Triassic journey: New exhibit pays tribute to an ancient survivor

Sue Vorenberg | The New Mexican

5/15/2008 - 5/13/08

In the broad spectrum of geologic time, Kirby the lungfish is a survivor.

His species was old long before the Triassic, a time period that began 250 million years ago, when the ancient creatures watched from murky rivers as 38-foot-long crocodilelike reptiles called phytosaurs sprang to the surface, munching down early dinosaurs.

The species survived when giants like T. rex dominated the landscape, ripping through herds of smaller plant eaters as our mouselike mammalian ancestors scurried to find safety.

And they survived through the more recent reigns of saber-toothed cats, woolly mammoths and the massive population growth of a little species known as humans.

So a move upstairs at the New Mexico Museum of Natural History and Science might seem trivial for Kirby, a museum resident since 1991.

But as the only living member of the museum's new Triassic Hall, the journey is also a tribute to his species' durability through time.

"He's a living fossil," said Spencer Lucas, the museum's paleontology curator and interim director. "Back in the Triassic, I don't think the lives of lungfish were very different than they are today. They lived in rivers and lakes. Looking at him now is almost like looking back into the Triassic."

On Saturday, visitors will get the first chance to see Kirby in his new home, which is also the largest Triassic Hall in North America, Lucas said.

It took more than 20 years to collect all the samples, gather funds and build the hall.

But now that it's finished, it completes the museum's trip through the history of New Mexico's dinosaurs — revealing to the public a world that existed here when the creatures first appeared, Lucas said.

"If you look at just about any group of animals through time, they start small and get larger," Lucas said. "And our example of that here is the dinosaurs. Most of the Triassic is marked by really small dinosaurs, with the biggest meat eaters as maybe the size of a human adult. This is the beginning of their story."

There were, at that time, some plant eaters that grew to about 25 feet long, but it wasn't until 200 million years ago, at the start of the Jurassic, that dinosaurs started to grow truly huge, he said.

The biggest dinosaurs roaming New Mexico during the Triassic were creatures like the Coelophysis, a 6-foot-tall, slender predator that walked on two legs.

Perhaps the most spectacular feature of the exhibit is a 4,500-pound rock found at Ghost Ranch in the 1940s, which has nine fossil coelophysis heads and body parts from about 24 animals.

It took museum preparator Larry Rinehart more than two and a half years to clean rock from the fossils so they are clearly visible, he said.

"When we first got it, it was a big lump of rock, about 5 feet thick," Rinehart said. "It weighed about 12,000 pounds, and we had to scrape each bone out. Something like a little paper-thin bone over the eye of one of these animals takes about a week. It took me 13 weeks to do one skull."

Coelophysis probably ate insects, small reptiles and mammals by grabbing them with its mouth and hands. The rock likely has so many of them because they were caught in a flood and washed into a lake or river bottom, Rinehart said.

"We assume they were killed by the flood fairly quickly," Rinehart said. "Their feces and vomit is still with them. Of course, we don't know for sure what happened to them. We can't really ask them."

The Triassic is also when the first mammal, adelobasileus, a mouselike creature only slightly bigger than your pinkie, appeared — the same creature that coelophysis was likely snacking on.

The hall is home to the oldest-known adelobasileus skeleton ever found, dating to the mid-Triassic, which was collected by the museum in 1989.

The hall is also home to oldest-known fossil turtle, which is another species that appeared during that time and, like Kirby, has survived into the modern era.

"New Mexico, during the Triassic, was very close to the equator," Lucas said. "It would have been much warmer and wetter than it is now. There would be very lush forests and swamps across the state. You'd see phytosaurs, big amphibians living in and around the water, insects and even some small proto-pterodactyls called pterosaurs, along with coelophysis and other early dinosaurs."

Each boundary of the Triassic, like most geologic time periods, is marked with a massive extinction event.

Before the Triassic, at the end of the Permian, an extinction event wiped out most of the creatures living in the ocean, especially many shelled animals like brachiopods.

At the end of the Triassic, many corals died out and almost all ammonites went extinct as did the giant crocodilelike phytosaurs and heavily plated reptiles called aetosaurs.

Dinosaurs, however, lived through that transition just fine, only to die out in the end of the Cretaceous. But their history is one that is common throughout evolution, Rinehart said.

"That's part of the story of the whole hall," Rinehart said. "It accentuates the fact that at any given time some animals are evolving, some are persisting and some are going extinct."

And Kirby, for his part, is a prime example of evolutionary persistence — and of a voracious appetite, said Mike Sanchez, an education specialist who cares for the lungfish.

"When he first came here, we had his tank set up with all sorts of fancy snails, clams and crawdads," Sanchez said. "He ate every one of them. He trenched his way through the gravel and ate all the crawdads."

Sanchez paused and laughed.

"We later put a catfish in there that was almost as big as he is, and he ate that too," Sanchez said.

Kirby's new home, as lord of the Triassic Hall, won't be cluttered with any little friends for him to eat, Sanchez said.

It's a place of respect for the 400 million-year-old species, he said, adding Kirby is a relatively young fish compared to one 75-year-old cousin in Australia. "Hopefully, he'll be around for a very long time," Sanchez said of Kirby.

Contact Sue Vorenberg at 986-3072 or svorenberg@sfnewmexican.com.

IF YOU GO
What: "Triassic New Mexico, Dawn of the Dinosaurs"
Where: New Mexico Museum of Natural History and Science
When: New permanent exhibit, opens Saturday
Cost: Included with regular museum admission: $7 for adults, $6 for seniors, $4 for kids 3-12