Field Museum

Have you ever seen something like this before? Does it remind you of any other animals you’ve seen? 

Thousands of Tully monster fossils have been found in
Illinois.

tully1.jpeg

Tully Monster

View the video below to learn more about this curious creature!

As you watch, consider the following questions:

The fossil invertebrate collection at The Field Museum holds several fossil specimens of the Tully Monster (Tullimonstrum gregarium). These rare fossils were first discovered by an amateur collector and it still remains a mystery what type of animal it is. Join Paul Mayer in this fascinating story and get a glimpse of how the Tully Monster may have looked.

The Field Revealed: The Tully Monster

One of the key mysteries scientists have spent the last fifty years trying to figure out is whether the Tully monster was an 

 Have you ever heard those terms before? What is an invertebrate? What is a vertebrate? Can you give an examples of each of these types of animals?

Move onto the next activity to learn more about invertebrates and vertebrates! 

Tully Monster Mystery

A vertebrate is an animal that does have a backbone or spine. Examples can include fish, mammals, birds, reptiles, and amphibians. Here are some examples of invertebrates from the Field Museum’s collections!

What is a vertebrate?

After 50 years of research and mystery, scientists finally pulled together enough evidence to solve the Tully Monster Mystery! 

Mystery Solved! 

 An invertebrate is an animal that does not have a backbone or spine, examples can include: insects, crabs, lobsters, snails, octopuses, and worms. Here are some examples of invertebrates from the Field Museum’s collections!

What is an invertebrate?

In this activity, try to label recognizable parts of this creature that for decades puzzled scientists, the Tully Monster! Can you identify: The body? The eye-bar? The proboscis (long trunk)? The fins? Try your hand and use the key at the end of the slideshow in the next activity to check your answers!  

Tully Monster ID 

Here are the parts of the Tully Monster in a labelled diagram. Were you able to find these parts in the last exercise? What made it difficult to identify these body parts?

Tully Monster ID Key

Here are some of the fossils in the Field Museum collections that scientists used to study the Tully Monster. Can you think about why it might be hard to reconstruct what a creature looked like from its fossils?

Tully Monster Fossils

This creature puzzled scientists for decades! Is it a vertebrate? Is it an invertebrate? Work your way through this kit to find out!

To give students additional opportunity to explore Mazon Creek fossils, consider renting the “300 Million Years Ago in Illinois” Experience Box from the 

Resource Kits

Object Library

Museums

Tully Monster Mystery

Tully Monster Mystery

Background Knowledge