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Earliest Parasitism Discovered by the Expert Team of Early Life Research Institute of NWU

On June, 2020, a ground-breaking research finding of animal evolution during the Cambrian explosion was published by the expert team of early life research institute led by Professor Zhifei Zhang, who works at the NWU’s Department of Geology.

Zhang’s team found that dating from 520 million years ago, the ancient brachiopods hosted a worm-like, tube-shaped creature, the ‘kleptoparasites’, which stole the brachiopods’ food as it was sucked in by their tentacles. The team also noted that this is the oldest case of animal parasitism found in the fossil record and that this host-parasitic relationship belongs to obligate parasitism, which has now vanished in nature. The research finding was published in Nature Communications.

Parasite–host systems are pervasive in nature but are extremely difficult to convincingly identify in the fossil record. Only one or several specimens were analysed in previous studies. Thus, it remains unclear whether an organism could impinge upon the biological fitness of the other.

After studying the 520million-year-old Cambrian linguliform clam-like brachiopod (the Neobolus Wulongqingensis) assemblages, Zhang’s team found that tube-dwelling organisms were encrusted to the brachiopod shells and that the brachiopods hosted them were smaller in size than those without them. Besides, the alignment of these tube-shaped objects aligns with the feeding intake of the brachiopods.

Brachiopods are the marine invertebrates with two shells. According to Professor Zhang, this research traces the origin of encrusting organism back to the early stage of the Cambrian period, which is at least 30 million years earlier than previous findings. This research identified the oldest case of obligate parasitism by using statistical analysis on fossil biota and verified that this unique parasitic relationship disappeared the first among other types of parasitism. Meanwhile, the study embarks on a new journey for researchers to study Cambrian parasites, as it reveals that antagonistic biotic relation is the driver of the evolution of biodiversity on the earth.

Live News, a news program of China Central Television (CCTV), reported on the research findings on 4th, June.