CATALOG OF ORIGINAL DESCRIPTIONS: Globigerina gravelli Bronnimann 1952
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.
Original Description The large, spinose, low trochoid test is composed of about two volutions, the final one with five to six appressed chambers. The outline is ellipsoid and only slightly lobulate. The spiral side is more or less convex. The subcircular umbilicus is large and deep, exposing the arcuate apertures of the last-formed chambers. The chambers are subglobular, flattened peripherally, elongate in direction of the axis of the test, and somewhat pointed on the umbilical side. The sutures are curved in the direction of coiling and well marked, except those of early stage. The large arcuate apertures with minute liplike borders open directly into the umbilicus. The walls of the early chambers are more coarsely perforate and pitted than those of the final chambers. Ths surface is covered with papillae. Those on the umbilical points are strongly developed. On the apertural faces are the absent or rare. The species is coiled in both directions. Size: Holotype: Coiling: dextral. Dimensions: maximum diameter of test, 0.425mm., end chamber, radial diameter, 0.125mm., tangential diameter, 0.2mm., height, 0.25mm. Diameter of umbilicus, ±0.125mm. Etymology: The species is named for the late D.W.Gravell in recognition of his contributions to the knowledge of orbitoidal Foraminifera. Extra details from original publication Remarks: The spinose surface refers this species to the characteristic group of spinose Globigerinae represented in the Trinidad Paleocene by G. soldadoensis, G. primitiva, and G. collactea. It differs from these forms by the large size, greater number of the closely oppressed chambers in the last whorl, and the large, subcircular umbilicus. The four to five-chambered G. collactea which resembles closely in its general form G. gravelli, is much smaller.
Occurrence: Both zones of the Lizard Springs formation, rare to common; Ramdat marl, rare.
References:
Bolli, H. M. (1957d). The genera Globigerina and Globorotalia in the Paleocene-Lower Eocene Lizard Springs Formation of Trinidad. In, Loeblich, A. R. , Jr., Tappan, H., Beckmann, J. P., Bolli, H. M., Montanaro Gallitelli, E. & Troelsen, J. C. (eds) Studies in Foraminifera. U.S. National Museum Bulletin . 215: 61-82. gsVO
Brönnimann, P. (1952d). Trinidad Paleocene and lower Eocene Globigerinidae. Bulletins of American Paleontology. 34(143): 1-34. gs
Globigerina gravelli compiled by the pforams@mikrotax project teamviewed: 29-5-2023
holotype illus_743.jpg
Bolli1957 pl16 01-03.JPG
holotype illus_743.jpg
Bolli1957 pl16 01-03.JPG
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