Legend has it that in the ocean there were super giant turtles, the sailors stood on its hard shell and thought it was a small island, only when it started to swim did they know something was wrong. . Can sea turtles really grow to that size? What is the largest sea turtle known to mankind?
In 1895, paleontologist George Reber Wieland discovered the fossils of a giant creature along the Cheyenne River in Custer County, South Dakota, United States. Wieland then transported the unearthed fossils to the Peabody Museum of Natural History at Yale University, where it was subsequently numbered YPM3000.
When the YPM3000 was cleaned and restored, what appeared before everyone was a giant sea turtle fossil. The integrity of the fossil is quite high, it only lost the skull and the right hind limb. Paleontologists surmise that the right hind limb is missing because in the past it was attacked by predators and torn apart by enormous external forces. In 1898, a second fossil of another giant sea turtle was discovered in the same area, in which this fossil still preserved the skull.
After studying fossils of this giant prehistoric sea turtle, Wieland named the large sea turtle Archelon ischyros, which is derived from the Ancient Greek word “ἀρχη” (meaning “head” first, earliest”) and “χελώνη” (meaning “turtle”).
In 1900, Wieland named the second species Archelon marshii. In 1909, Wieland realized that the ancient sea turtle Archelon marshii was in fact a Protostega rather than an Archelon, so he renamed it Protostega marshii.
In 1902, paleontologists discovered a third ancient sea turtle fossil from the Cheyenne River, and this time its fossil was even more complete than the previous two species. 90 years later, in 1992, the fossil of the fourth ancient sea turtle (Archelon) was found in Oglarakta County, South Dakota, it was the largest ancient sea turtle fossil ever discovered and people at the time. named it Brigitta.
Ten years after the discovery of the fourth giant sea turtle fossil, a fifth ancient sea turtle fossil was also found in Cooperstown, North Dakota, but the completeness of this fossil is not high. To this day, we have discovered a total of five ancient sea turtle fossils.
Archelon is the largest known sea turtle. The length of specimen YPM3000 is up to 3.52 meters, but it clearly does not represent the actual size of this ancient sea turtle. Meanwhile, the Brigita fossil is the largest known Archelon fossil with a body length of 4.6 meters, a width between the flippers of 4 meters and an estimated weight of 2.2 tons. Compared to today’s largest sea turtle – the leatherback turtle, the Archelon is actually much larger in size, in fact the leatherback turtle weighs only about 700 kg, in particular, there are a few individuals that develop mutations that can weigh up to close to 1 ton, they are still much smaller than Archelon.
Leatherback or leatherback turtles are the largest sea turtles today, they are the fourth largest reptile after three modern crocodile species.
The leatherback turtle is the only living species in the genus Dermochelys. They are easy to distinguish from other sea turtles today because they have no shells. Instead, their backs are covered with flesh and skin.
The appearance of the Archelon sea turtle was very similar to that of today’s leather turtles, and there is a certain relationship between the two species. The Archelon sea turtle has a large and long head, even longer than the upper body of an adult. The front part of the mouth of the Archelon turtle is similar to a parrot’s beak, the beak has hard horns and a very large bite force.
The body of the Archelon sea turtle has an oval shape, the ribs have also joined together to become the support part of the large body. Like the leatherback tortoise, the Archelon giant tortoise is covered with hard skin instead of a hard shell like a tortoise. On the back of the Archelon turtle has a thin and short tail, the limbs have long evolved into flippers for swimming, the front flippers are very large but the rear is relatively small. From a fossil point of view, the proportion of bones in the forelimbs of the Archelon sea turtle is very large, which suggests that it mainly relied on its front flippers to swim.
The Archelon sea turtle lived during the Late Cretaceous period 80 million to 74 million years ago. Their fossils show that they lived in the western Inland Sea, a warm shallow sea that divides North America into two parts. Considering the body structure of the Archelon, they are not suitable for long-distance swimming in deep seas, so most of the time they live in shallow seas. Compared to leatherback turtles, Archelon turtles are much more carnivorous, they will dive to the bottom of the sea to find shellfish, then use their mouths to squeeze the hard outer shell and eat the meat inside. In addition, Archelon’s food can also include various types of snails, squid, fish, etc.
North America 75 million years ago.
Restoration image of the Archelon sea turtle.
Archelon disappeared 74 million years ago. Paleontologists believe that the causes of their disappearance include land-based predators and marine predators, which seriously threaten the survival of newborn sea turtles. At the same time, anomalies appeared in the ocean such as erratic temperature rise and fall, making it impossible for them to live until the end of the Cretaceous period.
