Lab of Protozoology discovers new species in Shangyi Lake


ECNU scientists discover a unique  ciliate species in Shangyi Lake.

RESEARCH Scientists at the ECNU Lab of Protozoology recently discovered a unique ciliate species in Shangyi Lake at the ECNU Minhang campus. Ciliates are single-celled organisms that belong to the protozoan phylum Ciliophora; they are considered to be the most evolved and complex type of protozoan possessing locomotion and food accumulation.

The new ciliate species, known as Naxella paralucida, was confirmed by the Journal of Eukaryotic Microbiology as a novel discovery for the field of protozoology. Liao Wanying and Xinpeng of ECNU’s School of Life Sciences published the article about the findings.

 In the summer of 2015, research scientists spot the peculiar organism during a routine water sample collection.

On a trip to Shangyi River in the summer of 2015, research scientists spotted the peculiar organism during a routine water sample collection. Biological organisms that are subdued to high temperatures and receive adequate sunshine intake reproduce algae in mass, making Shangyi lake a natural habitat for a variety of protozoans and other microorganisms; this ecological environment was responsive to the reproduction of a new ciliate species.

Scientists must use special classification methods to identify species of ciliates. For instance, based on the type of nucleus and organelle structures of each ciliate, each one cannot be viewed from microscopic observation. So the researchers utilized stained specimens to observe the living cells through anatomical lenses.

The research scientists of ECNU found that there was no other species compatible with other protozoans and therefore, they collected more sample water from the Shangyi lake to expand on the new finding. After one month of sample collections and observations, they extracted the DNA to understand the genome sequence of Naxella paralucida.

The research scientists of the Lab of Protozoology released their scientific study of the new ciliate species in summer 2017, tracing it’s biological traits, historical records, and molecular systematic framework. They classified the new species into the Phylum Ciliophora of the Nassophorea classNassulida orderNassulidae familyand Naxella genus.

There have been reports on the discovery of eight species within the Naxella genus, the most recent one published in 1990 by Austrian scientists. In the last two and a half decades, studies on the diversity, geographical distribution and phylogenetic status of the Naxella genus became stagnated.  

The type specimen of Naxella paralucida.

The nomenclature of ECNU’s research finding was based on it’s similarity to another known organism--Naxella lucia, in terms of the mouthpart morphology that contains similar characteristics. The genetic code of the Naxella paralucida, SSU rRNA, was published into the Genbank, a comprehensive database that contains accessible nucleotide sequences for more than 240,000 organisms, representing a new phytogenic status of the Naxella genus.

According to recent standards of biological classification, every new specimen demands a precise description, name, type and place of origin--e.g., to classify each type of species by it’s biological characteristics and qualifications to meet scientific standards.

According to the paper about the new discovery, ECNU has already attracted widespread interest. Naxella paralucida was not only deposited into the Biological History Museum of ECNU, becoming one of the first holotype specimens of protozoan stored there. It’s paratype specimen is also currently exhibited at the British Natural History Museum.

Although it is rare to discover new species of protozoa in a metropolitan city, since they thrive in aquatic and forest environments; however, in 1998, a research scientist named Song Weibo found a new ciliate species at the Zhongshanbei campus referred to as Euplotes shanghaiensis.

It has been proven via the two discoveries in 1998 and 2017 respectively, that both ECNU campuses at Minhang and Zhongbei contain ecological environments suitable to a multitude of microorganisms.

It is possible that more species have yet to be unearthed. For example, the article about ECNU’s most recent finding also mentioned another organism found in the wetland of Chongqing Island in Shanghai. Because of it’s unique biological characteristics and phylogenetic status, the species was named A. Chongmingensis to denote it’s distinctive ecological features to the island. It also brought about a new genus called Arcanisutura.



East China Normal University