Stealth Frog-oid in the Permian Ponds: The Panzer Mudpuppy and its Sonar

“Ping….ping…..p i n g…..”

We heard it in the U-boat movie Das Boot. And in Run Silent, Run Deep. And in the History Channel special about the Battle of the Atlantic. A single “ping” figures in a plot twist during The Hunt for Red October. The “ping” is the sound of underwater hunting.

It’s the sound of sonar.

When early U-boats threatened to cut off England in 1917, British scientists worked feverishly to invent a way of tracking submerged subs. The answers came in the between-war years.  A machine would emit a metallic “ping” into the water. If there was a large object underwater nearby, the ping would echo back and be amplified by the machine. The time between ping and echo-ping told the distance; the strength of the echo told the direction.

Sonar went to war big time in 1939. Combined with the code-breakers who deciphered U-boat orders sent by radio, plus anti-sub aircraft, the Allies defeated the new U-boat offensives in 1943 and 1944.

What’s that got to do with our new fossil hall?

Plenty.

Our field crews have brought back the largest single fossil ever dug from the Permian Red Beds of north Texas. Check it out:

judy block david temple

It’s the “Judy Block”, a slab of pond sediment 10 feet long and three tons in weight. Inside are dozens and dozens of complete skulls and jaws from a new species of Panzer Mudpuppy. These were bottom-living amphibians, distant cousins of frogs, who crowded onto the riverbeds and ponds all through the Early Permian 295 to 275 million years ago.

And our Judy Block is a dramatic lesson in Nature’s Passive Sonar.

Active Sonar is used by porpoises and whales — they make clicky noises underwater and use the echoes to find food and, in the mating season, each other.

Passive Sonar is more elegant and delicate. The sonar operator doesn’t ping or click — that would give away the operator’s position to enemies. Instead, the passive sonar operator listens with extremely sensitive microphones. The Hunt for Red October demonstrates how submariners avoid making any noise but just listen and listen and listen — every tiny sound being amplified by the best acoustic equipment. The fossils in our Judy Block show Nature’s equipment in the fossil amphibian.

Look at the skull:

hall blog trimtneurocanalcolor

Running across the bones are a system of sonar canals (technical label: “lateral-line canals”). Most fish have those canals today. Many frogs have a similar apparatus. Under the microscope you’d see a marvelous device. Tufts of tiny sensory hairs are clumped together inside jelly capsules (the jelly is secreted by the cells that hold the hairs). The capsules are connected to nerves that run to the brain.

Imagine you are a Permian Mudpuppy and glance at the three scenes here:

cbl-trimersonacolorsucksmll

You sit still on your pond bottom. You are passive. But your sonar is super-alert. The water is so murky that you can’t see anything. Doesn’t matter. A fish wanders by above your head. It suspects nothing. But the fish’s tail sends out vibration waves through the water. Minute vibrations bump into the sensory hairs in your sonar canals. You’ve got thousands of the hair clusters, and so your brain knows where the fish is swimming and how fast it’s going.

Your fire-control computer in your brain knows instinctively what to do. Wait. Wait … wait … then FIRE!

You twist your head up. You open your jaws wide. The sudden suction draws the fish into your jaws. Chomp! Yum.

Sonar canals were features of most early amphibians. You can see them in the giant Gator-Headed Amphibian, Eryops, that ruled the waterways in the Red Beds times. In the new hall, we will display a complete Eryops across the pathway from the Judy Block.

When you come to the new exhibit, pause at the Judy Block. Stare at the sonar canals. Get lost in a time-travel reverie. Multitudes of those animals lived their lives through millions of years, each generation being successful through the high-tech acoustic machinery.

Discovery! HMNS Paleo Field Team Unearths Extremely Rare Dimetrodon

The Houston Museum of Natural Science Paleontology team has discovered an articulated specimen of a Dimetrodon on the Craddock Ranch in Baylor County!

