Tuesday, November 6, 2007

Shirley Smalley, Volunteer Team Member

"I love field work!"

Shirley Smalley is a retired geologist who has been volunteering at the Houston Museum of Natural Science for six years.

At the Museum, Shirley gives tours of the permanent exhibit halls to students, takes artifacts into the classroom as a docent-to-go, and volunteers with the HMNS dig team, as she is doing this week.

"I like digging for all fossils - no favorites here.Though I am most proud of the Araeoscelis I found here last time. That was a fun find."

In her career, she specialized in analysis of carbonate resevoirs (used by energy companies to find oil-producing locations) and environmental geology, which is used to evaluate the condition of sites that have been exposed to a contaminant.

Tarrington Rivers, Student Team Member

Tarrington Rivers is a freshman at Seymour High School who is "fascinated by paleontology."

"I go fossil hunting with my uncle from Fort Worth about 4 times a year, just looking around in dried creek beds. I am very fascinated by these simple fossils, and look forward at a chance to dig with a professional, especially with someone as prestigious as Dr. Bakker."

After high school, Tarrington plans to get a degree in Mechanical Engineering from Texas Tech.
Check back later this week to find out what Tarrington uncovers in the field with Dr. Bakker and the HMNS team.

Kim Beck - Not just a rock

School is out for the day, and I am cutting across a stretch of grass, cactus and mesquite trees, headed out to join the rest of the HMNS team. I kneel on the ground next to David Temple, who is marveling over a giant vertebra he just found and I smile, because just a few months ago, I would have looked at this slope of rocks and seen just that. Rocks. But ever since I got into paleo, I see a lot more than just a rock. I see a time span of millions and millions of years. I see a Lysorophus curled up into a ball, waiting for rains that never came. I also see classrooms full of students, throwing more questions at me than I can possibly answer in one 45-minute class period.

Welcome to paleontology, where few things are really all that they seem.

As a high school science teacher, I know from experience that there are a lot of chapters in a text book that are a lot like rocks. You move over and around them everyday, not even knowing to look for something fascinating that might be hiding under the surface of a chapter title like “Chapter One: Scientific Method.” I know from experience that sometimes the difference between a kid learning something and not even trying is simply a matter of presentation. So when I saw that lesson about steps for scientific method coming, I thought I might try something that my students surely hadn’t seen before.

I brought them a rock.

But not just any rock. I brought them a rock that I had found myself. I told them where I found it and I told them that I honestly had no idea about what it was when I picked it up (step one: state the problem!!). I asked for ideas (or dare I say “hypotheses”?) about what this rock could be and then I told them how I actually gathered information (step two!) about each one of those ideas. Then we tested each of those ideas together (step three!). I told them that the test that gave me the most information was actually sticking my tongue to the rock and when it stuck, I knew I had bone (paleontologists can be quite efficient!). “A bone?! But what kind of bone?! How did it get there??!” my students asked me in surround sound, and before I knew it, a room full of what used to be bored kids was now analyzing results and drawing conclusions with an enthusiasm that caught even me off guard. Scientific method suddenly made sense, now that we weren’t looking at it with glazed-over eyes.

With one rock – or chunk of mammoth tusk – I had stumbled upon a way to let kids get carried away in discovering what science really is. Don’t you see? Science is actually a world that is relevant to us, full of mystery and puzzle pieces just waiting to be put together.

Not just a rock.

Day 2: The Fin is In

Or should we say out?

This morning, the team headed out to the Aimee site, where they uncovered what looks to be an entire associated Dimetrodon skeleton. It started when Chris discovered the tip of a Dimetrodon fin spine on the surface, which led to an entire fin spine, which led to four more, and on and on and on...(video coming soon to a computer near you.)

At this stage, they've uncovered 5 full Dimetrodon fin spines (which supported this species' impressive fin); a vertebra that is attached to one of the fin spines; a series of Dimetrodon ribs; and a long, substantial and so-far unidentified bone. Tomorrow, they'll dig down from the upper surface and try to uncover more of this specimen, which Dr. Bakker said will likely be exhibition-quality.

The team works on multiple layers of the Amy site at once. Now, Kim knows "what it's like to feel the ground move underneath you."

