Thursday, August 1, 2013

Dinosaurs--part 2

When my husband and I first moved to Santa Barbara, Ca. we bought a house that was 90 years old.  It had a yard very overgrown with vegetation and  I was determined to weed out all the unwanted tangle of growth and return the yard to its original glory.  One day, sitting on my knees by a flower bed, I plunged a hand deep into a matte of weeds and ferns and suddenly a reptilian creature about a foot long came charging at me from the undergrowth--it raised up on its longer hind legs and, with mouth agape, bared its nasty looking razor-like teeth (okay, I may be exaggerating here).  Now I must confess a character flaw that has plagued my conscience for some 30 years--I grabbed a shovel and chopped that guy into a dozen one-inch-pieces!

Some time later I learned I had executed a member of a rare lizard family and this particular breed was on the very edge of extinction! For all I know, he was the last one.  I do know--he was the very last reptile I have knowingly annihilated.

 It was during the Cretaceous Period, when dinosaurs reached their evolutionary peak, that a massive extraterrestrial impact initiated the Cretaceous Extinction.  Dinosaurs, ammonites and marine reptiles were among the 50% of Earth's species that disappeared.

Son, Ron, is 6'3" tall and this is a 'medium sized' sauropod leg that lived 155-145 million years ago in the late Jurassic Period.
The Camarasaurus was one of the most common sauropods in western North America.  They were long-necked and were the largest animals to walk the earth. Adults are estimated to have reached lengths of up to 70 feet and weights of up to 47 tons.


The armoured Stegosaurus had large plates along it back and distinctive tail spikes.  They also had a very small brain and simple jaws and teeth.  Stegosaurs went extinct during the Early Cretacous,  

Allosaurus was the most common carnivorous dinosaur of the Jurassic Period in North America.  It was the top predator of its time--equipped with sharp, pointed, serrated teeth ideal for tearing flesh.  In this scene, Allosaurus has a helpless Camptosaurus on its back. 
Is there any doubt some of these reptiles were the predecessors of the birds?

The museum had many fish and amphibian fossils like this turtle that were indicators of the vastness of the Bearpaw Sea.

Eryops was a large carnivorous amphibian.  Although able to walk on land, it probably spent much of its time in the water.  With only its eyes and nose visible, it would float near the surface, waiting to catch unsuspecting prey.

These are the fossilized remains of the world's largest-known marine reptile, the ichthyosaur Shonisaurus Sikanniensis.  At 69 feet long it is 30% larger than any previously known ichthyosaur.  It took 3 summers to excavate this 'Triassic giant' from its location along the shores of the Sikanni Chief River in Northeastern British Columbia.
They first appeared about 245 million years ago at the beginning of the Mesozoic Era and died out about 100 million years ago.
(The diagram on the floor that indicated the size of this creature stretched out into another room)

A Dimetrodon of the Permian era.  Scientists are unsure but it is possible that their 'sails' were used for display to attract mates or to discourage competitors.

Here, I think of the lizards that travel along the back wall around my house in Tucson.  When confronted by a competitor they will raise up and fan out their colorful necks--but they never fight.

Pachyrhinosaurus lakustai has a large bump on the nose rather than a horn.  It was named for Al Lakusta, a high school science teacher who first found rib fragments of this species in 1974.
(I love the idea that a science teacher with such an unpretentious name got a dinosaur named after him.)

Centrosaurus apertus dominates several bonebeds in Dinosaur Provincial Park, including the largest ceratopsian bonebed known.  Containing the remains of over a thousand individuals of the same species, this mass grave provides evidence that some dinosaurs travelled in herds and displayed social behavior.

Anchiceratops ornatus was first discovered in 1912 along the Red Deer River.  The rectangular frill was edged by large triangular bony projections and has large orbital and nasal horns.

When discovered in Alberta in 1902, Stegoceras became the first dome-headed dinosaur known to science.  Its name means "horned roof" and refers to the assortment of bony knobs protruding from its skull.  75 million years ago.

I can't help it--this guy looks so 'extraterrestrial' to me.

A large blade-like crest that curves forward distinguishes this species of Lambeosaurus.  This specimen was buried rapidly after death, resulting in the preservation of a complete skeleton with skin impressions along the neck and forelimbs.

Gorgosaurus...a carnivore with robust jaws and serrated teeth.  Sturdy hind legs and clawed feet, an efficient killer and an opportunistic scavenger.

If you made it this far then I am impressed.  I hope this shows some of the incredible diversity of life that has come and gone from our planet.  If a spaceship from another galaxy visited us during the 200 million years when these animals were alive then they went away with a far different idea of life on Earth.
This museum was fascinating and well worth visiting.  Ron and I left here late in the day and headed to our campground where we would be for two nights. It is the place that most of these fossils were found.
(to be continued)

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