【太古の謎】ヘリコプリオンの渦巻く歯──2億7000万年、その在り処は誰も知らなかった

There are questions in this world that no one has yet answered. Welcome to today's mystery. Where exactly were the perfectly spiraling teeth of Helicoprion, a creature that lived in the Permian seas, located within its body? Emerging from the deep seabed is a beautiful spiral of countless teeth. This structure, which grows outward while simultaneously winding inward, has long posed a question to science: Where did this spiral reside within the body when the creature was alive? The clues to this question have been surprisingly limited. The setting is the warm, shallow seas of the Permian period, approximately 270 million years ago. Helicoprion, the master of this spiral, is thought to have had a body made of cartilage, similar to sharks and rays. After death, the cartilage would decompose and dissolve into the seabed, leaving only the hard teeth behind. In 1899, the Russian paleontologist Alexander Karpinsky first scientifically described this spiral, depicting it as teeth coiled around the tip of a nose. This marked the beginning of a century-long mystery. This creature never lost a single old tooth. Each time a new tooth grew, the old one was pushed inward, maintaining a beautiful spiral throughout its life. However, reconstructions of the spiral's location—whether on the dorsal fin or deep in the throat—were contradictory, lacking conclusive evidence. The turning point came with specimen IMNH 37899, stored in a repository in Idaho, USA. It preserved not only the tooth spiral but also the outline of the surrounding jaw cartilage. In 2013, Tapanilla and his research team analyzed this specimen using a CT scan and discovered that the spiral was not located on the tip of the snout or the dorsal fin, but deep within the midline of the lower jaw, where the left and right jaws meet. If the spiral was located deep in the lower jaw, it is believed that each time the jaw closed, the tooth spiral rotated, acting as a device to pull prey deep into the mouth while tearing through the flesh. However, this brilliant conclusion rests on a precarious footing, supported by virtually the only specimen with intact jaw cartilage. The arrangement of teeth may vary depending on the growth stage and species, and the possibility of a different genus cannot be completely ruled out. The answer of mandibular midline is not definitive, but rather the best possible hypothesis. The assumption that we know what it looks like if we find a fossil is quietly shaken here. This story of how a single scan corrected a century-old error leaves an even deeper impression of the delicate nature of reconstruction when listened to alone against the backdrop of the deep sea's silence. What stories will the countless specimens sleeping in the archives one day reveal? #EvolutionOfLife #MysteryExplanation #Helicoprion ━━━━━━━━━━━━━━━━━━━━━━━ ⚠ About this video • The video was created using an AI image generation model and is not a photograph of actual landscapes, people, or artifacts. • Voice and script are generated by AI, and humans handle planning, adjustment, and quality control. *The video content is based on generally known information and theories, but its accuracy is not guaranteed. Views may change with the latest research. If you are interested, please do your own research. You may make new discoveries. Please refrain from unauthorized reproduction or re-uploading. If you enjoyed the videos on this channel, please subscribe and give us a thumbs up.