Chinese researchers have discovered exceptionally well-preserved bryozoan fossils that provide the first definitive mineralized skeletal evidence for the group's origin in the Early Cambrian, pushing its fossil record back by at least 50 million years.
The findings, made by a research team from the country's Northwest University, were published on Wednesday in the journal Nature.
The fossils were unearthed from the Early Cambrian Xiannvdong Formation in Hanzhong City, northwest China's Shaanxi Province. The specimens are exceptionally preserved, retaining both mineralized skeletal structures and soft tissues.
Bryozoans are a major group of colonial aquatic invertebrates that today inhabit marine environments worldwide. Although researchers have long hypothesized that bryozoan ancestors existed during the Cambrian Period, conclusive fossil evidence has been lacking due to the organisms' tiny size and the difficulty of recognizing their fossils.
The newly discovered fossils preserve soft-tissue features, including membranous sacs and ring septa, as well as bryozoan skeletal structures such as zooecia and acanthostyles.
To examine the specimens, the research team employed a range of analytical methods, including scanning electron microscopy (SEM) and X-ray computed tomography.
Using the new fossil evidence, the researchers constructed a matrix comprising 50 morphological characteristics from 18 representative extant and fossil bryozoan genera. Phylogenetic analysis confirmed that the Cambrian fossils belong to the class Stenolaemata within the phylum Bryozoa.
The discovery pushes the fossil record of mineralized bryozoans back from the Ordovician Period to the Early Cambrian, extending it by at least 50 million years.
New fossils confirm Early Cambrian origin of bryozoans
The China (Inner Mongolia) Pilot Free Trade Zone is accelerating the implementation of reform measures including customs clearance facilitation at ports, in efforts to boost quality growth of the local region's open economy.
China expanded its pilot free trade zones (FTZs) to 23 in April with the establishment of the one in north China's Inner Mongolia Autonomous Region.
The State Council's plan on the new pilot FTZ specifies 19 reform and innovation measures, including developing border trade in an innovative way, strengthening international logistics services, improving the efficiency of technology transfer and application, and expanding external exchanges across multiple fields.
The China (Inner Mongolia) Pilot FTZ covers 119.74 square kilometers and comprises three subzones in Hohhot, capital of the autonomous region, Manzhouli, a northern border city, and Erenhot, an inland port on the China-Mongolia border, each tasked with differentiated functions and the development of industries tailored to local conditions.
At the intelligent freight checkpoint of the Manzhouli inland port, drivers can complete customs clearance within just a few seconds by showing a QR code to the scanning machine.
The QR code is generated by a smartphone application, which collects the relevant customs clearance information in advance.
"Only one QR code is needed for customs clearance here. We can go through all the required formalities and have the entire application documentation processed through electronic data transmission. After getting the QR code and having it scanned at the checkpoint, the driver will be allowed to enter the country. It's very convenient and fast," said Zhao Shuang, general manager of a freight company in Manzhouli.
From January to April, Manzhouli's total foreign trade volume increased by 43.1 percent year on year.
Inner Mongolia pilot FTZ accelerates reform to boost quality growth
