When Mosasaurs Swam in North America

[Mike Everhart <mike@oceansofkansas.com>]

Grumble, grumble.......

.....Having endured two hours of television 'fantasy' and too many silly
commercials (the beer ad comes to mind) while watching "When Dinosaurs
Roamed NA", I've spent the last couple of days fermenting about what I
saw, (easy to do in the 100+ degree Kansas summer heat)

....or really, it was about what I didn't see... Of course, I had the
usual problems with all the unproven "facts" that were so freely
provided, but I was most concerned with the obvious disregard for the
critters that I enjoy most......... yes, I'm going to talk about
mosasaurs... and if they aren't on your list of interesting fossils,
then delete this email and drive on other 'ground pounder' topics.  :-)

Having watched both Walking with Dinosaurs and When Dinosaurs roamed
North America, I don't believe that the word "mosasaur" was even spoken
once....... yes, they did include Jurassic ichthyosaurs and plesiosaurs
in WWD, but grossly over-stated the size of Liopleurodon and generally
passed marine reptiles off as a side-show.

In WDRNA, the Western Interior Sea was mentioned a couple of times,
mostly in reference to being the source a terrible storm that broke the
annual drought for the suffering dinosaurs, but there was no mention of
the interesting creatures that lived in or above it; the Ginsu sharks
and giant bony fish, the kite-like pteranodons and primitive toothed
birds, the speedy, "underwater-flying" pliosaurs and long necked
plesiosaurs, marine turtles bigger than Volkswagens, ... and yes, the
mosasaurs......

Just for fun and hopefully to prod a discussion along.... I'm going to
list some attributes of a composite, Maastrichtian mosasaur I will call
"Mosasaurus rex" along with those of the King of the ground-pounding
theropods at the same time (and if you don't think they pounded the
ground... just listen to the annoying soundtrack of WDRNA),
Tyrannosaurus rex. (I'm using a mosasaur composite because unlike T-rex,
there were a number of huge mosasaur species terrorizing the seas at the
time)..... feel free to disagree... or add an attribute of your own.

                 Mosasaurus "rex"               Tyrannosaurus rex
Affiliation      Squamata                       Theropoda
Adult length     55 plus feet - Huge            45 plus feet - Huge
Weight           <5-6 tons(no big legs)         6-7 tons plus
Length of skull  5-6 feet                       5-6 feet
Kinetic skull    Yes, and lower jaw             Yes
Tooth count      48 in jaws, 20 more on palate  50+
Tooth type       Cone shaped, seizing, crushing Serrated, heavy duty
                                                blades, bone shearing
Tooth replace.   Throughout life                Throughout life
Lifestyle        Swimming, marine carnivore     Bipedal, terrestrial
                                                carnivore
Primary prey     Fish, birds, other mosasaurs   Hadrosaurs
and
Ceratopsians
Feeding method   Kill and swallow whole         Kill and dismember
Habitat          Coastal marine waters, rivers? Woodlands, open savanna
Reproduction     Live birth                     Egg layer
Parental care?   Probably - limited             Probably - extended?
Life span        50-80 years?                   50-80 years?
Where found      Oceans worldwide, pole to pole Western North America
How many living
 at any one time Many thousands, millions?      Hundreds? Thousands?
Living relatives Monitor lizards, snakes(?)     Birds
When extinct     At or slightly before K/T      At K/T boundary

So, you ask, what's my point? .... Well, for two creatures that were
"Kings" of very different worlds, they don't seem that much different
from each other.  But, mostly I'm wondering why mosasaurs are so easy to
ignore when they were probably the most successful group of predators
ever to inhabit the oceans of the Earth. It can't be just because they
lived in the ocean.  I mean, "Shamu", "Flipper" and "Free Willie" are
doing okay. Even sharks get more respect!  Gotta find a better press
agent!!

Tongue in cheek,  :-)

Mike Everhart
Oceans of Kansas Paleontology