Naturwissenschaften

, Volume 101, Issue 1, pp 33–45

Comparisons of dental morphology in river stingrays (Chondrichthyes: Potamotrygonidae) with new fossils from the middle Eocene of Peruvian Amazonia rekindle debate on their evolution

  • Sylvain Adnet
  • Rodolfo Salas Gismondi
  • Pierre-Olivier Antoine
Original Paper

DOI: 10.1007/s00114-013-1127-1

Cite this article as:
Adnet, S., Salas Gismondi, R. & Antoine, PO. Naturwissenschaften (2014) 101: 33. doi:10.1007/s00114-013-1127-1

Abstract

Endemic South American river stingrays (Potamotrygonidae), which include the most diversified living freshwater chondrichthyans, were conspicuously absent from pre-Neogene deposits in South America despite the fact that recent phylogenetic analyses strongly suggest an older origination for this clade. To date, the rare representatives of this family were mostly represented by ambiguous isolated remains. Here, we report 67 isolated fossil teeth of a new obligate freshwater dasyatoid (Potamotrygon ucayalensis nov. sp) from the fossiliferous level CTA-27 (Yahuarango Formation), near Contamana, in the Peruvian Amazonia. We assigned this sample to a new representative of Potamotrygon by comparison with numerous fresh jaws of living specimens of Potamotrygonidae, thus providing the first detailed review of dental morphology for this poorly understood clade. These new fossils fill a long stratigraphic gap by extending the family range down to the middle Eocene (∼41 Mya). Moreover, the relative modernity and diversity in tooth morphology among Eocene freshwater stingrays (including Potamotrygonucayalensis nov. sp. and coeval North American dasyatoids) indicate that the hypothetically marine ancestor of potamotrygonids probably invaded the rivers earlier than in the middle Eocene. The first potamotrygonids and affiliates were possibly more generalized and less endemic than now, which is consistent with an opportunistic filling of vacated ecospace.

Keywords

Potamotrygonidae Palaeogene Neotropics Evolution Freshwater adaptation Biogeography 

Supplementary material

114_2013_1127_MOESM1_ESM.docx (18 kb)
ESM 1(DOCX 18 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Sylvain Adnet
    • 1
  • Rodolfo Salas Gismondi
    • 1
    • 2
  • Pierre-Olivier Antoine
    • 1
  1. 1.Institut des Sciences de l’Évolution, UMR-CNRS 5554 CC064Université Montpellier 2MontpellierFrance
  2. 2.Departamento de Paleontología de VertebradosMuseo de Historia Natural-Universidad Nacional Mayor San MarcosLima 11Peru

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