Mesozoic dinosaurs of several sorts evolved impressive, sometimes radically extravagant structures: horns, crests, frills, dorsal sails, giant bony plates and so on.
In an article from last month, I discussed how the giant, vaguely diamond-shaped plates of the famous Jurassic stegosaur Stegosaurus have sometimes been interpreted as specialised thermoregulatory structures, their size and shape being linked to the role of the plates as heat-collecting and/or heat-dissipating structures.
Now, don’t get me wrong – like many people interested in palaeobiology I’m more than happy to think that stegosaur plates may well have functioned in thermoregulation somehow, perhaps on a facultative or opportunistic basis. What I think we can doubt, however, is that this possible function ‘explains’ their evolution. In other words, it does not look likely that a role in temperature control was the factor driving the evolution of their size and shape. What seems more likely is that they were visual display devices: that they functioned in signalling of some sort. But what sort of signalling?
illustration by Nobu Tamura
hychlorions
