A team of international scientists has found a tapeworm body fossil in a mid-Cretaceous Kachin amber, dating back approximately 100 million years, according to the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences.

This fossil displays unique external and internal features that are most consistent with the tentacles of extant trypanorhynch tapeworms that parasitize marine elasmobranchs (mainly sharks and rays).

Cestoda, or tapeworms, are a specialized endoparasitic group of flatworms. They have a complex lifecycle requiring at least two different hosts, and are known to infect all major groups of vertebrates. Due to their soft tissue and concealed habitats, their fossil records are extremely sparse.

Wang Bo, researcher at the institute, said that this fossil marks not only the inaugural report of a partial body fossil of a tapeworm, but is also the most convincing body fossil of a flatworm globally at present, providing direct evidence for their early evolution.

Notably, this discovery also demonstrates that amber can preserve the internal structure of helminths. Luo Cihang, a doctoral candidate at the institute, suggested that this finding also presents a hypothesis regarding how a tapeworm from the ocean ended up in amber. "It may have parasitized the intestines of a ray. After the ray had been washed ashore and was preyed upon by a dinosaur, as the dinosaur ate the internal organs of the ray, the worm fell out and became enveloped by nearby resin."

The study, conducted by scientists from multiple countries including China, Germany, the United Kingdom and Myanmar, was recently published in the journal Geology. (Xinhua)