[ad_1]
With their long necks, protruding bodies and long tails, you had to be blind not to notice a sauropod. These were the largest creatures to ever walk on land – some reach towering heights of 12 meters (40 feet) – but how they managed to grow to such a gorgeous scale, surpassing all other herbivores, has always been the object of great debate among paleontologists. A new study suggests that the chronology of sauropods’ range expansion and growth in size correspond to a large extinction triggered by volcanic eruptions in the Lower Jurassic.
Like some dinosaurs they have long necks
Earth has been no stranger to global cataclysms that wipe out countless species. In the past half a billion years, there have been five great destructions, known as mass extinctions, in which well over half of all living creatures have disappeared in the blink of an eye. Among these major destructions, there have been minor extinction episodes, such as the Toarcian Oceanic Anoxic Event, during which a series of carbon dioxide-rich volcanic eruptions plunged the world into global warming some 182 million years ago.
Similar to human activity today, early Jurassic eruptions introduced excess carbon dioxide into the atmosphere, which made the oceans more acidic, thus causing a mass extinction of marine life. Although plants have a reputation for being a carbon sink, terrestrial ecosystems during that time were dominated by ferns, cycads, and ginkgoes, which did not do very well in the now arid and warmer climate. Instead, climate change proved ideal for conifers, which have flourished.
However, only animals tall enough to reach conifers and with stomachs hard enough to digest thorny leaves could access the nutrient source. One of these creatures must have been Bagualia alba, a five-ton heavyweight herbivore and the first eusauropod, or “true sauropod,” found to date.
B. albaThe fossils were first described by Argentine paleontologists in a study published today in the journal Proceedings of the Royal Society B. The fossils, including a partial skull of the ancient giant, were unearthed in the Cañadón Asfalto basin in Argentina. They suggest B. alba they had characteristics similar to the famous sauropods such as the diplodocus and the brontosaurus, such as wide legs, long necks in relation to the body, thick spoon-shaped teeth and wide and strong jaws.
During the early Jurassic, plant-eating sauropods competed with other herbivores, including members of their own clade with less powerful jaws and shorter necks. It hasn’t always been clear why eusauropods have grown by leaps and bounds, but we now have a very reasonable explanation: The new fossils show that the Toarcian oceanic anoxic event provided the perfect storm for sauropod dawn since long neck.
According to the study authors, this is the first time the availability of ancient plants has been linked to the evolutionary development of a dinosaur that included them in their diet.
“We show that eusauropod dominance was established after a massive magmatic event that impacted southern Gondwana (180-184 Ma) and coincided with severe climate disruptions and a drastic decrease in floral diversity characterized by the rise of conifers. with small scaly leaves. Flower and fauna records from other regions suggest that these were global changes that impacted terrestrial ecosystems during Toarcian warming and were part of a second-order mass extinction event, “they wrote. researchers from the Egidio Feruglio Paleontology Museum in Trelew, Argentina.
Source link
