Comparing body size of the sand tiger shark Striatolamia macrota from Eocene localities in the Eureka Sound Formation, Banks Island, northern Canada, and the Tuscahoma Formation, Meridian, Mississippi

Undergraduate Honors Thesis

Citations

Citeable URL: https://scholar.colorado.edu/concern/undergraduate_honors_theses/rb68xc32c

Abstract

As the most abundant vertebrate fossil in the geologic record, shark teeth have the potential to provide remarkable insight into the past. This is due to the added layer of enameloid in the teeth that make them exceptionally preservable. Among the most abundant fossil shark teeth discovered during the early to middle Eocene Epoch (55-50 Ma) belong to the sand tiger shark Striatolamia macrota. Two fossil localities, one from Banks Island, NWT, and the other known as the Red Hot Truck Stop in Meridian, Mississippi, contain a vast amount of Striatolamia macrota teeth. These two localities are of comparable age and paleoenvironment. An equation was found that relate the length of the largest anterior tooth to the body size of the shark. Approximately 400 Striatolamia macrota anterior teeth were measured from each locality in order to compare their body sizes. It was found that the teeth from Banks Island had a mean that was 2.34 mm larger than the Red Hot Truck Stop. This could be due to a difference in ocean paleotemperature and paleosalinity, however it is more likely a latitudinal difference. Bergmann’s rule states that mammal size increase with latitude due to a combination of factors. Eocene Striatolamia macrota may also follow this rule. In order to fully understand if Eocene sharks increase in size due to latitude, different species must also be studied.

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