Oldest insect resource pulses revealed by fossils from China
Resource pulses, i.e., occasional episodes of ephemeral resource superabundance, represent a fundamental mechanism by which energy, nutrients, and biomass are transported across ecotones. They are widespread in extant ecosystems; ...
Recently, Zhang Qianqi, a Ph.D. student from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS), under the supervision of Profs. Wang Bo and Zhang Haichun, and his collaborators reported one such resource pulse—the earliest-known mayfly swarm—in a newly discovered fossil locality in the Xiwan Basin of Hezhou City, in southern China's Guangxi Zhuang Autonomous Region.
The results were published in Geology and Historical Biology.
Mesozoic research in the Xiwan Basin has a long history, with reports of plenty of insect fossils from the Lower Jurassic Shiti Formation. However, the newly discovered fossil locality in the basin features an abundance of new insects as well as plants and shark egg capsules.
"In view of the abundance of the diverse insects and plants, we propose that the fossil assemblage in the lower unit of the Shiti Formation be named the Xiwan Biota, which is among the richest Jurassic biotas in China," said Zhang Qianqi.
In one fossil layer of the Xiwan Biota, the researchers found hundreds of mayflies. These mayflies were classified as a new taxon, Jurassephemera zhangi, and assigned to the extinct family Sharephemeridae, a stem group of mayflies in terms of taxonomic position. This is the first discovery of this mayfly family in China, and is the best-preserved fossil of the family.
Fig. 1 Three pieces of fossil surface with mayfly swarms from the Shiti Formation in southern China. All are the same scale and orientation. Credit: NIGPAS