New beetle found in fossil feces attributed to dinosaur ancestor
The little beetle Triamyxa coprolithica is the first insect to be described from fossil feces. The animal researchers must thank for the excellent preservation was probably the ancestor of the dinosaur Silesaurus opolensis, which 230 million years ago ingested the small beetle in large numbers.
In a study recently published in Current biology, vertebrate paleontologists from Uppsala University and entomologists from National University Sun Yat-sen (Taiwan), Friedrich-Schiller-Universität Jena (Germany) and Universidad de Guadalajara (Mexico) used synchrotron microtomography to reconstruct in 3D the beetles while they were still trapped in the fossilized fecal matter. The coprolite contained abundant body parts of beetles, most of which belonged to the same small species. A few specimens were found almost complete, with much of the delicate legs and antennae still intact. The state of conservation of these fossils made it possible to produce a detailed description of the new genus of beetle and to compare it to more modern genera. Triamyxa coprolithica represents a hitherto unknown extinct lineage of the suborder Myxophaga, the modern representatives of which are small and live on algae in humid environments.
“We were absolutely amazed at the abundance and fantastic preservation of the beetles in the coprolite fragment. In a way, we really have to thank Silesaurus, which was probably the animal that helped us accumulate them, ”says Martin Qvarnström, researcher at Uppsala University and one of the co-authors of the article.
Silesaurus opolensis – the likely producer of coprolite – was a relatively small dinosaur ancestor with an estimated body weight of 15 kilograms who lived in Poland around 230 million years ago. In a previous study, the authors attributed coprolites with disarticulated beetle remains to Silesaurus based on the size and shape of the coprolites as well as several anatomical adaptations in the animal. Silesaurus had a beak at the end of its jaws that could have been used to root in litter and perhaps peck insects on the ground, much like modern birds. But good Silesaurus ingested many individuals of Triamyxa coprolithica, the beetle was probably too small to have been the only target prey. Instead of, Triamyxa likely shared habitat with larger beetles, which are represented by disarticulated remains in coprolites, and other prey, which have never been found in coprolites in any recognizable form.
“I never thought we would be able to find out what the Triassic forerunner of dinosaurs ate for dinner,” says Grzegorz Nied? Wiedzki, paleontologist at Uppsala University and one of the co-authors of the article.
The preservation of beetles in coprolite is similar to that of amber specimens, which normally produce the best preserved insect fossils. Amber, however, was formed mainly during a relatively recent geological period. This study shows that coprolites can be useful in studying the early evolution of insects and, at the same time, the diet of extinct vertebrates.
The synchrotron scan was performed at the European Synchrotron Radiation Facility (ESRF) in Grenoble.
Warning: AAAS and EurekAlert! are not responsible for the accuracy of any press releases posted on EurekAlert! by contributing institutions or for the use of any information via the EurekAlert system.