Colour Me a Dinosaur

An interesting National Geographic article starts with the concrete dinosaur models of the park in Crystal Palace (https://www.nationalgeographic.com/family/reimagining-dinosaurs/). Although these concrete models, with their muted colours, are somewhat dated, they were once 'state of the art' imaginings and were immensely popular, attracting millions of visitors annually. The National Geographic account points to the impressive uses of modern technology to get a much better understanding of the appearances and behaviours of these fascinating reptiles. Birds are allocated their rightful place, as being essentially dinosaur survivors. In the past, fossil hunters often destroyed evidence of soft tissues in their attempts to extract the fossilised bones from their finds. The aqccount deals with lots of issues (e.g. how dinosaurs developed, moved and cooled themselves). I was most impressed, however, by the recent studies that have brought colour to dinosaur Palaeontology. Computer Assisted Tomography (CT) scans and The European Synchrotron Radiation Facility can both be used to look 'inside' fossils in much more detail. Laser beams can be employed to show that some dinosaur eggs were coloured and speckled, like those of modern birds. We know this because the lasers reveal that the fossil shells contain protoporphyrin and biliverdin (which colour egg shells in modern birds). It seems likely that the eggs of the dinosaur Deinonychus, for example, were blue, suggesting that this creature used an open-air nest and incubated its eggs. It seems likely that feathers evolved in dinosaurs for temperature regulation and/or sexual display (flight was just an 'add-on' initially by a few specialists). The colours of feathers and the skin are also determined by a variety of pigments. Professor Vinther (of the University of Bristol) has shown that one of them, melanin, is preserved in some fossils as melanosomes (tiny, sub-cellular sacs filled with the pigment). The shapes, sizes and distributions of the melanosomes makes it possible to deduce the probable colours of dinosaur skin and feathers. For example, Anchiornis, from China, had feathers and a red crest (possibly used in sexual displays). A herbivore Psittacosaurus had a reddish-brown skin which may have helped with camouflage. Even more impressively, another Chinese dinosaur, Caihong, appears to have had an array of irridescent feathers for display. One thing seems certain. The dinosaur world was much more colourful than that implied in the Crystal Palace 'models'.