New Zealand. New Zealand Journal of Geology and Geophysics. 8 [1965](6): 1088-1126. gs

Myatliuk, L. V. (1950). Stratigrafiya flishevykh osadkov severnykh Karpat v cveta dannykh fauny foraminifer [Stratigraphy of the flysch seditments of the Northern Carpathian Mountains in the light of the foraminiferal fauna.]. In, unknown (ed.) Microfauna of the USSR, 4. Trudy Vsesoyuznego Neftyanogo Nauchno-Issledovatel'skogo Geologo-Razvedochnogo Instituta (VNIGRI) . 51: 225-287. gs

Pearson, P. N., Wade, B. S. & Huber, B. T. (2018c). Taxonomy, biostratigraphy, and phylogeny of Oligocene Globigerinitidae (Dipsidripella, Globigerinita, and Tenuitella). In, Wade, B. S., Olsson, R. K., Pearson, P. N., Huber, B. T. & Berggren, W. A. (eds) Atlas of Oligocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication . 46(Chap 16): 429-458. gs O

Saito, T. & Bé, A. (1964). Planktonic foraminifera from the American Oligocene. Science. 145: 702-705. gs

Subbotina, N. N. (1953). Foraminiferes fossiles d'URSS Globigerinidae, Globorotaliidae, Hantkeninidae. Bureau de Recherches Geologiques et Minieres. 2239: 1-144. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Globorotalia gemma Jenkins 1966

Globorotalia gemma

References:

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