In 2014, a paleontologist from the Field Museum made an exciting discovery while working in Zambia. He found a small backbone, or vertebra, that he believed could change what scientists knew about ancient creatures. This discovery sparked a lot of interest in the paleontology community.
Brandon Peecook, a researcher at the Field Museum, was part of a team that had been exploring fossils in Zambia and Tanzania for over ten years. They were studying fossils from before and after the biggest mass extinction in Earth’s history. During one of these trips, they found a single vertebra in rocks from the Permian period, which is older than the time when dinosaurs first appeared.
Brandon thought this bone belonged to an early reptile, possibly a relative of dinosaurs and crocodiles. This was exciting because it could fill a gap in the fossil record, a concept known as a “ghost lineage.”
A ghost lineage is like a missing piece in a puzzle. Imagine trying to list every car model ever made. You’d need to look at old junkyards to find cars that aren’t on the road anymore. These missing cars represent the ghost lineage. In paleontology, ghost lineages are gaps in the fossil record where we know certain animals must have existed, but we haven’t found their fossils yet.
A famous example is the coelacanth, a fish thought to be extinct for 65 million years until one was found alive in 1938. This gap in the fossil record is the coelacanth’s ghost lineage.
Paleontologists use ghost lineages to predict where they might find fossils of certain animals. They create timelines with older fossils at the bottom and newer ones at the top. This helps them understand how different species are related, even if the fossil record is incomplete.
Brandon’s team was searching for early reptiles in Zambia, hoping to find evidence of these creatures before the End-Permian Mass Extinction, the worst extinction event in history. After this event, reptiles like dinosaurs and crocodiles became more diverse, but there should be fossils from before this time.
Finding fossils from certain periods can be difficult. Many rocks from the time of interest are located in high latitudes, and there’s a lack of fossils from around the equator. Land fossils are especially rare compared to ocean fossils.
Sometimes, animals thought to be extinct are found alive, like the coelacanth. These are called Lazarus taxa, named after the biblical story of Lazarus, who was brought back to life.
Brandon took his vertebra back to the museum for further study. He analyzed it and believed it was an early archosaur, a group that includes dinosaurs and crocodiles. He was excited to present his findings at a scientific meeting.
However, another researcher, Ken Angielczyk, had found a similar vertebra from the same period. Ken’s specimen had a complete backbone, which showed that Brandon’s bone was actually from a mammal relative, not a reptile.
Although this was a surprise, it highlighted the scientific process and the nature of discovery. Even though the initial hypothesis was incorrect, the research still contributed to understanding mammal evolution.
This story shows how science is an ongoing adventure. Discoveries can lead to unexpected outcomes, and new technologies and museum collections can help make significant findings. Even a single bone can teach us a lot about the history of life on Earth.
Using the information from the article, create a timeline that shows the major periods in Earth’s history, including the Permian period. Mark the End-Permian Mass Extinction and place the discovery of the vertebra on this timeline. This will help you visualize the context of the discovery and understand the concept of ghost lineages.
Choose a ghost lineage, such as the coelacanth, and research its history. Prepare a short presentation for the class explaining what a ghost lineage is, why your chosen example is significant, and what it tells us about the fossil record and evolution.
Participate in a simulated fossil excavation activity. Use a sandbox or a similar setup to “excavate” hidden objects representing fossils. Document your findings and try to identify what type of creature your “fossils” might belong to. Discuss the challenges paleontologists face when finding and identifying fossils.
Engage in a classroom debate about the importance of single fossil discoveries. One side will argue that single discoveries can significantly impact scientific understanding, while the other side will argue that they are less important without additional evidence. Use examples from the article to support your arguments.
Draw a comic strip that illustrates the story of Brandon Peecook’s discovery and the subsequent revelation about the vertebra. Highlight the scientific process, including the initial hypothesis, the discovery, and the correction. This will help you understand the nature of scientific inquiry and the adventure of discovery.
**Sanitized Transcript:**
What can scientists learn from a single bone? In 2014, a Field Museum paleontologist found a small backbone during fieldwork in Zambia. He thought the discovery would change decades of prior research, and then he got a phone call.
I’m Brandon Peecook, a postdoc at the Field Museum and a paleontologist.
EMILY: A couple of years ago, you made a significant discovery that sent ripples throughout the paleontology community.
BRANDON: It was a surprising implication. It was a great story of how science happens. You’re doing your work as best you can, thinking you have one thing, and it turns out you’re wrong for not awful reasons. Then it changes the whole story of what you were trying to discuss.
I’m part of a research group that’s been going to Zambia and Tanzania for over a decade, collecting fossils before and after the biggest mass extinction in Earth’s history. We find lots of new species and awesome specimens. Some of the things from the Triassic, for instance, are the first relatives of dinosaurs.
This one thing we found was in the oldest rocks we have there, from the Permian period, and it was a single vertebra, a bone from the neck. We were excited because we thought it belonged to a reptile, an early relative of dinosaurs and crocodiles from the Permian, which is not when we typically know them from.
