A new large squalodelphinid (Cetacea, Odontoceti) from Peru sheds light on the Early Miocene platanistoid disparity and ecology

Bianucci, Giovanni; Bosio, Giulia; Malinverno, Elisa; Muizon, Christian de; Villa, Igor Maria; Urbina, M.; Lambert, O. (2018). A new large squalodelphinid (Cetacea, Odontoceti) from Peru sheds light on the Early Miocene platanistoid disparity and ecology. Royal Society Open Science, 5(4), p. 172302. The Royal Society Publishing 10.1098/rsos.172302

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The South Asian river dolphin (Platanista gangetica) is the only extant survivor of the large clade Platanistoidea, having a well-diversified fossil record from the Late Oligocene to the Middle Miocene. Based on a partial skeleton collected from the Chilcatay Formation (Chilcatay Fm; southern coast of Peru), we report here a new squalodelphinid genus and species, Macrosqualodelphis ukupachai. A volcanic ash layer, sampled near the fossil, yielded the 40Ar/39Ar age of 18.78 ± 0.08 Ma (Burdigalian, Early Miocene). The phylogenetic analysis places Macrosqualodelphis as the earliest branching squalodelphinid. Combined with several cranial and dental features, the large body size (estimated body length of 3.5 m) of this odontocete suggests that it consumed larger prey than the other members of its family. Together with Huaridelphis raimondii and Notocetus vanbenedeni, both also found in the Chilcatay Fm, this new squalodelphinid further demonstrates the peculiar local diversity of the family along the southeastern Pacific coast, possibly related to their partition into different dietary niches. At a wider geographical scale, the morphological and ecological diversity of squalodelphinids confirms the major role played by platanistoids during the Early Miocene radiation of crown odontocetes.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences
08 Faculty of Science > Institute of Geological Sciences > Isotope Geology
08 Faculty of Science > Other Institutions > Emeriti, Faculty of Science

UniBE Contributor:

Villa, Igor Maria

Subjects:

500 Science > 550 Earth sciences & geology
500 Science > 560 Fossils & prehistoric life

ISSN:

2054-5703

Publisher:

The Royal Society Publishing

Language:

English

Submitter:

Igor Maria Villa-Toscani

Date Deposited:

18 Jun 2019 10:55

Last Modified:

23 Oct 2019 04:25

Publisher DOI:

10.1098/rsos.172302

PubMed ID:

29765678

BORIS DOI:

10.7892/boris.129763

URI:

https://boris.unibe.ch/id/eprint/129763

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