The Chinese catalpa duo from the Beijing Biosphere! Why do a fish and a tree have the same name?

In January 2025, a research team from the Institute of Zoology, Chinese Academy of Sciences, published a new fish species collected from the Beijing area - Cobitis beijingensis - in the international zoological journal Zoosystematics and Evolution.

Coincidentally, there is a tree growing in the mountain forests of Beijing that sounds exactly like the Beijing flower loach - the Beijing rowan ( Sorbus discolor ).

What is even more coincidental is that the two words "襸" and "饸" not only have the same pronunciation, but also the same phonetic component, but different radicals: "楸" is the wood radical, indicating that it is related to trees; "襸" is the fish radical, indicating that it is related to fish.

These creatures, which have the same name but different worlds, seem to be the ecological code that nature has customized for Beijing, the ancient capital of China. Through their life stories, we can feel the beauty of the symbiosis between the city and nature.

Beijing Flower Loach: A Journey of Discovery Spanning a Century

The discovery of the Beijing flower loach was not accidental, but the result of scientists' long-term research. In 2013, when researchers were sorting out specimens of Beijing loach (many specimens were collected in the 1930s, nearly a hundred years ago), they noticed that some specimens had variations in body shape and body color patterns, which may represent different species.

In recent years, the scientific research team has collected live specimens of this species of fish many times in waters such as the Chaobai River in Miyun District and the Huaijiu River in Huairou District, Beijing during the continuous tracking, monitoring and investigation of Beijing's fish diversity.

Combining historical specimens and using a variety of scientific methods such as morphology and molecular biology, it was finally confirmed to be a new species. This is the first time a new fish species has been discovered in Beijing in more than 40 years since 1981.

Ecological photos of Beijing loach:

(A) Male (B) Female (C) Photo in an aquarium

The species name "beijingensis" of the new species is directly taken from the pinyin "Beijing" of its type origin, China, and the corresponding Chinese name is "Beijing Flower Loach". Researchers hope to use it as a "symbol" of Beijing's freshwater fish, which not only reflects the regional characteristics, but also allows the public to pay more attention to the protection of other native fish in Beijing.

Beijing flower loach belongs to the Cypriniformes, Cobitidae, and Cobit genus. This species was once widely distributed in Beijing, but has become very rare since 1980, especially during the period of 2000-2010, when almost no specimens were recorded.

Currently, Beijing flower loach is only found in the Chaobai River system in Huairou District and Miyun District. They usually live in slow-flowing or still water environments and prefer waters with muddy bottoms and rich in submerged plants or filamentous algae.

Beijing loach

Photo credit: Sun, Z., Li, X., Li,

Type specimen

In biology, a "voucher specimen" is used to define and name new species. When scientists discover a new species, they use the most representative sample as a type specimen and record key information such as its morphological characteristics, collection time and location, etc.

The type specimen is like the "identity card" of a species, and other similar specimens must be compared with it to confirm their identity. For example, the type specimen of the Beijing loach is a male individual collected from Chaobai River in Miyun in 2024 and is now preserved in the Institute of Zoology, Chinese Academy of Sciences.

Beijing Sorbus australis - a local treasure that embellishes the autumn colors

The discovery of Sorbus discolor was very early, and it was named Sorbus discolor by botanists in 1873. Its Chinese name was given as Sorbus discolor because the model specimen of the plant was collected from the mountainous area of ​​Beijing.

Interestingly, the Beijing mountain ash was later named Sorbus pekinensis by others, and the species name pekinensis also refers to Beijing, but due to the rules of plant naming, Sorbus discolor was finally recognized.

In plant naming, "discolor" is usually used to describe a species whose organs (such as leaves or fruits) have color characteristics that are different from those of similar species.

The closest tree to the Beijing mountain ash in Beijing is the mountain ash (also known as the hundred-flowered mountain ash). Its fruits are red when ripe, while the fruits of the Beijing mountain ash are often white when ripe. Among the autumn fruits of mountain trees, they are like silver stars and are particularly eye-catching.

Beijing Sorbus is a deciduous tree of the genus Sorbus in the Rosaceae family. It is mainly distributed in mountains above 600 meters in Northeast and North China. It is an important ecological and ornamental tree species in northern China. Due to its small number in the wild in Beijing, it has been included in the "List of Key Protected Wild Plants in Beijing" to be announced in 2023.

In the survey of natural forest germplasm resources in Beijing in the past two years, researchers have discovered more distribution points of Beijing mountain ash.

Beijing Sorbus photo credit: Zhao Liangcheng

A promise of the same name - an ecological partnership to safeguard the future

Beijing flower loach and Beijing rowan, two species with the same name that span mountains and rivers, seem to have no intersection, but they form a wonderful resonance in ecological narratives. They are both components of Beijing's natural ecosystem. The flower loach, with its "small body", marks the health of the waters, and the rowan, with its "big body", builds the forest ecology.

The rediscovery of the Beijing flower loach and the increasing appearance of the Beijing mountain ash reflect the continuous improvement of Beijing’s aquatic and terrestrial biodiversity and the continuous improvement of the ecological environment in recent years.

The coincidence that the mountains and rivers have the same "name" is exactly the revelation that nature gives us - every species is an indispensable piece of the ecological puzzle.

When we are delighted to find the Beijing flower loach again, don't forget to look up at the white fruits swaying on the branches in the forest; when we encounter the Beijing flower tree in the wild, we can also look down and think about the schools of spotted small fish swimming in the streams and rivers. Protecting them is not only protecting nature, but also protecting mankind's eternal yearning for a better living environment.

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Author: Zhao Liangcheng, PhD in Botany, Researcher, Beijing Forestry University Museum

Li Yingchao, PhD in Zoology, Senior Experimenter, Beijing Forestry University Museum

Reviewer: Liu Ying, Li Peiyuan