Truncorotaloides danvillensis (Howe and Wallace), new generic assignment for a Late Eocene planktonic species of Foraminiferida

• Published in: Journal of Paleontology
• Main Authors: Godfrey, Woodson M., van den Bold, Willem A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1986
• Subjects: Paleontology; Planktonic foraminifera
• Online Access: http://dx.doi.org/10.1017/s0022336000022034; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022336000022034

Globorotalia danvillensis was described by Howe and Wallace (1932) from beds at Danville Landing on the Ouachita River, Louisiana. Fisk (1938) gave these beds formational status, because he considered them to be a mappable unit, representing the uppermost Eocene deposits in Louisiana. These beds are placed in the Globorotalia cerroazulensis s.l. Zone. Globorotalia danvillensis was later reported by Bergquist ( in Bergquist and McCutcheon, 1942) from upper Eocene beds in Mississippi. The present authors have found the same species in beds of the Lower Jackson Group at Montgomery Landing, Louisiana, which include the upper part of the Porticulasphaera semiinvoluta Zone and the lower part of the Globorotalia cerroazulensis Zone. During the investigation it was found that the species exhibits small, secondary, sutural apertures on the spiral side, which places it in the genus Truncorotaloides Brönnimann and Bermúdez (1953). Howe (1939), in his study of the Cook Mountain foraminifera, followed the custom of that time (see Cushman and Dusenbury, 1934, p. 63) of tentatively referring small coiled species of planktonic foraminifera to Globigerina cretacea d'Orbigny. Re-examination of samples from the Cook Mountain Formation of Saline Bayou, Winn Parish, Louisiana (H. V. Howe collection M 524–527) reveals that many of Howe's specimens belong to Truncorotaloides danvillensis . This species occurs here together with T. rohri Brönnimann and Bermúdez.