Travel Reference
In-Depth Information
jungle largely covered the land, for life in the sea? We might also ask the ma-
rine iguanas of our day, who have taken the same step. (Though not so giant
a step: Marine iguanas are fully amphibious, being as adept on land as in the
sea, whereas the mosasaurs may have left the sea only to lay eggs—or not at
all, giving live birth in the sea just like ichthyosaurs and whales.) The answer
to all these questions may be the same: food. The sea is rich in resources, and
the lure of that food has caused many lineages of animals to return to the
place of their ultimate ancestry. And if it was food that induced a previously
obscure lineage of small monitor lizards to abandon the land in the Late Cre-
taceous, what was the nature of that food? That particular answer is on dis-
play in virtually every natural history museum on earth. The seas of the
Mesozoic were filled with those ancient shelled cephalopods called am-
monites. Uncounted numbers of ammonite shells have been recovered from
Cretaceous-aged deposits bearing numerous circular holes that closely match
the size and shape of mosasaur teeth. Case closed: Mosasaurs ate ammonites
and left a record of their feasts behind, dramatic statements of ancient pre-
dation.
And so it is that countless natural history museums, if not lucky enough
to have a mosasaur skeleton to display, at least can show an ammonite shell
bitten, supposedly, by a mosasaur. The only problem is that in every case ex-
amined to date by a team of Japanese and Canadian scientists that has scru-
tinized this famous paleontological lore, the so-called mosasaur bite marks
are anything but the work of gnashing mosasaur teeth. In fact, they have a
Fossil Mosasaur of Cretaceous Age.
