In 1955, an amateur fossil hunter found a bizarre fossil in Illinois.
To this day, the exact nature of this monster remains a mystery.

As a kid, I loved monsters. King
Kong, Godzilla, Dracula, and Frankenstein
(among others) all vied for
top honors. One reason monsters are
fun is the fear they evoke. Another is
the thrill of imagining new creatures
unlike anything we find in nature.
The word that “monster” comes
from (Latin monstrum) can have both
meanings. On the one hand, it can suggest
something ominous, evil, awful,
or repulsive. On the other, it can simply
mean abnormal.

In 1955 an amateur fossil hunter
found a strange fossil, commonly
called the Tully monster (genus Tullimonstrum),
that puzzles scientists to
this day. At first glance, the “monster”
may appear somewhat frightening. To
a biologist, however, the monstrosity
in its name derives not so much from
the fear it evokes as from its mingling
of unusual parts.

The unexpected in nature makes us
all, even professional paleontologists
like me, uneasy. We prefer not to have
“monster mysteries”; we want every
creature to make sense within our
understanding of the world.

What Do We Know About the Tully Monster?

Clearly, the Tully monster was no
Godzilla, at least in terms of size.
Tully was a mere 4 inches (10 cm)
long. It was a soft-bodied animal with
eyes on “sticks,” had a single nostril,
and sported an elephant-like proboscis
with a crab claw on the end. This
diminutive monster is found exclusively
in Carboniferous rocks (300
million years old by conventional dating)
in the US state of Illinois, where it
is regarded as the state fossil.

Scientists have debated its identity
since its discovery. What other animal
is it most like—a crab, a slug, a reptile,
or something else? The fact that it is
largely known from only one location
in Illinois just adds to the mystery.

From a biologist’s perspective, a few
identifying clues stand out—but only a
few. One is that it had a notochord. A
notochord is a stiff rod made of cartilage
that runs down an animal’s back
like a backbone, providing support
while it is an embryo. All vertebrates
and some invertebrates have notochords.
In vertebrates, the notochord
can later become part of the vertebral
column. This makes it an important
clue to one of the most basic distinctions
in biology: was the Tully monster
a vertebrate or an invertebrate?

Tully Monster

Image by Nobu Tamura

The Tully monster challenges
us to keep seeking an even
deeper understanding of life.

Also interesting were blocks of muscle
called myomeres. These muscle
groups appear in W patterns in the
Tully monster and provide a clue for
how it swam. A living animal with
similar blocks of muscles is the eel-like
lamprey, which moves its body
through the water in a powerful wavelike
motion like a snake. The Tully
monster has less than half the number
of myomeres as lampreys. This lower
myomere count means it likely swam
using only its tail.

Though some of these clues may
not sound substantial, we are fortunate
to know anything about the Tully

Though some of these clues may
not sound substantial, we are fortunate
to know anything about the Tully
monster. Animals lacking hard parts
are rarely preserved at all. Its preservation
was unique enough (location,
sediment, and chemical conditions) to
allow us a glimpse of these interesting
creatures. In fact, its unique location—Mazon Creek in Illinois—is home to
many other soft-bodied creatures that
are not often preserved well. What
unusual conditions brought them
together? We’re still trying to learn
the answer.

How Do We Classify It?

The most fundamental question
upon discovery of an animal is
whether it had a backbone. That is,
was the animal a vertebrate or invertebrate?
This has a long tradition in
biology, going back to Carl Linnaeus’
Systema Naturae. Linnaeus was a
Lutheran and creationist whose thinking
is the basis of nearly all biological
classification today.

Attempting to delineate God’s created
kinds, Linnaeus divided the animal
kingdom into smaller and smaller
groups, starting with the phylum, which
is still used today. He grouped animals
with backbones in a manner very similar
to today, though Linnaeaus shoe-horned
everything without backbones
into only two places: insects or worms
(called “vermes”). If the Tully monster
had been discovered then, he would
likely have assigned it a place within
“Paradoxa” (a name showing that even
an early creationist recognized that not
all animals were easily classified).

Why Have Scientists Been So Confused?

Over the last 50 years the conventional
evolutionary community has
pondered a range of possible classifications
for the Tully. Scientists have
argued that it was a mollusk (like
squids), an annelid (like earthworms),
or a vertebrate.

Some studies have argued strongly
that it was a vertebrate, based on certain
features, such as the eye. Just last
year, scanning electron microscopes
and a technique known as spectrometry
revealed a retina characteristic of

However, others argue just as confidently
that it was not a vertebrate
because it lacks important vertebrate
characteristics. They explain away
vertebrate-like traits based on a phenomenon
called convergent evolution.
“Convergence” is the belief that evolution
regularly produces similar traits
in unrelated creatures.

Scientists enter the character traits
into a computer program that generates
evolutionary trees, but a little-discussed
fact is that these trees often
contradict one another. Why? If one
creature has a few odd traits that are
similar to many different animals, it
can mess up the results. The Tully
monster could have been a vertebrate
or an invertebrate, depending on how
a computer groups certain traits.

Creationists do not have a problem
with these conflicting results. We
aren’t attempting to figure out how
every trait evolved from less complex
creatures. We look at the overall traits
of the “kinds” of creatures the Creator
made, all at the same time, during Creation
Week. We aren’t surprised to find
similar traits in unrelated animals.
Such similarities point to one Designer.

The infinitely wise Creator also
inserted some surprises in his creatures
that defy our simplistic explanations.
In all honesty—for both creationists
and evolutionists—Tully is an
unusual group! It calls into question
some of our most basic assumptions
about the defining traits of organisms.

What we call a “monster” today
may simply reflect our simplistic
approaches to reality.

What we call a “monster” today
may simply reflect our simplistic
approaches to reality. Both creationists
and evolutionists have limited
knowledge about the world, despite
centuries of careful study. So the Tully
monster challenges us to keep seeking
an even deeper understanding of life.

Philosopher Thomas Kuhn notes in
Structure of Scientific Revolutions (1970)
that all scientists are limited and share
common blind spots. Keeping our eye
out for these “exceptions,” rather than
dismissing them, is at the root of scientific

Don’t get me wrong, I believe biological
classifications involve a lot of
wisdom. At the same time, perhaps
part of what makes Tully a “monster”
is it challenges some of our most basic
assumptions of biology, such as what
eyes, mouths, and backbones should
look like. Lack of easy answers is one
way God humbles us, while reminding
us all to keep learning about him by
continually “expecting the unexpected”
as we ponder his glorious work.

Dr. Neal Doran is professor of biology at Bryan College in
Dayton, Tennessee, where he teaches biology, geology, and
the philosophy of science. When he has a chance, he blogs at
Creation Model Reflections.

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