[OANNES Foro] Origin of the white shark Carcharodon (Lamniformes: Lamnidae) based on recalibration of the Upper Neogene Pisco Formation of Peru

[Mario Cabrejos]

Palaeontology
Volume 55, Issue 6, pages 1139-1153, November 2012
Article first published online: 14 NOV 2012
DOI: 10.1111/j.1475-4983.2012.01201.x

Origin of the white shark Carcharodon (Lamniformes: Lamnidae) based on recalibration of the Upper Neogene Pisco Formation of Peru
DANA J. EHRET1,*, BRUCE J. MACFADDEN2, DOUGLAS S. JONES2, THOMAS J. DEVRIES3, DAVID A. FOSTER4, RODOLFO SALAS-GISMONDI5

1 Monmouth University, West Long Branch, NJ, 07764, USA; e-mail: dehret en monmouth.edu Corresponding author.2 Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, USA; e-mails: bmacfadd en flmnh.ufl.edu, dsjones en flmnh.ufl.edu3 Burke Museum of Natural History and Culture, University of Washington, Seattle, WA 98195, USA; e-mail: tomdevrie en aol.com4 Department of Geological Sciences, University of Florida, Gainesville, FL 32611, USA; e-mail: dafoster en ufl.edu5 Departmento de Paleontologia de Vertebrados, Museo de Historia Natural Javier Prado, Universidad Nacional Mayor de San Marcos, Lima 11, Peru; e-mail: rodsalasgis en yahoo.com
Abstract:  The taxonomic origin of the white shark, Carcharodon, is a highly debated subject. New fossil evidence presented in this study suggests that the genus is derived from the broad-toothed 'mako', Carcharodon (Cosmopolitodus) hastalis, and includes the new species C. hubbelli sp. nov. - a taxon that demonstrates a transition between C. hastalis and Carcharodon carcharias. Specimens from the Pisco Formation clearly demonstrate an evolutionary mosaic of characters of both recent C. carcharias and fossil C. hastalis. Characters diagnostic to C. carcharias include the presence tooth serrations and a symmetrical first upper anterior tooth that is the largest in the tooth row, while those indicative of C. hastalis include a mesially slanted third anterior (intermediate) tooth. We also provide a recalibration of critical fossil horizons within the Pisco Formation, Peru using zircon U-Pb dating and strontium-ratio isotopic analysis. The recalibration of the absolute dates suggests that Carcharodon hubbelli sp. nov. is Late Miocene (6-8 Ma) in age. This research revises and elucidates lamnid shark evolution based on the calibration of the Neogene Pisco Formation.
------------ próxima parte ------------
Se ha borrado un adjunto en formato HTML...
URL: <http://lista.oannes.org.pe/pipermail/oannes-oannes.org.pe/attachments/20121115/24082b00/attachment.html>