For over a century, paleontologists have debated the origins of mysterious, fossilized bone fragments unearthed across Western and Central Europe. A new study from the University of Bonn finally puts this debate to rest, revealing the colossal creatures behind these bones – gigantic ichthyosaurs.
The story begins in 1850, with British naturalist Samuel Stutchbury reporting a peculiar find: a large, cylindrical bone fragment discovered at Aust Cliff, England. Similar fragments have since surfaced in various European locations, including Bonenburg, Germany, and the Provence region of France. These areas were once submerged beneath a vast ocean teeming with marine life during the Mesozoic Era.
The identity of the creatures these bones belonged to remained a puzzle. Stutchbury initially proposed a resemblance to Labyrinthodontia, an extinct amphibian. However, other researchers argued for alternative possibilities – long-necked dinosaurs, stegosaurs, or even entirely unknown dinosaur species.
Unveiling the Mystery with Bone Microstructure
Enter Marcello Perillo, a researcher at the University of Bonn. Intrigued by the “gigantic ichthyosaur” theory proposed earlier, Perillo embarked on a mission to analyze the bone microstructure of the unclassified fossils.
“Bone structure is a fingerprint for animal groups,” explains Perillo. “By studying the microscopic details of the tissue, we can determine the creature’s evolutionary lineage.”
Perillo examined samples from various locations in Europe. All the specimens exhibited a unique combination of features, hinting at a shared ancestry. Further analysis revealed an even more compelling clue – the bone wall displayed a previously unseen structure: interwoven strands of mineralized collagen fibers. This specific arrangement was absent in any other known animal bone.
The Ichthyosaur Connection
Interestingly, fossils of large ichthyosaurs from Canada displayed a remarkably similar bone structure. This striking similarity, combined with the absence of this structure in other animal groups, led Perillo to a conclusive answer: “The fragmented fossils belong to an ichthyosaur, not a land-dwelling dinosaur.”
The size of these prehistoric giants can be estimated by comparing the fragments to known ichthyosaur jawbones. Calculations suggest they could have reached a staggering 25 to 30 meters in length, aligning with earlier predictions based on the ichthyosaur theory.
“This is still an estimate,” cautions Perillo, “until we discover complete fossil remains.” Nonetheless, the sheer size of these creatures is undeniable.
The first ichthyosaurs emerged in the Triassic period, around 250 million years ago. Species rivaling whales in size appeared early on, with the largest individuals evolving later. However, most ichthyosaurs vanished by the end of the Triassic period, over 200 million years ago.
The unique bone structure of these giants, resembling carbon fiber composites, likely offered exceptional strength and facilitated rapid growth. “These massive jaws endured tremendous stress during feeding,” explains Perillo. “They might have even used their snouts for ramming prey, similar to modern orcas.” However, further investigation is needed to confirm this behavior.
This groundbreaking research sheds light on the identity of these enigmatic fossils, revealing a chapter in the story of colossal ichthyosaurs that once dominated the ancient European seas. It highlights the power of meticulous analysis in unlocking the secrets of prehistoric life.
The findings are published in the journal PeerJ.
Source: University of Bonn