'Giant' Fossils Change Views on Extinction Events

Scientists working on analyzing fossils of gastropods found to be dating just one million years after the Permian-Triassic extinction event were puzzled to discover specimens that were up to seven centimeters in size. The P-T boundary was the largest event of the five extinctions, leading to more than 90 percent of all species going extinct some 252.6 million years ago. Anthropologists and paleontologists know that any such event triggers the “Lilliput Effect,” which means that species grow smaller in size, so as to adapt to the new, post-apocalyptic environment. Under this theory, the new findings make no sense.

A group of scientists from France, Germany, Switzerland and the United States says that the new fossils call into question whether the Effect is actually founded in reality of not. Previously, experts believed that postcrisis biota tended to get a reduced size for at least several millions of years, after which time they were indeed expected to grow in size again. But evolutionary dynamics apparently work by other dynamics than the ones existing theories proposed. Biospheres also appear to be functioning quite differently than predicted, AlphaGalileo reports.

Details of the new investigation appear in the February issue of the esteemed journal Geology. The findings are all the more baffling since the fossils were found to be dating around the time of the P-T boundary, which destroyed most living things on Earth with a level of brutality that had never been equaled before or since. The two main implications of this are that either the importance of the Lilliput Effect has been gravely exaggerated, or that it did not exist in gastropods during the major part of the Early Triassic. Generally, this class of creatures, which includes snails, grows to be only about one centimeter in length, therefore finding the giants really doesn't make any sense.

At about the same time, around 251 million years ago, the reconquest of the seas appears to have been well underway. In addition to the gastropods, the researchers also found signs that other organisms, such as ammonites, were also replicating fast. These organisms are free-swimming cephalopod mollusks with external shells, which are similar to the modern nautilus, cuttlefish and squid. They were wiped out of existence during the K-T extinction event, more than 65 million years ago. This was the same devastation that killed off the dinosaurs.