title: A Link No Longer Missing: New Evidence for the Cetotheriid Affinities of Caperea.
abstract: The origins of the enigmatic pygmy right whale Caperea marginata, the only living member of its subfamily (Neobalaeninae), are an outstanding mystery of cetacean evolution. Its strikingly disparate morphology sets Caperea apart from all other whales, and has turned it into a wildcard taxon that holds the key to understanding modern baleen whale diversity. Morphological cladistics generally ally this species with right whales, whereas molecular analyses consistently cluster it with rorquals and grey whales (Balaenopteroidea). A recent study potentially resolved this conflict by proposing that Caperea belongs with the otherwise extinct Cetotheriidae, but has been strongly criticised on morphological grounds. Evidence from the neobalaenine fossil record could potentially give direct insights into morphological transitions, but is currently limited to just a single species: the Late Miocene Miocaperea pulchra, from Peru. We show that Miocaperea has a highly unusual morphology of the auditory region, resulting from a-presumably feeding-related-strengthening of the articulation of the hyoid apparatus with the skull. This distinctive arrangement is otherwise only found in the extinct Cetotheriidae, which makes Miocaperea a "missing link" that demonstrates the origin of pygmy right whales from cetotheriids, and confirms the latter's resurrection from the dead.
authors.affiliation: School of Biological Sciences, Monash University, 25 Rainforest Walk, Clayton, Victoria, 3800, Australia.|Geosciences, Museum Victoria, Melbourne, Australia.|Directorate of Earth and History of Life, Royal Belgian Institute of Natural Sciences, Brussels, Belgium.
authors.forename: Felix G
authors.initials: FG
authors.lastname: Marx
authors.affiliation: Department of Geology, University of Otago, Dunedin, New Zealand.|Departments of Vertebrate Zoology and Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington DC, United States of America.
authors.forename: R Ewan
authors.initials: RE
authors.lastname: Fordyce
mesh_terms: D000818:Animals; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology; D019143:Evolution, Molecular; D005580:Fossils; D006309:Hearing; D010802:Phylogeny; D014907:Whales / Q000033:anatomy & histology* / Q000235:genetics / Q000502:physiology*