Triassic fish for lunch? Chinese fossil reveals oldest preserved reptile stomach

A Chinese-led team has analysed a 240 million-year-old fossil with the oldest known preserved stomach, liver and intestinal soft tissue in reptiles.The complete skeleton fossil has highly specialised body features that indicate it lived in the water, suggesting the marine colonisation of archosaurs was earlier and more extensive than previously believed.The fossil of the Austronaga minuta from the Early Triassic period also offers a “unique opportunity” to study how Triassic reptiles made the vital evolutionary transition from land to sea.“We report on a well-preserved Triassic reptile representing the earliest stem-archosaur to evolve unequivocal aquatic specialisations,” the Chinese Academy of Sciences (CAS)-led team said in a paper published in the peer-reviewed journal Science Advances on Thursday.“The fossil exhibits the oldest known stomach, liver and intestinal preservations in reptiles.”Archosaurs are a group of reptiles that includes birds, dinosaurs, crocodiles and their extinct relatives. Stem-archosaurs refer to extinct reptiles along the evolutionary line.