YNU's research teams reveal evolution of early vertebrates' visual system

On Jan 22, leading international scientific journal Nature published a study by research teams led by Academician Xu Xing and Researcher Cong Peiyun of Yunnan University (YNU), in collaboration with scholars from the United Kingdom, revealing key evolutionary features of the visual system in early vertebrates.

A restored image of a fish in Kunming with four camera eyes. [Photo/Yunnan University news website]

The study, titled "Four camera-style eyes in the earliest vertebrates from the Cambrian Period", was conducted with the participation of Dr Jakob Vinther from the University of Bristol and Professor Sarah Gabbott from the University of Leicester.

Focusing on fossils of myllokunmingids from the Chengjiang Biota, the research combined morphological analysis, ultrastructural imaging and fossil molecular evidence. It provides the first confirmation that the earliest known vertebrates, dating back about 518 million years, possessed not only a pair of lateral eyes but also a pineal and parapineal complex with complete retinal and lens structures.

These organs functioned as fully imaging "camera-style eyes" rather than purely endocrine glands, suggesting that early vertebrates may have had four camera-style eyes.

The findings offer direct evidence addressing long-standing debates over the origin of the pineal organ and the evolution of vertebrate visual systems. They also indicate that during the Cambrian Explosion, complex visual systems may have conferred a crucial survival advantage to early vertebrates under intense predation pressure, providing new insights into evolution in early animal ecosystems.