Faunal Analysis and Paleoecology of Miocene Fossil Fish from Porters Landing, Effingham County, Georgia

Porters Landing is an early Miocene fossil site located on the Savannah River in Effingham County, Georgia. Two fossiliferous units have good outcrops at Porters Landing, the Marks Head Formation and the Porters Landing Member of the Parachucla Formation, both within the Hawthorn Group An age of 23 to 18 million years has been determined for Porters Landing. The Porters Landing Member, the older of the units, has an Aquitanian age (23 to 21 Ma) The Marks Head Formation is upper Burdigalian (18 Ma). The site is rich in vertebrate fossil material, especially cartilaginous and bony fishes (Chondrichthyes and teleosts, respectively). The chondrichthyans are represented by 20 taxa including 14 taxa of sharks The most abundant sharks are Carcharhinus spp., Physogaleus latus, and Rhizoprionodon terraenovae. Of the 7 taxa of batomorphs (skates, rays, and guitarfish), Dasyatis sp. and Rhynchobatus pristinus are the most abundant. A total of 6 teleost taxa were identified, with cf. Pogonias sp and Sphwaena sp. being the most abundant. Porters Landing represents a subtropical to tropical nearshore marine. This is confirmed by comparisons with age-equivalent sites from the Atlantic Coastal Plain. Faunal similarity was calculated, using the Simpson Coefficient between Georgia and early Miocene vertebrate localities from the following states: Delaware, Maryland, North Carolina, and Florida. The paleoecology of these sites corroborated with the findings at Porters Landing