Mary the Dimetrodon

20150126_120555 20150127_152525 20150202_153831Our newest skeleton is nicknamed “Mary” and is from an area called the transition zone from the Clyde (which is a terrestrial deposit) to the Leuders (which is a marine deposit). The Clyde is an old name for the geologic formation represented in the area we are now digging. Currently it is called the Waggoner Ranch formation, which falls within the Wichita group. So where we are digging is the uppermost or last stage in the Clyde/Waggoner Ranch formation before the arrival of the Leuders Limestone, which was deposited by an ocean. Fast forward and we see the Leuders disappear, meaning the ocean recedes and we see a return to the land or terrestrial ecosystems of the Arroyo formation which is within the Clearfork group. So in a nutshell we see Dimetrodons on land, then sharks in the ocean, then back to Dimetrodons on land. Formation wise, it is Waggoner Ranch is older than Leuders, which is in turn older than the Arroyo.

The age of the fossils is not clear, this is very important. The majority of our Dimetrodon research has been within the younger Arroyo formation, which dates at 287 Million years. Because not enough research has been done on identifying exactly when the Clyde transitioned to the Leuders, putting a number on it is difficult. Identifying the exact layer that shows the transition is difficult. But we can guess that it’s a few million years at most older.

This transition is very important because it represents a huge fauna change from one period of time to another, and more importantly the extinction of older species and the emergence of new species. This was the dark age of Dimetrodon evolution with a ton of unanswered questions. What was happening? How and why did they evolve? Some of the old Paleo greats, such as Edward Drinker Cope, Alfred Sherwood Romer, and E.C. Case, all huge forerunners in the exploration of the Permian in Texas, hinted at a big Dimetrodon transition. They suspected there was something going on in the Dimetrodon families but couldn’t really prove it. This was because not a lot of good skeletons had been found; only a few. Their suggestion was the occurrence of a formidable extinction that resulted in one or two Dimetrodons surviving into the next formation.

One of the important changes we see in the terrestrial ecosystem transition is the change in soil color. The Clyde is composed of classic Wichita Group gray clays. Our site is gray clay that represents the last of the classic Wichita Group fauna. In the next terrestrial ecosystem, the Arroyo formation of the Clearfork group, the clays are now oxidized and stained blood red. This is a huge ecosystem change. Big fauna change. Effected everybody, and especially Dimetrodons.

From the evidence dating back to the early 1900’s from lots of great Arroyo skeletons and lots of early to mid Waggoner/Clyde skeletons, Dimetrodons evolved pretty quick. In a nutshell, we see our newest skeleton Mary as a potential transition species that displays elements of multiple species that occur later. The fin was a big transition from pencil thin and straight fin spines to thicker, wavier spines that lean backward. So why did the fin expand backwards?? Greater display? Makes sense, the fins evolved quicker than any other part of the body. In the Arroyo, it’s easy to identify a Dimetrodon grandis and a Dimetrodon loomisi; grandis is BIG. Thick massive spines, huge teeth. Robust. Grandis also has short, stocky vertebrae. Much like Dimetrodon giganhomogenes who is in the Arroyo as well. Loomisi is much more gracile. Slender spines, sharper narrower teeth. Longer neck. Long vertebrae. The long neck is important. In our Clyde specimen, we see a long neck. But her back vertebrae are short. We see a mix of two species there. Plus the Mary specimen has very verrrrrry long fin spines that are straight as an arrow, which is a classic form in the Clyde formation. No backwards lean to them yet. Great evidence there that it hasn’t approached evolution yet. Think about it this way: Today we have lions and cheetas. Go back 10 million years from today and you see an animal that looks a lot like both. Once they started to evolve they split into different types of cats.

