Discovery! Mass Burial of Ancient Red Beds Amphibians Uncovered

PhD scientists aren’t the only ones to make spectacular new fossil finds. Case in point: a skilled bulldozer operator digging a cattle tank in Baylor County caught a glimpse of fossils – hundreds of tree trunks, branches, leaves and…skulls! It’s the biggest discovery ever of flat-headed, bottom-living frog-relatives in the famous Clear Fork beds.

Background of Discovery – the “Age of Frog-oids”

The north Texas Red Beds from the Early Permian Period are most famous for the fin-back reptile Dimetrodon, a tiger-sized predator who was close to the direct ancestry of furry mammals, including us. But the Red Beds habitats swarmed with amphibians too, creatures who hatched from frog-like eggs and breathed with gills early in life the way salamanders do today. So common and diverse were Red Beds amphibians that this geological time-zone can be called: “The Age of Frog-oids.”

Some frog-oids were huge and armed with alligator-shaped skulls. Some were tiny and squirmed through the mud like squatty snakes. Others ruled the pond bottoms and stream beds, hugging the mud with low, wide bodies and wide, flat jaws – a design ideal for ambushing crustaceans and fish passing overhead. One of the dominant bottom-huggers was the “Panzer Mudpuppy,” a twenty-pound amphibian with powerful jaws, curved fangs, and big eyes that scanned the water above. Known technically as Trimerorhachis (“Three-Part-Spine”, in honor of the vertebrae, which were composed of three sections), this flat-bodied hunter was an extraordinary geological success. It survived for twenty or thirty million years, a constant companion to the big Dimetrodons who prowled on shore.

The “Panzer” part of the nickname comes from the armored skin. Amphibians today have mostly naked, frog-oid/toad-oid skin. Red Beds amphibians were different. Their bodies usually were completely covered with thin bone scales that worked like the scale-armor suits of medieval warriors. Darwinian theorists have suspected that “Panzer Mudpuppies” were key elements in the Dimetrodon diet. Few land herbivores were available, so the fin-back predators may well have waded into the water to snag amphibians. If the theory is true, then Trimerorohachis played a vital role in the survival of our reptilian ancestors.

Gaps in the geological record

Despite 130 years of intensive study, “Panzer-Mudpuppy” history still had gaps. This amphibian was very common in the earlier Red Beds, like those in Archer County. But then it became rare. In the later Red Beds, the Clear Fork Group, good skulls and bodies are few and far between. What happened? Were there local habitats where “Panzer Mudpuppies” enjoyed reproducing and growing in Clear Fork time? No one knew, until Jimmy Smajstrla and his bulldozer arrived at the Craddock Ranch. Thanks to the generosity of Mr. Bill Whitley, ranch owner, the Houston Museum has been surveying all the fossil sites in the Clear Fork sediments that outcrop in the ranch. Bits and pieces of “Panzer Mudpuppies” were recovered but no specimen had a complete skull or jaws.

The Discovery

Mr. Smajstrla had a ranch job to perform: excavate a new tank to trap water for the cattle. However, he also had a talent for paleontological discovery. When his twenty-year-old Caterpillar, named “YSOB,” was digging down to the ten foot depth, the blade overturned grey clay chock full of fossilized plant parts. Smajstrla salvaged many valuable chunks and led the HMNS party to the spot. Fossil wood is rare in the Clear Fork, so the discovery was exciting.

Then came what no digger had dared to hope for. Even deeper went the ‘dozer. Fossil parts were in the bed below the plants. Not botanical remains this time, but what thrills the heart of every paleontologist: skulls and jaws, dozens and dozens of them, many perfect. For the very first time, science had a beautiful sample of later “Panzer Mudpuppies.” Some of the heads were larger than any previous discoveries. The official name of the skull-bed is “The Judy Site,” in honor of Mrs. Judy Whitley. What will the “Judy Site” tell us? Lots. We’ll know much more about the habitat choice of the “Panzer Mudpuppies.” And we’ll be able to detect micro-evolutionary changes. Investigations have just begun.

We look forward to sharing updates on our investigations as well as new finds with you. Stay tuned!

