Groundbreaking Discovery: Scientists Uncover Ancient Giant Arthropod in Yunnan Fossil Find

A scientific research team from Yunnan University and a team from a well-known foreign university jointly discovered a new genus and species of large appendage arthropods from the Ordovician.

Original title: A scientific research team from Yunnan University and a team from a well-known foreign university jointly discovered a new genus and species of large appendage arthropods from the Ordovician.

On October 29, 2024, Liu Yu’s team from the Institute of Paleontology of Yunnan University relied on its rich research experience accumulated in recent years in the three-dimensional non-destructive CT study of Cambrian Chengjiang arthropod fossils. Researchers from the University of California, Berkeley, formed an international research team and jointly published a paper titled A pyritized Ordovician leanchoiliid arthropod in the internationally renowned academic journal Current Biology (District 1, Chinese Academy of Sciences). “New genera and species of arthropods in the family Liidae”).

The new genus and species Lomankus edgecombei of the Lincholicaceae reported in this study was named from the Greek “loma” and “Edgecombe”, which means “edge” and “valley”. The project team specially paid tribute to Gregory, an academician of the Royal Academy of Sciences. Professor D. Edgecombe was named after him in recognition of his great contributions to the study of arthropod evolution.

Photo courtesy of left: Associate Professor Luke Parry (University of Oxford, UK) Photo courtesy of right: Researcher Liu Yu and PhD candidate Ran Ruixin (Yunnan University)

This study used the micro-CT equipment of the Institute of Paleontology of Yunnan University to conduct high-precision scans of new species fossils from the Ordovician Beecher’s Trilobite Bed biota in Upper New York State, USA, and used computer three-dimensional reconstruction and virtual anatomy technology. The first new genus species of Lincholidae from the Ordovician and its complete three-dimensional fine soft-body structure are reported. The animals of this biota live in relatively low-oxygen environments and are well-mineralized when buried in sediments, forming stunning formations as pyrite replaces the biological components of their bodies. golden fossils, so these fossils are also called “fool’s gold” fossils.

The body length of the new species ranges from 8 to 20 millimeters. The study found that the large whip-like appendage and tail of Lomankus edgecombei are relatively unique: compared with other species of the family Lincholidae, the distal segment of the large appendage reported this time is significantly smaller, and the slender flagellum is directly connected to the podomere, indicating that its function is sensing rather than hunting; the front end of the tail is an inverted triangle, and the rear end is a tail spine that is longer than the animal’s body length. A well-developed oral plate area (epistome-labrum) is preserved under the cephalon. This study further supports the hypothesis that the large appendage belongs to the deutocerebral segment.

Optical photo of Lomankus edgecombei

Based on detailed three-dimensional morphological data, the research team used the Bayesian method to conduct phylogenetic analysis. The results showed that Lomankus edgecombei and Linchouli species are sister groups and are located at the end of the branch. This is consistent with the new species and other large appendages. Consistent with the hypothesis that more traits change during evolution.

Large appendage arthropods are mostly found in the Cambrian Burgess-Shale Type biota. The discovery of Lomankus edgecombei shows that the dominant species in the Cambrian period, the Linchoidae arthropods, survived in the Ordovician. Its large appendages changed from a predatory function to a sensory function and the lack of evidence of eyes and other morphological characteristics changes, it is likely that this New species once occupied benthic ecological niches. This study also reflects the evolution of apex carnivores in the Cambrian to a certain extent, and provides new evidence and theoretical support for studying the evolution of early arthropods.

Luke A. Parry, the first author of the paper and associate professor at the University of Oxford, said: “It is not so much that Lomankus is the ‘end’ of the evolution of large appendages, but it shows us that large appendages are still becoming diverse after the Cambrian. “

Three-dimensional modeling and virtual anatomy of Lomankus edgecombei based on CT scans

Researcher Liu Yu of Yunnan University is the co-corresponding author of the paper. He and Ran Ruixin, a doctoral candidate under his supervision, are jointly responsible for the three-dimensional modeling, virtual anatomy and data analysis of the study. A doctoral candidate jointly trained by Yunnan University and the University of Leicester in the UK Dr. Robert J. O’Flynn was responsible for the phylogenetic analysis, and Dr. Mai Huijuan of Yunnan University was responsible for the CT scanning of the samples. The co-authors of the paper include Professor Derek Briggs, an academician of the American Academy of Arts and Sciences and Yale University, and Dr. Elizabeth G. Clark of the University of California, Berkeley.

Liu Yu said that this is the first time that a well-known foreign university has invited the scientific research team of Yunnan University to conduct scientific research cooperation on three-dimensional non-destructive research on arthropod fossils. The publication of this research result not only broadens the applicability of “micro-CT scanning + computer three-dimensional modeling and virtual anatomy technology” beyond the Chengjiang biota fossils, but also reflects the strong support from the country, Yunnan Province and Yunnan University Under the current situation, some key research directions in domestic paleontology are achieving rapid development, their influence in the international paleontological community is constantly expanding, and their acceptance and recognition are also increasing.

Yunnan Net reporter: Hu Jintao

Yunnan Daily-Cloud News Editor: Cai Fei

Editor in charge: Yun News