Ancient Teeth Reveal Hidden Diversity in Late Cretaceous Ecosystem of Argentina

For paleontologists, piecing together the puzzle of ancient life often relies heavily on fossilized bones. But what happens when those bones are scarce? A new study published in the journal PLoS ONE reveals the surprising power of isolated teeth to paint a vivid picture of past ecosystems.

The research, led by Ariana Paulina-Carabajal of Argentina’s INIBIOMA and CONICET, focused on the Late Cretaceous Cerro Fortaleza locality in Argentina. While nearby sites teem with diverse reptile remains, Cerro Fortaleza has yielded a surprising scarcity – with only giant sauropod Dreadnoughtus dinosaurs regularly turning up.

However, the researchers weren’t ready to throw in the towel. By meticulously examining the site, they unearthed a hidden treasure trove: 13 teeth and 9 tiny osteoderms (armor-like skin bones) representing a menagerie of ancient reptiles.

These seemingly insignificant fragments were a goldmine of information. Analysis confirmed the presence of carnivorous abelisaurs, armored ankylosaurs, and long-necked titanosaurs – dinosaurs previously absent from the site’s fossil record. But the real stars of the show were the teeth, belonging to a group known as peirosaurs, land-dwelling crocodile cousins.

Ankylosaur osteoderm, thin sections. Credit: Dr. I. Cerda

While the lack of complete skeletons prevents precise species identification, these fragmented remains paint a radically different picture of Cerro Fortaleza. They reveal a hidden ecosystem teeming with far greater reptilian diversity than previously suspected.

The findings extend beyond diversity, offering insights into geographic distribution. The presence of ankylosaurs bridges a gap between Patagonian and Antarctic records, while the peirosaurs represent the southernmost discovery of their kind in South America.

This study highlights the invaluable role of seemingly insignificant fossils. Even in the absence of complete skeletons, isolated teeth and bones can unlock the secrets of ancient ecosystems, revealing hidden diversity and shedding light on the movement and distribution of long-lost creatures. As the authors themselves say, “Sometimes the skeletons do not appear… tiny fossils reveal a faunal association that has not been previously found.” In a world where bones are rare, teeth become the key to unlocking the stories of the past.

Source: Public Library of Science

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