Boxplots showing maximum size ( = total body length) of marine tetrapod (‘amphibians’, reptiles) and maximum standard lengths of marine non-tetrapod vertebrates (osteichthyans, chondrichthyians).

<p>A. Tetrapod data for the Early Triassic (11 taxa) and the Anisian (30 taxa). Note that the apparent increase in size is not significant. B, C. Non-tetrapod data comprising marine bony fishes (Actinistia, Actinopterygii) and some chondrichthyans with reliable body size estimates in the Early Triassic and the Anisian (early Middle Triassic). The upper two columns in (B) depict the pooled data, whereas in (C) the Early Triassic is split into the respective sub-stages. Based on data taken from the literature for 111 and 107 species for the Early Triassic and the Anisian respectively (see Table S1 in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088987#pone.0088987.s001" target="_blank">File S1</a>). The boxes represent the 25–75 percent quartiles (bold horizontal lines indicate the medians) and the width of the tails the whole spread of data.</p

Spatial and stratigraphical distribution of Early Triassic and Anisian (early Middle Triassic) marine vertebrate predators.

<p><b>A.</b> Geological time scale (Permian-Middle Triassic) with absolute time calibration according to radiometric UPb ages: a based on <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088987#pone.0088987-Shen1" target="_blank">[9]</a>; b on <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088987#pone.0088987-Galfetti1" target="_blank">[34]</a>; c–e on <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088987#pone.0088987-Ovtcharova1" target="_blank">[33]</a>. Paleogeographical distribution of selected marine predatory vertebrates is given on the right using the same color code as in the geological time scale (globe modified from C. Scotese’s paleomap project; <a href="http://www.scotese.com" target="_blank">http://www.scotese.com</a>). <b>B.</b> Marine vertebrate apex predators during the Griesbachian to Smithian interval (left) and the Spathian to Anisian interval (right). Predators not exactly to scale; see text and Tables S1–S2 for details on body size and stratigraphic occurrence. Marine vertebrate apex predators: 1, <i>Wantzosaurus</i> (trematosaurid ‘amphibian’); 2, <i>Fadenia</i> (eugeneodontiform chondrichthyan); 3, <i>Saurichthys</i> (actinopterygian ambush predator); 4, <i>Rebellatrix</i> (fork-tailed actinistian); 5, <i>Hovasaurus</i> (‘younginiform’ diapsid reptile); 6, <i>Birgeria</i> (fast-swimming predatory actinopterygian); 7, <i>Aphaneramma</i> (trematosaurid ‘amphibian’); 8, <i>Bobasatrania</i> (durophagous actinopterygian); 9, hybodontoid chondrichthyan with durophagous (e.g. <i>Acrodus</i>, <i>Palaeobates</i>) or tearing-type dentition (e.g. <i>Hybodus</i>); 10, e.g., <i>Mylacanthus</i> (durophagous actinistian); 11, <i>Tanystropheus</i> (protorosaurian reptile); 12, <i>Corosaurus</i> (sauropterygian reptile); 13, e.g., <i>Ticinepomis</i> (actinistian); 14, <i>Mixosaurus</i> (small ichthyosaur); 15, large cymbospondylid/shastasaurid ichthyosaur; 16, neoselachian chondrichthyan; 17, <i>Omphalosaurus</i> skeleton (possible durophagous ichthyosaur); 18, <i>Placodus</i> (durophagous sauropterygian reptile). Printed under a CC BY license, with permission from Nadine Bösch and Beat Scheffold, original copyright [2013].</p

New fossil finds corroborating the presence of large predators in the Early Triassic.

<p><b>A-C</b>. Assemblage of skull and lower jaw elements of a large <i>Birgeria</i> sp. (PIMUZ A/I 4301) from the Lusitaniadalen Member (Smithian), Vikinghøgda Formation, Stensiöfjellet, Sassendalen, Spitsbergen. Note that specimen (<b>B</b>) represents the infilling of the Meckelian canal. <b>D</b>. Position of the large specimen (<b>A</b>) on the reconstruction of animal indicated by blue rectangle. <b>E-H</b>. Humerus (NMMNH P-65886) of a giant ichthyosaur from the mid to late Spathian in the Hammond Creek area, Bear Lake valley, southeast Idaho, USA. <b>I-K</b>. Nodule (PIMUZ 30731) containing large coprolite with fish remains from the Griesbachian of Kap Stosch, East Greenland, possibly from a temnospondyl ‘amphibian’. Br, branchiostegal rays; D, dentary; Mc, Meckelian canal (infilling).</p

Humeral proximodistal length-body length relation in Triassic ichthyosaurs.

<p>Note that the upper two data points (<i>Shonisaurus popularis</i> and <i>Shastasaurus sikanniensis</i>) are based on estimated body lengths, whereas the other points rely on complete specimens. Removing the two taxa from the plot results in a shift of the specimen from Bear Lake (southwest Idaho, USA) towards even larger body size estimates.</p