Anatomy of a new cetotheriid genus and species from the Miocene of Herentals, Belgium, and the phylogenetic and palaeobiogeographical relationships of Cetotheriidae s.s. (Mammalia, Cetacea, Mysticeti)

Abstract

Herentalia nigra gen. et sp. nov. is described and compared to other mysticetes. It belongs to Cetotheriidae s.s. and represents one of the best-preserved cetotheriid skulls from the southern border of the North Sea. A comprehensive phylogenetic analysis revealed that it is closely related to Nannocetus and to a Japanese Herpetocetus, suggesting that it belongs to the subfamily Herpetocetinae. The phylogenetic analysis performed tests the recent hypothesis that Caperea marginata belongs to Cetotheriidae. However the present results confirm that the pygmy right whale cannot be considered a member of Cetotheriidae. The phylogenetic analysis was used as the basis for a cladistic palaeobiogeographical analysis of Cetotheriidae that revealed that the family originated in the Pacific basin during the Burdigalian and subsequently underwent a sequence of dispersal and vicariance events that allowed its members to enter other ocean basins. The evolution of Cetotheriidae diversity was punctuated by two distinct phases of species originations (one in the Burdigalian and the other in the Tortonian) that broadly correspond to a massive increase of food availability in the ocean trophic webs.

http://zoobank.org/urn:lsid:zoobank.org:pub:DB1647B0-53E9-4014-B31A-F8B063923EB4

Keywords:

• Cetacea
• Cetotheriidae s.s.
• Herentalia nigra
• Mysticeti
• palaeobiogeography
• phylogeny

Acknowledgements

I want to express my gratitude to Klaas Post (Natuurhistorisch Museum, Rotterdam, the Netherlands) who brought the existence of this specimen to my knowledge in 2001 and organized my visits to Dutch institutions to study fossil mysticetes. Collaboration with Peter Van Bree was very useful, and he provided a lot of assistance during my visit at the Zoological Museum in Amsterdam in 2001. Reinier Van Zelst and John De Vos were of great help during my visit to Naturalis, Leiden, in 2012 to re-study the specimen. Annelise Folie, Olivier Lambert and Mark Bosselaers (all at the Royal Belgian Institute of Natural Sciences, Brussels, Belgium), Klaas Post (Natural History Museum, Rotterdam) and René Fraaye (The Groene Port, Boxtel, Holland) provided very kind assistance and help during my numerous visits to the Belgian and Dutch collections and made several specimens available for my comparative study. Many thanks are due to Olivier Lambert who provided data on the stratigraphy of Herenthals. Dave Bohaska (National Museum of Natural History, Smithsonian Institution) gave me access to the Metopocetus skulls that are used here. Rodolfo Salas Gismondi (Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Lima) warranted access to specimens of Piscobalaena nana. Many thanks are due to Mark Uhen, Tom Deméré and Adrian Lister (Associate Editor of the Journal of Systematic Palaeontology), who greatly improved the quality of the manuscript. My 2001 visit was funded by the Italian Ministry of University and Scientific Research, being a contribution of the Pisa Unit (unit coordinator Walter Landini, Dipartimento di Scienze della Terra, University of Pisa) to the research project ‘Palaeobiogeography of Central Mediterranean from Miocene to Quaternary’ (national coordinator Danilo Torre, Dipartimento di Scienze della Terra, University of Florence). My 2012 visit was funded by a Synthesys 2 grant (Synthesys Project http://www.synthesys.info/), which was financed in 2012 by the European Community Research Infrastructure Action under the FP 7 (NL-TAF Project n. 1730). A preliminary version of this paper was presented in the poster session of the Geologica Belgica meeting in Brussels in 2012.