25 Paleontology, Paleoecology, and Taphonomy (Posters)

Friday, 1 April 2016
8:00 AM - 5:30 PM
Exhibit Hall

PREDATION REPAIR FREQUENCY IN BRACHIOPODS OF THE ORDOVICIAN KOPE FORMATION IN KENTUCKY

Paper number: 25-10
Program: Technical Sessions
Time: 8:00 AM – 5:30 PM

Authors

Abstract

Paleoecology informs researchers about how prehistoric organisms interacted with each other and their environment. We examined predation through six stratigraphic samples from the Ordovician Kope Formation. We examined repair scars—evidence of unsuccessful predation on shelled organisms—as a proxy for predation intensity. These traces indicate if an organism was attacked, and that the organism survived the attack.

Samples were collected from the Kope Formation in Flemingsburg, KY. The stratigraphic trend among the samples is coarsening upward, indicating an increase in energy through time. Generic richness, evenness, and the Shannon-Wiener Diversity were calculated for each sample. The samples were ordinated using NMDS. In addition, we examined the orthide brachiopod Austinella for repair scars and calculated repair frequency.

The results show that richness (ranging from 8 to 11), evenness (ranging from 0.7 to 0.85), and Shannon’s H (ranging from 1.5 to 2.0) were fairly consistent among the samples. In the NMDS ordination, samples 2-4, which were stratigraphically adjacent and were collected in close proximity to one another, plotted together, while samples 1 and 6 were both isolated. In the examination of repair frequency, sample 1, (the oldest sample) contained no Austinella. Sample 2 contained 41 Austinella and had a repair frequency of 2.4%. Sample 3 contained 34 Austinella with no repair scars. Sample 4 contained 13 Austinella, with a repair frequency of 15.4%. Sample 5 contained 39 Austinella, with a repair frequency of 2.6%. Sample 6 contained 21 Austinella, with a repair frequency of 9.5%. There was no statistically significant correlation between repair frequency and the paleocommunity metrics, however they did exhibit similar increases and decreases stratigraphically. In the NMDS ordination, it was noted that the sample with the highest repair frequency, Sample 4, was the most distant of the 2-5 cluster, possibly indicating that ecological differences are related to the higher repair rate. Future research will include a more in-depth analysis of the community, looking at repair scars on all brachiopod taxa for each sample, and analyzing additional samples to obtain a more representative and statistically robust result.

Geological Society of America Abstracts with Programs. Vol. 48, No. 3

doi: 10.1130/abs/2016SE-273811

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