Catalog - Zeauvigerina zelandica

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.

Other pages this level: Z. aegyptiaca, Z. lodoensis, Z. parri, Z. teuria, Z. zelandica

Zeauvigerina zelandica

Citation: Zeauvigerina zelandica Finlay 1939

Type specimens: Plate 69, figs. 4a, b; 26775a

Type age (chronostrat): Bortonian, Eocene

Type locality: locality 5300 (Moeraki N.E. Survey District, 1 mile at 29° from trig E, "marly clay" of McKay), New Zealand

Type repository: Washington; USNM

Test minute, even for the genus. Microspheric form larger, fairly regularly and acutely tapering, about 8 chambers on each side and a small distinct proloculum, perfectly terminal and with no trace of coiling. Megalospheric form shorter and less acute, with a tendency towards a change in the angle of tapering on one side at lower third, about 6 chambers on each side. Greatest width usually across last 2 chambers, but sometimes the sides below this almost sub-parallel. Considerable variation in outline and proportions. Early chambers usually considerably compressed in microspheric form, of equal inflation with the later ones in megalospheric. Adult chambers sub-globular, somewhat compressed from front to back, and closely knit at sutures, which are never more than shallow grooves and frequently most obscured by ornament; they are not quite horizontal, but the angle is slight; a similar medial, undulating, shallow groove where chambers meet. There is never any trace of separation of the later chambers as in Eouvigerina gracilis Cushman. Final chambers not triserial, the whole structure of the shell being bolivine. Aperture rising abruptly from ultimate chamber where it meets penultimate, medial in position, a relatively stout and large tube with a fairly broad, phialine lip, sometimes very short or obscurely developed and occasionally with last part smooth, but the papillae usually run through right up to it.

Length of paratype 0.27 mm., breadth 0.175 mm.; thickness half to two-thirds width.

These are the dimensions of the figured specimen, which is from locality 3310 (greasy marl, interbedded with greensand, 1 mile North- west of Pahi, Paparoa Arm, Matakohe Survey District). Since the figure (which gives quite a fair idea of the species) was drawn, better preserved specimens have been found from a locality where the sequence of beds is also much clearer. The holotype is accordingly taken from locality 5300 (Moeraki N.E. Survey District, 1 mile at 29° from trig E, "marly clay" of McKay), and will be figured in a later paper. The latter locality is the highest of a sequence of beds -the Hampden or Kakahoian glauconitic marls- all definitely Bortonian (Eocene). This sequence can be subdivided but Zeauvigerina has not been found in the middle or lower parts. Also, in numerous other localities it occurs always associated with upper Bortonian species. It can be taken, therefore, as a good index of Upper Middle Eocene age, as distinct from the lower Bortonian, which is probably still middle Eocene.

The species is a characteristic one of the Wanstead horizon and occurs at numerous localities of this age in the Dannevirke and adjoining districts. It is also present in some of the chalk marls at the base of the Amuri limestone (e.g., Hurunui Mouth, left bank of river, first outcrop upstream from mouth) and incidentally proves the whole of the Amuri limestone in this area to be Tertiary and not older than Upper Eocene. It is again present at several places in the Te Hua marls of the Waitangi fault area and coeval beds in the Poverty Bay district, which are thus definitely referable to the Bortonian and cannot be Cretaceous in age.

References:

Finlay, H. J. (1939d). New Zealand Foraminifera: The Occurrence of Rzehakina, Hantkenina, Rotaliatina, and Zeauvigerina. Transactions of the Royal Society of New Zealand. 68(4): 534-543. 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

CATALOG OF ORIGINAL DESCRIPTIONS: Zeauvigerina zelandica Finlay 1939

Zeauvigerina zelandica

References:

Add Comment

Comments