Ninety million years ago, giant dinosaurs roamed the earth, pterosaurs flew through the air, and giant reptiles and fish hunted in the oceans. The area that is now Kansas was covered by water and one of its inhabi-tants was the plesiosaur—a reptile with an extremely long neck and a huge body.

This early reader about the ancient plesiosaur brings the prehistoric world of this ocean-dwelling animal to life, explain-ing how scientists think these reptiles lived, hunted, and became extinct. Back matter explores other reptiles both ancient and modern and provides additional print, visual, and web resources. A gallery of prehistoric marine reptiles, their prey, and their predators. Aiming for newly independent readers, Thomson describes in short sentences and simple language how plesiosaurs -- an oder tha included boht long- and short-necked varieties -- hunted, got about with their flippers ("Maybe it paddled like a duck. Maybe it glided like a sea turtle"), gave birth to live young, and succumbed at last to an extinction event 65 millions years ago. She provides broader context with comments about general features common to land and marine reptile of both the past and the present. Details both tantalize (the "smoth stones" in a plesiosaur's stomach "may have helped to crush food") and enlighten through concret example: "Some plesiosaurs were only a bit longer than a broomstick. Some could've stretched halfway across a basketball court." Throughout, Thomson carefully makes sure to emphasize that thre is much we still do not know. Plant juices up the presentation with dramatic (labeled) portraits of thrillingly toothy predators leaving trails of blood in the water as they eat and are eaten. 
Tempting fare for young dino-devotees.
--Kirkus Reviews

Thomson brings a third book in the series to life with an entry on the plesiosaur. Although not much is known for certain about these sea creatures, the author makes educated guesses about their everyday life. Plant’s dramatic and compelling illustrations add to the appeal for younger paleontology buffs. There is a balance of gentle scenes (a parent Nichollssaura swimming with its baby) and action-packed ones (a Dolichorhynchops trying to escape the jaws of a Tylosaurus). ­Labels with the scientific names of each creature are also included. VERDICT A title worth purchasing to round out a prehistoric animal collection, but not as a main resource.
--School Library Journal