Archelon

Lore & Background

A fifth partial skeleton was found in 2002 in North Dakota.

Reader's Guide

Archelon is significant as the largest turtle ever documented, providing insight into the evolution and ecology of ancient marine reptiles. Its leathery carapace, rather than a hard shell, and its osteosclerotic bones suggest adaptations for open-ocean travel, similar to modern leatherback sea turtles. The genus was originally placed in the extinct family Protostegidae, which is now thought to be a completely separate lineage from any living sea turtle. Archelon likely inhabited the northern Western Interior Seaway, a mild to cool temperate area dominated by plesiosaurs, hesperornithiform seabirds, and mosasaurs. Its extinction may have been caused by the shrinking of the seaway, increased infant mortality, higher predation on eggs and hatchlings, and a rapidly cooling climate. The species name ischyros means 'mighty' or 'powerful' in Ancient Greek.

Did You Know?

• Archelon had a leathery carapace instead of a hard shell, similar to the leatherback sea turtle.
• The largest specimen, nicknamed 'Brigitta', measures 4.6 m (15 ft) from head to tail and 4.0 m (13 ft) from flipper to flipper.
• The genus name comes from Ancient Greek words meaning 'first/early turtle'.
• Archelon's jaws were adept at crushing, suggesting it ate hard-shelled crustaceans, mollusks, and possibly sponges.