New single-celled species discovered in Jiangxi's Poyang Lake basin

A single-celled organism covered in tiny hairs, discovered in the Poyang Lake basin in Jiangxi province, has been identified as a species new to science — the first new member of its group found in China. Known as ciliates, these single-celled organisms are found almost everywhere there is water, even in soil or inside other organisms.

The species, named Stentor jiujiangensis after Jiujiang, where it was found, was jointly identified by researchers from the Jiujiang Scientific Observation and Research Station of Fisheries Resources and Eco-environment Protection under the Ministry of Agriculture and Rural Affairs and Shanghai Ocean University.

The finding was published on Aug 27 in the journal Zootaxa. Its genetic barcode sequence has been submitted to the National Center for Biotechnology Information's public database.

Researchers collected the unusual specimen and studied it in several ways: they looked at its shape under a microscope, used a stain to reveal its tiny hair-like structures, and extracted and analyzed its DNA. Comparisons with known species confirmed that the specimen had never previously been recorded.

According to the study, Stentor jiujiangensis is distinguished by a single spherical-to-ovoid macronucleus, yellowish-green cortical granules, and the absence of symbiotic algae. A closer look at its DNA also confirmed that it was different from other known species in the group.

The newly identified organism measures about 115 to 200 micrometers long. More than 20 Stentor species have been recorded worldwide.

Pan Hongbo, an associate professor at Shanghai Ocean University, said Stentors are highly sensitive to changes in aquatic environments and are internationally recognized as indicators of water ecosystem health. They also play basic roles in material cycling and energy flow in freshwater ecosystems.

The discovery adds to the known diversity of freshwater single-celled organisms and provides new scientific material for research into the biodiversity and evolution of aquatic microorganisms.