Oldest Fossilized Butthole Found in 290-Million-Year-Old Reptile : ScienceAlert

A remarkably detailed fossil impression discovered in Germany is rewriting the early history of reptiles. The imprint, dating back nearly 300 million years, reveals not only the scaly skin of an ancient reptile but also what scientists believe to be its cloaca – the single opening used for multiple bodily functions.

Unearthing the Past

The fossil was found within the sedimentary Goldlauter Formation in the Thuringian Forest Basin. Analysis indicates the reptile was approximately 9 centimeters (3.5 inches) long. Paleontologist Lorenzo Marchetti of the German Natural History Museum in Berlin notes that “such soft-tissue structures are extremely rare in the fossil record – and the further back we look in Earth’s history, the more exceptional they become.”

Did You Know? The newly discovered fossil, named Cabarzichnus pulchrus, represents a newly described species of reptile resting trace.

A Significant Discovery

Researchers have named the trace fossil Cabarzichnus pulchrus. The find pushes back the earliest known fossil record of a cloacal vent in amniotes – a group that includes reptiles, birds and mammals – by approximately 175 million years, surpassing a previous discovery involving a Psittacosaurus. This supports existing scientific understanding of the cloaca’s presence in early reptiles.

The impression reveals polygonal scales made of keratin, similar to those found on modern reptiles, rather than older forms of bony armor. The structure of the cloaca in C. Pulchrus differs from that of dinosaurs and crocodiles, more closely resembling that of turtles, lizards, and snakes.

Expert Insight: The preservation of soft tissue like skin and the cloaca is exceptionally rare in fossils of this age. This discovery provides a unique window into the anatomy of early reptiles and their evolutionary development, offering valuable data that would otherwise be lost to time.

Implications for Future Research

The reptile is believed to have been a bolosaurian, an early branch of the reptile lineage, living during the Asselian age of the early Permian period, a time when reptiles were beginning to diversify. Further research could focus on comparing C. Pulchrus to other early reptile fossils to better understand the evolution of skin structures and anatomical features. This proves also possible that additional trace fossils from the Thuringian Forest Basin could reveal further insights into the lives of these ancient creatures.

Frequently Asked Questions

What is a cloaca?

A cloaca is a multi-purpose opening used by many animals for functions such as defecation, urination, mating, and laying eggs.

How old is the fossil?

The fossil dates back approximately 295 million years to the Asselian age of the early Permian period.

Where was the fossil discovered?

The fossil was discovered in the sedimentary Goldlauter Formation in Germany’s Thuringian Forest Basin.

What further insights might be gleaned from studying trace fossils like this one?