New fossil evidence is challenging our understanding of early vertebrate evolution, with the finding of a 581-million-year-old myllokunmingid in southern China possessing an astonishing anatomical feature: four fully functional eyes. The remarkably well-preserved fossils,detailed in a new study published in Nature,provide an unprecedented look at the visual capabilities of some of our earliest ancestors. Researchers say the discovery not only rewrites what we thought we knew about the development of vision, but also offers clues too the origins of the pineal gland, sometimes referred to as the “third eye.”
Jakarta –
Fossil evidence of one of the earliest vertebrates reveals the creature possessed four eyes. The animal, a myllokunmingid dating back approximately 581 million years, was discovered in Chenjiang, southern China.
This animal from the Cambrian Period is notable for its unique anatomy. Paleontologists believe the myllokunmingid initially resembled a tadpole, with two prominent eyes positioned on the sides of its head, alongside two smaller eyes located more centrally, towards the front.
“These fossils preserve the eyes in incredible detail. We began by examining the larger, more obvious eyes to understand their anatomy – and were astonished to discover two smaller, fully functional eyes nestled in between. It was a truly exciting find,” said Professor Peiyun Cong of Yunnan University in a statement.
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Cong and her co-authors suggest the inner pair of eyes in the myllokunmingid evolved into what is now the pineal gland. While our pineal gland is now located internally, it still regulates melatonin production to control sleep cycles based on light exposure. In mammals, light detection has shifted to cells within the retina, but in some lizards, the pineal gland retains the ability to sense light.
The historical reference to the pineal gland as a “third eye” appears to have a basis in reality for this ancient animal. This discovery offers a fascinating glimpse into the evolutionary origins of vertebrate vision and the development of light-sensing organs.
“These animals didn’t just have a third eye – they had a fourth,” explained Dr. Jakob Vinther from the University of Bristol.
The finding is remarkable given the fragility of eyes, which are rarely well-preserved in the fossil record. Typically, scientists infer the characteristics of ancient vertebrate eyes based on the size and shape of eye sockets, extrapolating from modern counterparts.
However, the preservation of the eyes themselves, or even traces of them, is exceptionally rare.
“(These fossils) open a rare window into how extinct animals saw and experienced their world,” said Professor Emeritus Sarah Gabbott of the University of Leicester.
“It was a bold hypothesis, but we suspected that the eyes in these Chinese fossils might be preserved – and indeed they are, complete with light-absorbing pigments in the retina and lenses capable of forming images, demonstrating just how well our earliest ancestors could see,” she added.
The team even confirmed the four-eyed nature of two different myllokunmingid species: Haikouichthys ercaicunensis and another unnamed species.
Similarities in the composition of the inner and outer eyes bolstered the researchers’ confidence that these organs were analogous. Further evidence came from the presence of melanin, a versatile pigment crucial for light absorption, preserved within the myllokunmingid.
Myllokunmingid apparently lacked protective body armor. While other defenses, such as toxins, cannot be ruled out, they likely relied on detecting predators with their multiple eyes.
“In that environment, having four eyes may have given these animals a wider field of view, crucial for avoiding predators,” Vinther stated.
The study was published in Nature.
(ask/asj)
