A recent scientific investigation has brought to light an extraordinary ancient relative of modern crocodiles, which exhibited a remarkable shift in locomotion: starting life quadrupedally and later transitioning to exclusively bipedal movement in adulthood. This prehistoric reptile species has been named Sonselasuchus cedrus and belongs to the clade known as shuvosaurids. These creatures bore a strong resemblance to dinosaurs, sharing their habitat during the Late Triassic period, approximately 225 to 201 million years ago, according to reporting from Phys.org.
In the specialized journal where the findings were published, researchers from the University of Washington and the Burke Museum detailed the peculiar proportions observed in the recovered fossils. The investigators concluded that this ancient organism, comparable in size to a small dog, must have developed bipedalism. The lead author of the study, Elliott Armore Smith, explained that their examination of limb skeletal structures inferred that adopting a two-legged stance might have resulted from asymmetrical bodily growth. “We hypothesize that juveniles of Sonselasuchus possessed more balanced forelimbs and hindlimbs, but as they matured, their rear legs grew longer and more robust,” the scientist noted.
The specialist further elaborated: “Effectively, we suggest these animals began life on all fours… and subsequently transitioned to a bipedal gait upon reaching maturity. This pattern is particularly striking.” Graduate student Smith collaborated on this research with his colleague from the Burke Museum, Professor Christian Sidor. Professor Sidor was involved in 2014 excavations within an Arizona national park where the team uncovered 950 specimens of this species. Over a decade of work at this significant site has yielded more than 3,000 distinct fossilized bones.
The unearthed remains of Sonselasuchus, measuring around 63 centimeters in height, illuminate several aspects of its physical appearance. Experts postulate that the creature possessed an edentulous beak, prominent eye sockets, and hollow bones. Smith mentioned that while these features resemble traits found in certain dinosaurs, they evolved entirely independently. This convergence is attributed to the fact that the ancestors of crocodiles and those of birds inhabited comparable environmental conditions and adapted to similar ecological niches. The scientist emphasized that bipedalism, the toothless beak, and other analogous characteristics also appeared within the crocodilian evolutionary lineage.
The ancient creature inhabited forested areas, which explains the ‘cedrus’ component of its name, referencing the cedar trees present in that ancient time. The initial part of the designation derives from the geological stratum where the remains were discovered. Professor Sidor indicated that this project is the culmination of more than a decade of fieldwork. He added that new materials are continually being unearthed at the excavation site, showing no signs of depletion. “In addition to Sonselasuchus, the bone bed has yielded fossils of fish, amphibians, as well as dinosaurs and other reptiles,” the professor stated. Throughout these years, over 30 University of Washington students and volunteers have contributed to the project, and the scientists are pleased that the site continues to produce novel and interesting discoveries.
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