The Earth’s First Apocalypse: Texas Red Beds, 285 Million Years Ago

At a dig site in North Texas, the Houston Museum of Natural Science is investigating the animals that would have died off when this first mass extinction event occurred. Recently, a production crew from the History Channel came along on-site – and their footage of Dr. Bakker and the Museum’s team airs tonight at 8 p.m. as part of a two hour special called (aptly) First Apocalypse. UPDATE: In case you missed it, the special re-airs locally Saturday, Jan. 10 at 9 p.m. and a few hours later, Sunday morning at 1 a.m. (Check your local listings.)

In this post, Dr. Bakker explores several extinction events, including the first, Permian extinction you’ll see featured on the History Channel tonight.

Big Hairy Elephant
Creative Commons License photo credit: Yogi

ICE AGE DISASTER: MAMMOTHS & SABER-TOOTHS.

In the early 1800’s, paleontology astounded the world when fossils documented the phenomenon of mass extinctions, times when the whole menagerie of big terrestrial critters went extinct.

The first mass die-off that was discovered killed the gigantic mammoths, mastodons, ground sloths, saber-tooth tigers and dozens of other large mammals. This extinction event occurred during the Ice Age. The Ice Age Event didn’t hit small species – if you were a vole, mole, rat, bat or chipmunk, your species had a good chance of surviving.

Today, we know that the extinction took place between 2 million and ten thousand years ago.

DINO-DIE OFF – 65 MILLION YEARS AGO.

By the 1830s, a second giant extinction event was revealed. All the huge Dinosauria disappeared at the end of the Age of Reptiles. Small creatures – birds and salamanders, lizards and frogs, snakes and furry mammals – survived in great numbers.

DINO-DIE-OFF BOUNCE – OPPORTUNITIES FOR FURBALLS.

Mass extinctions weren’t all negative. Dino-die-offs kick-started evolution in the survivors. From the little furry mammals who survived came a wonderful new evolutionary wave of big predators and herbivores – horses, rhinos, hippos, water buffalo, elephants, bears, tigers, cheetahs and wolves. This Darwinian bounce happened every time there was a catastrophic extinction.

THE LATE PERMIAN DISASTER – 250 MILLION YEARS AGO.

Digging in oceanic strata during the mid-1800s showed yet another catastrophe, when the Permian Period ended. Most common species of marine life disappeared, including trilobites, corals, and many species of shellfish.

Die-offs struck the land too – most of the big land reptiles, who filled the role of Top Predator and Top Herbivore, died out. Many small species persisted and from these humble survivors came the next wave of big land animals, including the dinosaurs.

WHAT KILLED THE LAND GIANTS?

Many theories sprung up to explain the great die-offs: the agent of extinction was identified as:

sudden increases in earth temperatures, or

sudden decreases in temperature, or

changes in atmospheric gases, or

changes in humidity, or

abrupt rise of mountains, or

abrupt disappearance of mountains, or

draining away of shallow seas, or

increase in volcanic eruptions, or

sudden impacts of meteorites, or

invasion of foreign species from one continent to another.

TEXAS RED BEDS – EXTINCTION # 1, 285 MILLION YEARS AGO.

Diadectes, side and top view. (c) Dr. Robert T. Bakker

To sort through all the possible solutions, it would help to find the very first case when large land animals evolved and then died-off. North Central Texas preserves this earliest apocalypse in the red-stained rocks laid down in the Early Permian. This extinction was long before the event that struck at the Late Permian.

Beginning in 1877, Texas excavations showed how the earliest large land herbivores evolved. These plant-eating pioneers were wide-bodied, low-slung reptiles known as “Cross-Biters,” Diadectes. Diadectes and its kin were the first large land animals to acquire the wide molars and big guts needed to digest leaves and branches from terrestrial bushes and trees.

The members of the Diadectes Family were the commonest land herbivore for fifteen million years…..and then, suddenly, they went extinct. The pattern at this first die-off matches what we’ve seen in the other land extinctions – small species were far more successful in living through the event.

RED BEDS BOUNCE – EXTINCTION #1 OPENS OPPORTUNITIES FOR FAUNA # 2 – THE TEXAS WIDE-BODIES.

This first die-off opened niches for the survivors. New and spectacular large herbivores evolved from small ancestors. In the Texas Red Beds, we find super-wide-bodied caseid reptiles who reached weights of more than a half ton.

