Researchers unearth rare Devonian carpoid fossils

An unexpected and recent find at Penn Dixie has provided new insight into the evolutionary history of an unusual group of fossils.

In April 2023, two on-duty members of the University of Cincinnati’s education team, Jonathan Hoag and James Hanna, discovered the well-preserved remains of a mysterious and extremely valuable animal. rare—a «carpoid»—among the Devonian rocks at Penn Dixie. The remains, which are about 382 million years old, are of an ancient ocean-dwelling small invertebrate that covered our region long before dinosaurs existed.

Carpoids are extinct echinoderms—they are related to living starfish, sea urchins, sea lilies (lilies), and sand dollars. The unearthing of carpoid fossils from rocks of this particular age was unexpected.

Carpoids first appeared during the mid Cambrian period about 500 million years ago. They are rare – and their fossil record is unclear – making it difficult to trace their evolutionary history. They are usually not found between their first and last appearance on a rock record, making them a «ghost lineage»: they are there, but we don’t see them. However, we know this animal is alive because we see its ancestors and descendants as separate in the fossil record—perhaps tens of millions of years ago.

Preliminary identification of the newly discovered fossils suggests they belong to the class of echinoderms known as Solutes—a clade of carpoids previously thought to have gone extinct about 410 million years ago during the Early Devonian. If the initial interpretations are confirmed, the new Penn Dixie fossils would be identified as approximately 382 million years old—expanding the geological range of the dissolved substances by more than 25 million years.

The Penn Dixie carp is a «Lazarus taxon»: an animal that disappeared from the fossil record, then reappeared much later. Just as the Biblical Lazarus rose from the dead, a taxon Lazarus figuratively rose from the graveyard of global extinction. Thanks to the discovery of Penn Dixie, there is new life in these old fossils.

Council member Jon D. Rivera said: «The unexpected but important discovery of a carpoid fossil at the Penn Dixie Nature Reserve is just the latest example of the park’s uniqueness and further proof. This ground-breaking discovery has the potential to re-imagine and rewrite our planet’s geological record, communicating why Penn Dixie is a destination like no other. in our region. I’d like to congratulate the entire Penn Dixie staff who helped make this incredible discovery.»

«This is a really strange thing. In particular, in my five decades of studying Paleozoic fossils from the northeastern United States, I have looked at more than 1,000 Hamiltons. [rock formation] Paleontologist Dr. Carlton Brett, distinguished research professor at the University of Cincinnati, said.

«To the untrained, the specimen might look like the dead thing on the road in the Paleozoic. Luckily for us, Hanna and Hoag were able to see that what they had found was something. different and special.» Karl Flessa, a paleontologist at the University of Arizona.

«I have been collecting fossils at Penn Dixie since 2001 and have never heard of anyone finding a carpoid or a cystoid. [related animal] at the park. In fact, any relatively complete echinoderm is a rare find. As soon as I received the fossil in preparation from Jonathan, I realized it was a scientifically important find,» said Malcolm Thornley, a professional fossil preparer based in Ontario.

«This discovery is the most significant in the history of our institution, but it’s also a very special moment for science in Western New York. It’s been an honor in my career to be a part of it. very small into the ongoing process,» said Dr. Phil Stokes, geologist and executive director of the Hamburg/Penn Dixie Natural History Society.

«I feel very fortunate and honored to have been able to find such an amazing animal. It was a groundbreaking discovery that anyone can find, but we were in the right place at the right time. The fact that I found it with my good friend makes it even better,» said Jonathan Hoag, site manager at the Hamburg/Penn Dixie Natural History Association.