Citation: Globorotalia nagappai Raju 1968Rank: SpeciesDescribed on page(s) : 297Type specimens: Pl. IV, figs. 2a-cType sample (& lithostrat): core samples(226.5-229.5) PTK-1 wellType age (chronostrat): G. rex zone to G.palmerae zone, Lower EoceneType locality: Pattukottai well No.1, Cauvery basin, South India.Type repository: Baroda; Palaeontology Laboratory, Oil & Natural Gas Commission, Baroda, India.
Original Description Test small, low trochospiral, planoconvex; equatorial periphery lobate, axial periphery angular with distinct keel, ornamented with small spines; wall calcareous, finely perforate, occasionally spinose. Chambers strongly compressed, 13-15, 5½-6 in the last whorl increasing rapidly in size. Sutures on umbilical side radial, depressed; on spiral side curved,depressed. Umbilicus shallow, wide open. Aperture a low arch with a prominent lip; in a few forms relict apertures are observed. Size: Largest diameter of holotype 0.35.; greatest thickness 0.08 mm. Etymology: in honour of the late Shri Y. Nagappa, in recognition of his work on biostratigraphy of India. Extra details from original publication Remarks: This species has certain similarities with G. lehneri Cushman & Jarvis. It differs from the latter in being smaller in size; it has 5-6 chambers in the last whorl while G. lehneri has 6-7 chambers. Moreover, G. lehneri is known from Middle Eocene only. It differs from G. planoconica Subbotina in having well separated chambers. Rare forms morphologically transitional to G. nagappai and G. palmerae are found in the lower part of G. palmerae zone of PTK-1. Editors' Notes
Raju, D. S. N. (1968). Eocene-Oligocene planktonic foraminiferal biostratigraphy of Cauvery Basin, South India. Memoir of the Geological Society of India. 2: 286-299. gs
Globorotalia nagappai compiled by the pforams@mikrotax project teamviewed: 4-12-2022