Paleontologists have discovered that pigmented eggs dinosaurs of the entire group to which they belong, today’s birds.
People who are accustomed to see the eggs alone the hen, it is difficult to imagine how diverse is their colouring from other birds, from chocolate brown to emerald green, from brick red to bright blue. And there was this long before diversity of birds — with a single mutation that appeared in the dinosaurs millions of years ago. In an article published in the journal Nature, scientists reveal the details of this important event.
In fact, lay eggs many animals, but different in color only happens in birds. Therefore, until now it was thought that this adaptation came from the representatives of this group. On the other hand, recent findings suggest that the dinosaurs could lay eggs of different colors. In particular, Jasmine Wiman (Jasmina Wiemann) and her colleagues have discovered a fossilized egg of the oviraptorid age of 70 million years, the biliverdin is a pigment that makes them blue-green color. Were subsequently found and red-brown protoporphyrin: it is a combination of the two key pigments create all the color options of eggs in birds.
In the new work by the same team of researchers covered a much more extensive material of 19 species of dinosaurs and modern reptiles and birds. The biliverdin was able to find in the remains of eggs of seven different dinosaurs. They all belong to the group of Eumaniraptora, which will include modern birds. Attempts to detect traces of color in dinosaur eggs and other groups have been unsuccessful: all of them, apparently, was just white. Scientists believe that this indicates the appearance of color within the clade Eumaniraptora in the early stages of its evolutionary development, when splitting into subgroups has not yet occurred.
Most likely, it was a single event, even of uncertain mutation, which caused accumulation of biliverdin in the shell and made the eggs for the beginning of blue-green. On the other hand, causes a fixation of this mutation call is difficult. Maybe bright colors facilitate the search of eggs in thick grass or helped to distinguish them from eggs planted “brood parasites” like the modern cuckoo.