So, finding this and thinking that it’s a reptile means a lot. The global record of rocks from this age that preserve land-living ecosystems is lacking. Everyone knows these animals must have existed, but we don’t have a record of them. Sometimes those gaps are really long for certain groups of animals, which could be due to various reasons. This idea is encapsulated by the term “ghost lineage.”
EMILY: What is a ghost lineage?
BRANDON: For example, if you’re trying to catalog every car ever, you can’t just look at what’s on the road today; you have to go to junkyards to see all the cars from the past. By identifying related cars, you can make an educated guess about what came between models. These missing cars would be referred to as the Mustang’s ghost lineage, and the gap shortens as additional fossilized cars are found.
Ghost lineages exist throughout the fossil record. Take the coelacanth, for instance. Coelacanths are ancient fish with fossils spanning 300 million years from the Devonian through the Cretaceous. Then, no more fossil coelacanths were found, and it looked like they went extinct 65 million years ago. However, in 1938, a museum curator saw something strange in a fisherman’s catch. The discovery was astonishing.
Just because there are no fossil coelacanths doesn’t mean they weren’t around later than the Cretaceous; it just means they weren’t being fossilized. This 65 million year gap is the ghost lineage of the coelacanth.
EMILY: Tell me more about ghost lineages.
BRANDON: Paleontologists often draw timelines where older things are at the bottom and newer things at the top, like layers of rock. If we visualize this, we can see that things related to mammals have a long fossil record. For reptiles, the fossil record is less complete, but because they have relatives, we can infer relationships.
One of the things we’re doing in Zambia is looking for these reptiles, and that’s what I thought I had found. The End-Permian Mass Extinction was the worst event in the history of life that we know about. After it, reptiles like dinosaurs and crocodiles exploded in diversity, but there should be a record of them from the period before.
EMILY: Why is there such a gap?
BRANDON: Every ghost lineage in the fossil record might have different answers. In this case, it might relate to where the rocks are on the planet. The rocks preserving this time period are mostly from high latitudes, and we lack a good record of what’s going on around the equator. Fossils from land deposits are hard to come by, while ocean fossils are more common.
Most paleontology uses ghost lineages to look backward and predict where there should be animals. It’s rare for animals thought to be extinct to actually be alive, like the coelacanth, which is an example of a Lazarus taxon.
EMILY: What do you do with this information?
BRANDON: We bring it back to the museum, prepare it, and analyze the anatomy. It looked like it was an early reptile, and I conducted an evolutionary analysis of different features of bones from various animals. It indicated that this specimen is an early archosaur from the Permian.
I was excited to present my findings at the Society of Vertebrate Paleontology meeting. However, someone I work with, Ken Angielczyk, had done a different project on a mammal relative from the same age rocks. He had a specimen with a whole backbone that they CT scanned.
Ken showed me a digital rendering of a vertebra that was identical to mine. I only had one bone, while he had a whole skeleton. So, my presentation went from being very exciting to less interesting because it was no longer a unique find.
Despite this, I had to adapt my presentation to discuss the scientific method and the nature of discovery. I still had the bone, which has many interesting features. Paleontologists can learn a lot from isolated bones, as they help us understand the early evolution of groups like crocodiles, birds, and mammals.
This story illustrates the adventure of discovery in science. The analysis initially suggested it was a reptile, but it turned out to be a mammal relative. Science is always progressing, and it’s fascinating to explore the features that led to this misunderstanding, which may involve convergent evolution.
Brandon’s discovery may not have been the leap forward in reptile evolution he initially thought, but it was a step forward in understanding mammal evolution. Scientific work often leads to unexpected outcomes, and thanks to new technologies and museum collections, significant discoveries can be made.
[EXCITING, UPBEAT THEME MUSIC]
Paleontology – The scientific study of the history of life on Earth through the examination of plant and animal fossils. – Paleontology helps scientists understand how dinosaurs lived millions of years ago.
Vertebra – One of the small bones that form the backbone in vertebrate animals. – The human spine is made up of 33 vertebrae that protect the spinal cord.
Fossils – The preserved remains or traces of organisms that lived in the past. – Fossils of ancient plants and animals can be found in sedimentary rock layers.
Extinction – The permanent disappearance of a species from Earth. – The extinction of the dodo bird was caused by human activities and introduced predators.
Reptiles – A class of cold-blooded, egg-laying vertebrates that includes snakes, lizards, and turtles. – Reptiles are known for their scaly skin and ability to live in a variety of environments.
Species – A group of organisms that can interbreed and produce fertile offspring. – The African elephant is a species known for its large ears and tusks.
Evolution – The process by which different kinds of living organisms develop and diversify from earlier forms over generations. – Charles Darwin’s theory of evolution explains how species adapt to their environments over time.
Discovery – The act of finding or learning something for the first time. – The discovery of a new dinosaur species can provide valuable insights into prehistoric life.
Record – A collection of data or information that is preserved for future reference. – Fossil records help scientists trace the history of life on Earth.
Lineage – A sequence of species each of which is considered to have evolved from its predecessor. – The lineage of modern birds can be traced back to certain types of dinosaurs.
