For nearly 25 years a spectacular fossil that could answer scientists' questions about an ancient marine reptile lay buried in the basement of the Natural History Museum of Los Angeles County
. The fossil was of a plesiosaur
, a large four-flippered creature that roamed the oceans some 78 million years ago. But it wasn't just any fossil, this fossil was pregnant.
The fossil shows the mother, around 470 cm long, carrying a single fetus, around 150 cm long. The fetus has 20 vertebrae, shoulders, hips and paddle bones, and is believed to be about two-thirds grown. This is the first case of a pregnant plesiosaur fossil, and it shows that the creatures gave birth to live babies rather than hatching eggs. The finding also suggests that the creatures cared for their young similar to modern day whales and dolphins.