Catalog - Globigerina stainforthi Hofker <title>Catalog - Globigerina stainforthi Hofker

CATALOG OF ORIGINAL DESCRIPTIONS: Globigerina stainforthi Hofker 1956

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.


Higher levels: pf_cat -> G -> Globigerina -> Globigerina stainforthi Hofker
Other pages this level: << < G. scalena, G. schachdagica, G. scobinata, G. seminolensis, G. seminulina, G. semivera, G. siakensis, G. simulans, G. siphonifera, G. soldadoensis, G. soldadoensis angulosa, G. spinuloinflata, G. spiralis, G. spirata, G. stainforthi, G. stainforthi Hofker, G. steiningeri, G. stonei, G. subcorpulenta, G. subcretacea, G. subcretacea Chapman, G. subdigitata, G. subsphaerica, G. subtarchanensis, G. subtriloculinoides, G. supracretacea, G. taminensis, G. tarchanensis, G. tardita, G. taroubaensis, G. tecta> >>

Globigerina stainforthi Hofker

Citation: Globigerina stainforthi Hofker 1956
Rank: Species
Type specimens: Text-fig. 96, 97; P4916
Type sample (& lithostrat): Seca Formation, neritic facies; in shale. Abundant.
Type age (chronostrat): Upper Eocene
Type locality: Sea cliffs just west of Punta Mambra, 22 km south and 98.5 km west from the Plaza del Centenario monument in Guayaquil, Guayas Province, southwestem Ecuador.
Type repository: Washington; USNM

Current identification:


Original Description

Usually only three chambers visible on the ventral side, though sometimes part of a fourth can be seen. Chambers large, especially the last, which forms nearly half the test. The rate of increase in chamber  size is remarkably high, the length-ratio on the ventral side being 1.35: 1. Chambers greatly inflated on both sides. On the dorsal side all chambers may be visible, but in many tests the final coil envelops the earlier chambers. On the ventral side three chambers meet at the center, and there is no umbilical cavity. The aperture is a very narrow slit, often nearly invisible, with an inconspicuous rim, running suturally from the center. Pore-index 11-1, X 500 (an average of eleven pores per square centimeter, with an average diameter of 1 mm, at a magnification of 500X). Surface nearly smooth, with no reticular ornamentations.

Size:
Test medium-sized to large, greater diameter 0.36-0.75 mm, lesser diameter 0.30-0.50 mm, thickness 0.26-0.48 mm.

Etymology:

Extra details from original publication

Editors' Notes
Homonym of Globigerina stainforthi Brönnimann, 1952; see Globigerina aequatorialis Hofker and Thalmann, 1959, new name, and Globigerina hofkeri Bermúdez, 1961, new name.

Medium to large form (greater diameter 0.36-0.75 mm, lesser diameter 0.30-0.50 mm; thickness: 0.26-0.48 mm); 3 chambers visible on ventral side, strongly inflated on both sides; aperture a narrow slit, often nearly invisible; no umbilical cavity; surface nearly smooth with no reticular ornamentation. The tightly coiled (involute), trilobate chamber disposition and distinct, low/narrow apertural slit are characteristic features of this form.[Berggren & Wade 2018]

Six syntype specimens were deposited in the Cushman Collection (USNM P4816), Washington, D.C. (not seen). Illustrated specimens figured in Ellis and Messina Catalogue resemble Subbotina utilisindex and, to a lesser extent, S. linaperta and/or S. angiporoides. These forms range into the lower Oligocene but all have a distinctly reticulate surface ornamentation. An examination of type material at the USNM and selection of a neotype is required before a decision on definitive taxonomic affinity/identity can be made.[Berggren & Wade 2018]

References:

Berggren, W. A. & Wade, B. S. (2018). Problematica. In, Wade, B. S., Olsson, R. K., Pearson, P. N., Huber, B. T. & Berggren, W. A. (eds) Atlas of Oligocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication . 46(Chap 20): 511-524. gs V O

Hofker, J. (1956e). Tertiary foraminifera of coastal Ecuador; Part II - Additional notes on the Eocene species. Journal of Paleontology. 30(4): 891-958. gs

Hofker, J. (1956d). not known. Paläontologische Zeitschrift. 30: 76-x. gs


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Globigerina stainforthi Hofker compiled by the pforams@mikrotax project team viewed: 30-1-2023

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