Title
A new inioid (Cetacea, Odontoceti, Delphinida) from the Miocene of Peru and the origin of modern dolphin and porpoise families
Date Issued
01 January 2017
Access level
metadata only access
Resource Type
journal article
Author(s)
Publisher(s)
Oxford University Press
Abstract
In this paper we describe Brujadelphis ankylorostris gen. nov., sp. nov., a new delphinidan (Cetacea, Odontoceti, Delphinida), based on a well-preserved skull with ear bones, associated mandibles, most of the teeth in situ and a fragment of the atlas, from the late middle to early late Miocene (Serravallian to early Tortonian) of the Pisco Formation, Pisco Basin, Peru. The new taxon differs from all other delphinidans in the following unique combination of character states: partial ankylosis of the thickened premaxillae above the mesorostral groove; presence of premaxillary eminences; premaxilla does not contact nasal; inflated nasals with a transversely convex dorsal surface; presence of an internasal fossa; and a longitudinal crest on the vertex formed by transversely pinched frontals. Our cladistic analyses of a supermatrix that includes molecular and morphological data identifies B. ankylorostris as an inioid (Iniidae + Pontoporiidae) that is more closely related to Inia than to Pontoporia. This result persists even if a molecular scaffold based on published Bayesian analyses is used. The inclusion of a large sample (12 taxa) of ‘kentriodontids’ allows us to confirm the paraphyly of this group of archaic Miocene delphinidans but contradicts the prevailing views in placing all of these taxa outside of Delphinoidea (Delphinidae + Monodontidae + Phocoenidae). In our unconstrained analysis ‘kentriodontids’ are split into five separate clades that occur along the stem of Inioidea + Delphinoidea. Based on our most parsimonious trees, we discuss published calibration points for molecular divergence estimates within Odontoceti and propose one new point: 18 Ma for an unnamed clade including Delphinida + Ziphiidae.
Start page
919
End page
946
Volume
179
Issue
4
Language
English
OCDE Knowledge area
Biología (teórica, matemática, térmica, criobiología, ritmo biológico), Biología evolutiva
Zoología, Ornitología, Entomología, ciencias biológicas del comportamiento
Subjects
Scopus EID
2-s2.0-85023630299
Source
Zoological Journal of the Linnean Society
ISSN of the container
00244082
Sponsor(s)
We wish to thank A. Altamirano-Sierra, C. Argot, L. G. Barnes, D. J. Bohaska, T. Deméré, S. J. Godfrey, Y. Hasegawa, H. Ichishima, T. Kimura, S. A. McLeod, J. G. Mead, C. de Muizon, D. Ormezzano, J. J. Ososky, C. Potter, N. D. Pyenson, G. Raineri, R. Salas-Gismondi, C. Sarti, N. B. Simmons, E. West-wig and R. Varas-Malca for providing access to the collections under their care. Many thanks to W. Aguirre, E. Díaz and R. Salas-Gismondi for the preparation of the holotype of Brujadelphis anky-lorostris and to all the members of the Departamento de Paleontología de Vertebrados of the MUSM for their support during our stays in the lab and in the field. Character codings for Eodelphinus kabatensis and Pterophocaena nishinoi were based, in part, on CT data generously provided by M. Murakami. We also wish to thank C. Di Celma for his valuable insights on the geological section and marker beds of Cerro la Bruja and M. D. Uhen for his contribution to the marine mammal parts of the Paleobiology Database. Constructive comments of the reviewers N. D. Pyenson and R. A. Racicot and the handling editor J. G. M. Thewissen considerably enhanced the quality of this work. This work was partly supported with a grant from the Italian Ministero dell’Istru-zione dell’Università e della Ricerca (PRIN Project 2012YJSBMK to G.B.) and another from the National Science Foundation (DEB 1025260 to J.H.G.).
Sources of information:
Directorio de Producción Científica
Scopus