Citation: Globigerina stonei Weiss 1955Rank: speciesType specimens: Plate 5, figures 16-21Type sample (& lithostrat): Holotype from I. P. Co. well 3297, core depth 1561-1579 feet.Type age (chronostrat): PaleoceneType locality: northwestern PeruType repository: New York, AMNH
Original Description Test small, consisting of about two whorls, dorsal side flattened, ventral convex with a large, open umbilicus, periphery rounded and lobulate; four chambers in the last whorl, enlarging gradually as added, sub-globular, with a slight ventral taper; sutures depressed, distinct; wall conspicuously perforate and covered with fine papillae; aperture an arched slit at the base of the last septal face, extending from the open umbilicus toward the periphery, often with a slight lip. Size: Greatest diameter of holotype 0.25 mm. Etymology: Extra details from original publication
Globigerina cf. G. pseudobulloides Plummer, CUSHMAN & STONE, 1949, Cushman Lab. Foram. Research Contr., vol. 25, p. 57, pl. 10 fig. 15
Cushman and Stone's well-figured specimen was reported from the Chacra formation of the La Brea-Pariias property, where it is sometimes larger than the Pale Greda holotype. However, G. pseudobulloides Plummer is composed of five and sometimes six highly ventricose chambers and does not agree closely with the Pale Greda or Chacra forms. There are also more compressed variants of G. stonei present in both the Chacra and Pale Greda formations. These range through all intermediate stages toward the end form which differs from the typical G. stonei in its more tightly coiled globorotalid test with three and one-half to four more appressed chambers, a less lobulate periphery, and a smaller umbilicus.
Both end types and all transitional forms of G. stonei are fairly common throughout the Pale Greda formation. Editors' Notes Weiss published two papers in 1955 on the same material, in Micropaleontology and Journal of Paleontology. The details on the planktonic foraminifera are given in the paper in Micropaeontology but the original descriptions are in the paper in Journal of Paleontology.
Weiss, L. (1955a). Foraminifera from the Paleocene Pale Greda Formation of Peru. Journal of Paleontology. 29(1): 1-21. gs
Weiss, L. (1955b). Planktonic index foraminifera of northwestern Peru. Micropaleontology. 1: 301-319. gs
Globigerina stonei compiled by the pforams@mikrotax project teamviewed: 27-11-2022