Wednesday, December 15, 2010

A FISHY CROC TALE

A variety of things have caused me to put off posting here for a while. They couldn't be avoided. Nevertheless, its time to get this train back on the tracks. So let’s start with a story of fossil discovery remarkable even for a place like Dinosaur National Monument which has provided paleontologists with so many remarkable discoveries.

Dinosaurs are the most spectacular fossil to come out of the Monument, but by no means the only fossils. There were many other denizens of the Morrison ecosystem and they also generously contributed their remains, large and small, to the fossil record. Among the most amazing of these is that of a dwarf crocodilian Hoplosuchus kayi.

Hoplosuchus, the seven inch terror, on exhibit at the Carnegie Museum.


When speaking of crocodilians, almost everyone thinks of the big brutes, like the man killing salt water crocs of Australia. Throughout most of their history there have been croc species filling the role of large fresh water predator, but that is not how the group began. The earliest crocs, such as Protosuchus, are smallish, terrestrial animals with long slender limbs held upright beneath their armored bodies. They were probably capable of running and, given their small size, fed on insects and other small invertebrates and vertebrates. While there are no such crocs in the modern world, there were a number of them throughout the Mesozoic and one lived in what is now Dinosaur National Monument.

“Pop” (J. LeRoy) Kay is an interesting individual. Originally a resident of the Uintah Basin he joined Earl Douglass in the excavations at the Carnegie Quarry. After those excavations ended in the early 1920s he migrated eastward to the Carnegie Museum and became Curator of Paleontology. From the 1930s through the 1950s he was involved in the study of Eocene and Oligocene vertebrates.

Back in 1917, while working at the Carnegie Quarry, Pop’s brother-in-law, Jesse York (just10 years of age), visited and was eager to help with the building a trail down from the excavations. As one might guess, his help was sincere but not all that helpful. Kay thought he could prevent Jesse from getting injured by sending him off on another project, drilling a blasting hole in a nearby sandstone outcrop. Kay was surprised when Jesse returned to report he had a four inch hole dug. Being a man of his word, Pop put in a small charge of powder, a blasting cap, and set it off.

After the blast Pop, Jesse, and a few others began looking at the chunks of rock blown down the hillside. To everyone’s surprise, someone found a part of a small skeleton in a block. With that trail work stopped and everyone came over to search for the rest. Hours later it turned up in the rubble and fit perfectly onto the piece already in hand.

Both pieces were shipped back to the fossil preparation lab at the Carnegie where they were put back together and the fossil carefully exposed.  The specimen was astounding. Measuring in at a whopping 7 inches total length, it was a three dimensionally preserved small crocodile with a skull, all the armor in place, and the limbs folded up underneath it. In 1926 Gilmore (1) described the specimen, naming it Hoplosuchus kayi, the specific epithet honoring Pop Kay, although Kay was embarrassed by the honor – he thought Jesse had more to do with the discovery than anyone else. Today you can see the actual specimen on exhibit in the recently redone Jurassic Hall in the Carnegie Museum.  A cast replica will be in the new exhibits when the Visitor Center reopens in the Fall of 2011.

To this day, the specimen (CMNH 11361), is the only known specimen of Hoplosuchus. In all the excavations in the Morrison Formation that have been done in the following 90+ years across the western US, not another bone of this small, insect eating crocodile has turned up. In addition, it is still the best small vertebrate skeleton ever found anywhere in the Morrison. Every paleontologist would love to find a similar fossil. Not a bad discovery for a blast in a hole dug randomly by a 10 year old brother-in-law.

One could not be blamed for being a bit skeptical about this tale of discovery. It has the sound of an urban legend and Gilmore did not recount it in his description of Hoplosuchus. That probably accounts for why it is so poorly known even in the paleontological community. Has it been embellished in the retelling over the years? The answer to that question is a resounding NO, because nearly four decades later, Pop Kay himself recounted the events in a short, popular article about the paleontology exhibits at the Carnegie (2). It’s a good thing he did because the story is so improbable that it is damn near unbelievable.


Pop Kay in 1970 at an Eocene fossil fish locality in Utah.


References

(1) Gilmore, C.W. 1926. A new aetosaurian reptile from the Morrison Formation of Utah. Annals of the Carnegie Museum XVI (2): 325-349.

(2)Kay, J.L. 1951. More dinosaurs. Carnegie Magazine 25: 90-91, 102.

Photos: Hoplosuchus: NPS.. Pop Kay: Dale Gnidovec, Orton Geological Museum, Ohio State University.

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