GSA Annual Meeting in Phoenix, Arizona, USA - 2019

Paper No. 118-9
Presentation Time: 9:00 AM-6:30 PM

CLASSIFYING MEGALOSPHERIC AND MICROSPHERIC CIBICIDOIDES WUELLERSTORFI


ROARK, Erin and BURKETT, Ashley, Boone Pickens School of Geology, Oklahoma State University, 105 Noble Research Center, Oklahoma State University, Stillwater, OK 74078

Benthic foraminiferal species can be divided into two subgroups based on reproductive mechanisms: megalospheric and microspheric. Asexually reproducing megalospheric foraminifera tend to produce a large proloculus (initial chamber) with an relatively small test size. Conversely, microspheric foraminifera have a small proloculus and large test diameter as a result of sexual reproduction. Through the comparison, examination, and documentation of test and proloculus diameters, this project seeks to establish more efficient means of classifying megalospheric and microspheric specimens of the paleoceanographically significant species, Cibicidoides wuellerstorfi. MicroCT imaging makes it possible to obtain accurate measurements of the cross-sectional view of the specimen’s skeletal structure without destroying the samples. This ensured the widest parts of the proloculi and tests may be measured in each individual organism. Measurement data was graphed in order to differentiate between megalospheric and microspheric Cibicidoides wuellerstorfi. This process and its results provide insights on the morphology and ontogeny of foraminifera, as well as aid in future paleoclimatology studies.