So, we don’t know what species Mary is, which makes it exciting. Mary could be a new species or one that is a transitional species identified by paleontologists from the early 1900’s, the latter of the two is always the most likely. Our goal with this is to finally have an excellent Dimetrodon species that is representative of the last sample of vertebrates in the Clyde before a possible extinction and subsequent rapid evolution of the animal. We can hopefully finally answer the question of why the Dimetrodon species of the Arroyo formation look the way they do and how they got there through evolution. Ultimately we can prove the old guys from the turn of the 20th Dimetrodon extinction did occur followed by a rapid evolution.


George the Dimetrodon!!!

If you couldn’t tell I’m just cuckoo for Dimetrodons and Edaphosaurs and Eryops’es and Diadectes’es and Lysorophus’es and Seymourias and Captorhinus’es and Secodontosaurus’es and Varanosaurus’es…

Our newest dig site has a really great Dimetrodon, and that has us very excited because of the odd preservation and deposition. We are typically used to floodplain sediments, but this guy, nicknamed George, was preserved in conglomerates, which is essentially cemented gravel. Highly unusual for our area. Plus, the conglomerates seem to be Pennsylvanian limestone as well which dates back thirty or more million years, so double-weirdness.

So this is what we have…


Part One… The Setting

A Dimetrodon carcass that was swept downstream intact and articulated during a major flooding event in which older gravel has been stripped up and re-transported. The skeleton was still covered in flesh and muscle and tendons and so on as it flowed in the mix of gravel before settling to its present location. The finer sands then swept in as the flood concluded, so the majority of the bones are in the gravel, with portions of them in the overlying sands. The sand and conglomerates over time contributed to the excellent preservation of the bones, leaving them free of hard, penetrating and destructive caliche rinds. Over the past few thousands of years or so, the bluff that exposes the channel has been eroding, along with the conglomerate tombs.


Part Two… Who the heck is giganhomogenes?!

So our main bone bed a few miles to the west of the George site has a prettttty specific cast of characters. Abundant boomerhead Diplocaulus’es and Dimetrodon’s of the species grandis and loomisi. That’s pretty important. Our ecosystem at the main quarry represents two specific species of D-Don. The classic Dimetrodon giganhomogenes is really nowhere to be seen. Neither is any evidence of the boomerheads. The bones tell the story of who they are. Grandis is, well, grand. Very large, robust vertebrae. Truly a big boy in the Permian. Loomisi, the most common D-Don at the quarry is a pretty girl, so to speak. Very long, skinny vertebrae. Many of our D-Don skeletons have nicknames that refer to actresses with long necks. Don’t ask. Uma, for instance, referring to Uma Thurman, is a beautiful D-Don with a long, pretty neck. Keira Knightly, another loomisi with a long neck. Grandis has its own celebrity necks represented too. Alec Baldwin, for example is a D-Don with, er, a very wide, short neck. I suppose if grandis was human, he would be represented by William “The Refrigerator” Perry, the old great Defensive Lineman for the Chicago Bears. Basically, sporting a cervical vertebrae that is enormously robust and short, covered by thick muscles, gives the beast the impression of no neck at all. And then we have giganhomogenes. Described early in the history of Permian fossil studies back in the late 1800’s early 1900’s. The vertebrae are weird… short and stocky like grandis, but narrow in the middle of the centrum. Right in-between loomisi and grandis. George is the first of his species we’ve seen in articulation or partial articulation. The neck is hauntingly similar to a loomisi. However, when you look at his sacral and lumbar, and thoracic vertebrae, you are astounded by the difference.

George is pretty weird. Even his neural spines are odd. Loomisi has a pretty square, dainty neural spine. Grandis, very square, light grooves running up the side, but fat. Very very fat. Giganhomogenes seems to have some fluctuating thickness on his spines. They begin flat-ish in the articulation to the vertebrae, then widen grotesquely and then narrow again quickly, retaining a very strong figure-8 cross section. They also seem to lean posteriorly, which is much different than what we’ve seen in loomisi and grandis, whose neural spines are for the most part erect. So imagine if you will, the typical Dimetrodon with a fin whose spines rise straight up from the vertebrae. George’s fin seems to sway gently back. Pretty nifty.


