Isonychia taishunensis

A new species of mayfly, identified by its larval morphology and genes, was published in the academic journal Zootaxa. Captured in the Daxiyuan Provincial Wetland Park, Taishun County of Wenzhou, it was named Isonychia taishunensis after its collection locality. The new discovery signals the biodiversity of Taishun, a mountainous county.

According to Mr. Cheng Hongyi, one of the new species discoverers, from Zhejiang Normal University College of Life Sciences, a new insect species collection team of the university captured a mayfly larva at Daxiyuan in April 2022. The team initially considered the larva and the previously- caught Jiangxi mayfly to be the same species but DNA barcoding proved over 10% genetic difference between the two, which indicates the larva should be a new species. However, with no more specimens found, the inference cannot be confirmed. On May 10, 2023, eight mayfly mature nymphs were collected at the same place , which added weight to the identification of the Taishun mayfly as a new species. In addition, the team found that despite the Taishun species morphologically similar to Jiangxi maybes, the two can be distinguished by the color of the gill plates. The Taishun mayfly bears two dark or purple speckles and the Jingxi one has different colour patterns. Furthermore, a light-colored midline only appears on the first to fourth dorsal plates of the former but on all the plates of the latter. Enough number of samples, and their genetic and morphological straits all support the the identification that the Taishun mayfly is a new species.

Taishun, as a national ecological county and key functional area for demonstration, is among the most biodiverse counties in Zhejiang Province. The new species provides a new basis for evolutionary study of mayflies and species formation in Taishun. It helps to study genetic differentiation and interactions between Taishun mayfly mature nymphs and those of Jiangxi, and to explore their adaptations to the environment. On the other side, the taishunensis, as a valuable indicator of water pollution, provides an additional water quality monitoring means. In recent years, with every effort to implement biodiversity protection projects, Taishun County has completed biodiversity survey and assessments in its whole region, including ecological function account investigation in the Wuyanling National Nature Reserve, resulting in  discovery of 11 new species, such as Taishun tropiduchidae. Furthermore, with support from this country's first academician and expert workstation of biodiversity, the county has made wild yellow-bellied pheasant population multiply to more than 500; focusing on the integration of tourism and tourists’ study and experience, it has constructed the city's first biodiversity experience site, first field museum in Wuyanling, and Daxiyuan Butterfly Valley.