Anatomy and phylogeny of the large shark-toothed dolphin Phoberodon arctirostris Cabrera, 1926 (Cetacea: Odontoceti) from the early Miocene of Patagonia (Argentina)

VIGLINO, MARIANA; BUONO, MÓNICA R.; FORDYCE, R. EWAN; CUITIÑO, JOSÉ I.; E. FITZGERALD

ZOOLOGICAL JOURNAL OF THE LINNEAN SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2018 p. 1 - 32

0024-4082

The early Miocene of Patagonia (Argentina) provides one of the best-known records of odontocetes for an age intervalwith scarce fossils. Most of these taxa are historically old and briefly described, which has contributed, in part,to their controversial taxonomic position. The shark-toothed dolphin Phoberodon arctirostris was described almost100 years ago and suggested as a member of Platanistoidea and Squalodontidae. However, it has not been analysedrecently and has never been included in a phylogenetic analysis. Recent fieldwork in the early Miocene sediments inPatagonia yielded a new specimen referred to this species, allowing for its modern and detailed description and thefirst phylogenetic analyses. Analyses recovered P. arctirostris as a stem Odontoceti or an early-diverging platanistoid,more closely related to an unnamed Oligocene specimen from New Zealand and not in a clade with Squalodoncalvertensis (i.e. Squalodontidae). The reconstructed body length of P. arctirostris indicates that it is one of thelargest stem Odontoceti. Our results suggest that during the early Miocene of Patagonia, archaic odontocete forms(i.e. P. arctirostris) cohabited with archaic and more crownward platanistoids (i.e. Aondelphis talen and Notocetusvanbenedeni), helping to characterize the early Miocene cetacean communities of Patagonia.