Paleontologists from the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences, and others have discovered a partial fossil of an ancient tapeworm preserved in Kachin amber from Myanmar from the mid-Cretaceous period.
A 99-million-year-old amber fragment containing a tapeworm fossil (long tentacles) and other inclusions: (AB) Overall view of the amber fragment. (C) Trichophytes of Gleichenidae. (D) Scale insect larva. (E) Sand grains. Scale bar – 2 mm inches (A, B), 0.1 mm inches (CE).Image credit: Luo other., doi:10.1130/G52071.1.
Parasites, especially parasitoids, are ubiquitous in extant ecosystems but poorly preserved in the geological record.
One such group is Sestoda (tapeworms), a special group of internal parasites flatworm.
These organisms have complex life cycles with at least two hosts and infect all major vertebrate groups.
However, due to its soft tissue and hidden habitat, the fossil record is very sparse, with the only widely accepted example of a pre-Quaternary period being a shark egg found in a Permian coprolite. be.
The lack of body fossils greatly hinders our understanding of early evolution.
Dr. Bo Wang, a researcher at the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences, said: “The fossil record of tapeworms is extremely poor due to its soft tissue and endoparasite habitat, which is a major hindrance in understanding its early evolution. ''. Science.
The new fossil exhibits unique external (armature pattern) and internal (partially invaginated tentacles and rootless hooks) features that are most consistent with extant tentacles. Trypanolhynch tapeworm Parasitic substances of marine life elasmobranch (mainly sharks and rays).
“This discovery is the most convincing platyzoan fossil ever discovered,” said Dr. Cihang Luo. candidate at Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences.
“Our study provides an exceptional example of a marine endoparasite trapped in amber and also sheds new light on amber taphonomy.”
“Specifically, we showed that amber can preserve the internal structure of helminths.”
“Using high-resolution micro-CT, we discovered that inside the modern fossil, a folded vertical structure extending spirally around the longitudinal axis extends to the very front. It matches the tentacle you entered.”
“On the other hand, rootless hooks are the same as trypanorhynch hooks.”
“Previous studies have shown that internal structures can be preserved intact, similar to modern forms, but all such studies have focused on arthropods.”
A hypothetical ecological recreation of the Trypanorhynch tapeworm fossil. Image credit: Dinghua Yang / Luo other., doi:10.1130/G52071.1.
“Our results show that amber can preserve the internal structure of helminths such as tapeworms over geological time scales,” Dr. Wang said.
“In addition to remarkable examples of marine endoparasites trapped in amber, several Gleichenia trichomes and scale insect larvae were also preserved in the same amber specimen along with partial insect remains. I did.”
“This clearly indicates that it was in a terrestrial or terrestrial environment at the time it was trapped in the resin.”
“Additionally, many sand grains are evenly distributed throughout the amber, suggesting that the fossil was buried in a sandy environment.”
“Furthermore, evidence so far indicates that Kachin amber was deposited in a near-shore environment.”
“One possible scenario for the tapeworm being deposited in the amber is that its elasmobranch host became stranded by tides or storms.”
“In such a scenario, the host would have been bitten by a high level of terrestrial predator or scavenger.”
“When the host was consumed by a predator, the tentacles were pulled apart, detached from the intestine, and attached to nearby resin.”
“Our study further supports the hypothesis that Kachin amber was probably deposited in a paleoenvironment in the Pala region, and also highlights the importance of amber studies in paleoparasitology.”
team's paper It was published in the magazine geology.
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Jikyoura other. Exceptional preservation of marine tapeworm tentacles preserved in Cretaceous amber. geology, published online March 22, 2024. doi: 10.1130/G52071.1
Source: www.sci.news
