Discovery of Tertiary crocodile fossils in Lang Son

The research team of Lang Son Museum and experts from the Museum of History have just discovered 5 fossil sets of ancient crocodiles in the Na Duong coal mine area, Lang Son province. This is an important discovery, contributing to supplementing research documents on the paleontological system in this area.

Mr. Nong Duc Kien, Director of Lang Son Museum, said the survey took place in 8 days, from the end of December 2024 to the beginning of January 2025. The survey team discovered 5 sets of crocodile fossils. Among them, crocodile upper jaw fossils with 2 specimens measuring 41cm long and 12cm wide; The crocodile snout fossil has a cylindrical shape, measuring 12 cm long and 8 cm wide. It is determined that it may belong to the long-snouted crocodile species; part of the upper jaw bone of a crocodile holding food from an unidentified animal, measuring 27.5 cm long and 10 cm wide.

In addition, the team also discovered 88 samples of crocodile feces and a number of other pieces of skin and bones of this reptile.

The group used the plaster casting method to preserve the original state of the artifacts, process them, and collect a set of artifact samples for research and display at the Museum.

Mr. Nong Duc Kien said that the fossil samples were found in the sedimentary layers of coal slag and brown coal seams at an altitude of 173 to 230 meters on the slope of coal mining pit No. 1 of Na Duong Coal Company. . “Through classification and comparison of shapes, we initially identified the fossils as belonging to at least 2 crocodile species out of the 3 species that have been researched and published in the Na Duong valley,” Mr. Kien said.

In addition to crocodiles, the research team also discovered fossils of freshwater turtles, animal bones, clams, snails and some plant fossils. The above specimens were dated to the Tertiary period of the late Eocene and early Oligocene, about 41 to 33 million years ago.

According to Associate Professor, Dr. Nguyen Khac Su, former Head of the Stone Age Research Department, Institute of Archeology, the new discoveries in Na Duong add to the collection of animal and plant fossils, including species such as crocodiles, amphibians, marine mollusks, and plants. “These fossils confirm that the Lang Son area was previously a swamp environment, belonging to the period before and after the Neogene period,” Associate Professor Su said. In Vietnam, besides Na Duong, Son La is also an area with great discovery value but has not had much in-depth research.

These findings open up in-depth research on the ancient environment before the Pleistocene period. This is the period of formation of ancient ecosystems and creatures, including pre-human species. However, Associate Professor Su emphasized that to determine the value of discoveries, it is necessary to gather complete information and documents from previous discoveries, such as the type of fossil plants and animals, the rate of fossilization. lithofacies, determining their age and the geological formation to which they belong.

“Based on this data, we can comprehensively restore the ancient environment in the Lang Son region in particular and the Northeast region of Vietnam in general,” Mr. Su said. These additional findings not only enrich the collection but also facilitate further research in the future.