KOREA INSTITUTE OF GEOSCIENCE AND MINERAL RESOURCES

Fascinating Secrets of the Earth:

Fossils of Ordovician Trilobite & Mystic Dinosaur of ‘Deinocheirus mirificus’

Excavating fossils are like discovering fascinating secrets of ‘Mother Nature,’ which were safely tucked in by time. In this expedition, The Geological Museum of Korea Institute of Geoscience and Mineral Resources (KIGAM) is leading awakening the earth by researching its history. The Geological Museum is a research-based organization and functions far more than collecting and exhibiting earthy materials.

Aside from the R&D projects, the Geological Museum’s prime target is also the public for familiarizing Geoscience and Geology in general. The recent R&D Projects of the Geological Museum are developing experiential exhibits and educational content for the young generation. The big picture is to develop a series of educational 3D models and/or assembly kits using the fossils of Korea for the time of paleontological research.

1. Time-Determining Trilobite

The lower Paleozoic sedimentary rock unit, the Joseon Supergroup, is distributed in the Taebaeksan Basin in the mid-eastern part of Korea, which is subdivided into three groups, i.e. Taebaek, Yeongwol, and Mungyeong groups.

In the Taebaek and Yeongwol groups, the base of the Floian (Ordovician) Stage has been suggested by the occurrences of a trilobite genus ‘Kayseraspis,’ which has been known to occur in the upper part of the Dumugol Formation of the Taebaek Group and the lower part of the Yeongheung Formation of the Yeongwol Group for more than 20 years. Few Ordovician fossils are known from the Mungyeong Group.

Recently, the Geological Museum’s research team found a pygidium of Kayseraspis for the first time from the uppermost part of the Mungok Formation below the Yeongheung Formation, Yeongwol Group. It implies that either the upper part of the Mungok Formation is already Floian or the Kayseraspis is not an appropriate indicator for the basal Floian. It was necessary to reassess the age of all Kayseraspis bearing faunas of Korea.

The new occurrence of Kayseraspis and the comparison between the biostratigraphy of trilobites and graptolites within the Taebaeksan Basin suggest that the Kayseraspis-bearing faunas in Korea can be assigned to the upper Tremadocian rather than basal Floian.

The Tremadocian age of Kayseraspis seems to be conformable to the trilobite biostratigraphy especially of North China whose paleobiogeographic linkage was strong with the Taebaeksan Basin during Cambrian-Ordovician, although the genus has been reported from Floian strata in many other parts of the world.

The unexpected discovery of a trilobite sparked a restudy to consolidate the Lower Ordovician chronostratigraphy of the Taebaeksan Basin. It seems that additional integrative studies on trilobites, graptolites, and conodonts are further required.

The fossil specimen is housed in the Geological Museum of KIGAM.

2. Deinocheirus mirificus; Genus Name Meaning for “Horrible Hand” in Greek.

Mysterious dinosaur ‘Deinocheirus’ skeleton was completely restored in 3D digital model after about half-century of its first discovery in 1965.

Deinocheirus was discovered first in 1965 in the Gobi Desert of Mongolia, but no other fossils have been found except for its 2.4m-long forearms with sharp claws. So, it was given the scientific name, meaning for 'Horrible Hand' in Greek.

In October 2014, Dr. Yuong-Nam Lee (currently, professor of the Department of Earth and Environmental Sciences, Seoul National University), who was the director of the Geological Museum of KIGAM at the time, published with co-authors a research paper about the true identity of Deinocheirus in journal Nature, and resolved the long-standing enigmas of it.

Deinocheirus was 11 meters in length and weighed 6.4 tons, and it must have been similar in size to Tyrannosaurus and had a unique appearance with a hump back like an Arabian camel. The restoration team conducted follow-up studies using comparative anatomical knowledge to create a three-dimensional (3D) digital skeleton model.

It is the result of meticulously examining the precise photographs and measured data and drawings of most of the hundreds of adult and young fossil skeletons. Because the skull was severely skewed and crushed, they had to recreate whole skull bones in digital model based on the restorati`on drawings, and its internal structure was created with reference to similar dinosaur skulls.

In the process of digital restoration, new facts and characteristics were also identified that were unknown from the initial research.

The team concluded that Deinocheirus is a more gentle, round shape on the dorsal. They also revealed the size and shape of its abdomen, through the three-dimensional restoration of ribcage and dorsal vertebrae.

Based on the research, they made a grazing posture of the Deinocheirus to show its waterside habits and diet, after rearranging the whole body skeletal joints.

Deinocheirus, which was found to have no teeth, ate soft waterside plants, cut and swallowed by scissor-blade-like sharp keratin beak. It may also have had a long tongue for passing food through its throat, inside a long narrow snout. Over 1,400 of gastroliths (gastric stones) found at the excavation site are another evidence of that it is herbivorous. However, the scales and vertebrae of fish were found together in the stomach contents, which means the omnivorous nature of Deinocheirus.

The reconstructed three-dimensional skeletal parts of the Deinocheirus were printed with 3D-Printers precisely one by one. Then, after assembling each part, it was painted using the colors and textures of the original fossils.

Now, one-fourth-sized whole skeletal model and life-sized skull model of the Deinocheirus can be viewed at the Main Hall of the Geological Museum.

The Korea Institute of Geoscience and Mineral Resources developed also educational contents using the publicity mascots ‘Denny’ and ‘Cathy’, characterized after Deinocheirus.

‘Denny’ and ‘Cathy’ are honorary residents of Yuseong at the Daejeon Metropolitan City.

For More Information:

Dr. Lee, Seung-bae (sblee@kigam.re.kr)

Director, Geological Museum

Korea Institute of Geoscience and Mineral Resources

Mr. Lee, Hang-Jae (fossilis@kigam.re.kr)

Senior Researcher, Geological Museum

Korea Institute of Geoscience and Mineral Resources