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Ancient Reptile, Tuatara, Predates Dinosaurs, Has a Third Eye

Ancient Reptile, the Tuatara, Predates Dinosaurs, Has a Third Eye

The Tuatara is an ancient living reptile species with a distinct third eye, known since the nineteenth century. This reptile, Sphenodon punctatum, looks like a lizard, but technically it isn’t.

Today, the idea of the third eye remains on the fringe for mainstream scientists and the media. However, the Tuatara is one example of when scientists actively examined and studied the third eye.

Tuatara, screenshot via YouTube

The Tuatara, an Ancient Reptile

The Tuatara almost went extinct and remains only on islands off the coast of New Zealand. In young individuals, you can see its parietal eye, and it’s complete with a retina and nerve endings. As they age, scales grow, concealing the hidden structure (see videos below). 

Image: Screenshot via YouTube/Ben G Thomas

Notably, it’s the last species of an ancient reptile group, Rhynchocephalia, which evolved over 240 million years ago. This group, the “beak heads,” roamed the earth with the dinosaurs. However, their origins predate the dinosaurs by some 20 million years.

Somehow, it survived when its relatives could not but recently was nearly wiped out when humans and rats arrived in New Zealand.

Images via YouTube

Related: Several Dinosaurs Related to Velociraptor Evolved Flight

Thus, they are considered “living fossils” to some and may individually live for 60-100 years.

 In the Māori language, Tuatara means “peaks on the back” for the crest along their spines. As with some other reptiles, males tend to have more exaggerated crests and can grow to around two feet long.

Image: Tuatara by Sid Mosdell via Wikimedia Commons, CC BY 2.0

A Relic from Our Reptilian Past?

When scientists first discovered the third eye in Tuatara, they believed it was nonfunctional, much like the pineal gland in people.

According to the Atlantic:

“This animal possessed, in addition to two perfectly ordinary eyes located on either side of its head, a third eye buried in the skull which was revealed through an aperture in the bone, covered by a transparent membrane, and surrounded by a rosette of scales. It was unmistakably a third eye, but upon dissection, it proved to be nonfunctional,” wrote John N. Bleibtreu.

At the time of discovery, finding the third eye in the Tuatara was puzzling and still holds mystery. Perhaps, they thought, it was a vestigial sight organ, a “relic from our reptilian past.” If so, it couldn’t explain why a similar structure is found in most vertebrates and people, the light-sensitive pineal gland or epiphysis cerebri. It resembles a miniature pine cone in the middle of the brain, sitting atop a dual “stalklike appendage” connected to the spine.

“Though it still possessed the structure of a lens and retina, these were no longer in good working order; also lacking were appropriate neural connections to the brain. But the presence of this eye in the Tuatara still poses a puzzle to present-day evolutionists, for almost all vertebrates possess a homologous structure in the center of their skulls. It is present in many fish, all reptiles, birds, and mammals (including humans).”

Why did the primitive dinosaur-like creature have such a distinct third eye? Was it an advantage for early reptilians? It could be related to regulating hormones, helping with thermo-regulation, or determining what time of day it is. However, these little guys are mostly active hunting at nighttime. An exception is young Tuataras, which hunt during the day to avoid being eaten by adults.

See more from Ben G Thomas about “The Lonely 3-Eyed Reptile”

Tuatara Evolving Faster Than Any Other Animal

Strangely, the Tuatara may be one of the fastest evolving creatures. In 2008, a DNA study from an 8,000-year-old tuatara skeleton found their DNA was evolving faster than any other animal yet examined. Outwardly, you wouldn’t know.

“What we found is that the tuatara has the highest molecular evolutionary rate that anyone has measured,” Professor Lambert, from the Allan Wilson Centre for Molecular Ecology and Evolution said.

For some reason, these creatures have DNA that evolves rapidly.

“Of course we would have expected that the Tuatara, which does everything slowly — they grow slowly, reproduce slowly and have a very slow metabolism — would have evolved slowly. In fact, at the DNA level, they evolve extremely quickly, which supports a hypothesis proposed by the evolutionary biologist Allan Wilson, who suggested that the rate of molecular evolution was uncoupled from the rate of morphological evolution.”

Could this reptile’s rapid evolutionary rate be related to why they survived the dinosaurs? Or could it relate to their uniquely distinct third eye? 

Well, one known reason may be that they have the longest egg incubation period for any reptile. Tuataras may gestate for 8 months and shelter in the egg for 16 months in the cool New Zealand climate. Since reptiles are cannibalistic, perhaps they could avoid being eaten by hiding out in the egg until they have grown more (see video below). 

Related: Adolescent Tyrannosaurus Rexes Made Life Hell for Prey That Could Escape Slower Adults

More about the Tuatara’s third eye and much more from Discovery UK:

Related: Anole Lizards That Act Like Scuba Divers with Natural Oxygen Tanks 

The Pineal Gland and Amphibians

Strangely, the pineal gland was part of an experiment involving amphibians in 1917. Some 300 million years ago, the first reptiles may have evolved from amphibians.

In the experiment, scientists put crushed pineal glands in water containing tadpoles. Then, the tadpole’s skin would lighten. By studying this process scientifically, we eventually learned that the pineal gland is a functioning gland.

“The chemical substance melanin is the pigment which darkens skin color. It is located in specialized cells scattered through the topmost layer of skin. Pineal extract caused these cells to contract in tadpole skin and in certain other reptiles which change their skin color in response either to mood or environmental setting.”

Later, Yale Medical School professor Aaron B. Lerner isolated the substance causing the contraction of melanin-producing cells. After dissecting 250,000 cattle pineal glands, he discovered melatonin, one hormone produced by the gland. Later, serotonin, associated with psychedelic states, was found to be a precursor for melatonin.

Thus, the little pine-cone was not merely a vestigial sight organ or relic from reptilians. However, the full extent of the pineal gland’s purpose remains unknown to scientists.

By 1898, German physician Otto Heubner discovered that precocious puberty in children could sometimes be associated with cancer in the pineal. Later experimentation by biochemist, Julius Axelrod confirmed that melatonin suppresses physiological sexuality in mammals. Further, he and co-workers found the pineal gland produces chemicals in timing with circadian rhythms, responding to light. It’s known there are photoreceptors in the pineal gland even though it’s deep between the two hemispheres of the brain.

Pineal Gland and a Sixth Sense

From the times of the Thracian worship of Dionysius, Western tradition held that the truth was obtainable through a state of mind that caused ecstatic revelation. Then, consciousness could access an ultimate “paranormal” reality apart from the mundane.

However, Western philosophy abandoned this concept after Plato’s rational pupil Aristotle ushered in Aristotelian philosophy. 

Today, that mindset remains scientific and technically oriented, opposed to the metaphysical. Mainstream Western scholars often hold the third eye to be nothing but a metaphor, but this may obstruct the advance of true understanding.

See also: Understanding the Potential of ‘Fantastic Fungi’ to Transform Everything

Nevertheless, others believe the pineal gland can open up very real abilities. For example, a sixth sense, magnetoreception, is increasingly the subject of discussion. Many animals have this ability, so perhaps it lays dormant, waiting to be reawakened.

Related: Scientists Discover Evidence of Bird Navigation Superpowers

See more in the great video from Universe Inside You:

Featured image: Screenshot via YouTube/Discovery UK with Third Eye by doreen_kinistino via PixabayPixabay License

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