The fore limbs especially resemble the flippers of Pliosauridae more than they resemble the typical plesiosaur morphology .
Pliosauridae is an extinct group of less elongate marine reptiles that shared the seas with plesiosaurs .
The fore limbs especially resemble the flippers of Pliosauridae , an extinct group of less elongate marine reptiles that shared the seas with plesiosaurs , more than they resemble the typical plesiosaur morphology .