Turtle+Exinct

The Odontochelys semitestacea is the oldest sea turtle that have been discovered. This species of turtle was estimated to have lived in the late Triassic which is around 220 million years ago. They were originated in China. They are around 30 cm in size. The meaning of this genetic name is ‘toothed turtle’ or ‘half-shelled turtle’. However, many of the features of the Odontochelys semitestacea is still a mystery for today’s scientists. The odontochelys, like modern green sea turtles, lived near the shore where the water was shallow because it was where it could find its food and also they could also escape from their predators easily by going on shore. The odontochelys also stayed near coral reefs and green algae in order to hide from predators. At the time when the odontochelys still existed, it was still the Triassic period which means that Pangaea haven’t split yet, meaning that the weather back then was extremely different to what it is like today. By having all the land closer to the equator, there were cold winters as well as hot summers. The odontochelys, as scientists believes, lived in cooler regions, which, depending on the season, would be either on the north or south side of Gondwana. The picture below is an illustration of how the odontochelys’s habitit would have looked like.
 * Odontochelys **
 * click hereto look at modern green sea turtle **
 * Overview **
 * Habitat for odontochelys **

However, although odontochelys frequently went to shore, they did not stay there for long. On shore, there were enormous carnivores such as the //ticinosuchus// and the Tyrannosaurus Rex. So most of the time, the odontochelys habitat was in the ocean. The only time they odontochelys needed to get on to land was when the female had to lay their egg. The odontochelys lived at the time period when there were still ancient dinosaurs. Odontochelys also did not stay near swamps as there were crocodiles which are predators to the odontochelys. However, in the Triassic period, there were many volcano eruptions that took place, and the lava would get inside the water, causing the shallow sea to be replaced with burning lava. The odontochelys, as believed by scientists, had to change to different habitats many times due to natural disasters.

This is an adaption in which modern sea turtles do not have. Odontochelys fossil were found to have teeth on their lower and upper jaws. This adaption might have occurred in order for Odontochelys to have a more variety of food. For example, having teeth can allow turtles to not eat only jellyfishes, but also large sized fish which may have existed in the Triassic period. The interesting fact about the teeth is that, teeth are scientifically proven to be a complex creation and would take generations for them to evolve. The interesting fact is that modern turtles such as sea turtles do not have teeth, which scientifically means that the ancestors are more advanced than the modern turtles. Another way their teeth might have benefited them was because Odontochelys are omnivores, which means that they eat plants and meats. Odontochelys spent half of their life time on land, which means that they hunted for land animals with their teeth. The armored belly of the Odontochelys indicates that they have lived under water. The armored belly is called the plastron. The Odontochelys did not have top shell, also known as the carapace as today’s modern sea turtles have. The plastron provided protection from below. It is assumed by scientists that the turtle adapted this way because odontochelys lived near the coastline which is usually crowded with sharp rocks and needed protection from these. This is an evidence for Odontochelys being a sea based animal because the plastron would be useless for land based animals. The plastron also enabled the odontochelys to walk swiftly on land, unlike today’s modern turtles with large full body shells. Odontochelys spent around half’s of its lifetime on land, therefore it was extremely easy for them to catch preys and even escape from their own predators. The odontochelys, unlike modern turtles, have claws, or webbed feet such as the beaver, bear and crocodile. Their legs are particularly designed for flexibility through the water. However, the odontochelys does not have paddle like limbs, specially designed for water. The reason is because the odontochelys spent half of its lifetime on shore and the webbed feet also gave them flexibility on shore, while modern sea turtles are helpless with its paddle like limbs on shore. The odontochelys may have adapted to this feature to dig up food on the ocean floor. Even though the odontochelys does not look like paddle shape, it serves a purpose of a ‘flipper’. This allows them to escape from predators or even chase their prey. Because of their webbed feet, Odontochelys do not have many restrictions in food and can eat food other than algae and seaweeds. Also, the webbed feet act as a claw and allowed odontochelys to catch their prey on land. Because of the under belly shell, scientist believed that the odontochelys was a marine animal and not a land animal. At the time of the Triassic period, there were numerous carnivore predators such as the //Tyrannosaurus Rex//, //Alectrosaurus// and etc. There were less carnivore predators in the sea; therefore it was safer for them to stay under water. However, when they were searching for food, the odontochelys would walk around the coastline to search for small preys, such as crabs and many other preys that existed at that period. The odontochelys, like modern turtles had to lay their eggs on land, which was the most dangerous. In the ocean, the odontochelys stayed near coral reefs which allowed odontochelys to have more protection. Also, by staying under water, it allowed odontochelys to gain access to more food, as in the ocean, there are many school of fish. The odontochelys has a partial shell, extending from its backbone. Scientist believed that the odontochelys visited land frequently for a short period of time. The partial back allowed the odontochelys to move flexibly on land, and also it allowed the odontochelys to swim more swiftly through the sea. However, the disadvantage of this was that the partial shell was far softer than what the modern sea turtles have, therefore provided no protections from above. However, it allowed them to escape from their predators faster. The partial shell was not full body armor but only a set of ribs. The odontochelys did not simply extinct but evolved to sea turtles and tortoise we know today. Over time, the odontochelys have evolved to new features to survive climate changes. The climate in the Triassic period was constantly changing with volcano eruptions happening everywhere, and the climate cooling down due to global cooling which may have caused many of the odontochelys to die out. However, some remained and evolved to modern sea turtles. Some of the odontochelys may not have found enough food in the ocean due to decrease in population of fish (caused by lava), therefore evolved into land creatures such as the tortoise. From then on, the odontochelys evolved into different types of turtle. This was caused by environment change.
 * The teeth **
 * Under Belly shell **
 * Claws **
 * Staying under water **
 * Partial back **
 * Extinction pressure **

Lam, M. (2008, December 2). Odontochelys, a transitional turtle - The Panda's Thumb. //The Panda's Thumb//. Retrieved June 26, 2011, from [] Myers, P. (2008, November 26). Odontochelys, a transitional turtle - The Panda's Thumb. //The Panda's Thumb//. Retrieved June 26, 2011, from [] Wikipedia. (2011, May 13). Odontochelys - Wikipedia, the free encyclopedia. //Wikipedia, the free encyclopedia//. Retrieved June 26, 2011, from []