A NEW SPECIES OF BLACK DRUM (ACANTHURIFORMES: SCIAENIDAE: POGONIAS) FROM THE LATE MIOCENE OF ARGENTINA

NORIEGA, JORGE IGNACIO; PERALTA, MATÍAS; MONSALVO, EDUARDO S.; BRANDONI, DIEGO; MOGLIA, BELÉN; CESARINI, CÉSAR; BUSTOS, JUAN; BRUNETTO, ERNESTO; GOTTARDI, MARÍA G.

General Roca

Congreso; Reunión Anual de Comunicaciones de la Asociación Paleontológica Argentina; 2023

Asociación Paleontológica Argentina

Sciaenidae is a family of Teleostei composed of 67 genera and approximately 283 species with a worldwide distribution, occurring in tropical to temperate marine coasts, brackish estuarine environments, and freshwater. They are commonly known as drums or croakers due to their typical vocalizations. The paleontological record of Sciaenidae starts in the Lower Eocene of U.S.A., but most fossils concentrate in the Oligocene and Neogene marine deposits of Europe and America. Until now, numerous isolated bones coming from the Paraná and Ituzaingó formations in Argentina had been identified at the family level. The fossil record of the genus Pogonias includes three Miocene extinct species based on otoliths: the uncertain Pogonias styriacus from Austria, Pogonias stringeri from U.S.A, and Pogonias tetragonus from Peru. The living Pogonias cromis is also reported from the Miocene in USA and the Late Pleistocene in Argentina, Brazil, and Mexico. We report the exceptional finding of an articulated black drum in sediments of the Late Miocene Paraná Formation at western Entre Ríos Province. The specimen, CICYTTP-PV-P-3-561, comprises a very complete skull, eight abdominal vertebrae, ribs, pectoral girdle with its corresponding fin, and the basipterygium. The material included in a rocky concretion was scanned at CEMENER on a Positron Emission Tomograph/Multislice Helical Computed Tomograph (PET/CT General Electric Discovery 710) at 140 kV and 275 mA, with a slice spacing of 1.25 mm for a total of 208 slices, and then mechanically prepared. Comparative and phylogenetic analyses show that the new specimen belongs to the genus Pogonias by having the parasphenoid with a flat and semicircular face encircled anteriorly by a thin crest-like rim, the intercalar making contact with the epiotic, and a large and massive lower pharyngeal jaw formed by the fully coalesced fifth ceratobranchials. Several cranial features rule out the assignment of CICYTTP-PV-P-3-561 to any of the two extant species Pogonias cromis and Pogonias courbina: the subtriangular dorsal outline of the anterior neurocranium, with the lateral borders of frontals delimiting an isosceles triangle; the subparallel orientation of the parietals; the straight dorsal outline of the hyomandibula, and the robust and craniocaudally wide hyomandibula, with a strongly ossified anterior expansion. The unique combination of primitive and derived characters exhibited by the studied material allows the erection of a new species of black drum.