Archelon

Live reconstruction of Archelon Ischyros

• North America, USA: South Dakota, Arkansas, Texas, Kansas, Nebraska

• Archelon Ischyros

Archelon is an extinct genus of sea turtles relatives ( Chelonioidea ) from the Upper Cretaceous of North America. This turtle fossils date from the time of the Campanian, about 72 million years ago. The Ischyros known only by the type species of the genus Archelon is the largest ever discovered turtle; the largest known land turtle ( Testudinidae ) Testudo atlas from the Pleistocene of India.

Description

Archelon reached a length of up to 4.5 meters, the tips of the outstretched front paddles were up to 4 feet apart. The carapace shows a strong tendency to regression of skin bone plates. The carapace ( carapace ) consisted only of transverse bone bands that sprang from the ribs. Presumably, the carapace was covered only by a thick leathery skin, similar to the leatherback turtles, the closest living relatives, or maybe he was of horn plates ( Scuta ) covered.

Way of life

Their enormous size offered an adult Archelon probably sufficient protection from their predators, hence the bone part of the tank could be reduced, which facilitated the movement in the water. The turtle had no teeth, so one assumes that they fed on an omnivore of soft animal food such as jellyfish and plants. She lived in the shallow waters of the Western Interior Seaway, a Epikontinentalmeer that covered most of the interior of North America during the Cretaceous.

Scientific classification

Archelon heard within the leatherback turtles relatives to Protostegidae, an extinct lineage ( taxon ) of marine turtles that are performed in the classical biological systematics in the rank of a family. This group is normally only the older Santanachelys gaffneyi from the Lower Cretaceous ( Albian ) sufficiently proven by fossil discoveries and scientific researches.

Santanachelys gaffneyi

Archelon Ischyros

Other Protostegidae ( Notochelone, Desmatochelys )

Leatherback turtles ( Dermochelyidae )

Genuine sea turtles ( Cheloniidae, now living and fossil species)

Localities and stratigraphy

, Arkansas, Texas were from the deposits of the Western Interior Seaways in South Dakota ( uppermost Pierre lineup Montana Group ) (both Taylor Group, Marl Marl Brook ), Kansas and Nebraska recovered some fossils of Archelon. The first record made ​​G. R. Wieland on the south arm of the Cheyenne River, about 56 kilometers east of the Black Hills in South Dakota in 1895. In this area the mid- 1970s was also discovered the largest and most complete skeleton to date, which is now in the Natural History Museum in Vienna is issued. Also from South Dakota, near the capital, Pierre, come the two most recent finds from the years 1996 and 1998.