Scientists discover miniature Jurassic crocodile that offers clues to the evolution of modern reptiles
Paleontologists have unearthed the fossil remains of a species of crocodile that roamed the Earth around 148 million years ago during the Late Jurassic period, a breakthrough that sheds light on the evolution of modern fangs.
According to the researchers, the newly discovered species, Burkesuchus mallingrandensis, was a relatively small animal – around 70 cm long – and belonged to the Mesoeucrocodylia group, which includes all living crocodiles and their fossil relatives.
In the study, published in the journal Scientific Reports, scientists analyzed the fossilized remains of the animal’s skull, spine, and lower limbs collected from beds in the Toqui Formation, which rise from mountains flanked by rivers. Maitenes and Horquetas. in southern Chile.
They said the crocodile ancestor lived alongside giant dinosaurs, at a time when huge sauropods as well as smaller herbivorous species like Chilesaurus diegosuarezi traveled through what is now South America.
“Nonetheless, its body size is within the size range – less than 1m in total length – that was usual for most land crocodyliformes from the Triassic and Jurassic, âthe scientists noted in the study.
The fossil thigh bone of the crocodile ancestor indicates that it had a “sprawling position” and tail-based gait and locomotion similar to that of modern crocodiles when they swam and entered the water.
Based on an analysis of the forelimbs, the researchers said the crocodile ancestor may have had a more upright posture than that seen in modern crocodiles.
But they added that the acquisition of the sprawling posture seen in our extant crocodilians may not have evolved simultaneously in the forelimbs and hindquarters, but through separate processes and under different conditions.
âAlthough speculative, it is possible that the hind limbs, which tend to be more important for locomotion in living crocodiles, changed shape before the forelimbs. It’s possible that Burkesuchus illustrates this intermediate condition with somewhat straight forelimbs and sprawling hindlimbs, âthe researchers noted in the study.
While the biological reasons behind the retention of small sizes among these crocodile ancestors are currently unknown, researchers believe competition with large, ecologically dominant terrestrial dinosaurs may be a reason.
However, they say this constraint on body size was released in the marine forms of crocodile ancestors during the Jurassic Age, as well as in different clades during the Late Cretaceous Era.
Burkesuchus mallingrandensis, paleontologists say, expands our understanding of the diversity of crocodile ancestors from the Jurassic period and sheds more light on the evolution of different lineages of fangs.
“This new discovery expands the meager record of non-pelagic representatives of this clade for the Jurassic period, and with Batrachomimus, from the Upper Jurassic beds of Brazil, supports the idea that South America represented a cradle for the evolution of crocodyliformes derived during the Upper Jurassic, âthe scientists noted in the study.