Abstract
The Tallahatta Formation, Lisbon Formation, and Gosport Sand are the three lithostratigraphic units that make up the lower-to-middle Eocene Claiborne Group. In Alabama, these marine units are among the most fossiliferous in the state and a long history of scattered reports have attempted to document their fossil diversity. In this study, we examined 20931 elasmobranch and bony fish elements, including otoliths, derived from Claiborne Group units in Alabama and identified 115 unequivocal taxa. Among the taxa identified, one new species is described, Carcharhinus mancinae sp. nov., and Pseudabdounia gen. nov. is a new genus erected to include two species formerly placed within Abdounia Capatta, 1980. New taxonomic combinations proposed include Pseudabdounia claibornensis (White, 1956) gen. et comb. nov., Pseudabdounia recticona (Winkler, 1874) gen. et comb. nov., Physogaleus alabamensis (Leriche, 1942) comb. nov., and Eutrichiurides plicidens (Arambourg, 1952) comb. nov. We also report the first North American paleobiogeographic occurrences of Aturobatis aff. A. aquensis Adnet, 2006, Brachycarcharias atlasi (Arambourg, 1952), Eutrichiurides plicidens comb. nov., Galeorhinus louisi Adnet & Cappetta, 2008, Ginglymostoma maroccanum Noubhani & Cappetta, 1997, Gymnosarda sp., Mennerotodus sp., Rhizoprionodon ganntourensis (Arambourg, 1952), Stenoscyllium aff. S. priemi Noubhani & Cappetta, 1997, Trichiurus oshosunensis White, 1926, and the first North American occurrence for a fossil member of the Balistidae Risso, 1810. Our sample also included 26 taxa that represented first paleobiogeographic occurrences for Alabama, including Abdounia beaugei (Arambourg, 1935), Albula eppsi White, 1931, Ariosoma nonsector Nolf & Stringer, 2003, Anisotremus? sp., Anomotodon sp., Brachycarcharias twiggsensis (Case, 1981), Burnhamia daviesi (Woodward, 1889), Eoplinthicus yazooensis Capetta & Stringer, 2002, Galeorhinus ypresiensis (Casier, 1946), Gnathophis meridies (Frizzell & Lamber, 1962), Haemulon? obliquus (Müller, 1999), Hypolophodon sylvestris (White, 1931), Malacanthus? sulcatus (Koken, 1888), Meridiania cf. M. convexa Case, 1994, Palaeocybium proosti (Storms, 1897), Paraconger sector (Koken, 1888), Paralbula aff. P. marylandica Blake, 1940, Phyllodus toliapicus Agassiz, 1844, Propristis schweinfurthi Dames, 1883, Pycnodus sp., Pythonichthys colei (Müller, 1999), Scomberomorus stormsi (Leriche, 1905), Signata stenzeli Frizzell & Dante, 1965, and Signata nicoli Frizzell & Dante, 1965, and the first Paleogene occurrences in Alabama of a member of the Gobiidae Cuvier, 1816. A biostratigraphic analysis of our sample showed stratigraphic range extensions for several taxa, including the first Bartonian occurrences of Eoplinthicus yazooensis, Jacquhermania duponti (Winkler, 1876), Meridiania cf. M. convexa, Phyllodus toliapicus, and “Rhinobatos” bruxelliensis (Jaekel, 1894), range extensions into the late Ypresian and Bartonian for Tethylamna dunni Cappetta & Case, 2016 and Scoliodon conecuhensis Cappetta & Case, 2016, the first late Ypresian records of Galeorhinus louisi, the first Lutetian occurrence of Gymnosarda Gill, 1862, and a range extension for Fisherichthys aff. F. folmeri Weems, 1999 into the middle Bartonian. Larger biostratigraphic and evolutionary trends are also documented, such as the acquisition of serrations in Otodus spp., possible population increases for the Rhinopterinae Jordan & Evermann, 1896 and Carcharhiniformes Compagno, 1973 in the Bartonian, and the apparent diversification of the Tetraodontiformes Berg, 1940 during the same stage. This study helps better our understanding of early-to-middle Eocene elasmobranch and bony fish diversity, paleobiogeography, and biostratigraphy in the Gulf Coastal Plain of North America.
Highlights
The lithostratigraphic units that comprise the lower-to-middle Eocene Claiborne Group in Alabama (USA), the Tallahatta Formation, Lisbon Formation, and Gosport Sand, are three of the most productive geologic units in the state with respect to the diversity of marine fossils
Several of the bulk samples processed were housed at the South Carolina State Museum (SC) in Columbia, USA, Wright State University – Lake Campus (WSU) in Celina, Ohio, USA, and the bulk field sample library at McWane Science Center (MSC) in Birmingham, AL, USA
We identified only 21 specimens belonging to B. twiggsensis, this taxon appears confined to the Bartonian Gosport Sand, a lithostratigraphic unit that is temporally slightly older than the B. twiggsensis type unit in Georgia (NP19/20), the Dry Branch Formation
Summary
The lithostratigraphic units that comprise the lower-to-middle Eocene (upper Ypresian to Bartonian) Claiborne Group in Alabama (USA), the Tallahatta Formation, Lisbon Formation, and Gosport Sand, are three of the most productive geologic units in the state with respect to the diversity of marine fossils. In 1858, Mallet published the Second Biennial Report on the Geology of Alabama (Tuomey 1858), and incorporated many of the geological notes left behind by Tuomey, including a list of 14 sharks he had identified from Eocene strata in the state. This list did not include specific collecting localities or formations, Tuomey (1858) did mention collecting shark teeth along Pigeon Creek (site ACon-6) in Conecuh County, a locality that exposes the contact of the Tallahatta and Lisbon formations. Mallet shipped a subset of Tuomey’s vertebrate fossil collection to London in 1859, a fortunate turn of events because the majority of Tuomey’s remaining fossil collection was destroyed by fire at the end of the American Civil War (White 1956; Ebersole & Dean 2013)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
