Sea Rex 3D swims into IMAX!

Explore an amazing underwater universe inhabited by larger-than-life creatures that ruled the oceans millions of years ago in Sea Rex 3D – now showing in HMNS IMAX!.

Mosasaurus hoffmannii skeleton on display at the
Maastricht Natural History Museum,
The Netherlands

Guided by Georges Cuvier, considered by many to be the father of paleontology, viewers learn about predators such as the ichthyosaur, plesiosaur, and mosasaur. These ancient creatures could grow up to 50 feet and could weigh as much as 15 tons.

Learn about the Triassic, Jurassic, and Cretaceous eras and how life evolved in the deep oceans of Earth. See a mosasaur battle the Great White Shark’s ancestor and witness the mating habits of the plesiosaur.

You’re going to love the film’s time line of the history of the Earth, showing the evolution of the first single cell organisms to the mammals that evolved and began to walk on land. What I found fascinating is the amount of time each of the dinosaurs ruled the world in comparison to humans. Dinosaurs walked the earth for over 160 million years, while humans have only been around for about 200,000 years comparatively.

Evidence of giant marine predators were first discovered in a mine shaft in the Dutch city of Maastricht in 1770, when the partial skull of a Mosasaurus hoffmannii was uncovered. Sea Rex 3D takes you on a journey from the creation of earth until the meteor that killed off 95% of life 65 million years ago. Don’t miss this incredible story about our planet’s history and the monsters that ruled the sea for over 120 million years.

Can’t see the video? Click here.

Sea Rex 3D is now showing in the Wortham IMAX Theater. See show times on our Film Schedule.

The Ghost Sharks of The Jurassic

Fish Pieced Together by Committee

Our HMNS at Sugar land exhibition on Archaeopteryx is festooned with splendid finny fossils, the ichthyological gems of the Late Jurassic. Some of the Jurassic fish were new comers, recently evolved clans that were poised to conquer the watery ecosystem. Teleosts are one such progressive group.  But there are Jurassic living fossils. These are old, old clans that had evolved a hundred million years before the Jurassic, or more. And these groups had stalled out, in evolutionary terms, changing little.

Chimaeras, the “ghost sharks,” are the most exotic of the Jurassic living fossils. The label “Chimaera” evokes the mythological critter that was put together with spare parts from many species. The real chimaera fish do seem to be constructed that way. The huge eyes and  nibbling snout look like a rabbit’s, inspiring the label “Rabbit Fish.” The front fins are huge, resembling those of a butterfly-fish. The tail is long and thin, like a rodent’s – hence another nickname “Rat-Fish.”

In fact, Chimaeras are distant cousins of sharks and rays.

Chimaeras were already an antique group by the Jurassic, with an origin going back almost to 400 million years ago. The body form had been standardized by the Coal Age, 330 million years ago. The key feeding feature was the solid, strong, stiff heads. Teleost fish gained success by loosening up face and jaw bones, so the mouth could expand. Chimaera evolution went the other way. Their skulls were solidly knit together, with jaws, face and braincase units braced against each other.

Global paleogeographic reconstruction of the Earth in the late Carboniferous (“Pennsylvanian”)
period 300 million years ago.
Creative Commons License photo credit: Dr. Ron Blakey

The solid chimaera skull was co-evolved with flat, thick teeth that could crunch and crack crabs, clams and all sorts of other hard-shelled teeth. In other words, the chimaera was the fishy equivalent of a sea-otter. For protection, chimaeras were outfitted with a sharp, tall spine at the front of their dorsal fin.

Even though they hadn’t upgraded their adaptive equipment for a long time, Jurassic chimaeras continued to succeed as  bottom-hunting predators of shellfish. And they kept on going, and going, and going….

….surviving through Period after Period. They’re still around today. In their anatomy, the modern chimaeras are barely different from the Jurassic species. But habitats have changed dramatically. Jurassic chimeras thrived in shallow water of the Solnhofen lagoons and reefs. And the earlier chimaeras too were mostly inhabitants of the shallows. Most species alive now are  deep-water specialists. The same slide from shallow to deep water happened to one group of bony fish, the coelacanths.