They also excavated several other locations within the Aimee site; one with tiny fish scales and coprolites, and another with an enormous amount of Xenacanth cartilage, poison spines and teeth. With all this after this morning's surprising discovery about yesterday's finds, it was quite a day.

A piece of Xenacanthus coprolite found on the upper layer of the Amy site. This layer is proving to be riddled with shark bones, cartilage and coprolite.

An unidentified amphibian jaw (next to an unidentified vertebra, at right), found at a lowest level of the Aimee site.

A piece of Xenacanthus spine found on the surface of the Amy site.

A Dimetrodon claw found at the Aimee site.


Technical difficulties are keeping us from posting photos tonight, but check back tomorrow - we're hoping to upload the video of today's excavation, along with photos and more updates.

UPDATE - photos and captions inserted above. We're still working on video.



video


UPDATE: Good things come in small packages. In this video, Dave shows his excavation of a small site, just off the main Aimee layer, that is yielding fish scales and other small fossils, like coprolites.


video


UPDATE: On the first day of excavation at the Aimee site, Dr. Bakker knew the team was on to something. Seeing the video is even more exciting, knowing what we know now.

A Case of Mistaken Identity

In science, it's important to keep an open mind, so you can evaluate all the facts equally and come to the most accurate result. This statement has the virtue of being true - but it's also convenient code for "oops!"

Yesterday, we reported the discovery of two separate Edaphosaurus found in two distinct layers at the K2 site. Early this morning, Dr. Bakker was examining several of the Daffy fossils from the lower layer, when two of them fit together, perfectly - in a way that couldn't possibly come from an Edaphosaurus. What we actually had was a single, giant Diadectes vertebra.

The first bones discovered at the lower level of the K2 site yesterday; the large bone on the right is one of the two we believed to be Edaphosaurus - until today.

At the K2 site yesterday, Dr. Bakker holds what was believed to be an Edaphosaurus vertebra.


The two pieces, together - a Diadectes! The seam can be seen running diagonally through the middle.

Here's how we know:

The fossils show evidence of four interlocking surfaces. Edaphosaurus - and humans, for that matter - have only two. However, Diadectes has four. Due to these extra connections, Diadectes could not twist its spine from side to side as we do, for example, when we turn to look over our shoulder.

However, these extra interlocking surfaces made Diadectes incredibly strong. As Dr. Bakker put it, "We could all stand on its back and ride it into town. Pound for pound, this species might have the strongest backbone that has ever evolved."

So, you certainly won't catch Diadectes dancing to Chubby Checker, but it had strength in spades. The question is - why? Why would an herbivore need such impressive might?

Another identifying feature is the actual structure of the individual vertebra - which can be seen more clearly when the two parts found are put together in the right way, as they were this morning. Diadectes vertebrae have an enormous superstructure - the part running along the top - that made each bone very top-heavy. This also made the top of the spine stronger, which was required for Diadectes - the stress of walking went through the top of it's spine, rather than the center.

So, one of our Daffys is really a single Diadectes - they are commonly found as individuals at Red Beds sites, so this is normal. But why? Were they loners by nature? Or were there great, unpreserved herds roaming the Permian plains somewhere else?

Reagrdless, this one was found near a shed Dimetrodon tooth, which is the first CSI evidence the team has uncovered of Dimetrodon eating Diadectes.

So what about the other supposed Edaphosaurus? We have 7 Edaphosaurus vertebrae from the upper level of the K2 site that do not have the additional interlocking surfaces; in addition, they do have distinctive bumps on the vertebrae that are only present in Edaphosaurus.

Now we just have to find the rest. In the meantime, here are some pictures from today's efforts, at the Amy site, a slope leading in to the main dig area:

The HMNS team begins to dig on the Amy site this morning. So far, they've found a site with several Dimetrodon fin spines in place (left); a site with tiny fossils of fish scales (top) and coprolite; and a site with many examples of Xenacanthus cartilage (right).

A tiny Xenacanthus tooth. In the background, a team member excavates a site yielding fossilized cartilage from this species.

The jawbone of a Permian amphibian, found by Kathleen Zoehfeld this morning.


An unidentified (so far) vertebra found at the Amy site this morning.
We'll post more information on today's finds this evening. What are you curious about? Let us know!