Scientists have discovered the location on Earth where the first dinosaurs appeared, but they are unable to reach it. (photo)

Over billions of years, our planet has become home to an astonishing array of species: some animals, like dinosaurs, have long since gone extinct, while others continue to thrive today. For centuries, scientists have discovered fossils of ancient creatures, allowing us to learn more about how they lived and evolved, as reported by Science Alert.

Now, researchers believe that the ancient fossils of some of the world's earliest dinosaurs may be buried in locations that are nearly impossible to explore. This conclusion was reached by the authors of a new study from University College London and the UK Natural History Museum.

The oldest known dinosaur fossils date back 230 million years. These specimens are believed to have been found in areas that were once part of Gondwana—the southern half of the now-disintegrated supercontinent Pangaea. Scientists know that these fossils belong to relatively distant branches of the dinosaur family tree, suggesting that they had already evolved and possibly spread across the globe for millions of years.

Furthermore, the discovery of dinosaurs from the same period in what was the northern part of the supercontinent, Laurasia, has further upended our understanding of dinosaur history. However, some paleontologists argue that the true "starting point" for dinosaurs has yet to be established. In the new study, scientists proposed that the origin of all these "terrible lizards" may actually be hidden in some of the most inaccessible places on Earth.

Between the claims of each hemisphere regarding the earliest fossils lies a significant gap in the record around the equator. It is easy to assume that where dinosaur fossils have not been found, predators simply did not exist, but this is not necessarily the case. There are several reasons for this.

According to lead author Joal Heat, for fossils to be found, they must have initially preserved. For trace fossils, such as footprints, a print in soft mud must be filled with loose sand that is then compacted. For body fossils to form, the carcass of an animal must be covered with mud or silt soon after death to prevent complete decay.

However, even in the case of ideal fossil formation, scientists may not necessarily be able to find it, especially in hard-to-reach locations. In their new work, the team notes that paleontological expeditions to the Amazon and Sahara have not been widespread enough for us to discover anything similar. Moreover, such efforts are extremely challenging to implement.

The authors of the study suggested that areas such as the Sahara and the Amazon may actually be the "starting points" for dinosaurs. It is also well known that socio-economic factors and the legacy of colonialism, combined with political instability, have likely hindered research efforts in these regions.

In their research, scientists modeled the radiation of dinosaurs in reverse, using known fossils of predators, taxonomic data on dinosaurs and their reptilian relatives, as well as the geography of the period. Instead of assuming that areas without fossils equate to areas without dinosaurs, these regions were categorized as lacking information.

In each of the three scenarios, researchers examined three different situations based on proposed evolutionary trees.

The origin from Gondwana in low latitudes, evidenced by the Sahara and Amazon, is most convincingly supported by a model in which silesaurids are the ancestors of ornithischian dinosaurs. It is noteworthy that ornithischian dinosaurs are one of the three main groups of dinosaurs, yet they are strangely absent from the early fossil record. However, if silesaurids are their ancestors, they could fill this gap.

Researchers considered the possibility that low-latitude Gondwana serves as a midpoint between the earliest dinosaur fossils in our current record. The authors of the study note that no dinosaur fossils have yet been found in regions of Africa and South America that once comprised this part of Gondwana. However, scientists acknowledge that this may simply be because researchers have yet to stumble upon the right location.