That’s a general evolutionary principle: fish that ranged through upper waters in the past tend to get restricted to the deep today.  Why? Maybe new predators and competitors tend to evolve first in shallow water. And thus shallow water becomes the most dangerous place for old clans who don’t evolve fast. Going deep may free the old-style fish from many of the exuberant new clans.

Maybe….

Learn more about evolution by visiting our unique collection of fossils in Archaeopteryx: Icon of Evolution, now on display at HMNS at Sugar Land.

Shark Progressives in the Jurassic Period

Maybe you have heard this Shark Myth:
The Great White is a Living Fossil, a man-eating hold-over from the dim reaches of time.

No.  It is true that the oldest sharks do go back to 400 million years ago. However, an enormous amount of evolutionary change separates these primordial sharks from a modern-day Great White Shark. The final episode of shark modernization didn’t really get going until the Jurassic about 150 million years ago. The vertebral columns became far firmer and stronger, so the body and tail muscles could contract with greater power – and that meant faster speeds. The Great White and many other sharks alive today inherited their firm vertebrae from Jurassic ancestors. Plus – this  Darwinian revolution gave some sharks, including the ancestors of Great Whites, bigger brains and more complex behavior.

Guitar Fish Rhinobatis

The modernized sharks that evolved in the Jurassic included the “normal” shaped sharks and the flat-bodied skate/ray group. The skates and rays of the Late Jurassic at Solnhofen had already evolved a modern stage of vertebral column, fins and jaws. Guitar-fish are rays with long, elegant, pointed snouts. The Solnhofen Guitar Fish Rhinobatis is so thoroughly modern-looking that it would look at home today in Bermuda or Sumatra. Wide, flat pectoral fins and a flat underside let the guitar-fish hug the sand while searching for shrimp buried beneath. Special sensory organs could detect the electrical impulses from living bodies hidden from view. They had tightly packed rows of small, blunt teeth worked to crush clams, snails and other hard-shelled prey.

For some mysterious reason, people the world over look at these flat sharks and think of folk music and rock ‘n roll. Hence the nickname “Guitar Fish.” Because of a difference in the culture of stringed instruments, the guitar fish are called by a different name in Russia: here they are known as “Balalaika Fish.”

Poison Spine Sharks – Hybodonts

Solnhofen hosted both the most modern, advanced sharks and some hold-overs, families that were already a hundred million years old at the time. Hybodonts are an excellent example of ancient shark technology in body form. The vertebral column was still  constructed from soft connective tissue, not the tough cartilage of modern sharks. Hybodont teeth were dual function. Up front were sharply pointed nippers for grabbing prey. In the back were many flat teeth for crushing lobsters, crabs, snails, clams and sea urchins.

Hybodonts had the ancient way of protecting themselves from predators. They carried  poison-spines at the leading edge of the two dorsal fins. A gland at the base of the spine secreted venom that oozed up along a groove. Any predator that attacked would run the risk of getting a painful jab that would leave a throbbing wound.

How do we know about poison from hundreds of millions of years ago? Because there are some sharks today with this type of weaponry. The Horned Shark, Heterodontus, is a smallish species with a slow-swimming style. Both dorsal fins have spines, and venom is produced at the base of the spines. Horned Sharks are small enough to be swallowed whole by some bottom-living predators. But when the attacker feels the spines poking into the roof of its mouth, the Horned Shark is spit out with no harm done. The anatomy of Horned Shark spines is close enough to what we seen in fossilized hybodonts that we are safe to conclude that the hybodonts too were poisonous.

Another common shark alive today, the Spiny Dogfish, is also outfitted with hard spines and poison glands, though the toxic properties of the apparatus isn’t as extreme as that of Horned Sharks.

Poison spines go way back in shark evolution, and both fresh-water and salt-water species were equipped with the venom-delivery system in the Coal Age, some 340 million years ago. It’s intriguing that the modernization process in the Jurassic caused a shift – most of the new clans of sharks would give up the bigs spines. Great Whites are not protected by spines, nor are Tiger Sharks, Blue Sharks, Bull Sharks and most other “normal” sharks.

