Monday, November 5, 2007

Day One: Surprise!

Today, the plan was simply to evaluate progress at existing sites to determine how to proceed for the rest of this week. Instead, the Museum team knocked it out of the park with several new and surprising discoveries.

The team split up early on - one half worked on the K2 site, where 7 Seymouria bones had been uncovered previously. Last night, we wondered if the find was a fluke, or if there was more to be discovered.

The answer - definitely more to be found. The team at K2 uncovered two distinct horizontal layers, about 2 feet apart, each with it's own Edaphosaurus remains. Even more astounding - the fossils are in place, not eroding out of the soil.

The first Edaphosaurus fossils found at K2 by Chris Flis - evidence that there is much more to this site than we thought. The team worked back into the layer horizontally, uncovering several other Edaphosaurus fossils, including an ankle bone and several ribs. UPDATE - As further fossil evidence emerged, this was later determined to be part of a Diadectes fossil. You can see how that conclusion was reached here.

So, this individual is still resting as he died and was covered over by soil 285 million years ago. By taking directional and GPS readings of the fossils' locations, the team can figure out how the body was manipulated by external forces after death - like river currents.

Dr. Bakker holds an unusually large Edaphosaurus vertebrae - "It just leapt out and yelled 'bonzai!!'" - as Chris Flis and Kathleen Zoehfeld continue to excavate horizontally into the geologic layer in which it was found. Perhaps they'll discover even more of this individual tomorrow.

In addition, the team found a wide diversity of other Permian species, including Captorhinus, Seymouria, Diadectes, Diplocaulus, Eryops - and Dimetrodon, in the form of 9 shed teeth, proof that the Texas Finback was feeding here, most likely on Daffys. A very rare, very small Dimetrodon toe bone was also found.

UPDATE: In this video, Dr. Bakker explains what has been uncovered as a new layer in the K2 site.

The biggest question from this site is posed by the multiple Edaphosaurus individuals - there are multiple deaths and multiple burials of a very rare species, in one spot. Why?

The braincase of an Eryops; the round pitted surface on the right is a tooth socket.

The other half of the team headed out to Edge - a site a few miles away that was discovered on the Teachers' Expedition last summer. A complete Dimetrodon hip was uncovered on the surface, and this half of the team worked on prospecting the entire canyon in which Edge is located, to find additional sites that should be excavated.

Dr. Bakker and Chris Flis look for more coprolite in front of a partial view of the Edge canyon.

What they found was coprolite - and lots of it, in all different colors (coprolite is stained by whatever surrounds it). Said Dr. Bakker, "I didn't know coprolite could be so beautiful and abundant - wonderful, wonderful, wonderful. It just looks cool. To find such abundant evidence of where Xenacanthus lived - it's beyond our wildest imagination."

A handful of prehistoric shark poop. The characteristic spiral can be seen in the middle-most piece. According to Dr. Bakker, this site was "happy shark time. They weren't being preyed on where they ate."

Hundreds of perfect examples - uncrushed, with the recognized spiral pattern - were found. They range in size, but none are particularly large. According to Dr. Bakker, this means that "there was age segregation among the sharks here. This was a middle school for sharks." No poison spines are found here - which is unusual as well. David Temple, who discovered the site, will post a description of the experience here tomorrow.

They also found a site with Dimetrodon fin spines in place, next to a vertebra.

A Dimetrodon vertebra also found today at Edge. The horizontal line shown in the middle of the fossil represents the characteristic "pinching" that identifies it as a Dimetrodon.

At another, they found a fossil Calamites - a large leafy plant with beautiful striations, or fine lines, throughout the leaves, as well as fragments of petrified wood that might be large enough to tell us what kinds of trees were growing here in the Permian.

Fragments of petrified wood found at a new site in the Edge canyon.

Overall, the Edge environments are completely different from K2. At Edge, no shed teeth were found; the Dimetrodon site represented only one individual, rather than the many individuals of many species found at most other sites; bones are articulated, with pieces that are still attached or that easily click together; and reduction zones are present - tiny green areas in the red soil representing the presence of organic material - like worms or roots - that prevented the soil from oxidizing. There is also lots of sandstone - each layer represents the river overflowing its banks, covering any dead animals and facilitating the process of fossilization, but also preventing these animals from being eaten - which makes figuring out their ecosystem more difficult.

The team regrouped toward the end of the day to focus on excavating the K2 site, and to prospect at Nicole - a nearby site where many Lyserophian burrows have been found. Another giant Edaphosaurus vertebra was found at this site as well, along with what might be fossilized shark cartilage.

Possible shark cartilage found at the Nicole site.

A tiny vertebra found at the main K2 site this afternoon; Dr. Bakker believes it to be the smallest he has ever seen.

As if that weren't enough excitement for one day, they also found lots of big, very clear arthropod footprints in pale blue-gray sandstone just as the sun set - the first such tracks found at this site.

As Dr. Bakker said today, and as we are all discovering, "every site has its own character; and yet, there are patterns." Check back with us tomorrow to see what other patterns are developing.

Gretchen Sparks, Volunteer Team Member

This week is Gretchen's first dig with the Museum, and she says learning to find fossils is "like downloading something into a computer. You have to get your 'search image' set, so you know what you're looking for. At first, it's impossible to distinguish the fossils from the plain old rocks, but then all of the sudden it's like 'There's one!' and 'There's one!' and 'There's one!'"

As a child, Gretchen was inspired by her father's "rock hound" best friend. She became an enthusiastic California camper and rock lover - she even started her high school's geology club.
She turned that enthusiasm into a Master's degree in geology, and she worked at ExxonMobil for 13 years. After raising her family, she started volunteering at the Houston Museum of Natural Science as a way to get back into geology. That was over six years ago. Since, she's become an integral part of the volunteer team, leading student tours of the exhibit halls, teacher workshops, and tours of the Wiess Energy Hall and special exhibitions, including Lucy's Legacy; being a "Docent to Go;" and manning the touch carts that allow visitors to get "hands-on" with the Museum's exhibitions.
"Digging is like getting back to your roots. I like looking at the details - the small picture, layer by layer. And it's geology - so it's cool."

Kathleen Zoehfeld, Volunteer Team Member

With a Master's degree in English literature and creative writing, you might wonder how Kathleen Zoehfeld ended up digging fossils on the Craddock Ranch this week with the Museum's team.

It all started when she helped develop a geology class for science-phobic humanities majors. After graduating, she became an editor of science books for kids, eventually deciding, "I can do that!" She currently has over 60 science titles for children in print, including Dinosaur Babies and What's Alive? This spring, she'll release the latest title, Finding the First T. Rex, based on recently released historical papers.

She has been digging with Dr. Bakker at Como Bluff in Wyoming for 7 years. Of Texas, she says that "everything is either very big, or bites, or is poisonous. And, it's hotter here. But it is also more beautiful than any place I've ever been." It's also more personal - the "K" in the K2 site that the Museum team is excavating this week stands for "Kat," in her honor.