DAO 120:1-7 (2016)  -  DOI: https://doi.org/10.3354/dao03012

Beak deviations in the skull of Franciscana dolphins Pontoporia blainvillei from Argentina

Pablo Denuncio1,2,*, M. Victoria Panebianco2,3, Daniela Del Castillo2,3, Diego Rodríguez1,2, H. Luis Cappozzo2,3,4, Ricardo Bastida1,2

1Instituto de Investigaciones Marinas y Costeras (IIMyC), Departamento de Ciencias Marinas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata—CONICET, Funes 3350, B7602AYL Mar del Plata, Argentina
2Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C1429DDA Buenos Aires, Argentina
3Laboratorio de Ecología, Comportamiento y Mamíferos Marinos, Museo Argentino de Ciencias Naturales Bernardino Rivadavia (MACN), Av. Ángel Gallardo 470, C1405DJR Buenos Aires, Argentina
4Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnósticos (CEBBAD), Fundación de Historia Natural Félix de Azara, Departamento de Ciencias Naturales y Antropología, Universidad Maimónides; Hidalgo 775, piso 7, C1405BDB Buenos Aires, Argentina
*Corresponding author:

ABSTRACT: The Franciscana dolphin Pontoporia blainvillei is characterized by a long rostrum, a feature that is shared with the families formerly classified as river dolphins (Pontoporiidae, Platanistidae, Iniidae, Lipotidae). Although there are occasional reports on the existence of beak deformations, very little published information exists describing this process. The object of the present study was to describe and quantify the beak anomalies of Franciscana dolphins from the coastal waters of Argentina. Of 239 skulls analyzed 12% showed beak deviations (BD), affecting the premaxillary-maxillary and dentary bones to different extents. The occurrence of BD in the dentary bone represented 58%, whereas premaxillary-maxillary BDs were observed in 14% of the studied specimens, while the complete rostrum (dentary, premaxillary and maxillary) was affected in 28% of the skulls. Dorsoventral axis BD was more frequent than lateral BD (48 and 38%, respectively), and double BD was only observed in the dentary bone. Most of the BD observed in this study could be classified as mild/moderate, and we assume that it did not affect the feeding activities of individuals; however, 2 specimens (<1%) showed a severe and complex curvature that probably did affect them. The cause of these anomalies (natural or anthropogenic origins) is unknown but may be related to important parasite loads, heavy metal and organic contaminants and plastic ingestion that could affect the coastal dolphin in different ways. A more detailed and thorough study of these cranial anomalies is necessary.


KEY WORDS: Franciscana dolphin · Pontoporia blainvillei · Cetacean · Skull anomalies · Rostral bones deviations


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Cite this article as: Denuncio P, Panebianco MV, Del Castillo D, Rodríguez D, Cappozzo HL, Bastida R (2016) Beak deviations in the skull of Franciscana dolphins Pontoporia blainvillei from Argentina. Dis Aquat Org 120:1-7. https://doi.org/10.3354/dao03012

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