January 10, 2020 & Behavior

Blood from a golden stone: discoveries within amber by W. Scott Persons1 | Postdoctoral Research Fellow; Philip J. Currie1 | Professor; Corwin Sullivan1 | Associate Professor

1: Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada

This Break was edited by Max Caine, Editor-in-chief - TheScienceBreaker ABSTRACT Beautiful prehistoric flower petals, pristine exoskeletons of insects, delicate silken spiderwebs, and even entire desiccated carcasses of small lizards have been discovered inside amber. But until recently, even the largest pieces of amber seemed too small to contain a dinosaur.

Image credits: Pixabay – CC0

In his novel Park, Michael Crichton among small meat-eating . Many dinosaur envisioned dinosaurs being cloned using DNA from species are known to have had , and there the blood inside ancient mosquitoes preserved are many ways feathers can be trapped in tree resin. within amber. Amber is a fossilized tree resin (not More recently, one tiny piece of amber shocked the sap) that often contains plant and remains paleontological community. It comes from northern and protects them from many forms of decay. Myanmar, a region long renowned for amber with Beautiful prehistoric flower petals, pristine inclusions that date back roughly 99 million to exoskeletons of insects, delicate silken spiderwebs, the Late . The piece contains many , and even entire desiccated carcasses of small lizards including prehistoric ants and flakes of bark, but the have been discovered inside amber. But until most important is nothing less than a section of recently, even the largest pieces of amber seemed dinosaur tail! The tail segment comes from near the too small to contain a dinosaur. tip, and probably became encased in the resin after the death of its owner. The tail is completely covered The first known dinosaur fossils within amber in feathers and belonged to a dinosaur intermediate were collected in Alberta, Canada, and reported in in size between a sparrow and a . 2011. They were not whole dinosaurs, but just partial dinosaur feathers. It is now well-established that Although the phrase “tiny dinosaur” may seem feathers appeared long before evolved from oxymoronic, modern paleontologists have a growing

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appreciation for how many different kinds of tiny of hemoglobin from dinosaur blood! Does that dinosaurs there actually were. However, the remove the need for a mosquito middleman and put researchers who described the tail segment, led by us on track for dinosaur cloning? Unfortunately not, Lida Xing of China University of Geosciences, had to given the vast gulf between hemoglobin-derived iron rule out the possibility that the specimen belonged and intact dinosaur DNA. Despite having been sealed to a . Birds were already present in the in amber rather than fully exposed to decay, any Cretaceous. Some other amber specimens from the genetic material in the residue would be too of Myanmar enclose avian feathers fragmentary for even the theoretical prospect of and wings, and even, in one case, the near-complete reassembly into a dino genome. body of an unlucky . However, the tail segment can be identified as almost undoubtedly non-avian. More importantly, the tail reveals an entirely new The tails of birds, like those of some of their closest type. In modern bird feathers, filaments dinosaurian relatives, fans of broad, leaf- (barbs) branch symmetrically off a sizeable hollow shaped feathers that can produce aerodynamic shaft (rachis). These barbs have their branching forces useful in flight. Furthermore, in all modern filaments (barbules), which hook onto the barbules and most birds, the portion of the tail formed of neighboring barbs in Velcro-like fashion. The by flesh and bone is short, with feathers making up amber tail feathers each have a solid shaft, with the rest. The amber tail segment, by contrast, clearly barbs that branch in an alternating (rather than belonged to an animal with a longer tail skeleton. symmetrical) pattern, and hookless barbules. Such There are prehistoric birds with such tails, but they feathers do not fit neatly into previous models of appear to have been confined to the Jurassic and feather evolution. They indicate that dinosaurs Early Cretaceous and are still extended by broad, evolved a variety of feather types for different flight-assisting feathers. Not so with the amber tail. functions, such as insulation and display. The Its short, pliable feathers are like a shaggy coat – evolutionary history of feathers was not a straight suitable for holding in body heat, but useless for line. Instead of progressing from simple hair-like flight. filaments to the elaborate aeronautic of modern birds, the history was as complex and multi- To facilitate identification of this feather-shrouded branched as feathers themselves. tail fragment, CT scans, and an analysis of its chemical composition were produced using a This discovery also shows the potential of what synchrotron. This analysis revealed eight tail might be found in the future. Before this discovery, vertebrae that could be attributed to some kind of the idea of a dinosaur encased in amber would little meat-eating dinosaur. Probably, one less bird- previously have been considered too far-fetched like than Velociraptor and looking similar to the more even for science fiction. In the coming years, more primitive Compsognathus. amber specimens will be collected and scrutinized in Myanmar and elsewhere. This time, we got a tail. Surprisingly, small amounts of iron associated Next time, it could be a head. with the bones and feathers are probably a residue

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