CLOSE, R.A., JOHANSON, Z., TYLER, J.C., HARRINGTON, R.C., FRIEDMAN, M. 2016. Mosaicism in a new Eocene pufferfish highlights rapid morphological innovation near the origin of crown tetraodontiforms. Palaeontology, 59, 4, 499-514. DOI: 10.1111/pala.12245
Roger A. Close, Zerina Johanson, James C. Tyler, Richard C. Harrington, and Matt Friedman- Roger A. Close - University of Oxford Department of Earth Sciences Oxford UK (Email: roger.close@gmail.com)
- Roger A. Close - University of Birmingham School of Geography, Earth and Environmental Sciences Edgbaston Birmingham UK
- Zerina Johanson - Natural History Museum Department of Earth Sciences London UK
- James C. Tyler - National Museum of Natural History Department of Vertebrate Zoology Washington DC USA
- Richard C. Harrington - University of Oxford Department of Earth Sciences Oxford UK
- Richard C. Harrington - Yale University Department of Ecology and Evolutionary Biology New Haven CT USA
- Matt Friedman - University of Oxford Department of Earth Sciences Oxford UK
- Manuscript Accepted: 08 May 2016
- Manuscript Received: 11 January 2016
Tetraodontiformes (pufferfishes and kin) is a taxonomically and structurally diverse, widely‐distributed clade of acanthomorphs, whose members often serve as models for genomics and, increasingly, macroevolutionary studies. Morphologically disparate Palaeogene fossils suggest considerable early experimentation, but these flattened specimens often preserve limited information. We present a three‐dimensionally preserved beaked tetraodontiform from the early Eocene (c. 53 Ma) London Clay Formation, UK. Approximately coeval with the oldest crown tetraodontiforms, †Ctenoplectus williamsi gen. et sp. nov. presents an unprecedented combination of characters, pairing a fused beak‐like dentition with prominent dorsal‐fin spines that insert atop transversely‐expanded pterygiophores roofing the skull. Bayesian total‐evidence tip‐dating analysis indicates that †Ctenoplectus represents the sister lineage of Triodontidae and highlights considerable levels of homoplasy in early tetraodontiform evolution. According to our dataset, rates of morphological character evolution were elevated at the origin of crown Tetraodontiformes, especially within gymnodonts, but declined after the principal body plans were established. Such ‘early burst’ patterns are regarded as a hallmark of adaptive radiations, but are typically associated with diversification at smaller spatiotemporal scales. However, denser sampling of Neogene and Recent taxa is needed to confirm this pattern.
Data for this study are available in the Dryad Digital Repository http://dx.doi.org/10.5061/dryad.304n7 Wiley Online Library (Open Access)