Ancient Seas #9

Ancient Seas

Archelon

Photo from Wikipedia

Kingdom: Animalia

Class: Reptiia

Conservation Status: Extinct (EX)

Era: Late Cretaceous

WHAT WAS IT?

Archelon was a large marine turtle, believed to be the largest ever documented sea turtle. The largest specimen, named Brigitta, was 4.5m (15ft) from head to toe; 4m (13ft) flipper to flipper; and weighed 2,200kg (4,900lbs). Instead of a hard shell, they had a leathery carapace with ridges up to 5cm (2inches) long. Its head was distinct with a narrow and elongated shape, and had horizontal nostrils on the top of its skull which is unusual in comparison to its modern counterparts.

WHERE AND WHEN DID IT LIVE?

The Late Cretaceous was 66-100 million years ago. During this time period, there was a large inland sea splitting North America into two land masses. This was called the Western Interior Seaway and its where the archelon lived. At its largest, this body of water was 700m (2,500ft) deep, 970km (600 miles) wide, and 3,200km+ (2,000miles+) long; it stretched from the Gulf of Mexico to the Artic Ocean. These waters were cool and mild, and home to plesiosaurs and mosasaurus.

Photo from Prehistoric Life Wiki

HOW DID IT LIVE?

It is believed they had a 100 year life span. Like their modern ancestors, they came to shore to nest and lay their eggs. They also took no part in rearing their young. They would have spent most of their lives in shallow waters. They are capable of travelling through deeper ocean waters, but their flippers were weak and not designed for deep waters. 

Upon the sea bed is where they were believed to hunt, while moving slowly. They had a strong, powerful jaw which would have been great at chomping down on crustaceans and mollusks. Archelons were obligate carnivores, meaning their nutrient requirements were found only in animal flesh. Their hooked beak could have been used to shear flesh from prey such as seabirds, but they could also have been used in combat.

WHY DID IT DIE OUT?

The world has changed a lot since archelon swam in the seas. Namely, the ocean in which it lived is now North America. So, it is believed that they died out due to shrinking habitat and the climate cooling overall. There was also believed to be increased predation on their eggs and hatchlings.

Photo from Prehistoric Planet

FUN FACTS

• Archelon was the same size as a small great white shark.
• There is a sea turtle protection society in Greece named after Archelon. 
• The leatherback sea turtle was believed to be the closest living relative to archelon.
• It has now been concluded that they are not related at all.
• In fact archelon shares no common ancestor with any turtle - contemporary or modern.

Listening to: Crazy Ex-Girlfriend Concert