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Home , Dolichorhynchops, Henodus, Styxosaurus

Video: Sea Monsters

1. Kanas ______million years ago was a vast sea. This was a sea and one of the most ______seas of all time.

This video is about a , which is a of polycotylid plesiosaur from the of , containing two , D. osborni and D. herschelensis. Dolichorhynchops was an oceangoing prehistoric . Its Greek generic name means "long-nosed eye," perhaps because its eyes seem placed rather far forward on its lengthy snout. The holotype specimen of Dolichorhynchops osborni was discovered in the upper Smoky Hill Chalk Logan County, Kansas, by George F. Sternberg, as a teenager, in around 1900. The remains were collected by him and his father, Charles H. Sternberg, and then sold to the University of Kansas (Lawrence, Kansas). In 1918, Charles H. Sternberg found a large mosasaur, , with the remains of a plesiosaur in its stomach. The mosasaur specimen is currently mounted in the United States National Museum (Smithsonian) and the plesiosaur remains are stored in the collections. Although these important specimens were briefly reported by C. H. Sternberg (1922), the information was lost to science until 2001. This specimen was rediscovered and described by Everhart (2004a). It is the basis for the story line in the 2007 National Geographic IMAX documentary Sea Monsters: A Prehistoric Adventure, and a book by the same name (Everhart, 2007).

2. Doli is a marine ______. Often the bones of Dolichorhynchops are found together with many ______indicating that they gathered in protected shallows to give birth. How plesiosaurs reproduced is still a real sticky problem because of the astounding lack of evidence. There are no (published) cases of embryonic plesiosaurs found within pregnant females. It is very odd when you think about all the ichthyosaurs there are with embryos. Still many suspect that plesiosaurs were fully marine and viviparous, developing the embryo inside the body of the mother, eventually leading to live birth. It is also possible that Plesiosaurs laid eggs on land and could haul themselves up beaches.

3. Ammonites move by ______. and they probably defended themselves by expelling ______.

4. Doliʼs kind probably developed from ______reptiles in ______period.

5. Considering the number of teeth collected from Cretaceous sediments, it appears that these Cretaceous marine predators were as abundant and as deadly then as today. ______.

Match the rest: from this list of genera:

Tusoteuthis (two so TOOTH is) (HEN o dus) (zi FAC tin us) Tylosaurus (TIE lo sore us) (hes per OR nis) (STIK-so-SAWR-uhs) Henodus (HEN o dus)

6. This had tentacles and lacked an external shell. It is identified by the fossilized ʻpenʼ that was inside its body. ______7. This bird-like marine reptile swam but could not fly. ______8. This immense bony fish had a powerful tail that allowed it to swim very fast. ______9. This marine reptile was wider than it was long, and has distant relatives swimming the seas and lakes today. ______10. Name the snake-like marine reptile at the top of the food chain in the Cretaceous seas. ______11. This distant cousin of the Dolichorhynchops had a super-sized neck that equaled more than half its length. ______12. This marine reptile was wider than it was long, and has distant relatives swimming the seas and lakes today. ______