Why did so many progressive sharks discard the venom-delivering spines? The loss of spines occurred as the most advanced bony fish were shifting from thick, armored scales to thinner, more flexible body coverings. It looks like evolution favored speed and agility over passive defensive structures.

Learn more about evolution by visiting our unique collection of fossils in Archaeopteryx: Icon of Evolution, now on display at HMNS at Sugar Land.


Edward Hitchcock

Archaeopteryx: Icon of Evolution is coming back, a week from tomorrow! Don’t miss the exhibit as it flies into the Houston Museum of Natural Science in Sugar Land, opening Oct. 22, 2010. Famed paleontologist Bob Bakker provides more insight into this unique fossil.

The Reverend Edward Hitchcock -
The Man Who Predicted Archaeopteryx – a Quarter Century before the Discovery.

Who discovered Archaeopteryx?  In 1861 Herman von Meyer recognized a Solnhofen fossil as a bird.

But another scientist had predicted that Archaeopteryx HAD to exist, back in 1836.

Edward Hitchcock was the State Geologist of Massachusetts, and a leading Biblical scholar of the time. He was a serial creationist who believed that Creation was accomplished through many events spread across geological ages. Hitchcock was a Jurassic specialist who dug hundreds of fossil footprints from the Connecticut Valley. From this evidence, he figured out that there must have been  birds in the Jurassic. Some of Hitchcock’s Jurassic birds were as tiny as sandpipers. Others were as large as rhinos.

Hitchcock didn’t have any good fossil skeletons from his Jurassic digs. But still he  reconstructed the toe bones from the imprints in the rock.  First he ran all sorts of living animals on muddy fields, from turkeys to frogs to raccoons to barefoot farm boys. He diagrammed where the toes fit in the footprint. Soon the Reverend Hitchcock knew more about the animal sole than any other scholar.

Here are the clues he gathered from scrutinizing feet:

  • The dominant beasts who left their tracks in Jurassic rocks walked on their hind-feet – like birds.
  • The Jurassic creatures walked with their ankles high off the ground in long strides – like birds.
  • These animals had three long hind toes spread out, with the longest toe in the middle – like birds.
  • There was a little toe on the inside of the foot, pointing inwards and backwards – like birds.

Then Hitchcock reconstructed the details of the foot skeleton of the Jurassic track-makers.  He discovered that joints where two toe bones came together usually were supported by a thick pad of skin. So, using the pad marks in fossil tracks, Hitchcock worked out the toe bone geometry. The first toe had two bones, the second had three, the third had four, and the fifth toe was absent. The toe-bone design was exactly like a bird’s!

Hitchcock never suspected that his track-makers were dinosaurs, because at the time all dinosaurs were reconstructed with lizard-like feet, five-toed and flat-footed.

One discovery bothered Hitchcock – occasionally he found imprints of the forefeet where his animals had rested. The fingers had sharp claws, things that normal birds didn’t carry.

By 1840, Hitchcock was sure that a special subclass of birds had ruled the Jurassic – birds with clawed hands.

But where were the fossil bones?

In 1861 the first skeleton of Archaeopteryx was discovered. The bones testified that Hitchcock had been right. Here was a bird with feathers and toes arranged perfectly to make Hitchcock’s tracks. Plus, the hands had sharp claws.

In 1868, Professors Thomas Henry Huxley and John Phillips added more proof that the Jurassic had been ruled by birds. They restudied bones of meat-eating dinosaurs and exposed the mistakes in previous reconstructions. Dinosaurs were NOT flat-footed at all. Instead, carnivorous dinosaurs had bird-style hind feet that fit Hitchcock’s tracks. Hitchcock’s Subclass of Jurassic birds turned out to be dinosaurs!

Archaeopteryx was both a bird and a dinosaur.

In the 1990’s, Chinese discoveries showed that many carnivorous dinosaurs had feathers.