Lalieudorhynchus gandi , ancestor of mammals, was an animal that lived before the dinosaurs on Pangea, the ancient supercontinent. Looking like a plump lizard with a disproportionately small head, this animal was about four meters long and led a semi-aquatic lifestyle similar to that of the hippopotamus.
The genus and species of this amphibian were previously unknown. Scientists have named it Lalieudorhynchus gandi .
Fossils of this ancient animal were first discovered a few years ago, in 2001, in the Lodève Basin in southern France by co-author of the study and paleontologist Jörg Schneider, professor in the Department of Paleontology and Stratigraphy at the University from Freiberg (Germany), and doctoral student Frank Körner. The remains included two large ribs, each measuring 60 centimeters. On subsequent visits to the area, Körner found other bones of the mysterious animal: a 35-centimetre-long femur and a 50-centimeter shoulder blade.
The analysis of the bones has lasted 20 years. The reason, the researchers reported, was that the fossils were encased in concrete-hard sandstone, which required years of preparation.
From the remains, which, although limited, were well preserved, paleontologists deduced that the primitive animal was a type of caseid , a group of extinct reptiles that possessed mammalian features and are thought to be the ancestors of mammals, of the genus Lalieudorhynchus . In their press release, the researchers described it as a “chubby lizard” and a 3.5-meter-long “lump of meat” that lived in the Permian, a period that began about 299 million years ago. and ended about 252 million years ago with the start of the Triassic period and the appearance of the dinosaurs.
Caseids were mostly herbivores , perhaps among the earliest herbivores in evolutionary history. Their bodies were barrel-shaped and housed large digestive tracts for breaking down plants. The caseids had small heads and although they looked like reptiles, they were actually the ancestors of mammals.
Fewer than 20 species of caseids have been identified in the fossil record so far. Most came from the United States and Russia. Some have recently been found in southern Europe. Frederik Spindler, co-author of the study and scientific director of the Altmühltal Dinosaur Museum in Denkendorf, Germany, told Live Science that L. gandi could be a particularly advanced caseid species , unlike any other.
The newly identified creature is one of the youngest caseids found to date and as such could be very useful in understanding the evolution of mammals. “ L. gandi could be the apex of evolution of all caseids before they went extinct, meaning the species had the most advanced features of the group, Spindler said.
L. gandi could have led a semi-aquatic lifestyle like that of hippos since when viewed under a microscope, its bone structure is spongy and flexible. Specimens of L. gandi probably weighed a few hundred kilos and all that weight would have needed additional support to get into the water. L. gandi , however, is not related to hippos.
“Spongy bones may imply a diving lifestyle in some extinct marine amphibians and reptiles,” Spindler said. By comparison, most mammals, including hippos, have denser bone tissue. “Our new casoid would swim better, whereas hippos walk closer to the ground,” Spindler said.
“A semi-aquatic lifestyle with little navigation is what large caseids share with hippos, if we’re right,” Spindler said. ” Lalieudorhynchus gandi could be said to have ‘invented’ a niche that hippos later repeated.”
Referencia: Werneburg, R., Spindler, F. et. al. 2022. A New caseid Synapsid from the Permian (Guadalupian) of the Lodève basin (Occitanie, France). Palaeovertebrata. DOI: 10.18563/pv.45.2.e2
