Ben Kligman is a seasonal paleontologist at Petrified Forest National Park working May through August at the park. He is a Ph.D. candidate in paleontology in the Department of Geosciences at Virginia Tech University in Blacksburg Virginia. He and a team of young paleontologists have focused on 220 million-year-old microfossil bone beds of the Late Triassic Chinle Formation for the last three years.
The beds contain the remains of ancient small ponds, slow-moving streams, and rivers in a lush tropical forest. Rather than collecting individual fossil specimens, the project seeks to recover an entire fauna within these fossil beds. The significance of the project is that it gives a snapshot of the biodiversity of an entire ancient, highly diverse tropical ecosystem.
This research is ongoing at a fossil locality known as Thunderstorm Ridge, discovered in 2018 by PEFO paleontologists in the recently acquired eastern expansion lands east of Blue Mesa. The fossil site is named Thunderstorm Ridge after Park Paleontologist Bill Parker was caught in a thunderstorm while digging there.
Park paleontologists remove blocks of fossil-bearing mudstone to recover the fossils, a soft, fine-grained sedimentary rock. The mudstone is transported to the PEFO laboratory, where it is soaked in water to dissolve the mudstone matrix.
The dissolved mudstone and its formerly embedded fossil material are sifted through wire mesh screens to release and concentrate the fossil bone, and this fossiliferous concentrate is sorted microscopically to isolate and organize the fossils.
Recovered micro-fossils are, as the name implies, quite small, most less than a centimeter. The micro-fossils are studied using a micro-CT (also known as CAT) scanner to examine internal canals for nerves and blood vessels. With the use of a 3D scanner, the fossil material can also be magnified using 3D printing for detailed study.
These fossil beds are very productive and tens of thousands of fossil bones and bone fragments have been found within them. To date, paleontologists have identified fifty-three species of vertebrates, including several species of fresh water shark; bony fish species including species similar to modern gar fish; coelacanths; giant salamander-like amphibians known as metoposaurs; frogs; a diversity of reptiles including close relatives of early dinosaurs, and stem-mammals.
Kataigidodon venetus
One of the most significant recent discoveries is a newly described species of cynodont, or stem mammal: Kataigidodon venetus. Found at Thunderstorm Ridge, the name, Kataigidodon, is derived from the Greek words for thunderstorm, “kataigidos,” and tooth, “odon,” and the Latin word for blue, “venetus,” referring to the blue color of the rocks at the location of the discovery.
Cynodonts are precursors to modern-day mammals and this animal would have been about the size of a mouse or small rat. Two lower jaws were found with incisor, canine, and complex post-canine teeth similar to those of modern mammals.
This find is additionally significant as it is the second verified cynodont found within Triassic rocks in western North America. The pointed shape of its teeth and small body size, suggests to Kligman that it likely fed on a diet of insects.
Skybalonyx skapter
Another recent find, described by Xavier Jenkins, an Idaho State University Ph.D. student and PEFO paleontology intern in 2019, is Skybalonyx skapter, a species new to the science of an extinct reptile in the Drepanosaur group, a lineage of reptiles that lived in the Triassic period 220 million years ago.
About the size of modern iguanas, this species differs from other drepanosaurs in that it is a burrowing animal rather than a tree dweller. Skybalonyx skapter has unusual hand claws, much wider than those of other drepanosaur species, used for burrowing. It likely spent most of its life underground. Skybalonyx skapter means “digging dung claw” from Ancient Greek, referring to the abundant fossilized dung found alongside the fossil bone at Thunderstorm Ridge.
