In 1859, Charles Darwin published On the Origin of Species, outlining the theory of natural selection. In his text, Darwin candidly acknowledged one of the most formidable potential objections to his theory: the apparent lack of transitional “missing links” in the geological record connecting major biological classes. Barely two years later, in 1861, a quarry … Read more

Across the rich fossil beds of the Late Cretaceous Hell Creek and Lance Formations of western North America, one dinosaurian silhouette stands out as the ultimate paragon of evolutionary defense: Triceratops. With its massive three-horned skull, expansive solid bone neck frill, and compact nine-ton quadrupedal stance, Triceratops was the dominant herbivorous mega-dinosaur of the terminal … Read more

Among all organisms that ever walked on solid ground across Earth’s four-billion-year history, sauropod dinosaurs stand entirely alone in their sheer scale. While modern terrestrial mammals reach physical upper limits of 10 to 15 metric tons — represented by the extinct hornless rhino Paraceratherium and large African bull elephants — giant sauropods like Argentinosaurus, Patagotitan, … Read more

No creature in the 3.8-billion-year chronology of terrestrial life captures the primeval power of the Mesozoic Era quite like Tyrannosaurus rex. Roaming the coastal plains and subtropical river valleys of western North America (Laramidia) during the terminal Cretaceous period (approximately 68 to 66 million years ago), this colossal theropod was among the largest terrestrial carnivores … Read more