This elephant size mammalian, Lisowicia bojani went on the ground in late triass, just as the dinosaurs developed in large…
Imagine if you crossed a rhino with a giant turtle and then supersized the result: You can get something like Lisowicia bojani a newly discovered Triassic mammal cousin who had a body shaped like a rhino, a beak like a turtle, and weighed as much as an African elephant, about 9 tons. Paleontologists say that this startling creature gives a new view of the age of dinosaurs. “Who would ever have thought there were giant elephant-big mammal cousins living with some of the first dinosaurs?” marvels Stephen Brusatte, a vertebrate paleontologist at Edinburgh University.
Researchers had found that during the late triasses, from about 240 million to 201 million years ago, early mammals and their relatives returned to the shadows while the dinosaurs rose and grown to large sizes, Brusatte said. “This is the story I tell my students in my lectures, but this throws a wrench into the simple story,” which indicates that the same evolutionary forces as favored giant minosuries were also working on other beings.
The new fossil, a skeleton described online this week in Science is an old planter called a dicynodont; The name means “two dog teeth”, referring to the characteristic teeth on the upper jaw that resemble oversized dogs. Aside from the teeth, dicynodonts were mostly toothless, with a horny beak like the turtles of the day. They are part of the major evolutionary group called synapse pages, which includes our mammalian fathers, and they were some of the richest and most diverse land animals from the intermittent period to the middle tribe, from 270 million to about 240 million years ago
Dicynodonts’ is the first group of vertebrate animals that could successfully eat plants, “says Tomasz Sulej, a paleontologist at the Polish Academy of Sciences’s Paleobiology Institute in Warsaw.
Dicynodonts developed a striking assortment of shapes: A burrowed as modern molar, another is the first known vertebrate to live in trees. Some grew as big as today’s hippos, which weighs about 1.5 tonnes. The fossil record, however, suggests that the group was in decline at the time L. Bojani lumberedde in sight. And even in the dicynodontic heyday they did not come close to early dinosaurs in size.
Sulej, with the Institute of Palaeobiology Jerzy Dzik and Grzegorz Niedźwiedzki, a paleontologist at Uppsala University in Sweden, discovered the new fossil in a clay pit once milled for masonry, in the village of Lisowice, about 100 kilometers northwest of Krakow in the south Poland. In 2006, the team got a tip that someone had found bone fragments on the spot. On their first visit, they found fossils within 15 minutes; During 11 years of field work, they dug more than 1000 legs.
They did not immediately recognize the new dicynodont as such – partly because it’s so big, Sulej says. “Our first idea was that it was a sauropod”, which were the largest known herbivores during this period, reaching 11 meters long. But skull fragments and bones identified the animal as the largest, latest dicynodont ever found. The team named it after the village and the 18th century comparative anatomist Ludwig Heinrich Bojanus; They estimate that it was more than 4.5 meters long and 2.6 meters long.
Most dicynodons had a body posture that seems uncomfortable to the modern eye: Their hind legs were straight, as in today’s mammals, but their forelegs sprawled, lizard, with a bend at the elbow. The team suggests that because of the upper leg of the leg L. Bojani with its axis, its front legs must be oriented vertically, giving a more sincere attitude than in modern reptiles. This posture, such as that of sauropod dinosaurs and modern mammals, may have helped to support its massive weight. But other precautions to reconstruct posture without soft tissue can be difficult.
L. Bojani s also missed the lines that in most dicynodont fossils mark periods when bone growth slowed. The animal may have become immensely fast, or not yet grown when it died. Given the “really amazing” size of the creature, “it was likely to be rapid,” says paleontologist Jennifer Botha-Brink from the Bloemfontein Palaeo Systems Center and National Museum in South Africa. But she adds that lines that signal slower growth may have been eradicated when the leg was rebuilt during adulthood, which happens in elephants today.
Researchers have assumed that sauropods grew large to avoid being eaten. It may have been true for L. Bojani Sulej also says. The Lisowice leg bed also contains the remains of a 5 meter tall predator – probably a dinosaur and coproliter (fossilized feces) containing dicynodont bone.
The researchers will seek more copies further east in Russia and Ukraine. “There is definitely more to discover,” said Niedźwiedzki. “How many surprises are we still waiting for in the rocks?”