title: A new species of Metopocetus (Cetacea, Mysticeti, Cetotheriidae) from the Late Miocene of the Netherlands.
abstract: The family Cetotheriidae has played a major role in recent discussions of baleen whale phylogenetics. Within this group, the enigmatic, monotypic Metopocetus durinasus has been interpreted as transitional between herpetocetines and other members of the family, but so far has been restricted to a single, fragmentary cranium of uncertain provenance and age. Here, we expand the genus and shed new light on its phylogenetic affinities and functional morphology by describing Metopocetus hunteri sp. nov. from the Late Miocene of the Netherlands. Unlike the holotype of M. durinasus, the material described here is confidently dated and preserves both the tympanic bulla and additional details of the basicranium. M. hunteri closely resembles M. durinasus, differing primarily in its somewhat less distally expanded compound posterior process of the tympanoperiotic. Both species are characterised by the development of an unusually large fossa on the ventral surface of the paroccipital process, which extends anteriorly on to the compound posterior process and completely floors the facial sulcus. In life, this enlarged fossa may have housed the posterior sinus and/or the articulation of the stylohyal. Like other cetotheriids, Metopocetus also bears a well-developed, posteriorly-pointing dorsal infraorbital foramen near the base of the ascending process of the maxilla, the precise function of which remains unclear.
authors.affiliation: Department of Geology and Palaeontology, National Museum of Nature and Science , Tsukuba , Japan.
authors.forename: Felix Georg
authors.initials: FG
authors.lastname: Marx
authors.affiliation: Directorate of Earth and History of Life, Royal Belgian Institute of Natural Sciences, Brussels, Belgium; Marine Vertebrates, Koninklijk Zeeuwsch Genootschap der Wetenschappen, Middelburg, The Netherlands.
authors.forename: Mark E J
authors.initials: ME
authors.lastname: Bosselaers
authors.affiliation: Department Geology/Research Unit Palaeontology, Ghent University , Ghent , Belgium.
authors.forename: Stephen
authors.initials: S
authors.lastname: Louwye
keywords: Baleen whales; Cetotheriidae; Late Miocene; Metopocetus; Mysticeti; Paroccipital concavity; Phylogenetics; Primary dorsal infraorbital foramen
references.citation: R Soc Open Sci. 2015 Apr 15;2(4):140434
references.pmid: 26064636
references.citation: Naturwissenschaften. 2013 Apr;100(4):365-71
references.pmid: 23525578
references.citation: Proc Biol Sci. 2012 Dec 19;280(1753):20122645
references.pmid: 23256199
references.citation: BMC Evol Biol. 2011 Apr 25;11:112
references.pmid: 21518443
references.citation: Naturwissenschaften. 2013 Mar;100(3):257-61
references.pmid: 23358804
references.citation: PLoS One. 2015 Sep 02;10(9):e0135500
references.pmid: 26331471
references.citation: Syst Biol. 2008 Feb;57(1):15-37
references.pmid: 18266181
references.citation: Am J Anat. 1986 Nov;177(3):353-68
references.pmid: 3799488