Research Highlights: Scientists Discovered Thick-Shelled Turtle Egg with Embryonic Remains from Cretaceous Period

Scientists Discovered Thick-Shelled Turtle Egg with Embryonic Remains from Cretaceous Period

Fossil record lacks specimens about turtle eggs containing embryos.
Researchers provide the first description and taxonomy information of an egg with a preserved fossilized embryonic turtle.
The fossil was discovered from the Upper Cretaceous Xiaguan Formation of Henan Province in China.
The specimen is assigned to the Nanhsiungchelyidae which is an extinct group of large terrestrial turtles.
The egg is one of the largest and thickest shelled turtle eggs from the Mesozoic Era.
The egg is described as rigid and spherical.
The new discovery allowed the identification of other Nanhsiungchelyid egg clutches and comparisons to those of Adocidae.
Adocidae are extinct, omnivorous freshwater cryptodiran turtles and are mainly known from Cretaceous and Paleogene Asia and North America.^[1]
Nanhsiungchelyidae and Adocidae form the basal extinct clade Adocusia of the Pan-Trionychia which consists of the living soft-shelled turtles.
Nanhsiungchelyids had different habitats compared with adocids.
However, Nanhsiungchelyidae and Adocidae shared some reproductive traits including thick eggshells, mid-size clutches, and large eggs.
The unusual thickness of Nanhsiungchelyids eggshell may be associated with a nesting style adaptation to a very harsh environment.