Paleontologists have unearthed the fossilized skeletal remains of Confractosuchus sauroktonos, a previously unknown genus and species of crocodyliform, with exceptionally preserved abdominal contents comprising parts of a juvenile ornithopod dinosaur.
Confractosuchus sauroktonos lived in what is now Queensland, Australia, some 95 million years ago (Cenomanian stage of the Late Cretaceous epoch).
It belonged to Eusuchia (literally, true crocodiles), a clade that includes living crocodilians and their closest relatives.
The animal’s fossilized remains — a near-complete skull with dentition and postcranial skeleton missing the tail and hind limbs — were discovered on Elderslie Station, near the north western margins of the Winton Formation, in 2010.
“Confractosuchus sauroktonos represents only the second crocodyliform discovered from the Winton Formation,” said Dr. Matt White, a paleontologist with the Australian Age of Dinosaurs Museum of Natural History and the Palaeoscience Research Centre at the University of New England, and his colleagues.
“The other, Isisfordia duncani, comprises multiple semi-articulated and partially complete skeletons.”
The researchers also found the partly digested remains of a juvenile ornithopod dinosaur in the crocodile’s stomach.
“Collectively, the ornithopod remains comprise three dorsal vertebrae, two sacral centra, three distal caudal centra, both proximal femora, left tibia, and several other elements; all presumably from a single individual,” they said.
“These gut contents oddly represent the first recorded skeletal remains of ornithopods from the Winton Formation and may represent a new species.”
The dinosaur’s estimated body mass (1.0-1.7 kg) falls well within the size range for expected prey of Confractosuchus sauroktonos, which has an estimated body length of 2.5 m (8.2 feet) based on the preserved elements.
Yet, despite its last meal, the crocodile was likely not a dinosaur specialist.
“While Confractosuchus sauroktonos would not have specialized in eating dinosaurs, it would not have overlooked an easy meal, such as the young ornithopod remains found in its stomach,” Dr. White said.
“The find suggests dinosaurs were intrinsically part of the Cretaceous ecology as scavengers, predators and prey,” he added.
“It is likely dinosaurs constituted an important resource in the Cretaceous ecological food web.”
“Given the lack of comparable global specimens, this prehistoric crocodile and its last meal will continue to provide clues to the relationships and behaviors of animals that inhabited Australia millions of years ago.”
The findings were published in the journal Gondwana Research.
Matt A. White et al. Abdominal contents reveal Cretaceous crocodyliforms ate dinosaurs. Gondwana Research, published online February 10, 2022; doi: 10.1016/j.gr.2022.01.016
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