Rediscovered 45-million-year-old skull turns out to be a large, extinct bird species

Around 45 million years ago, during the Eocene Epoch, the Geiseltal region of present-day Germany was a vast, humid swamp that teemed with life. Ancient horses, early tapirs, giant tortoises, large land crocodiles, and countless birds flourished in this tropical paradise. Among these creatures roamed Diatryma, a massive, flightless bird that stood 4.6 feet (1.40 meters) tall.

With its robust frame and enormous beak, this prehistoric giant was once thought to be a fearsome predator. However, modern research has revealed a different story – Diatryma was likely a gentle herbivore.

This bird’s legacy remained shrouded in mystery for decades, but a recent discovery by an international team of researchers has brought it back into the spotlight.

Led by scientists from the Martin Luther University Halle-Wittenberg (MLU) and the Senckenberg Research Institute, the research team has analyzed a fully preserved Diatryma skull, making it only the second such specimen known in the world.

The findings, published in the journal Palaeontologia Electronica, highlight how museum collections continue to yield remarkable scientific revelations.

A fossil lost in time

The newly examined Diatryma skull was not freshly excavated. Instead, it had been sitting unnoticed in the extensive Geiseltal Collection at MLU for decades. It was originally unearthed in the 1950s in a lignite mining area in Geiseltal, a site known for its rich fossil deposits.

However, due to a misclassification, the fossil led a shadowy existence for years. It was mistakenly identified as a crocodile skull, a forgivable mix-up given the variety of prehistoric reptilian remains found in the region.

For years, the skull sat in storage, unrecognized for what it truly was. It wasn’t until Michael Stache, a geological preparator at MLU’s Central Repository of Natural Science Collections, rediscovered the fossil that its true significance came to light.

“The find was initially misidentified as a crocodile skull,” remarked Stache. Upon closer examination, he realized the error and undertook the painstaking process of restoring and analyzing the specimen.

As Stache worked on the fossil, he noticed that another fragment in the collection seemed to belong to the same skull. By combining the two pieces, he successfully reconstructed what is now recognized as an almost entire preserved Diatryma skull.

A rare and remarkable find

The rediscovery of the fossil attracted the attention of Dr. Gerald Mayr, a researcher at the Senckenberg Research Institute. He examined the specimen closely and confirmed what few paleontologists ever expected to find – a nearly complete Diatryma skull.

Until this discovery, only one other fully preserved skull of this species was known to exist; it is housed at the American Museum of Natural History in the United States.

“This shows, once again, that many of the most interesting discoveries in paleontology occur in museum collections. Just a few years ago, nobody would have thought that the Geiseltal Collection would contain such surprises,” commented Mayr.

The skull’s excellent state of preservation offers scientists a rare opportunity to study the anatomy of this ancient bird in greater detail than ever before.

The fossil is now part of the Geiseltal Collection, which consists of approximately 50,000 specimens. These fossils, considered a national heritage asset, provide an invaluable window into the ancient ecosystems of the Eocene.

Even though the mining operations in Geiseltal ceased in 1993 and fossil excavations ended long ago, new discoveries continue to emerge from the collection, reshaping our understanding of prehistoric life.

A gentle giant, not a predator

For decades, scientists debated Diatryma’s place in the prehistoric food chain.

Early theories suggested that this towering bird was a predator that hunted small horses and other mammals in the swamps of Geiseltal. Its size and formidable beak led researchers to compare it to later, more aggressive species of giant flightless birds.

However, recent studies, including those based on the newly examined skull, have painted a very different picture. Diatryma was most likely a herbivore that used its massive beak to process tough plant material rather than to tear flesh.

Its anatomy suggests it was built for foraging rather than hunting, much like modern, large, plant-eating birds such as ostriches and emus.

“This research expands our understanding of the Eocene Epoch in the Geiseltal even though the excavations were completed long ago,” says Stache. Scientists now believe that Diatryma lived alongside early mammals that fed on vegetation rather than preying on animals.

Significance of the Geiseltal collection

The Geiseltal region has long been a treasure trove for paleontologists. Once a mining area rich in lignite deposits, it also preserved an astonishing diversity of prehistoric life.

Fossils from this region include everything from tiny insects to massive reptiles, providing an unparalleled glimpse into an ecosystem that thrived 45 million years ago.

Even though large-scale excavations in the area ended decades ago, the work of researchers at MLU and other institutions continues to uncover new findings. The rediscovery of the Diatryma skull proves that museum collections hold many secrets that are waiting to be revealed by keen-eyed scientists.

The Geiseltal Collection remains a hub of international research. Scientists from around the world visit MLU regularly to study its fossils, eager to expand the knowledge of life in the Eocene.

Each fossil offers a new puzzle piece in the story of evolution, shedding light on how prehistoric species adapted and thrived in their environments.

Insights from the Diatryma fossil

With only about 40 known Diatryma fossils in the Geiseltal Collection, researchers believe the bird was a relatively rare sight in the region.

“Diatryma was probably a rare guest in the Geiseltal. Otherwise, there would probably be more fossils,” concluded Stache.

The rediscovery of its skull is not just a victory for paleontology but also a proof of the enduring value of museum collections.

While excavation sites may eventually close, the knowledge they yield continues to evolve, driven by curiosity and scientific advances.

Diatryma, once lost in the depths of a misidentified fossil collection, now stands as a symbol of how history can be rewritten with patience, research, and a touch of serendipity.

The study was published in the journal Palaeontologia Electronica.

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