Researchers Detect Heme in 115 Million-Year-Old Dinosaur Bone

Researchers have detected heme and cell-like structures in a 115 million-year-old dinosaur fossil discovered in northeastern Brazil, according to demokratis.co.id.

The findings, published Monday in the Proceedings of the National Academy of Sciences, concern a partial hind limb belonging to Aratasaurus museunacionali, a theropod dinosaur from the Early Cretaceous period. The fossil was excavated in 2008 at Mina Pedra Branca in northeastern Brazil, within the Romualdo Formation.

Inside microscopic vascular canals in the bone, the team identified numerous oval-shaped structures resembling red blood cells. Scientists combined advanced microscopic imaging with chemical analyses to examine their appearance, mineral composition, location and molecular signatures.

The research also identified traces of manganese oxides, minerals that may have contributed to stabilizing and preserving the microscopic structures. According to the study authors, these findings provide multiple lines of evidence supporting the possibility that biological material can survive fossilization.

Lead author Kliti Grice, an organic geochemist and John Curtin Distinguished Professor at Curtin University in Perth, Australia, said the discovery could influence how scientists investigate other prehistoric remains.

"The exciting implication is not just what we have found in this dinosaur. It is that we now have approaches that can be applied to other fossils to ask how much original biological information may still be hidden within them," Grice said in an email.

Grice explained that molecular preservation could provide information beyond what conventional fossil analysis reveals about anatomy, movement, growth and evolution.

"Bones provide extraordinary information about anatomy, growth, locomotion and evolution. But cellular and molecular preservation potentially gives us access to a different layer of biological information: the chemistry of the living animal and its tissues," Grice said.

She cautioned that one specimen cannot establish whether the preservation process reveals a common feature of dinosaur fossils or an exceptionally rare occurrence.

"One of the first questions is whether this is an extraordinarily rare occurrence or whether similar preservation has simply been overlooked in other fossils," Grice said.

She also suggested that existing museum collections could contain previously unrecognized biological evidence.

"There may therefore be fossils sitting in museum collections around the world that contain molecular and cellular information that has simply never been investigated," Grice said.

Grice and her colleagues plan to examine fossils from additional species, geological periods and environments to determine how frequently similar molecular evidence survives. The researchers hope these investigations will eventually provide more information about oxygen transportation, tissue function and the biology of extinct animals.

Nevertheless, the discovery does not establish that dinosaur DNA has survived. Timothy Cleland, a physical scientist at the Smithsonian Institution's Museum Conservation Institute who was not involved in the study, emphasized that heme and DNA are different molecules with different preservation processes.

Cleland said the research creates opportunities to investigate the preservation of heme b, the most common form of heme, in fossilized bone.

"This study opens new research avenues to explore heme b preservation within bone, especially in exceptional sites like this one," Cleland said in an email.

He also raised questions about whether comparable preservation exists in other fossils from the same geological formation and in deposits elsewhere.

"Additionally, this study begs the question, does this kind of preservation extend beyond this single dinosaur to other species within the Romualdo Formation as well as to other locations with exceptional preservation?" Cleland said.

The researchers also acknowledged that the microscopic structures differ in size and shape from red blood cells found in living birds and crocodilians. They cautioned that modern animals may not provide an ideal comparison for non-avian dinosaurs and that the fossilized structures may have changed shape since the animal was alive.

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