Megalocoelacanthus revisited: New skull restoration

I know we've been over giant coelacanths from Kansas before on this blog, but they're so strange and rare that we can't get enough of them. Combine that with the fact that besides Hugo Dutel et al's paper on this specimen and this blog page, there is a dearth of information out there on the web about this critter. Consider it public education.

Megalocoelacanthus in all its glory

Megalocoelacanthus is known from just 2 specimens in Kansas: the holotype specimen that we prepared at the RMDRC that now resides at the American Museum of Natural History, and a second far less complete specimen that I discovered back in 2007, which Mike Everhart are hopefully publishing on in the near future (no pressure, Mike). The holotype was molded and cast several years ago, and we also molded the principal coronoid off of the second one to fill in a missing part for a more complete skull. Our first attempt was done without taking out any of the flattening distortion that is common in the Niobrara Chalk, and the results can be seen here. Over the past several weeks, Bryan Smalls has been attempting a second restoration attempt with guidance, assistance and not-always-helpful commentary from yours truly. The results were much improved.

total skull length is approximately 65 cm

Huge gular plates 

One thing we learned in this project was that people really need to illustrate certain parts of coelacanth anatomy better. Specifically the inside of the mouth and how the cliethra attach/fit. Also how catazygals go along the notochord. Get on it, smart people!

Almost dorsal view showing neurocranium ornamentation

Megalocoelacanthus restoration in progress

As many of you know, here in the lab we have a thing for rare stuff out of the Niobrara chalk. We've found the only articulated skeleton of Protosphyraena, described the giant filter-feeder Bonnerichthys, we make a habit of collecting excellent cephalopod mouthparts like Spinaptychus and Rugaptychus, and even discovered the only open coiled ammonite out of the whole formation. So when it comes to new giant coelacanths out of Kansas, yeah we're on that too!

The second specimen (left) with a cast of the left lower jaw of the first specimen

The first specimen of Megalocoelacanthus from Kansas was prepared by our lab in 2005. It was given the name "mystery fish" since the bones looked nothing like what we usually work with. The bone quality was pretty nice, and comprised a nearly complete skull. It was eventually identified by Dr. Ken Carpenter (at the Denver Museum at the time) as a coelacanth, and the specimen went off to a repository.

Sculpting a body with the Vienna Latimeria specimen  blown up to size

While preparing and molding the specimen, I discovered a second specimen in 2007 much higher in the chalk consisting of a left lower jaw. As far as we know, these are the only two specimens of Megalocoelacanthus ever discovered in 150 years of paleontological prospecting in the entire Niobrara.

Side fiew of the unpainted and almost finished prototype

From past projects, it is obvious that we are the only people crazy enough to do 3d restorations of Kansas fish. We had disarticulated casts of the whole head of this giant coelacanth, so why not attempt a restoration?

No teeth, but it could nearly swallow me whole with that maw

Well, here's our first stab at it. In the future we're going to have to un-flatten the mandibles so they better fit the floor of the mouth. One thing is for sure though: it's still a strange fish even when all put together.

The Coelacanths of Kansas

Most everyone is aware of the story of the "living fossil" fish, the coelacanth. One was caught off the coast of Africa in the 1930s, surprising everyone since they were thought to have gone extinct at the end of the Cretaceous period along with the dinosaurs. Today there is but one genus left, Latimeria. They are strange animals, even for people experienced in working with fish.

Cast of the extant coelacanth Latimeria in the RMDRC

We recovered and prepared 2 specimens of the giant coelacanth Megalocoelacanthus from western Kansas in the past decade. As far as I know they are the only two examples of this big coelacanth ever recovered from the Niobrara chalk. The first specimen was excavated from the lower chalk around MU5 (Coniacian age) is fairly complete, and will be our basis for a 3d reconstruction of the skull and body. The second specimen was a fragmented left lower jaw found in the upper chalk, under MU20, putting it early Campanian in age. We used the coronoid from this specimen in our reconstruction to replace the missing one from the first.

About 20% of the skull material found with our first Megalocoelacanthus

Someone once said "go big or go home". We're taking that to heart as our first reconstruction will consist of a 3d skull on a panel-mounted restoration of the body. We're basing the postcranial skeleton heavily on Latimeria, since we only have a few parts of the pectoral and dorsal fins. Coelacanths don't have ossified vertebrae (or ribs for that matter) meaning skulls and fins are about all you are ever going to find.

RMDRC sculptor Mary working on our prototype

Our specimen is truly going to be a giant, coming in at about 9 feet 4 inches (3m) in length. As far as I can tell this will also be the very first restoration attempt of Megalocoelacanthus. Of course we'll be molding the thing, so hopefully it can be placed in museums worldwide. Ours isn't the largest specimen ever found, but it sure seems it is by far the most complete.