Plates For Heating

The plates on the back of Stegosaurus were not necessarily for heating or cooling, although that is one credible hypothesis. That sort of hypothesis was very popular for all animals with any kind of sail or large area of potentially highly vascularized tissue for a very long time. During the years just prior to the "rediscovery" of the older hypothesis of warm bloodedness in dinosaurs (see The Dinosaur Heresies for the backstory on the endotherm-ectotherm-endotherm history of hypotheses) the hypotheses of ectothermic blood heating using plates and sails was widely published upon by many authors. These include papers by Marsh describing the restoration of Stegosaurus (describing all three species); Farlow, Thompson and Rosner (1976) which considers heat loss; and Farlow, Hayashi, and Tattersall (2010) which discusses vascularization of the plates. The last paper is much more current than the first two, but it does still discuss the plates and their vascularization. Farlow is very serious about his Stegosaurus plates, and that level of commitment is quite commendable. Also, after almost 50 years the idea that we still have much to learn about the plates on the back of a dinosaur is quite amazing as well. The classical studies of Stegosaurus (aside from Marsh's remarks) are still available online in many places as well. These older papers include the 1914 comments of C. W. Gilmore on the osteology of armored dinosaurs in general. The book includes a number of line drawings of Stegosaurus and other armored dinosaurs. The drawings of Stegosaurus are worth looking through the pages of the book. The number of illustrations in the book of Stegosaurus alone is staggering and, as someone that always encourages reading the original descriptions, Gilmore's treatment of Stegosaurus is a read I certainly highly recommend.