Part Three… Now what?

The slope that has been weathering out for a few million years is loaded with fragments of neural spines. Most likely, George was laying on his side, his fin facing towards the eroding bluff. As the conglomerates weathered away, the fin fragmented along with it. The first project was collecting all the loose fragments, which number in the hundreds. Next, we have been digging into the soils at the base of the bluff that have accumulated from the weathering. These “float” sediments contain hundreds of fragments as well. Then we focus on the “in-place” sediments at the top of the bluff where we suspect the origin of the body is. There, we discovered and plaster-jacketed a portion of his skeleton represented by a few articulated neck bones, a few ribs, and a few sacral vertebrae. As we dig in to the hard sandstone overlying the gravel conglomerates, we have been finding more evidence of George, including ribs, spines, and possibly parts of a pelvis. A beautifully preserved adult D-don femur, or thigh bone, was found a few meters away, which may or may not be a part of George. We’ll be studying that more and making our conclusions. Right now its fifty-fifty as to who it belongs too.

George is coming along. He has many many more secrets to give us before we have a good idea of why he is where he is, and more importantly why his is, what he is. Stay tuned for more updates from the field!

Chris Flis
Museum Director





Welcome to the Whiteside!

The Whiteside Museum of Natural History will open its doors for the first time this summer. I can’t think of another small town that is more deserving and long overdue for recognition of its cultural and scientific importance. Thanks to the endless vision and charitable generosity displayed by Judge Clyde Whiteside, the people of Seymour will soon receive an institute that not only celebrates the incredible fossils found nearby, but will praise the community as well. From Elvis to Seymouria, the latter being Seymour’s paleontological namesake, the town has witnessed more than 280 million years of cultural and natural history.

The focal point of much of the areas rich fossil history is the Craddock bone bed, a truly amazing place with its colorful biological record preserved magnificently in the red clays. Discovered around 1909 by Lawrence Baker of the University of Chicago, the Craddock Ranch has continued to relinquish its ancient secrets, depicting a prehistoric world full of monsters.

I walked into Dave Temple’s office one afternoon 8 years ago, shortly after being hired by the Houston Museum of Natural Science. I had heard from coworkers the Dave was a renaissance man, knowledgeable of everything from bugs to bones, the latter of which struck my interest, as I had been digging fossils since a child. We became fast friends and soon began chatting about a rancher he had heard about whom had access to Permian fossils on his famous Craddock Ranch. “Want to dig Permian?” he asked me. I was thrilled. I hadn’t had yet experienced the Permian, but I was well aware of the monsters that thrived there. If you had told me that 8 years later I would be moving to a little town to run a museum next to the worlds greatest Permian bone bed, I would probably have chuckled politely and moved on. But here I am, building a museum from the ground up.

What do I look forward to the most? Sharing my knowledge with others. Educating the town of Seymour of the tremendous significance it represents to the scientific community is a dream come true. No other town in Texas can proudly say, “One of the best Permian bone beds in the world is right down the street.” 280 million years ago, fabulous finback Dimetrodons and Edaphosaurs called this area home. Seymour’s paleontological namesake, Seymouria, was first discovered in 1882 by a young Charles Sternberg, a legend in the world of Paleontology. The small reptile-like creature possessed both amphibian and reptile features, and is an immensely important character in the Permian lineup. As the Permian became arid and dry, Seymouria became adapted to surviving in both wet and dry environments.

In the past decade, the Houston Museum of Natural Science has maintained an important presence at the site, making astounding fossil discoveries every year, including multiple species new to Science. It’s a pleasure and an honor to have the opportunity to preserve these incredible natural resources native to Baylor County and share them with the current tenets of this ever-changing world. The enjoyment I receive out of sweeping away the red dust from sleeping giants hundreds of millions of years old mirrors the gratification I gather from sitting down for coffee and pancakes with strangers I now call friends and colleagues.

-Chris Flis
Museum Director