Fossil of the Month: Agglutinated foraminifera

Many fossils can only be seen with a microscope. The fossil of the month for April 2018 is a microfossil called an agglutinated foraminifera. Forams are tiny protists. Protists are not animals, plants, or fungi, but rather a distinct phylum of the eukaryote kingdom. Most foraminifera are marine, benthic (living on or near the seafloor) organisms. At least 4,000 different species are known in the world’s oceans today. Forams have thin outer shells or coverings, called “tests.” Agglutinated forams are a special type of foraminifera in which the test is composed of cemented sediment grains rather than calcite or other secreted substances.

The microscopic agglutinated foraminifera Hyperammina kentuckyensis, shown at 50 times their size. From Conkin (1961, Plate 21, Figs. 1–9), used with permission of the Paleontological Research Institution.

Agglutinated forams were chosen as our fossil of the month in memory of Dr. James Conkin, a Kentucky paleontologist who passed away last year; he studied agglutinated forams (among many other things). Hyperammina kentuckyensis is an example of an agglutinated foram. Although the KGS collection does not have samples of this fossil, it was named for and found in Kentucky. It was initially described and named by Dr. Conkin in 1954 from samples he found in the Lower Mississippian (Osagean) Coral Ridge fauna of the New Providence Member of the Borden Formation south of Louisville, Ky. Specimens have also been found in other parts of the New Providence Member and the Floyds Knob Bed of the Muldraugh Member of the Borden Formation (Conkin, 1961). The tests of these foraminifera are 0.4 to 1.6 millimeters in length, conical, slightly curving, and composed of well-cemented silt grains.

James Conkin founded the Geology Department at the University of Louisville in 1964 and taught there from 1957 through 2001 (the geology department was subsequently merged into the Department of Geography and Geosciences). In Kentucky, Dr. Conkin is perhaps best known for the many field guides and booklets he co-wrote with his wife, Barbara, concerning the geology of the greater Louisville area and the Falls of the Ohio, but he also wrote many research articles on foraminifera and on Devonian and Mississippian stratigraphy and paleontology. Jim was an avid field geologist and teacher. In his life, he had three fossil species named for him by other paleontologists, which in itself is a tribute to his career:

  1. Costalocrinus conkini, a small Devonian crinoid from the Jeffersonville Limestone
  2. Phillibole conkini, a Lower Mississippian proetid trilobite from the Coral Ridge fauna of the New Providence Member of the Borden Formation near Louisville, which was found by Dr. Conkin, and later described and named for him
  3. Polaricyclus conkini, a Lower Mississippian goniatite (an ammonoid cephalopod) from the Coral Ridge fauna of the New Providence Member of the Borden Formation near Louisville, several specimens of which were first found by Dr. Conkin, and later described and named for him

References

  • Conkin, J.E., 1954, Hyperammina kentuckyensis n. sp. from the Mississippian of Kentucky, and a discussion of Hyperammina and Hyperamminoides: Cushman Foundation Foraminifera Research, Contributions, v. 5, pt. 4, no. 119, p. 165–169.
  • Conkin, J.E., 1961, Mississippian smaller foraminifera of Kentucky, southern Indiana, northern Tennessee, and south-central Ohio: Bulletins of American Paleontology, v. 43, 241 p.

 

View all archived specimen of the month from KGS collection

 

Last Modified on 2018-06-22
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