YSM Issue 97.1

Paleontology
FOCUS
IDENTIFYING
EZEKIEL’S WHEEL
Honoring the Legacy
of a Fossil Hunter
BY FAITH PENA
PHOTO COURTESY OF PAUL-ALEXANDER LEJAS
Imagine walking into your friend’s house and finding that
it’s filled with fossils. Well, that’s exactly what Derek Briggs,
a professor of earth and planetary sciences and curator of
invertebrate fossils at the Yale Peabody Museum, encountered
during his first visit to Samuel J. Ciurca, Jr.’s house some twenty
years ago. “His entire house was full of eurypterids, such that
there was hardly anywhere to sit down, which was amazing,”
Briggs said. Ciurca was a chemist with Kodak in Rochester,
New York, and a dedicated fossil collector who specialized in
eurypterids, which are commonly known as sea scorpions.
One of Ciurca’s most prominent discoveries was a mysterious
fossil he nicknamed Ezekiel’s Wheel. Ciurca discovered this
fossil alongside eurypterids in a quarry in southern Ontario.
Despite his experience, neither he nor others could figure out
which genus or species Ezekiel’s Wheel belonged to. As a result
of interactions with Briggs and his group, many thousands of
Ciurca’s fossils ended up at the Yale Peabody Museum and have
been studied by Yale students. One of those students, Nicolás
Mongiardino Koch GSAS ’21, worked with Briggs to resolve
the nature of Ezekiel’s Wheel. Their success illustrates the
importance of working with gifted fossil collectors to acquire
important material for advancing science.
Even though Ciurca was not a professional paleontologist,
his approach to fossil collecting was scientific in the way that
he kept careful notes of the fossils and localities he visited. His
paleontological exploits focused on western New York and
southern Ontario, Canada, where a sequence of Silurian rocks
called the Bertie Group is located. The Silurian period is a
geologic period of the Paleozoic Era that occurred more than four
hundred million years ago. Ciurca amassed extensive collections
from the Bertie Group and became an authority in these rocks
and the fossils they contain. In the early 2000s, Yale acquired a
large number of specimens from Ciurca, amounting to over ten
thousand eurypterids. However, within this collection was the
unusual specimen that Ciurca called Ezekiel’s Wheel. “The
fossil itself consists of radiating layers of tubes, and it vaguely
looks like a wheel,” Briggs said. The wheel-like shape fascinated
Ciurca, and he wrote on the slab with the most preserved
version of the specimen: “the most beautiful fossil ever found.”
Briggs taught a course titled “Extraordinary Glimpses of
Past Life,’’ where students studied the processes involved
in preserving exceptional fossils and completed a research
project as part of the assessment. In 2015, Mongiardino Koch
was given specimens of Ezekiel’s Wheel for his project and
made important progress in interpreting its identity. Ciurca
continued to add fossils to his collection until he died in 2021.
In the meantime, Yale placed Ciurca’s fossils on temporary
display at the Peabody Museum, and Briggs and his group wrote
several papers with him. Upon his death, Ciurca bequeathed
many additional fossils to Yale, including new examples of
Ezekiel’s Wheel. With this collection, Briggs and Mongiardino
Koch were finally able to solve the mystery. A combination of
careful study of the anatomy and microstructure of the fossils
and an analysis of its relationships with other fossil species—
also known as phylogeny—showed that Ezekiel’s Wheel is
related to a group of tiny pseudocolonial animals called
cephalodiscids. Today, cephalodiscids are attached to rocks
on the seabed. Ezekiel’s Wheel, however, is unique among
cephalodiscids because it has a large float supporting a series
of radiating tubes, each of which houses a tiny organism. “We
increased the known range of form of cephalodiscids, living
and fossil, and added to the number of known fossils in the
Bertie Group associated with eurypterids,’’ Briggs said. The
information reveals a new kind of organization that existed
420 million years ago in the history of marine life.
All in all, the identification of Ciurca’s Ezekiel’s Wheel
is one example of how fossil collectors can make an impact
on paleontology and evolutionary biology. Fossils that are
difficult to interpret may spend some time sitting in museum
drawers, but new specimens and methods will eventually reveal
their secrets and add to our knowledge of the history of life on
our planet. ■
www.yalescientific.org
March 2024 Yale Scientific Magazine 9