Catalog - Globigerinita martini martini

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.

Globigerinita martini martini

Citation: Globigerinita martini martini Blow & Banner 1962

Type sample (& lithostrat): sample FCRM 1932

Type age (chronostrat): Cribrohantkenina danvillensis Zone, Upper Eocene,

The small test consists of about three whorls of chambers coiled in a low trochospire. The first whorl consists of five relatively slowly enlarging, moderately inflated chambers; in succeeding whorls four chambers only are present, and they become increasingly inflated and more rapidly enlarging, until (in the largest of specimens) only three and a half chambers are visible ventrally. In equatorial profile the test is subcircular to subtriangular and the equatorial periphery is broadly and moderately strongly lobulate. In axial profile the test is oval to slightly ovate; the cahmbers are subglobular , becoming slightly ovoid and more inflated ventrally in the final part of the test. There is no distinct dorso-peripheral shoulder. In dorsal view, the earlier chambers are semicircular, but they become increasingly inflated and become as broad as long. The dorsal sutures are initially obscure but they later become increasingly, but still relatively weakly depressed. The dorsal intercameral sutures are initially curved, meeting the lobulate spiral suture at broad angles, but they later become subradial. The ventral intercameral sutures are subradial and distinctly depressed. The ventral umbilicus is narrow and shallow; it is not clearly delimited, as delimited, as the umbilical margins of the chambers are of uniform convexity. Relict parts of earlier primary apertures are not visible. A strongly inflated but fairly small bulla covers the umbilicus and the primary apertures are not visible. A strongly inflated but fairly small bulla covers the umbilicus and the primary aperture of the final chamber. The bulla is attached to the umbilical margins of the first and second and final chambersof the last whorl. One single large accessory aperture is present; it is situated at the base of the poisterior side of the bulla, above the umbilical margin of the penultimate chamber, and it frequently extends along the interior part of the umbilical face of the antepenultimate chamber, and the most posterior part of the apertural face of the last chamber. The accessory aperture is furnished with a very narrow and thin, but usually distinct, lip along the associated margin of the bulla. The primary aperture of the final chamber may sometimes be observed trough the accessory aperture where it may be seen to be a very low intraumbilical arch, furnished with a very narrow rim-like thickening. The bulla is so strongly inflated that it very markedly portrudes above the ventral surfaces of the primary chambers; it is of subglobular form and is usually restricted to the umbilical limits, although in some specimens it extends almost to the periphery of the first chamber of the last whorl. The fairly thick wall of the primary chambers is quite coarsely perforate relative to the size of the test; the surface is densely and relatively coarsely hispid. The wall of the bulla is distinctly thinner and more finely perforate than that of the primary chambers; usually its surface shows little trace of hispidity, but some exceptionally large specimens may posess a uniformly hispid bulla.

Maximum diameter of holotype 0·19 mm

This species is named for F. C. R. Martin, geologist of the British Petroleum Co. Ltd, whose careful collections and field work made this study possible.

Remarks: This subspecies should be compared to Globigerinita martini scandretti, described below. The small size of the adult test, the form of the adult chambers the structure and surface of the wall, the shape and position of the bulla, are all among the many characteristic features which serve to distinguish this species.

Stratigraphical range: In the Lindi area, this subspecies ranges from at least the upper part of the Truncorotaloides rohri Zone (Middle Eocene) to the top of the Globigerina turritilina turritilina Zone (Upper Eocene). It has not been found to occur in the G. oligocaenica Zone (Oligocene).

References:

Blow, W. H. & Banner, F. T. (1962). 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. 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

Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (2006a). Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (2006). Taxonomy, biostratigraphy, and phylogeny of Eocene Globigerina, Globoturborotalita, Subbotina, and Turborotalita. 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 6): 111-168. 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 6): 111-168. gs O

Pearson, P. N. & Wade, B. S. (2015). Pearson, P. N. & Wade, B. S. (2015). Systematic taxonomy of exceptionally well-preserved planktonic foraminifera from the Eocene/Oligocene boundary of Tanzania. Cushman Foundation for Foraminiferal Research, Special Publication. 45: 1-85. Cushman Foundation for Foraminiferal Research, Special Publication. 45: 1-85. gs

Spezzaferri, S., Olsson, R. K., Hemleben, C., Wade, B. S. & Coxall, H. K. (2018d). Spezzaferri, S., Olsson, R. K., Hemleben, C., Wade, B. S. & Coxall, H. K. (2018). Taxonomy, biostratigraphy, and phylogeny of Oligocene and Lower Miocene Globoturborotalita. 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 8): 231-268. 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 8): 231-268. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Globigerinita martini martini Blow & Banner 1962

Globigerinita martini martini

References:

Add Comment

Comments