Ancient 'sea monster' was pregnant

Plesiosaur dinosaur fossil solves breeding puzzle

plesiosaur

plesiosaur

plesiosaur

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An adult Polycotylus latippinus, one of the giant, carnivorous, four-flippered reptiles known as plesiosaurs that lived during the Mesozoic Era, is shown giving birth in this publicity illustration released to Reuters August 12, 2011. A paper published in the journal Science Friday states that a fossil of the creature on display in Los Angeles with bones in its abdomen are evidence of a fetus, and that this species produced offspring through live birth. REUTERS/Stephanie Abramowicz/Natural History Museum of Los Angeles/Handout.

A photograph of the fossil of a 78-million-year-old, 15.4-foot-long adult Polycotylus latippinus, one of the giant, carnivorous, four-flippered reptiles known as plesiosaurs that lived during the Mesozoic Era is shown in this publicity photo released to Reuters August 12, 2011. A paper published in the journal Science Friday states that the bones in the creatures abdomen are evidence of a fetus and that this species produced offspring through live birth. REUTERS/Natural History Museum of Los Angeles/Handout.

This undated handout photo provided by the journal Science shows the detail of a Polycotylus latippinus' embryo. The giant reptile was pregnant when she died more than 70 million years ago, according to a new analysis of the remains that offers the first proof that Plesiosaur gave birth to live young rather than laying eggs. AP Foto/Science.

A photograph of the fossil of a 78-million-year-old, 15.4-foot-long adult Polycotylus latippinus, one of the giant, carnivorous, four-flippered reptiles known as plesiosaurs that lived during the Mesozoic Era is shown alongside a chart of its bones in this publicity photo released to Reuters August 12, 2011. A paper published in the journal Science Friday states that the bones in the creatures abdomen are evidence of a fetus and that this species produced offspring through live birth. REUTERS/Natural History Museum of Los Angeles/Handout.

In this photo released by the US Fish and Wildlife Service on Thursday July 21,2011, Patrick Druckenmiller holds a perfect piece of bone removed from the Bearpaw Shale. In order to protect loose bones for transport, each was wrapped tightly in a piece of aluminum foil. (AP Photo/Marcus Hockett /USFWS)

In this photo released by the US Fish and Wildlife Service on July 21,2011, a Plesiosaur Vertebrae fragments of bone protruding from the top edge of this piece of shale is shown. Much like the modern-day whale, plesiosaurs breathed air. The aquatic reptiles swam through the sea with four paddle-like flippers, catching fish and other prey with razor-toothed jaws. (AP Photo/ Marcus Hockett / USFWS)

In this photo released by the US Fish and Wildlife Service on Thursday July 21,2011, preparing the skull, Pat Patrick Druckenmiller works carefully to prepare the plesiosaur skull for its plaster jacket. Druckenmiller is one of the world's experts on marine reptiles, having completed graduate studies at Montana State University under Jack Horner and a PhD from the University of Calgary, Alberta, Canada. He is the Earth Science Curator at the University of Alaska Museum in Fairbanks and Assistant Professor in the Department of Geology and Geophysics. (AP Photo/USFWS, Marcus Hockett).