Шинэ судалгаагаар 72-100 сая жилийн өмнөх далайн аварга махчин амьтан 19 метр хүртэл урттай байсныг тогтоожээ.
Япон болон Канадаас олдсон 27 ширхэг эрүүний үлдэгдлийг шинжлэх ухааны “Science” сэтгүүлд нийтэлснээр, эдгээр олдвор нь Nanaimoteuthis haggarti хэмээх төрөлд хамаарахыг тогтоожээ. Хэдийгээр зөөлөн эд нь хадгалагдан үлддэггүй ч эрүүний бүтцийг орчин үеийн цефалопод буюу толгой хөлтөн амьтадтай харьцуулан загварчилснаар уг амьтны биеийн хэмжээг тооцоолсон байна. Энэхүү олдвор нь тухайн үеийн далайд сээр нуруугүй амьтад ч дээд зэргийн махчин байж чадсаныг харуулж буй чухал нотолгоо юм.
Хоккайдогийн их сургуулийн палеонтологч, профессор Ясүхиро Ибагийн тайлбарласнаар, эртний эдгээр наймаалж нь далайн хүнсний гинжин хэлхээний оргилд байсан аварга махчин амьтад байжээ. Тэдний биеийн бүтэц нь найман тэмтрүүлтэй, олзоо холын зайнаас биш, харин ойртон очиж барьж иддэг ангуучлах өвөрмөц арга барилтай байсныг илтгэж байна. Олдворуудын тархалт нь энэхүү амьтан эртний далайд өргөн хүрээтэй тархсан байсныг гэрчилж байна.
Энэхүү судалгаа нь сээр нуруугүй амьтад 400 сая жилийн турш сээр нуруутан амьтдын ноёрхож ирсэн экосистемд хэрхэн ухаалаг, аварга том махчин болон хувьсан өөрчлөгдөж чадсаныг шууд баталж буй анхны тохиолдол болж байна. Тухайн үеийн далайд амьдарч байсан мозазавр 17 метр, аварга загас 10 метр хүрдэг байсан бол энэхүү цефалопод нь тэдгээр аваргуудтай ижил түвшний махчин байжээ. Хэдийгээр олдворууд хэсэгчилсэн байдалтай байгаа ч эрүүний бүтцийн хувьд маш тогтвортой байгаа нь тэднийг нэг төрөлд хамаарахыг баталж байна.
Дэлгэрэнгүйг эх сурвалжаас харах
↓Эх сурвалжийг нээх ↓
A newly analyzed set of fossils suggests that an ancient octopus-like creature may have reached around 19 meters in length, placing it among the largest marine predators of the Cretaceous seas. The study, published in Science, is based mostly on jaw remains attributed to Nanaimoteuthis haggarti.
For a long time, scientists have known that Cretaceous oceans were packed with large predators, from mosasaurs to sharks, but cephalopods of this scale were difficult to confirm because their bodies rarely fossilize. That leaves researchers working with partial remains, trying to rebuild entire animals from fragments that survived deep time.
In this case, the clues come from fossils collected in both Japan and Canada, dating back tens of millions of years. The paper reports that the consistency of these remains is what pushed scientists to reconsider just how large some cephalopods may have grown.
Ancient Fossils Discovered Across Oceans
The study is based on 27 fossil samples found across sites in Japan and Canada. Japanese researchers publishing in Science place these remains between 72 and 100 million years old, firmly within the Late Cretaceous period.
“Our findings suggest that the earliest octopuses were gigantic predators that occupied the top of the marine food chain in the Cretaceous,”explained Professor Yasuhiro Iba, a paleontologist at Hokkaido University.
Even though incomplete, the fossils share very similar jaw structures, which is the key point. That consistency suggests they belong to the same genus, Nanaimoteuthis, rather than unrelated species.
Their wide geographic spread also raises the possibility that this animal, or close relatives, had a broader distribution in ancient oceans than previously assumed.
Rebuilding A Giant From A Jaw
Most of the reconstruction work relies on the jaw, since soft tissues almost never survive fossilization. That makes estimating size complicated, but still possible through comparison.
Researchers used scanning methods and computer models to match fossil jaws with those of modern cephalopods. The scientists explains that this approach leads to an estimated length of about 19 meters, or roughly 62 feet, for Nanaimoteuthis haggarti.
To put that in context, modern giant squids can reach around 14 meters. That already places them among the largest living invertebrates, but this ancient species appears to go even further. The estimate remains dependent on modern comparisons, which means there is still a margin of uncertainty.
What Kind Of Predator Was It?
The anatomy of Nanaimoteuthis haggarti suggests eight arms, without the long feeding tentacles seen in many modern squid species. That difference likely changed how it captured prey.
Instead of striking from a distance, it probably relied on close contact, using its arms and beak to seize prey directly. The Japanese research team highlighted in Science describes this as a fundamentally different hunting style from many modern cephalopods.
There are also subtle signs of lateralization in the fossil record, where one side of the body may have been favored over the other. In modern octopuses, this kind of trait is sometimes linked to more complex behavior patterns.
“This study provides the first direct evidence that invertebrates could evolve into giant, intelligent apex predators in ecosystems that have been dominated by vertebrates for about 400 million years,” Professor Iba said.
In the same oceans, mosasaurs grew to about 17 meters, while large sharks reached roughly 10 meters. That puts this cephalopod in the same group of extremely large predators, even if much of its life is still pieced together from limited, fragmentary evidence
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