Appendix3

Species list of dinosaurs, from 1824-201

Appendix1

Summary data for the Early tetrapods and Dinosaurs studies, together with calculations and live versions of Figures 1-10

Relationship between habitat (proportion of terrestrial species) and net diversification rates.

<p>Data are shown for animals (a) and vertebrates (b). Predominantly marine forms are highlighted blue, and predominantly terrestrial forms, brown. Based on data in [<a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.2000724#pbio.2000724.ref023" target="_blank">23</a>] and [<a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.2000724#pbio.2000724.ref024" target="_blank">24</a>], respectively; drafted by Simon Powell (University of Bristol).</p

A Cretaceous snake feeding on hatchling sauropod dinosaurs.

<p>A 3–5-meter-long madtsoiid snake, <i>Sanajeh indicus</i>, waits to feed on hatchling sauropod dinosaurs as they emerge from their eggs, in a scene from the Upper Cretaceous, some 70 million years ago. The sculpture is based on a fossil dinosaur nest from western India, reported in this issue of <i>PLoS Biology </i><a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1000321#pbio.1000321-Wilson1" target="_blank">[11]</a>. The scales and patterning of the snake's skin is based on modern macrostomatan snakes, relatives of the fossil form. The hatchling dinosaur is reconstructed from known skeletal materials, but its color is conjectural. The eggs are based directly on the fossils. In making their detailed paleobiological interpretations, Wilson and colleagues <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1000321#pbio.1000321-Wilson1" target="_blank">[11]</a> used all three methods advocated in this review—empirical observations of a remarkable specimen, coupled with comparison with modern analogs and biomechanical modeling. In detail, the authors incorporated museum-based research, field research, stratigraphy and sedimentology, histology, embryology, and use of modern analogs into their interpretation of <i>Sanajeh</i>. (Sculpture by Tyler Keillor and original photography by Ximena Erickson; image modified by Bonnie Miljour).</p

Finite element analysis of the skull of <i>T. rex</i>.

<p>The skull of <i>T. rex</i> is perhaps one of the most talked about fossils of all time, coming as it does from perhaps the most fearsome, and certainly the largest, terrestrial predator that ever lived. But the anatomy of the skull reveals a paradox; while <i>T. rex</i> is assumed to have been capable of producing extremely powerful bite forces, the skull bones are quite loosely articulated. Does this mean that the skull would have expanded and distorted if its owner bit too hard into a <i>Triceratops</i> carcass, or did <i>T. rex</i> have to control its bloodthirsty efforts? Emily Rayfield <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1000321#pbio.1000321-Rayfield1" target="_blank">[19]</a> studied all the available skulls (A) and constructed a mesh of triangular elements, small triangular or cuboid cells that define the 3-D shape in preparation for engineering analysis. The technique used is FEA, a numerical method worked out in the 1940s to study the physical properties of buildings. In Rayfield's FEA model of the <i>T. rex</i> skull, modeled bite forces of 31,000–78,060 newtons were applied to individual teeth, and the distortion of the element mesh observed (B). The bite forces had been taken from calculations by other paleobiologists, and from observations of tooth puncture marks (a piece of bone bitten by <i>T. rex</i> showed the tooth had penetrated the bone to a depth of 11.5 mm, equivalent to a force of 13,400 newtons, or about one-and-a-half tons). Rayfield's results show that the skull is equally adapted to resist biting or tearing forces and therefore the classic “puncture-pull” feeding hypothesis, in which <i>T. rex</i> bites into flesh and tears back, is well supported. Major stresses of biting acted through the pillar-like parts of the skull and the nasal bones on top of the snout, and the loose connections between the bones in the cheek region allowed small movements during the bite, acting as “shock absorbers” to protect other skull structures. (Image Credit: Emily Rayfield)</p

Appendix4

Species lists of Early tetrapods and of Dinosaurs, sorted by geological period, by old lands vs. new lands, and in other ways

Appendix2

Species lists of Early tetrapods, by major subclade, and by time

<i>T. rex</i> trotting along beside a <i>T. rex</i>-sized chicken.

<p>Calculations of the muscle mass required to power a fast-running <i>T. rex</i> showed that this was impossible—a 6-tonne chicken would have needed leg muscles making up almost 100% of its body mass. Realistically, <i>T. rex</i> had the muscles to run at about 5 meters per second (18 km/h, 11 mph) <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1000321#pbio.1000321-Hutchinson2" target="_blank">[26]</a>. (Painting courtesy of Luis Rey.)</p

The history of biodiversity on land and in the sea.

<p>Note the postulated cross-over 125 million years ago, when life on land (brown line) became more diverse than life in the sea (blue line). The species-level plots are extrapolated from family-level plots in [<a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.2000724#pbio.2000724.ref005" target="_blank">5</a>], and ideas expressed in [<a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.2000724#pbio.2000724.ref010" target="_blank">10</a>]. Abbreviations: C, Cambrian; Crb, Carboniferous; Cret, Cretaceous; D, Devonian; J, Jurassic; O, Ordovician; P, permian; S, Silurian; Tert, Tertiary; Tr, Triassic; V, Vendian. Drafted by Simon Powell (University of Bristol).</p

Supplementary Figure 5

Supplementary Figure