New research published in the journal Current Biology has provided graphic and conclusive evidence of predator-prey interactions in the fossil record dating back over 240 million years ago. The study focused on the unusual long necks of two Triassic species of Tanystropheus, a marine reptile distantly related to crocodiles, birds, and dinosaurs.
These Tanystropheus species had remarkably elongated necks composed of 13 vertebrae and strut-like ribs, indicating a stiffened neck structure that allowed them to lie in wait and ambush their prey. However, the researchers discovered bite marks on the fossilized neck bones of two specimens, with one specimen showing bite marks at the point of neck breakage. This finding provides rare and gruesome evidence of predator-prey interactions targeting the vulnerable necks of these long-necked marine reptiles.
Stephan Spiekman of the Staatliches Museum für Naturkunde Stuttgart, Germany, who conducted the study during his doctoral work at the Paleontological Museum of the University of Zurich, explained that this discovery confirms the long-held speculation among paleontologists that the long necks of these marine reptiles made them susceptible to predation. Despite previous depictions of such vulnerabilities, there had been no direct evidence of attacks targeting the necks of these reptiles until now.
The research team, led by Spiekman and Eudald Mujal of the Stuttgart Museum, carefully examined the fossil specimens and determined that the necks had been severed by other animals. The skulls and necks were preserved undisturbed, while the rest of the bodies were absent. The researchers believe that the predators were likely less interested in the slender necks and small heads, opting to focus on the more substantial body parts instead. The findings suggest that both individuals were decapitated during hunting events rather than being scavenged, although scavenging cannot be entirely ruled out for fossils of this age.
The study also highlights that the unique neck structure of Tanystropheus, characterized by narrowness and stiffness compared to other long-necked marine reptiles like plesiosaurs, represents an exceptional evolutionary adaptation. The elongated necks provided advantages for these reptiles, despite the associated risk of predation. The researchers emphasize that evolving a long neck proved to be a highly successful evolutionary strategy, observed in various marine reptiles over a span of 175 million years.
In conclusion, the research provides valuable insights into the trade-offs and risks associated with evolutionary adaptations. Despite the vulnerability of their long necks, Tanystropheus and other long-necked marine reptiles thrived for millions of years, demonstrating the evolutionary success of this unique trait. Tanystropheus, in particular, had a successful existence spanning at least 10 million years and was distributed across different regions, including Europe, the Middle East, China, North America, and possibly South America.
Source: Cell Press