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.



Photo From You: Insect Identification

 A Mole Cricket
photo provided by Rachel Drew

Hello again, dear readers and bug lovers! I was very pleased to discover this week that we recieved a photo all the way from Virginia Beach, Virginia. This one can be a real head-scratcher for those of you who have never seen one before, which is probably most of you!

I first happened upon this insect in college while collecting insects in a huge parking lot at night. I saw some sort of large insect jumping and flying for several feet at a time. When I finally caught up to it, I was honestly taken aback by what I saw. It was a mole cricket; an insect that spends nearly its entire life underground, only coming to the surface to forage at night. So, Rachel Drew from Virginia Beach – that is what you found on your livingroom floor! Now, let me tell you a little bit about these odd – looking creatures.

Mole crickets make up the family of orthopterans (grasshoppers, katydids, and crickets) called Gryllotalpidae. These crickets are made for digging, and if you look at them closely, their head, thorax, and front legs really do make them look just like a mole! The rest of their body looks more like a normal cricket. Their front legs are equipped with little claws which help them dig and construct their tunnels. These claws are called dactyls and their number and arrangement help scientists differentiate between certain species.

Most species have well developed wings which can carry them for about 5 miles during their mating season. They are also very good swimmers. Mole crickets are omnivores, and they will will feast on worms, insect larvae, and roots underground as well as grasses at the surface. I’m not sure which species is pictured here, but more than likely the Southern mole cricket or the tawny mole cricket. It looks as if it may be immature due to the lack of well developed wings. These two species are most common in the southern part of the country. Unfortunately, they are both introduced species and can be considered pests in some areas. These little guys are harmless, however, and for those who are lucky enough to spot one, a really great photo opportunity!

Well, thank you so much for sending in the great photo Rachel, and for reading about us in Virginia! This insect will always hold a special place in my heart as one of the weirdest looking things I’ve seen! As always, Happy bug watching!

Want to learn more about insects? Keep reading.
Check out an insect that spends the summer singing.
Costa Rica: bug geek paradise.
Mantis maaaaadness!

Summer Encounters – Around the House

Green Anole on ti plant
Creative Commons License photo credit: mannyh808

Summertime in Houston has been very exciting for me. This is my second summer living here and each year I discover new animals.  Last year, I was thrilled to learn about Anoles, Mediterranean House Geckos, and of course, American Alligators. My first job at the Museum was to assist in teaching field camp during the summer for our Xplorations program.  I quickly became familiar with the wildlife of Houston’s surrounding areas along with learning how to survive the heat and humidity while hiking.  My previous experiences with animals in Oregon and New Mexico did not prepare me for the entirely different array of wildlife here in the South.

Tersa Sphinx caterpillar
Tersa Sphinx caterpillar

My first encounter with a new animal this summer happened in my own back yard. On my small butterfly bush, I happened accross a very large, brown, spotted caterpillar.  Since childhood I have had a fascination with these lovely little insects and so I promptly ran inside to get my camera to document my find.  I later had the caterpillar identified by one of the Museum’s entomologists, Laurie.  She quickly ID’d my caterpillar to be a Tersa Sphinx, Xylophanes tersa.  I was amazed at the size of this butterfly larva.  After enduring the bites of the huge zebra-striped mosquitoes and now seeing this large caterpillar, I was once again reminded that everything’s bigger in Texas.

On the other hand, last month we were asked to identify a tiny, writhing, worm-like creature.  It was found near our office which added to the curiosity of this animal.  It was only about 2 inches long, very smooth, not slimy, and appeared to have scales with a pointy tip for a tail.  Was it a type of worm?  The diminutive size and shape suggested worm, but it was somewhat hard to the touch, a bit shiny, and without any of the mucous normally occuring with worms.  Could it be a caecilian?  No, those don’t live in Texas and would definitely be slimy.  Could it be a very tiny snake baby?  Aha! Perhaps we were getting somewhere.

Texas Blind Snake
Texas Blind Snake, Leptotyphlops dulcis

After consulting with my friend who’s an herpatologist by hobby (thanks, Ira!), we discovered that we did indeed have our hands on a tiny snake.   Judging by its size & character, this itty-bitty critter was a juvenile Texas Blind Snake, Leptotyphlops dulcis.  I was reassured of this animal being a snake when I noticed it would occasionally stick out its tongue.  This small serpent would only grow to be about 8 inches in length, by far the smallest snake I have ever had the pleasure of meeting.  Many Texans may come across this snake in their gardens under logs or bushes, mistaking it for a worm.   It emerges from its hiding place in the soil to feed on termite and ant larvae, making it a welcome hunter to any gardener.  Like many other native species, it has been adversely affected by the red imported fire ant

Update. The BBC has published an article on 8/4/08 about the world’s smallest snake, Leptotyphlops carlae, found in Barbados.  This smaller relative to the Texas Blind Snake will only reach 4 inches at maturity, half the size of our native Leptotyphlops dulcis.

The final animal I’d like to share today is the first new mammal I’ve seen in Houston.  Much to my dismay, my dogs (Sasha & Dione) like to dig holes in our backyard.  Dione is quick enough to catch any unfortunate animals that may happen to find themselves in her territory.  As fas as I can tell, she is more interested in playing with the animals than eating them.  One evening, she finally managed to dig up an Eastern mole, Scalopus aquaticus.  I’m sure she’s been hunting them for a while, hence all the holes in our yard.  I rescued the poor mole from the dogs and brought it inside to investigate as I’ve never seen one until now.  It was covered in slobber so I wasn’t able to enjoy the silky smooth coat that is a normal characteristic of moles.

Mole
Eastern Mole, Scalopus aquaticus

The most amazing feature of this mole were its feet.  The front feet are very large, broad, paddle-shaped feet with webbing between the toes – perfect for digging.  In comparison, the hind feet were very small, similar to those of a mouse.  The mole’s eyes, ears, and nose also indicated a subterrestrial life.  We were unable to see any eyes or ears through its fur.  There really isn’t much to see underground and protruding ears would simply get in the way of digging. The nose was long and sensitive, great for smelling prey in the dark.  One type of mole, the Star-Nosed Mole, has an extremely sensitive sniffer.  It has even been found to sniff underwater.  Our Eastern Mole may not be able to smell underwater, but they do consume a great many invertebrates that can be potentially damaging to plants.

If you have crossed paths with an unfamiliar Texas animal, please share with us as we enjoy hearing about other people’s experiences.  Look for Summer Encounters – Brazos Bend State Park as my next blog post when I share some of my adventures in hiking around BBSP roasting alligators and hunting marshmallows….oops.  Well, you know what I mean.