Dinosaur embryos yield organic material in ‘mind boggling’ discovery by Canadian-led team -
With the discovery of some of the oldest known fossilized dinosaur embryos, a Canadian-led research team has also found evidence of what may be preserved collagen — organic remains of an animal that lived in the early Jurassic, 190 million years ago.
Jurassic embryos do not a Jurassic Park make. For lead author Robert Reisz, a paleontologist at the University of Toronto Mississauga, the discovery is quite a bit better.
“People have focused on the great possibilities of DNA, which is much more delicate,” says Reisz. While DNA degrades quickly as bones become fossils, collagen lasts longer and has become a cutting-edge research tool for probing molecular links between species.
Preserved collagen was how another Canadian research team recently showed that a 3.5-million-year-old fossil found in the high Arctic belonged to an animal in the camel family.
The research is the cover story of this week’s issue of the prestigious journal Nature.
“This is really important fundamental baseline work that every subsequent study on dinosaur embryos is going to have to cite. That’s the most simple way of putting it,” said Royal Ontario Museum Vertebrate Paleontology Curator David Evans, who has worked with Reisz on previous dinosaur embryo research but was not involved in this study.
Timothy Huang of the National Chung Hsing University first discovered the fossil site in Yunnan province, southwest China. A chemist with a penchant for paleontology, he invited Reisz to come investigate.
After excavating one square metre of the bone bed, they uncovered 200 embryonic bones from a species called Lufengosaurus, dinosaurs from the long-necked prosauropod family.
The discovery was an exciting find for several reasons. First, the specimens are around 190 million years old, matching the age of another oldest-known set of dinosaur embryos found in South Africa. Embryonic material is a rare find to begin with, and much of what has been found dates to the Cretaceous, at least 125 million years younger than these fossils.
Secondly, the bone bed held fossils from several of different animals at various stages of embryonic development, rather than a single nest of several animals exactly the same age. That allowed Reisz’s team to show that, for example, Lufengosaurus femur bones doubled in size while still in the egg, a surprisingly quick growth rate.
But the most important discovery was of preserved complex proteins, probably collagen.
That find came almost by chance — Hwang, the chemist, wanted to test for it despite the odds. Researchers have found organic material in dinosaur fossils before, but always from large specimens like the T. Rex, says Reisz.
The discovery of preserved proteins in something as delicate and porous as an embryonic bone is “mind boggling,” says Reisz.
“I never would have even thought of looking for it.”
The next step is to try to find a way to extract the material, which would hypothetically allow researchers to extract a molecular fingerprint from it that can be matched to that of living species.
Reisz also wants to start looking for collagen in other fossils, embryonic or not.
“I suspect that if we start using this methodology elsewhere, we will find it more frequently than we think,” he says.
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