The mammalian ancestor looked like a chubby lizard with a small head and had a hippopotamus-like lifestyle
An animal that lived before the dinosaurs looked like a round lizard with a very small head and had a semi-aquatic lifestyle similar to that of a hippopotamus, according to fossils recently discovered in France.
The amphibian animal, which represents a previously unknown genus and species of mammal ancestor, was about 12 feet (4 meters) long, researchers reported in the October issue of the journal. Paleo Vertebrates, published online in July. They dubbed the new species Lalieudorhynchus gandi; he lived about 265 million years ago on the pangea supercontinent, just before the age of the dinosaurs.
Fossils of this unusual animal were first discovered in 2001 in the Lodève basin in southern France by study co-author and paleontologist Jörg Schneider, a professor in the Department of Paleontology and Stratigraphy at the University of Freiberg in Germany, and doctoral student Frank Körner. . They found two large ribs, each 24 inches (60 centimeters) long, in a rocky creek bed. During subsequent visits to the site, Körner found additional bones of the mysterious animal: a femur measuring 14 inches (35 cm) long and a shoulder blade measuring 20 inches (50 cm) long.
Their analysis took 20 years, largely because the fossils were encased in hard sandstone and took years to prepare, the researchers reported in the study.
From this partial but well-preserved skeleton, paleontologists deduced that the primitive creature was a type of caseid – an extinct group of fossil reptiles that possessed mammalian traits and are considered mammalian ancestors – of the genus Lalieudorhynchus. Described in the press release as a ‘chubby lizard’ and a 3.5 meter long ‘pile of meat’, the creature lived during the Permian, a period that began around 299 million years ago. and ended about 252 million years ago with the start of the Triassic period (and the rise of the dinosaurs).
Related: The ancient hippo-sized reptile was a fast and ferocious killing machine
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Caseids were primarily herbivores – possibly some of the earliest herbivores in evolutionary history. They had small heads and barrel-shaped bodies which contained large digestive tracts for decomposing plants, and despite their reptilian appearance, caseids were the ancestors of mammals. .
“The highly diverse group of mammalian ancestors was the dominant group before the age of the dinosaurs,” Frederik Spindler, study co-author and scientific director of the Dinosaur Museum Altmühltal in Denkendorf, Germany, told Live Science. . When Spindler examined the new fossils, he concluded that they belonged to a new species. There have been fewer than 20 caseid species identified in the fossil record to date; most were from the United States and Russia, but some have recently been found in southern Europe, Spindler said.
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However, L. gandi could be a particularly advanced caseid species the likes of which have never been seen before, Spindler added. “New genera are diagnosed by detailed anatomical comparisons”, and the analysis on L. gandi was conducted by the study’s lead author, Ralf Werneburg, director of the natural history museum at Bertholdsburg Castle in Schleusingen, Germany, Spindler said. Werneburg identified five unique features “not known in any other caseid, and another 20 that constitute a unique combination within this family,” Spindler explained.
This newly identified creature isn’t a so-called missing link in an evolutionary line of the mammalian family tree, but its status as one of the youngest caseids ever found may be important for understanding mammals. evolution. “It increases the known diversity of large caseids, marking them as a very important herbivorous group,” Spindler said. What else, L. gandi could be the pinnacle of evolution of all caseids before their extinction, meaning the species had the most advanced features of the group, Spindler said.
The structure of L. gandiThe bones of , which were spongy and flexible when viewed under a microscope, hinted to the study authors that the ancient caseid may have led a semi-aquatic lifestyle, much like that of the modern one. hippos. In life, L. gandi probably weighed hundreds of pounds, and all that body weight may have required additional support from water immersion, according to the study.
However, L. gandi is not a relative of the hippopotamus, and any similarities to modern hippos are in the ancient animal’s habits, not its anatomy, Spindler said.
“Spongy bones may implicate a diving lifestyle in some extinct marine amphibians and reptiles,” Spindler said. In comparison, most mammals, including hippos, have denser bone tissue. “Our new caseid would swim better, while hippos walk closer to the ground,” Spindler said.
“A low-navigation, semi-aquatic lifestyle is what large caseids share with hippos, if we’re right,” Spindler said. “You could say that Lalieudorhynchus gandi “invented” a niche that the hippos later repeated.”
Originally posted on Live Science.