The wide-bodied caseid reptile. (c) Dr. Robert T. Bakker

EXTINCTION #2 OPENS OPPORTUNITIES FOR FAUNA #3 – THE DOME-HEADS.

The wide-bodied caseids flourished for millions of years in the Middle Permian – then, the second extinction struck. Caseids disappeared. Evolving into the gap were advanced mammal-like reptiles with thick bone foreheads. There were both giant carnivores (anteosaurs) and giant herbivores (keratocephs).

Keratocephus, having a bit of trouble with anteosaurus. (c) Dr. Robert T. Bakker

The Houston Museum continues digging in north Texas, where the Red Beds record the earliest waves of large land animal evolution and the first extinction events. Many mysteries remain. But one pattern seems confirmed:

Mass die-offs on land are targeted like smart bombs. If you’re a big herbivore or big carnivore, you have the highest probability of going extinct.

Learn more about the First Apocalypse, and see Dr. Bakker and the Museum’s paleontology team in action, tonight at 8 p.m. on The History Channel.



Your Dino Mummy Questions, Answered

Ed. Note: Leonardo has only been on display in Dinosaur Mummy CSI: Cretaceous Science Investigation for a few weeks – but we’ve already gotten a ton of fascinating questions from visitors. In this post, Dr. Bakker  answers them. If you have a question about Leonardo – or anything on exhibit at the Houston Museum of Natural Science – send it to blogadmin@hmns.org and we’ll post the answer here.

Dinosaur Mummy CSI presents scans of Leonardo that show gut contents and even a possible heart. Does Leonardo have lungs preserved?

There are some curious iron concretions revealed by the x-rays here but nothing definite.

Duck-bill dinosaurs do not have hollowed-out bones of the sort we see in birds and raptors and tyrannosaurs. Therefore we don’t expect that they had the very small lungs and big air chambers in the body cavity characteristic of modern birds.

The lungs would be tucked up high in the chest, covered by rib numbers 3,4,5,6 – if the lungs were like those of birds and crocodiles.

The drawings of Leonardo in the exhibit are very colorful – how do you know what colors dinosaurs had on their skin?

…theoretical stripes.

Think “Okapi.” That’s the giraffe-like thing in wet woodlands today.

Dinosaurs had bird-style eyes, so camouflage had to match habitat colors. Dull browns and greys were not good enough to fool an eagle-eyed gorgosaur.

Early Judithian environs had wet forests with big conifer trees and, in the rainy season, thick underbrush. Dry season would bring browns & rust colors.

So……..Mike Berglund (a dinosaur illustrator) has made a testable theory with his partially banded Brachy. Breaking the profile by having the tail a different color would help flummox predators, who would have a more difficult time seeing the whole body and tail shape. The thick verticals would help the beast blend in among the tree trunks.

How can we test color ideas?  More paleo-environmental research. More thinking about fossil pollen, turtles, crocodiles & salamanders….all witnesses to rainfall, groundwater, and floral geometry.

What animals alive today would be most like Leonardo?

Eland
Creative Commons License photo credit: The Anti-ZIM

The Antelope Family – most diverse family of medium-large planteaters on land today. The Antelope Family includes cows and buffalo, gazelles and oryx, funny-faced hartebeest and gnu, cute duikers and stately eland. Muskoxen and sheep and goats. Antelope supply most of the prey for lions, leopards, cheetah and hyenas.

The Duckbill Family is the most diverse, big-ish plant-eaters in the last part of the dinosaurian age, the Late Cretaceous. The Duckbill Family includes our HMNS Edmontosaurus, and the Trombone Dinosaur, Parasaurolophus (kids’ favorite). And the “Good-Mother” Maiasaura, who left us fossil eggs and nests. Leo’s species, Brachylophosaurus, is a duckbill too. Duckbills supplied most of the prey for all the tyrannosaur meateaters, such as Gorgosaurus, Daspletosaurusand the famous Tyrannosaurus rex.

The technical name for the Antelope Family is Family Bovidae, or “bovids” for short.

The technical name for the Duck Bill Family is Family Hadrosauridae, or “hadrosaurs” for short.*

Want to learn more about Leonardo and other dinosaurs?
See how we moved the 6-ton fossil into the museum.
See David Temple repairing and gluing a fossil back together.
Draw a dinosaur with Dr. Bakker.