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.
Supplementary Data File - Ctenoplectus Movie Rendering
Movie rendering of digitally-prepared specimen of NHMUK PV P. 63336, Ctenoplectus williamsi gen. et sp. nov.
Supplementary Data File 1 - Ctenoplectus.mov
Supplementary Data File - Ctenoplectus_P63336_laser_surface_scan
3D surface model of NHMUK PV P. 63336 Ctenoplectus williamsi, gen. et sp. nov. specimen.
Supplementary Data File 2 - Ctenoplectus_P63336_laser_surface_scan.ply
Supplementary Data File - Genbank Accession Numbers
Genbank accession numbers for taxa not drawn from Santini et al.'s (2013) molecular phylogenetic analysis of Tetraodontiformes.
Supplementary Data File 4.xlsx
Supplementary Data File - PLY models of NHMUK PV P. 63336
3D model of digitally-prepared skeleton of NHMUK PV P. 63336 Ctenoplectus williamsi, gen. et sp. nov., consisting of individual PLY files for separate skeletal regions.
Supplementary Data File 8 - PLY models of NHMUK PV P. 63336.zip
Supplementary Data File - Ctenoplectus_morphological_matrix
Morphological character matrix of Santini and Tyler (2003) including scoring of †Ctenoplectus williamsi gen. et sp. nov.
Supplementary Data File 3 - Ctenoplectus_morphological_matrix.nex
Supplementary Data File - Ctenoplectus BEAST XML
XML file for BEAST Total Evidence tip-dating analysis of Tetraodontiformes.
Supplementary Data File Ctenoplectus BEAST.xml
Supplementary Data File - Output of Four Replicates of BEAST SA FBD analysis of Tetraodontiformes
Output of four replicates of the BEAST Sampled Ancestor Fossilized Birth Death analysis of Tetraodontiformes, including Ctenoplectus williamsi gen. et sp. nov. Included are tree posteriors for molecular and morphological clocks, Tracer log files, and Maximum Sampled Ancestor Clade Credibility trees calculated from the combined four replicates.
Output of Four Replicates of BEAST SA FBD analysis of Tetraodontiformes.zip
Supplementary Figure 1
Figure 1: Photographs of †Ctenoplectus williamsi (NHMUK PV P. 63336) in (a) dorsal, (b) anterior, (c) right-lateral, and (d) left-lateral views.
Dryad Figure 1.jpg
Supplementary Figure 2
Figure 2: Sagittal tomographic section through jaws of NHMUK PV P. 63336. (a) Sagittal tomographic section through jaws of NHMUK PV P. 63336, showing presence of walls posterointernal to tooth-bearing layers in upper and lower jaws. (b) Axial tomographic section. pmx, premaxilla; den, dentary; piw, posterointernal wall; tbl, tooth-bearing osteodentinic layer.
Dryad Figure 2.jpg
Supplementary Figure 3
Figure 3: Kernel probability-density estimates of divergence times for crown Tetraodontiformes and extant tetraodontiform families.
Dryad Figure 3.pdf
Supplementary Figure 4
Figure 4: Median among-branch morphological rate estimates for internal (red circles) and terminal (yellow triangles) branches on the Maximum Sampled-Ancestor Clade Credibility tree, using midpoint ages. Moving averages are represented by solid LOESS lines.
Dryad Figure 4.pdf
Table 1 - GenBank accession numbers
GenBank accession numbers for Zeus faber and Kentrocapros rosapinto sequences.
Table 2 - PartitionFinder Scheme
Optimal partitioning scheme as determined by PartitionFinder.
Table 3 - Tip Ages for Fossils
Table 3 - Tip-ages and justifications for fossil taxa.
Table 4 - Monophyletic taxon sets
Table 4. Taxon sets for which monophyly was enforced in BEAST analysis.
Table 5 Acanthomorph root-age
Table 5. Calculation of root-age prior for Acanthomorpha based on published divergence-dating studies.
Table 6 Tetraodontiform crown prior age
Table 6. Calculation of node-age prior for crown Tetraodontiformes based on previous published divergence-dating studies.
Fused PLY model of Ctenoplectus williamsi NHMUK PV P63336
Fused PLY model of Ctenoplectus williamsi NHMUK PV P63336.