Conclusion The combination of a CM close to the hips that still enabled effective terrestrial locomotion, an inability to become negatively buoyant, and a body (when immersed) with a tendency to roll onto its side unless constantly resisted by limb use, suggests that Spinosaurus was not highly specialized for a semi-aquatic mode of life. Furthermore, the floating characteristics of the Spinosaurus model were similar to those of models of other predatory dinosaurs, indicating that there was nothing special about the buoyant characteristics of this animal, and that other theropods could have successfully taken to water to the same degree as well. Terrestrial activity would still have been part of its normal life of Spinosaurus, similar to the interpretations given for other large predatory dinosaurs. Lastly, the new reconstruction of Spinosaurus is based on a composition of remains from multiple individuals of varying sizes and proportions that come from different locations, and were scaled to match the presumed proportions of a single individual. This does not seem like a good platform for building hypotheses about what this animal was like as a once living organism.

Supplemental Information Density profile. Density values for body model slices in kg/m3. DOI: 10.7717/peerj.5409/supp-1 Download Vertex triples defining model surface. First value in file is number of slices (S) defining the model. Second value is the number of vertices (V) per slice. Remaining values are S*V (X, YZ) coordinate triples. Coordinates are in meters. DOI: 10.7717/peerj.5409/supp-2 Download Edge colours. Set of colour index values for drawing the edges of the polygons. DOI: 10.7717/peerj.5409/supp-3 Download Opacity values. Index values for the degree of translucency of the polygons. Not used in the present model, but required by the software. DOI: 10.7717/peerj.5409/supp-4 Download Fill values. Colour values used to colour the polygons when drawing them. DOI: 10.7717/peerj.5409/supp-5 Download Polygon definitions. Multiple sets of 5 numbers that describe each polygon in terms of the vertices defined in "body.vertex.dat". The first number in set is the number of vertices for a given polygon, the remaining four are the four vertices of the polygon. DOI: 10.7717/peerj.5409/supp-6 Download Computer program written for PV-WAVE scientific visualization package. Program to assemble the components to produce a 3D digital model of an animal (living or extinct), and then determine the equilibrium state of the model with respect to the competing forces of gravity and buoyancy. Program also produces graphical output in the form of animations or selected images. Program developed on a UNIX computer system and converted to an MS-Windows plain text file. DOI: 10.7717/peerj.5409/supp-7 Download