Paleontologists from the Nanjing Institute of Geology and Palaeontology at the Chinese Academy of Sciences and elsewhere have found a partial body fossil of an ancient tapeworm preserved in mid-Cretaceous Kachin amber from Myanmar.
Parasites are ubiquitous in extant ecosystems but rarely preserved in the geological record, especially parasitic worms.
One such group is Cestoda (tapeworms), a specialized endoparasitic group of flatworms.
These creatures have a complex lifecycle with at least two hosts, infecting all major groups of vertebrates.
However, their fossil record is extremely sparse due to their soft tissue and concealed habitats, with the only widely accepted example before the Quaternary being eggs discovered in a shark coprolite from the Permian period.
The lack of body fossils greatly hampers our understanding of their early evolution.
“The fossil record of tapeworms is extremely sparse due to their soft tissues and endoparasitic habitats, which greatly hampers our understanding of their early evolution,” said Dr. Bo Wang, a researcher with the Nanjing Institute of Geology and Palaeontology at the Chinese Academy of Sciences.
The new fossil displays unique external (armature pattern) and internal (partially invaginated tentacle and rootless hooks) features that are most consistent with the tentacles of extant trypanorhynch tapeworms that parasitize marine elasmobranchs (mainly sharks and rays).
“The find is the most convincing body fossil of a platyhelminth ever found,” said Cihang Luo, a Ph.D. candidate with the Nanjing Institute of Geology and Palaeontology at the Chinese Academy of Sciences.
“Our study, which provides an exceptional example of a marine endoparasite trapped in amber, has also shed new light on the taphonomy of amber.”
“Specifically, we showed that amber can preserve the internal structure of helminths.”
“Using high-resolution micro-CT, we discovered that the interior of the current fossil has a folded…
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