CATALOG OF ORIGINAL DESCRIPTIONS: Rugoglobigerina (Plummerella) hantkeninoides costata 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 test is stellate in outline and comprises in the last volution five chambers arranged in a depressed trochoidal spiral. The early chambers are slightly, the end chambers strongly, inflated to subglobular. The trochoidal structure is clearly visible from the frontal side. The peripherally well-separated chambers, except the end chamber, are elongate in the radial direction into roughly axially situated points, which correspond to the spines of the central type Rugoglobigerina (Plummerella) hantkeninoides subsp. hantkeninoides Bronnimann. The end chamber does not possess a spine, thus indicating that this feature disappears in the course of the ontogeny (see remarks on the occurrence of spines in subsp. hantkeninoides). The spines are separated by angles of 70 to 80 degrees. The rather shallow umbilicus is not well defined and is filled with matrix. No details are visible on the spiral side. The straight sutures are deep and clearly marked. The aperture is large, semicircular and opens into the umbilicus. The walls seem to be thick and the surface is strongly rugose; the individual ridges and spines - at least of the end chambers - radiate from a central point on the surface. The strong ornamentation of the early chambers of the last volution is irregular. The only well-preserved specimen coils to the right-hand side. Size: Holotype:Maximum diameter 0.35mm. Radial diameter of first spinose chambers 0.15mm. Etymology: Extra details from original publication Remarks: This subspecies is transitional between the central type hantkeninoides and the 3-spined,strongly trochoid subspecies inflata. It differs from the typical form by the distinct trochoidal tests, by the stronger inflated chambers, and by the complete reduction of the spine of the end chamber. It can be separated from inflata by the reduction of the number of spinose chambers to 2 or 3, and by the less inflated end chambers.
Occurrence: Only found in the Globotruncana mayaroensis zone. Scarce. Editors' Notes
References:
Brönnimann, P. (1952c). Globigerinidae from the Upper Cretaceous (Cenomanian-Maestrichtian) of Trinidad, B. W. I. Bulletins of American Paleontology. 34(140): 1-70. gs
Rugoglobigerina (Plummerella) hantkeninoides costata compiled by the pforams@mikrotax project teamviewed: 6-2-2023
Bronnimann 1952_3f4-6-280.jpg
holotype-280.jpg/Rugoglobigerina (Plummerella) hantkeninoides costata/Bronnimann 1952_3f4-6-280.jpg)
Bronnimann 1952_3f4-6-280.jpg/Rugoglobigerina (Plummerella) hantkeninoides costata/holotype-280.jpg)
holotype-280.jpg
Comments
(0)