Japanese researchers have found a fragment of what it claims to be the world¡¯s oldest German cockroach from third century ruins in Nara Prefecture.

Nara Women¡¯s University announced Wednesday that a joint research team of the university and the Osaka Museum of Natural History discovered a piece of the cockroach during a 2018 excavation of the Makimuku Ruins in Sakurai, Nara Prefecture.

The discovery marks what could be the first evidence of the presence of the species during Japan¡¯s Kofun Period (250 to 552), the university said in a press release.

The excavation site, a soil pit named SK38, dates back to the early half of the Kofun Period, in the late third century. The research team sifted through the soil of a lower layer ¡ª an older section ¡ª ultimately revealing various animal and plant remains along with the cockroach fragment, the university said.

Historically, the German cockroach was thought to have origins in northeastern Africa, eventually spreading to Europe aboard ships. It is also thought to have reached the United Kingdom in the mid-19th century and later to North America and Australia.

It was thought that the German cockroach arrived in Japan during the late Edo Period (1603 to 1868) due to trade activity. However, the recent discovery adds to other evidence that the species could have already existed in Japan centuries earlier.

After the recent revelation, the team found past research on the discovery of what was then thought to be a fragment of another cockroach species at an excavation site in Osaka dating back to the Kofun Period. The fragment has since been found to be that of a German cockroach, adding to archaeological evidence supporting the alternate theory.

Around 3,500 species of cockroaches exist across the globe. The German cockroach is one of the most commonly found worldwide and is considered an invasive species in Japan.