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Hocking DP, Marx FG, Park T, Fitzgerald EMG, Evans AR. A behavioural framework for the evolution of feeding in predatory aquatic mammals. Proc Biol Sci 2018; 284:rspb.2016.2750. [PMID: 28250183 DOI: 10.1098/rspb.2016.2750] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 02/09/2017] [Indexed: 11/12/2022] Open
Abstract
Extant aquatic mammals are a key component of aquatic ecosystems. Their morphology, ecological role and behaviour are, to a large extent, shaped by their feeding ecology. Nevertheless, the nature of this crucial aspect of their biology is often oversimplified and, consequently, misinterpreted. Here, we introduce a new framework that categorizes the feeding cycle of predatory aquatic mammals into four distinct functional stages (prey capture, manipulation and processing, water removal and swallowing), and details the feeding behaviours that can be employed at each stage. Based on this comprehensive scheme, we propose that the feeding strategies of living aquatic mammals form an evolutionary sequence that recalls the land-to-water transition of their ancestors. Our new conception helps to explain and predict the origin of particular feeding styles, such as baleen-assisted filter feeding in whales and raptorial 'pierce' feeding in pinnipeds, and informs the structure of present and past ecosystems.
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Affiliation(s)
- David P Hocking
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia .,Geosciences, Museums Victoria, Melbourne, Australia
| | - Felix G Marx
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia.,Geosciences, Museums Victoria, Melbourne, Australia.,Directorate of Earth and History of Life, Royal Belgian Institute of Natural Sciences, Brussels, Belgium
| | - Travis Park
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia.,Geosciences, Museums Victoria, Melbourne, Australia
| | - Erich M G Fitzgerald
- Geosciences, Museums Victoria, Melbourne, Australia.,National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.,Department of Life Sciences, Natural History Museum, London, UK
| | - Alistair R Evans
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia.,Geosciences, Museums Victoria, Melbourne, Australia
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Bever GS, Norell MA. A new rhynchocephalian (Reptilia: Lepidosauria) from the Late Jurassic of Solnhofen (Germany) and the origin of the marine Pleurosauridae. R Soc Open Sci 2017; 4:170570. [PMID: 29291055 PMCID: PMC5717629 DOI: 10.1098/rsos.170570] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 10/09/2017] [Indexed: 06/07/2023]
Abstract
A new rhynchocephalian is described based on a recently discovered and well-preserved specimen from the Late Jurassic (Kimmeridgian) marine limestones of Solnhofen, Bavaria. Phylogenetic analysis recovers the new taxon as the sister group to Pleurosauridae, a small radiation of rhynchocephalians representing the oldest marine invasion of crown-clade Lepidosauria. The relatively strong evidence for this taxonomically exclusive lineage, within a generally volatile rhynchocephalian tree, places the new taxon in a position to inform the early history of the pleurosaur transition to the sea. The early steps in this transition are distributed throughout the skeleton and appear to increase hydrodynamic efficiency for both swimming and aquatic feeding. This early history may also have included a global truncation of plesiomorphic ontogenetic trajectories that left a number of skeletal features with reduced levels of ossification/fusion. The exact degree to which Vadasaurus had adopted an aquatic ecology remains unclear, but the insight it provides into the origin of the enigmatic pleurosaurs exemplifies the potential of Rhynchocephalia for generating and informing broad-based questions regarding the interplay of development, morphology, ecology and macroevolutionary patterns.
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Affiliation(s)
- Gabriel S. Bever
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA
| | - Mark A. Norell
- Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA
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