The team named the fossil “Wet Willi”—“Wet” because it was found while excavating a drainage trench for the quarry, and “Willi” for Samuel Williston, a paleontologist and educator who was active at the site one hundred years ago. Dimetrodon bones are common in the Craddock quarry, but articulated fossil skeletons, like “Wet Willi,” are extremely rare. Most of the Dimetrodon fossils on display in museums across the country, and even globally, have come from this area of north central Texas.

Our Associate Curator of Paleontology Dave Temple shows what makes Wet Willi so special in this clip:

Can’t see the video? Click here to view it on Vimeo.

“Willi” represents a subspecies, Dimetrodon giganhomogenes, originally described by Paleontologist E.C. Case in 1907. The type of specimen he used for his description had no head; “Willi” is the first example of this species found with the head attached.

Wet Willi! New Dimetrodon Discovered by HMNS team
Get a load of those TEETH.
See the full set of photos from the site on Flickr.

In life, “Willi” was the dominant predator of his world, and he would have been 11 feet long with a four-foot vertical fin running the length of his body. The purpose of the prominent fin that defines this species has been debated since it was first discovered by Edward Cope in Texas in 1878. It was originally suggested that the fin was used for thermoregulation—self-regulation of body temperature, even when outside temperatures may vary drastically. However, it now seems more likely that this dramatic fin was for show—to intimidate enemies and fascinate potential mates.

“Wet Willi” will be the star of the Permian section of the Museum’s newly renovated paleontology hall, opening in 2012, and will serve as an ambassador from this geologic period for millions of patrons. The Permian ended with the worst mass extinction known, and was a direct precursor to the rise of dinosaurs. At present, the Museum has a mural of the Permian Period featuring a Dimetrodon, but no fossils on display.

Wet Willi! New Dimetrodon Discovered by HMNS team
See the full set of photos from the site on Flickr.

Over the past five years, HMNS field crews under the direction of Dr. Robert T. Bakker, paleontology curator for the Houston Museum of Natural Science, have collected hundreds of bones, teeth, and coprolites, as well as complete skeletons of the smaller reptiles and amphibians that lived alongside “Willi.”

“There is a very strong Texas connection to Dimetrodon, and we are thrilled to be able to display one in Houston, along with the other animals that made up this ancient ecosystem,” said Dr. Bakker, adding that the specimen is “jaw droppingly beautiful.”

Area ranchers agree; local cattleman Donald Coltharpe remarked, “The only thing prettier is a new born calf.”

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!

100 Years – 100 Objects: Brachiopod

The Houston Museum of Natural Science was founded in 1909 - meaning that the curators of the Houston Museum of Natural Science have been collecting and preserving natural and cultural treasures for a hundred years now. For this yearlong series, our current curators have chosen one hundred exceptional objects from the Museum’s immense storehouse of specimens and artifacts—one for each year of our history. Check back here frequently to learn more about this diverse selection of behind-the-scenes curiosities—we will post the image and description of a new object every few days.

This description is from David Temple, the museum’s curator of paleontology. He’s chosen a selection of objects that represent the most fascinating fossils in the Museum’s collections, that we’ll be sharing here – and at 100.hmns.org/ – throughout the year.

Brachiopod, Grandaurispina kingorum
(Permian, Willis Ranch Member, World Formation, Brewster County, Texas)

CHI_7629The Glass Mountains are famous for silicified fossils of Permian age, such as this Brachiopod. Unique build-ups of fossil shells, both wave-generated accumulations of dead shells and massive brachiopod-dominated reefs, produced by the complex interactive growth of millions of marine invertebrates that occur in the Glass Mountains.

Fossils from the Glass Mountains are of special interest because of their level of detail. Blocks of limestone from the Glass Mountains can be treated with weak acids to dissolve the limestone from the acid-resistant silicified fossils. This process often leaves unharmed the delicate spines and ornamentation found on some brachiopods and bivalves.

Wander among prehistoric beasts in the Paleontology Hall, a permanent exhibition at the Houston Museum of Natural Science.

You can see more images of this fascinating artifact – as well as the others we’ve posted so far this year – in the 100 Objects section at 100.hmns.org.