🌅 Humans’ Earliest Ancestor Was a Four-Eyed Noodle

SOURCE

Lei et al. (2026)

WHAT TO KNOW

• Researchers analyzing rare fossils unearthed in China of the earliest recorded creatures with spines—inch-long noodle-like jawless fish that lived half a billion years ago known as myllokunmingids—found the animals had two sets of surprisingly sophisticated eyes: one pair of large lateral eyes like you’d find on many vertebrates today and a second set of smaller, centrally positioned eyes located between the larger pair. The authors believe having four eyes may have given myllokunmingids a wider field of view and helped them avoid predators during a period in Earth’s history fraught with danger for our small, soft-bodied vertebrate ancestors.

WHY IT MATTERS

• The study found the second set of eyes represents the ancestral markers of a primitive eye-like feature found in the brains of modern vertebrates (including humans) called the pineal gland, which helps regulate sleep by responding to light and producing melatonin. The pineal complex can still detect light in some modern fish, amphibians, and reptiles, and is sometimes referred to as the animals’ “third eye” (pineal glands in humans cannot directly detect light).

CONNECT THE DOTS

• Myllokunmingids lived during the Cambrian period, not long after a small increase in oxygen levels in the Earth’s atmosphere and oceans caused a rapid burst of evolution known as the Cambrian Explosion around 530 million years ago. During the event, a wide variety of animals emerged as marine organisms evolved most of the basic body forms found in modern animal groups today. Among the animal groups that arrived on the scene were chordates, to which vertebrates (animals with backbones) belong, including humans.