Red Hill Fossil Hunting Trip - Devonian Fossils - Early Fish Fin Spine
A view of the Red Hill Fossil Site in Central PA
Red Hill Fossil Trip Report - Early Fish Fin Spine and a Hyneria Tooth With Feeding Damage
It's been a while since my last visit to the famous central Pennsylvanian Devonian fossil locality known as "Red Hill". This famous fossil
location contains the remains of the two oldest tetrapods in the United States - Hynerpeton and Densignathus.
Although finding one of these early tetrapods is next to impossible, this place preserves a wonderful Devonian ecosystem that thrived in the muddy lakes and streams running down from the Acadian Mountains.
Commonly found are fragments of Placoderms (bizarre armored fish), huge lobe finned fish (fish with fins that look like feet), freshwater sharks, Acanthodians (very early jawed fish), and also many early plants.
On this fossil hunting trip, as with the previous ones to Red Hill, I was dead set on finding a nice fin spine from an enigmatic Acanthodian. The fossils here are very fragmentary, and it's difficult to find large intact fossils.
I climbed the roadcut and found a spot to excavate. The key here is to slowely carve out a large section of cliff, and pry it out. That way if there is a large fossil in it, it would still be intact. After about an hour, I had a huge chunk pried out of the cliff. Carefully excavating it, i found nothing! Plan B was to do it all over again. This time the local Paleontologists, who runs the site, Doug Rowe pointed out a nice bone bed to try. After a few minutes, I discovered part of a large fin spine. The rest of the day was spent trying to dig into the cliff, exposing the spine without breaking it. I was fairly successful, as I ended up with about a 4" length of fin spine. Both ends are not present, but it's the largest complete section of a fin spine I found so far.
While I was doing this, Amy was searching the cliffs for fossils sticking out of the matrix (this method actually works well for Hynera teeth (large lobe finned fish). She ended up finding a nice one. I was called over to try to extract it. After carefully chiseling it out, I noticed the tip was broken. Perplexed, because I was way too careful to have broken the tip, I extracted it and wrapped it up for protection.
After getting home, I cleaned the tooth up and noticed the tip was actually sheered off in a couple different directions. This looked identical to sperm whale teeth with feeding damage. It clearly did not look like post fossilization breakage. My only explanation is the tooth bit into something very hard... twice... causing the damage. This is the first tooth we have found with apparent feeding damage.
Overall, this was a successful trip! We came back with a fin spine and an Hyneria tooth with feeding damage!
If you are interested the transition from fins to feet, and Tetrapod Evolution, I strongly suggest:
Gaining Ground, Second Edition: The Origin and Evolution of Tetrapods (Life of the Past)
by David R. Schwimmer, 2002
This book, full of comparative illustrations and photos, tells the story of tetrapod evolution, how it started 370 some million years ago, and goes through the different interpretations of the various early tetrapods. It is a must for anyone interested in Tetrapod evolution. If you have ever fossil collected at Red Hill, this book puts everything in perspective.
Below are pictures and fossils from the Devonian Red Hill fossil hunt:
Fossil Hunting at Red Hill. It was cold that morning.
This is the fossil Hyneria tooth with feeding damage.
This is the fossil Hyneria tooth with feeding damage. hyneria was a very large lobe finned predator at Red Hill
This is the Gyracanthus (Acanthodian fish) fin spine as found. It's the little circle thingy above my fingers.
The Gyracanthus (Acanthodian fish) fin spine after being extracted and prepped.